JAEA-Review 2008-067

研究炉（JRR-3 及び JRR-4）利用における研究成果集（平成１８年度）

日本原子力研究開発機構 東海研究開発センター 原子力科学研究所
研究炉加速器管理部（編）研究炉利用課（2008 年 10 月 10 日受理）

平成 18 年度、研究炉 JRR-3 は 7 サイクルの運転（1 サイクル：26 日連続運転）、JRR-4
については、37 サイクル（デイリー運転：151 日）の施設共用運転を行なった。
JRR-3 は、中性子散乱、即発ガンマ線分析、中性子ラジオグラフィなどの実験利用
及び、放射化分析、原子炉燃料材料、ラジオアイソトープ製造、フィッショントラッ
ク年代測定の照射利用等、様々な目的に利用されている。
JRR-4 については、医療照射（Boron Neutron Capture Therapy：BNCT）、即発ガンマ
線分析、放射線測定器の感度試験、原子炉研修運転実習等の実験利用、及び放射化分析、
ラジオアイソトープ製造、フィッショントラック年代測定のための照射利用等、様々な目的に利用されている。
本報告書は、研究炉の利用者（原子力機構外を含む）から成果の提出を受け、中性子
散乱 11 分野（構造、磁性、超伝導など）、中性子ラジオグラフィ、即発ガンマ線分析、
放射化分析、その他、の分野別に研究成果を取りまとめたものである。

原子力科学研究所：〒319-1195

茨城県那珂郡東海村白方白根 2-4i

JAEA-Review 2008-067
Activity Report on the Utilization of Research Reactors (JRR-3 and JRR-4)(Japanese Fiscal Year, 2006)(Ed.) Research Reactor Utilization Section
Department of Research Reactor and Tandem Accelerator
Nuclear Science Research InstituteTokai Research and Development Center
Japan Atomic Energy Agency
Tokai-mura, Naka-gun, Ibaraki-ken(Received October 10, 2008)
In the fiscal year 2006, The research reactor JRR-3 was operated 7 cycles (cycle operation :26days/cycle) for utilization sharing of the facility. And JRR-4 was operated 37 cycles (daily
operation : 151 days).
JRR-3 is used for the purposes below;- Experimental studies such as neutron scattering, prompt gamma-ray analyses,
neutron radiography- Irradiation for activation analyses, radioisotope (RI) productions, fission tracks- Irradiation test of reactor materialsetc.
JRR-4 is used for the purposes below;- Medical irradiation (Boron Neutron Capture Therapy : BNCT)- Prompt gamma-ray analyses- Sensitivity measurement of radiation detectors- Experiment in the nuclear reactor training- Practice of Reactor operation- Irradiation for activation analyses, RI productions, fission tracks
etc.
The volume contains 294 activity reports, which are categorized into the fields of neutron
scattering (11 subcategories), neutron radiography, neutron activation analyses, RI productions,prompt gamma-ray analyses, and others submitted by the users in JAEA and from otherorganizations.
Keywords: JRR-3, JRR-4, Research Reactor, Neutron Scattering, Neutron Radiography,
Neutron Activation Analysis, Neutron Beam, Irradiationii

JAEA-Review 2008-067目

次

はじめに .......................................................................................................................

1

研究成果一覧 ................................................................................................................

3

1. 中性子散乱 .............................................................................................................

231)構造・励磁 ........................................................................................................

23

2)磁

性 ................................................................................................................ 101

3)強相関電子系 .................................................................................................... 189
4)非晶質･液体 ...................................................................................................... 2295)高分子 ................................................................................................................ 243
6)生物 ................................................................................................................... 283
7)基礎物理学･中性子工学 ................................................................................... 3018)装置 ................................................................................................................... 309
9)超伝導現象 ........................................................................................................ 331
10)残留応力 ............................................................................................................ 335
11)その他 ................................................................................................................ 343
2.

中性子ラジオグラフィ ........................................................................................ 351

3.

即発ガンマ線分析 ................................................................................................ 369

4.

放射化分析 ........................................................................................................... 387

5. その他 .................................................................................................................... 431
おわりに ....................................................................................................................... 477
謝 辞 ............................................................................................................................. 478
付 録 ............................................................................................................................. 479

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JAEA-Review 2008-067

Contents

Preface ............................................................................................................................... 1
Research Reports ............................................................................................................... 3
1. Neutron Scattering .................................................................................................... 23
1) Structure･Excitation .............................................................................................. 232) Magnetism ........................................................................................................... 101
3) Strongly Correlated Electron Systems ............................................................... 189
4) Amorphous・Liquid ............................................................................................ 229
5) Polymer ............................................................................................................... 243
6) Biology................................................................................................................ 283
7) Fundamental Physics・Neutron Optics .............................................................. 301
8) Instrument ........................................................................................................... 309
9) Superconductivity ................................................................................................ 331
10) Residual Stress ................................................................................................... 335
11) Others.................................................................................................................. 343
2. Neutron Radiography .............................................................................................. 351
3. Prompt Gamma-ray Analyses ................................................................................. 369
4. Neutron Activation Analyses.................................................................................. 387
5. Others...................................................................................................................... 431
Conclusion ....................................................................................................................... 477
Acknowledgments ............................................................................................................ 478
Appendixes ...................................................................................................................... 479

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JAEA-Review 2008-067

研究炉利用における研究成果集(平成 18 年度)

は じ め に

平成１８年度には、ＪＲＲ－３において７サイクルの共同利用運転、ＪＲＲ－４において３７サイクルの共同利用運転が行なわれ、これに伴いさまざまな利用が行われた。
本報告書は、利用者（原子力機構外利用者を含む）から当該利用の成果の提出を受け、取りまとめたものである。
提出して頂いた成果の件数は、中性子散乱２６１件、中性子ラジオグラフィ８件、即発ガンマ線分析４件、放射化分析１４件、その他７件で合計２９４件であった。なお、本報告書の一部は、貴重な研究成果を公開する機会を広げるため、下記報告書の中から転載させて頂いたものである。
最後に、原稿を提出して頂いた利用者の皆様のご協力に感謝するとともに、今後も研究炉が有効に利用され、種々の研究がさらに進展されることを期待します。
研究炉利用課長
和田 茂

1)標

題

：ACTIVITY REPORT ON NEUTRON SCATTERINGRESEARCH issued by ISSP-NSL,University of Tokyo（東京大学物性研究所発行）

レポート番号：Vol.14
編者：東京大学物性研究所

年：２００７年

2)標題：原子力機構施設利用共同研究成果報告書（平成１８年度）

編者：東京大学大学院工学系研究科原子力専攻共同利用管理本部

発行

発 行 年 ：２００６年－ 1 －This is a blank page.

JAEA-Review 2008-067－ 3 －This is a blank page.

JAEA-Review 2008-067

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1-1-7
1-1-8
1-1-9
1-1-101-1-111-1-121-1-131-1-141-1-151-1-16

1-1-171-1-181-1-19

1-1-201-1-21
1-1-22
1-1-231-1-24「 Title 」
Neutron Scattering - Structure ・ Excitation Low-Energy Phonon Anomaly and Electron-Lattice Interaction in the Pr-Filled Skutterudites
K. Iwasa, Y. Mori, L. Hao, Y. Murakami, M. Kohgi, H. Sugawara, H. Sato
Split H-site model in synthetic Al-for-Ga substituted germanate-muscovites: FTIRand neutron powder diffraction studies
K. Ishida, Y. Kato, Y. Kawakita, S. Takeda
Possible structural transformation in the Eu-Ag-In 2/1 approximant and its relation to the
Cd-Yb quasicrystals
T. J. Sato, C. P. Gomez, A. P. Tsai
Neutron scattering study of phonon dynamics on type-1 clathrate cage compounds (Ba,Sr)
8Ga16Ge30
C. H. Lee, H. Yoshizawa, I. Hase, M. A. Avila, T. Takabatake
Neutron scattering study of phonon dynamics on La3Pd20Ge6
C. H. Lee, H. Yoshizawa, I. Hase, T.Watanabe, Y. Nemoto, T. Goto
Modulated structure of ion-exchanged Ca0.4CoO2
Y. Miyazaki, D. Igarashi, Y. Hasegawa, T. Kajitani
In-situ observation of the tetragonal-cubic phase transition in the CeZrO4 solid solution
T. Wakita, M. Yashima, Y. Ando, T. Tuji, Q. Xu, T. Ueda, Y. Kawaike, R. Ali
Crystal structure and the structural disorder of ceria
M. Yashima, S. Kobayashi, T. Yasui
Diffusion path of oxide ions in the yttria-doped ceria
M. Yashima, S. Kobayashi, T. Yasui
Crystal Structure Analysis of (Ga0.93Zn0.07)(N0.90O0.10) Oxynitride Photocatalyst
M. Yashima, K. Maeda, K. Teramura, T. Takata, K. Domen
Phonons in NaNbO3
I. Tomeno, Y. Tsunoda, M. Nishi, K. Oka
Phonon dipsersion relations in PbTiO3
I. Tomeno, Y. Tsunoda, M. Nishi, Y. Ishii, K. Oka
Low temperature neutron diffraction studu of (La0.8Sr0.2)ScO3-δ perovskite
K. Nomura, H. Kageyama, K. Kakinuma, M. Yashima
Low temperature neutron diffraction study of Ba(Zr0.8Y0.2)O3-δ perovskite
K. Nomura, H. Kageyama, K. Kakinuma, M. Yashima
Martensitic transformation of Heusler-type Ni2MnGa shape memory alloy
K. Inoue, Y. Yamaguchi, H. Hiraka, Y. Ishii, H. Yamauchi
Measurement of Thickness of Thin Lubricant Film at Solid-Solid Interface by Neutron
Reflectometry
T. Hirayama, T. Uno, K. Inoue, S. Tasaki, M. Hino, T. Ebisawa
Phase Transition and Debye-Waller Factor of KDP
H. Mashiyama, T. Asahi, H. Kasano, T. Miyoshi
A coupling between an acoustic phonon and the diffuse scattering in the relaxor
ferroelectric（1-x )Pb(Mg1/3Nb2/3)O3-x PbTiO3 near morphorobic phase boundary
M. Matsuura, K. Hirota
Investigation of the local crystal distortion in the relaxor ferroelectric(1-x )Pb(Mg1/3Nb2/3)O3-x PbTiO3 (0.0 < x <0.40) using extinction effect
M. Matsuura, K. Hirota
Damped acoustic phonon in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3
M. Matsuura, K. Hirota
The diffuse scattering in the relaxor ferroelectric compound
H. Iida, M. Matsuura, K. Hirota, Y. Noguchi, M. Miyayama
Crystal structural change of Ba-doped-tricalcium phosphate
Y. Kawaike, M. Yashima, T.Wakita, T. Tsuji, R. Ali, Y. Matsushita
Magnetic fluctuation in ternary alloy CuFePt6
M. Takahashi, E. Ahmed, T. Shishido, K. Ohshima
Structure and phase transition in a lead-based inorganic-organic perovskites
M. Takahashi, K. Kawasaki, K. Kataoka, Y. Fujii, M.Watanabe

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JAEA-Review 2008-067

1-1-25 Diffusion Path of Oxide Ions in a Fast-ion Conductor La0.64(Ti0.92Nb0.08)O3
with a Double Perovskite-type Structure
R. Ali, M. Yashima, F. Izumi
1-1-26 Crystal Structure of Apatite-type La9.7(Si5.7Mg0.3)O26.3
R. Ali, M. Yashima, F. Izumi, H. Yoshioka, Y. Matsushita, T.Wakita, T. Tsuji, Y. Kawaike,
T. Komatsu, Y. Phat
1-1-27 Crystal structure and the structural disorder of yttrium tantalate
T. Tsuji, M. Yashima, T.Wakita, Xi Qu, T. Ueda, Y. Kawaike, T.Komatsu, Y. Phat, R. Ali
Y. Matsushita
Dependence of thermodynamic stability and crystal structure on substisution and
Li content of Lix(Mn,Ni,Co,M)O2 as a cathode active materila for Li secondary
1-1-28battery
Y. Idemoto, T. Matsui
Magnetic Structure of PrxY1−xMn6Sn6 Alloys
1-1-29T. Hori, H. Shiraishi
Magnetic excitation spectrum in the frustrated magnet CuFe1-xAlx02
1-1-30
M.Yamada, K.Igarashi ,S.Mitsuda ,T.Nakajima ,N.Terada
1-1-31 Crystal Structure and Origin of Polarization of Hydrogen-Bonded Organic
Ferroelectrics Composed of pi-Condugated Supramolecules
R. Kumai, S. Horiuchi, H. Sagayama, T. Arima, M.Watanabe, Y.Noda, Y. Tokura
1-1-32 Investigation of drag reduction phenomena in a surfactant solution by a surfactant
solution by neutron refrectometer
N.Takenaka, H.Suzuki, Y.Nakanishi, R.Nakamura, T.Nishimura, H.Watanabe
1-1-33 Successive Magnetic Transitions and H-T Phase Diagram of Kagome Staircase
Compound Co3V2O8
Y. Yasui, Y. Kobayashi, T. Moyoshi, M. Soda, M. Sato, K. Kakurai
1-1-34 Phonon Dispersion of Martensitic Material showing 2nd-order-like Transformation
T. Ohba, D. Kitanosono
1-1-35 Dependence of ferroelectric performance and crystal structure on composition andheat treatment of (Bi,M)4(Ti,Si)3O12(M=La,Nd) ferroelectric oxide
Y. Idemoto, E. Iso
1-1-36 Magnetic excitations in La2-xCaxCoO4
K. Horigane, T. Uchida, H. Hiraka, K. Yamada, J. Akimitsu
1-1-37 Preliminary experiments of D2O scattering for MIEZE spectrometer with AGNES
S.Tasaki, Y.Abe, Y.Edura, M.Hino, T. Ebisawa
1-1-38 The Ordering Structure of Water Molecules in The Superconductor
NaxCoO2.yD2O and The Magnetic Excitation in Na0.5CoO2
T. Moyoshi, M. Soda, Y. Yasui, M. Sato, K. Kakurai
Phonon Measurements on Protonic Conductor K3H(SeO4)2
1-1-39F. Shikanai, K. Tomiyasu, S. Ikeda, T. Kamiyama
Powder Neutron Diffraction of Ta- and Al-doped Zn2TiO4
1-1-40S. Takai, H. Okada, T. Esaka
Phonon Dispersions in Hexagonal BaTiO3
1-1-41
H. Shigematsu, T. Miyoshi, Y. Akishige
Structural change of a zirconia-scandia solid solution
1-1-42
T. Ueda, M. Yashima, Y. Ando, Q. Xu, T. Tsuji, Y. Kawaike, K. Ohoyama, K. Kawachi
1-1-43 Neutron Diffraction Analysis of Hydrogen-Bonding Networks of the Inosine
5’-Monophosphate Hydrate Stable in Medium Humidity Range II
S. Yamamura, Y. Sugawara, H. Kimura, Y. Noda
Pr-site filling fraction in the filled skutterudite PrFe4Sb12 synthesized under high1-1-44 pressure
K. Kuwahara, K. Tanaka, Y. Kawahito, D. Kikuchi, H. Aoki, Y. Aoki, H.Sato, H Sugawara
1-1-45 Crystal Structure Refinement of visible-light driven photocatalyst
H. Ishikawa, T. Matsumoto, K. Uematsu, K. Toda, M. Sato
1-1-46 Structure Determination of Ordered Perovskite-type Oxides, Ca2MTeO6 (M =Mn, Co) by Neutron Diffraction
Y. J. Shan, K. Tezuka, Y. Kanai, S. Hosokawa, H. Imoto

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1-1-47 In situ experiment of magnetic scattering, dielectric constant and electric
polarization of ErMn2O5 and TmMn2O5
Y. Noda, M. Fukunaga, H. Kimura, K. Nishihata, K. Kohn
1-1-48 Structure Analysis of P-type Icosahedral Zn-Mg-Ho Quasicrystal
H. Takakura, T. Moriwaki, A. Yamamoto, T. J. Sato, H. Kimura, Y. Noda
1-1-49 Phonon modes of beta-Na0.33V2O5
T.Kajitani, D.Abe, D.Igarashi, Y.Miyazaki
1-1-50 Phonon Dispersions in the Thermo-electric Material of Bi0.88Sb0.12
M. Nishi, S. Tomiyoshi, O. Yamashita
In situ neutron diffraction study of formation and decomposition process in
1-1-51 clathrate hydrate
A. Hoshikawa, H. Fukazawa, H. Yamauchi, N. Igawa, Y.Ishii
Structural analysis and Observation of Spin-Gap in Vanadium Oxide V4O9
1-1-52
S. Yamazaski, M. Nishi, M. Isobe, H. Ueda, K. Ohoyama, Y. Ueda
Phase transition mechanism of KTaO3 doped with Li by neutron quasi-elastic
1-1-53 scatterings
Y.Uesu, H.Yokota, S.Asanuma, Y.Tsunoda
Colloidal Complexes obtained from Charged Diblock Copolymer and Oppositely
1-1-54 Charged Surfactant
M. Annaka, K. Morishita
New-Type Phase Transition of Honeycomb Lattice System Li2RuO3
1-1-55
Y. Miura, Y. Yasui, M. Sato, N. Igawa, K. Kakurai
1-1-56 Magnetic Microstructure of LaMnO3+δ Nanocrystals in Mesoporous Silica
H. Kira, H. Tamura, Y. Murakami, T. Shinohara, J. Suzuki
1-1-57 Crystal Structure Analysis of LiGa5O8 by Neutron Powder Diffraction
H. Yamauchi, T. Suzuki, Y. Ohishi
1-1-58 Neutron Diffraction Study on Successive Structural Phase Transitions of
TlCoCl3
Y. Nishiwaki, A. Oosawa, K. Kakurai, T. Kato
1-1-59 Location of Deuterium Atoms in BaSn0.5In0.5O2.75 by Neutron
Powder Diffraction at 77-473 K
T. Nagasaki, T. Ito, K. Iwasaki, M. Yoshino, N. Igawa, Y. Ishii
1-1-60 Observation of CO2 Molecule in Clathrate Hydrate by Maximum Entropy
MethodN. Igawa, T. Taguchi, H. Fukazawa, H. Yamauchi, Y. Ishii
1-1-61 Neutron Study Suggests Ferroelectric Ice in the Universe
H. Fukazawa, H. Yamauchi, N. Igawa, Y. Ishii
Analysis of Crystal LiMn2O4 Size in Composite Sample by Neutron Scattering
1-1-62 K. Basar, Xianglian, S. Siagian, K. Ohara, T. Sakuma, H. Takahashi, O. Abe, N. Igawa
Y. Ishii
Ferroelectric Phonon Mode in Relaxor K1-x LixTaO3
1-1-63 S. Wakimoto, G. A. Samara, R. K. Grubbs, E. L. Venturini, L. A. Boatner, G. Xu
G. Shirane
Assessment of Vanadium Alloys
1-1-64
A. Hoshikawa, S. Kakei, H. Yoshinaga, T. Ishigaki, T. Kamiyama

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1-2-1
1-2-2
1-2-3
1-2-4

1-2-5

1-2-6
1-2-7
1-2-8
1-2-9
1-2-101-2-11

1-2-121-2-131-2-141-2-151-2-16
1-2-171-2-181-2-19
1-2-201-2-21
1-2-22
1-2-23
1-2-24「 Title 」
Neutron Scattering - Magnetism Magnetic structure of single-crystalline RRhGe (R=Tb, Dy) compounds
G. Nakamoto, Y. Ueda, M. Kurisu, Y. Andoh, T. Tsutaoka
Critical behavior of S=1/2 triangular antiferromagnet Cs2CuBr4
T. Ono, K. Goto, Y. Kubota, H. Tanaka, N. Metoki, F. Honda, K. Kakurai
Magnetism of S=1/2 Square-Lattice Antiferromagnets (CuX)LaNb2O7 (X=Cl,Br)
H. Kageyama, Y. Tsujimoto, Y. Ajiro, K. Yoshimura, M. Nishi, K. Hirota
Magnetic Structures of (MX)LaNb2O7 (M=Cu, Mn...; X=Cl, Br)
H. Kageayma, Y. Ajiro, K. Yoshimura, Y. Tsujimoto, T. Watanabe, Y. Baba, A. Kitada
M. Nishi, K. Hirota
Magnetic ordering and excitations in the Zn-Fe-Sc-RE (RE: rare-earth) icosahedral
quasicrystals
T. J. Sato, S. Kashimoto, C. Masuda, T. Onimaru, I. Nakanowatari, K. Iida, R. Morinaga
T. Ishimasa
Uniaxial pressure induced first-order phase transition in Pt3Fe alloy
R. Matsui, Y. Tsunoda
Magnetic excitation in the Ni4 magnetic cluster
K. Iida, Y. Qiu, S. Lee, T. J. Sato
Magnetic correlation and excitation in triangle and hexagonal magnetic molecules
K. Iida, K. Hukaya, H. Ishikawa, G. Kamohara, T.Yamase, T. J. Sato
Spin excitations in chormite spinel
K. Tomiyasu
Inelastic neutron scattering in the antiferroquadrupole material, PrPb3
T. Onimaru, T. Sakakibara, N. Aso, T.J. Sato, H. Yoshizawa, H.S. Suzuki
Magnetic Field Dependence of Two Kinds of Magnetic Correlations in Random
Magnet Fe65(Ni0.78Mn0.22)35
K. Motoya, Y. Muro, T. Igarashi
Magnetic Structure of RPdSn(R=Tb ,Dy and Ho) Compounds
Y. Andoh, Z. Ingjie, M. Kurisu, G. Nakamoto, T. Tsutaoka
Neutron Diffraction Studies on a Dy7Rh3 Single Crystal
T. Tsutaoka, A. Tanaka, Y. Andoh, Zgy Ingjie, G. Nakamoto, M. Kurisu
Zero-Field Random-Field Effect in Diluted Triangular Lattice Antiferromagnet
CuFe1-xAlxO2
T. Nakajima, S. Mitsuda, T. Komiya
Magnetic Structure in the Multiferroic Phase of Frustrated Magnet CuFe1-xAlxO2
T. Nakajima, S. Mitsuda, S. Kanetsuki, H. Kimura, Y. Noda
The magnetic field effect of ZnCr2O4
T.Arai, Y.Tsunoda
Thermodynamic anomaly specific to PD phase of spin frustration system CuFeO2
S. Mitsuda, T. Nakajima, T. Fujii, N. Terada
Phase Stability and Site Occupancy for the L21-type phase in Co2YGa (Y = Ti,
V, Cr, Mn and Fe) Alloys
K. Kobayashi, R. Y. Umetsu, R. Kainuma, K. Ishida, K. Ohoyama, Y.Yamaguchi
Magnetic Ordering of β -MnOs alloys
R. Y. Umetsu, A. Fujita, R. Kainuma, K. Fukamichi, T. Hori
Neutron Diffraction Studies on R7Rh3Dx
T. Tsutaoka, A. Tanaka, G. Nakamoto, M. Kurisu, Y. Andoh
Neutron Diffraction Experiments with 30T Pulsed Magnets
K. Ohoyama, N. Katoh, H. Nojiri, Y.H. Matsuda, H. Hiraka
Electric Control of Spin Helicity in TbMnO3
Y. Yamasaki, H. Sagayama, T. Goto, M. Matsuura, K. Hirota, T. Arima, Y. Tokura
A puzzling magnetic phase in HoCu2Si2
T. Shigeoka, M. Tanaka, M. Nishi
Neutron Diffraction Study on La2-xCaxCoO4
K. Horigane, T. Uchida, K. Ohoyama, K. Yamada, J. Akimitsu

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1-2-25 Anisotropic magnetic diffuse scattering in a helical magnet ErNi2Ge2
Y. Tabata, R. Yamaki, T. Kido, S. Kawarazaki
1-2-26 Neutron scattering in O2 adsorbent magnet
T. Masuda
1-2-27 Neutron scattering in Ba2MnGe2O7
T. Masuda
1-2-28 Neutron scattering in O2 adsorbed CPL-1
T. Masuda, K. Hirota
1-2-29 Magnetic and Neutron Diffraction Study on Ni2In type Mn65(Sn1-xTx)35
T=(Ga,Ge)
H.Shiraishi, T.Hori, N.Ohokubo, K.Ohoyama
1-2-30 Inelastic Neutron Scattering Measurements on a Quadrupolar Ordering in Yb
monopnictides
A. Oyamada, K. Kuwahara, K. Ohoyama, K. Iwasa, M. Kohgi, S.Maegawa
1-2-31 Successive magnetic phase transitions of DyB4
T. Matsumura, D. Okuyama
1-2-32 Chiral Helimagnetism in CuB2O4
Y. Kousaka, K. Shimoda, K. Hirota, M. Nishi, J. Akimitsu
1-2-33 Magnetic Structure Analysis in CuB2O4
Y. Kousaka, K. Shimoda, S. Yano, Y. Noda, J. Akimitsu
1-2-34 Magnetic Structure in the Shastry-Sutherland Lattice TmB4
F. Iga, A. Shigekawa, S. Michimura, T. Takabatake, S. Yoshii, T.Yamamoto
M. Hagiwara, K. Kindo, K. Ohoyama
1-2-35 Competing magnetic correlations in the paramagnetic phase of HoB4
T. Matsumura, D. Okuyama, T. Mouri
1-2-36 Anomalous magnetic transitions of TbCu2Si2
T. Shigeoka, M. Tanaka, M. Nishi
1-2-37 Magnetic Structure of CrB2 in Magnetic Field
S. Yano, R. Suwa, H. Ichikawa, M. Nishi, K. Hirota, J. Akimitsu
1-2-38 Competition of magnetic correlations in the paramagnetic phase of HoB4
T. Matsumura, D. Okuyama, T. Mouri
1-2-39 Magnetic structure analisys of incommensurate phase in multiferroic R Mn2O5
H. Kimura, K. Nishihata, Y. Noda, K. Kohn
1-2-40 Spin dymamics of multiferroic compound of HoMn2O5
H. Kimura, Y. Noda, K. Kohn
1-2-41 Field-induced ordered state in the rare-earth compound Pr0.97La0.03Pb3
T. Onimaru, N. Aso, T. Sakakibara, T.J. Sato, H. Yoshizawa, H.S. Suzuki
1-2-42 Magnetic and Crystal Structures of Tm2CrS4
K. Tezuka, M. Abe, Y. Watanabe, T. Nambo, Y. J. Shan, H. Imoto, K. Ohoyama
1-2-43 Neutron Diffraction Study of Magnetic Transitions in M2(OD)3X
X.G. Zheng, M. Hagihala, K. Ohoyama
1-2-44 Magnetic structure and crystalline-electric-field splitting in the tetragonalrare-earth compound CeB2C2
I. Nakanowatari, T. Onimaru, K. Ohoyama, H. Onodera, T. J. Sato
1-2-45 Magnetic Structures of Square-Lattice Antiferromagnets (MX)LaNb2O7 (M=Cu,
Mn...; X=Cr, Br)
H. Kageyama, A. Kitada, T.Watanabe, Y. Baba, Y. Ajiro, K.Yoshimura, M. NIshi,
K. Hirota, N. Tsujii, Y. Matsushita
1-2-46 Magentic structures of R2Pd2X (X=In, Sn)
T. Hataya, R. Watanuki, K. Suzuki
1-2-47 Polarized Neutron Inelastic Scattering Study of Spin Fluctuation in
La2-x (Sr,Ba)xCuO4
S. Wakimoto, K. Kakurai, M. Takeda, M. Matsuda, M. Fujita, K. Yamada
J.M. Tranquada
1-2-48 Successive Phase Transitions of LuBaCo4O7 with Kagome and Triangular
Lattices
M. Soda, T. Moyoshi, Y. Yasui, M. Sato, K. Kakurai

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1-2-49 Direct Observation of the Pressure-Induced Ferromagnetic Order in
Valence Transition Material YbInCu4
T. Osakabe, K. Kojima, K. Hiraoka
1-2-50 Magnetic Structure of TbRhIn5
T. Sugai, F. Mizuno, N. Metoki, Y. Haga, N. V. Hieu, T.Takeuchi
K. Sugiyama, R.Settai, Y. Onuki
1-2-51 Magnetic Structure of TbMnO3 Studied with Spherical Neutron Polarimetry
R. Kajimoto, M. Matsuda, M. Takeda, K. Kakurai, Y. Mitsui, H. Yoshizawa, T. Kimura
Y. Tokura
1-2-52 Unusual Magnetic Structure and the Successive Transition in NpFeGa5
N. Metoki, F. Honda, S. Jonen, K. Kaneko, T. Sugai, F. Mizuno, G. H. Lander
D. Aoki, Y. Homma, Y. Shiokawa
1-2-53 Coulomb Interaction in NpCoGa5 Probing through Phonon Spectroscopy
K. Kaneko, N. Metoki, S. Raymond, J.-P. Sanchez, P. Piekarz, K. Parlinski,
A. M. Ole´s, D. Aoki, Y. Homma, Y. Shiokawa, S. Ikeda, T. D. Matsuda, Y. Haga,
Y. Onuki, G. H. Lander
1-2-54 Polarized Neutron Inelastic Scattering Study of Central Mode in TlCoCl3
A. Oosawa, K. Kakurai, Y. Nishiwaki, T. Kato
1-2-55 Magnetic Structures in Mn3Cu1-x Gex N: Evidence for the Close Relationshipwith Magneto-volume Effect
S. Iikubo, K. Kodama, K. Takenaka, H. Takagi, S. Shamoto
1-2-56 Evaluation of Magnetization on Fe16N2 Nanoparticles
by Polarized Neutrons Diffraction
Y. Ishii, M. Takeda, K. Kakurai, T. Kikuchi, T. Shinohara, T. Oku, J. Suzuki,
Y. Sasaki, M. Kishimoto, M. Yokoyama, Y. Nishihara
1-2-57 Magnetic Structure of Fe-N Nanoparticles for Magnetic Recording Tape Studied
by Small-angle Polarized Neutron Scattering
T. Kikuchi, T. Oku, T. Shinohara, J. Suzuki, Y. Ishii, M. Takeda, K. Kakurai,
Y. Sasaki, M. Kishimoto, M. Yokoyama, Y. Nishihara
1-2-58 Successive Phase Transitions of LuBaCo4O7 with Kagome and Triangular
Lattices
M. Soda, T. Moyoshi, Y. Yasui, M. Sato, K. Kakurai
1-2-59 Magnetic Excitations in Lightly-Doped La2-xSrxCuO4
M. Matsuda, S. Wakimoto, M. Fujita, K. Yamada, J. M. Tranquada
1-2-60 New-Type Phase Transition of Honeycomb Lattice System Li2RuO3
Y. Miura, Y. Yasui, M. Sato, N. Igawa, K. Kakurai
1-2-61 Direct Observation of the Pressure-Induced Ferromagnetic Order in
Valence Transition Material YbInCu4
T. Osakabe, K. Kojima, K. Hiraoka
1-2-62 Magnetic Structure of TbRhIn5
T. Sugai, F. Mizuno, N. Metoki, Y. Haga, N. V. Hieu, T.Takeuchi,
K. Sugiyama, R.Settai, Y. Onuki
1-2-63 Magnetic Structure of TbMnO3 Studied with Spherical Neutron Polarimetry
R. Kajimoto, M. Matsuda, M. Takeda, K. Kakurai, Y. Mitsui, H. Yoshizawa, T. Kimura
Y. Tokura
1-2-64 Unusual Magnetic Structure and the Successive Transition in NpFeGa5
N. Metoki, F. Honda, S. Jonen, K. Kaneko, T. Sugai, F. Mizuno, G. H. Lander,
D. Aoki, Y. Homma,Y. Shiokawa
1-2-65 Coulomb Interaction in NpCoGa5 Probing through Phonon Spectroscopy
K. Kaneko, N. Metoki, S. Raymond, J.-P. Sanchez, P. Piekarz, K. Parlinski
A. M. Ole´s, D. Aoki, Y. Homma, Y. Shiokawa, S. Ikeda, T. D. Matsuda, Y. Haga
Y. Onuki, G. H. Lander
1-2-66 Softening of Magnetic Excitations Leading to Pressure-Induced Quantum Phase
Transition in Gapped Spin System KCuCl3
K. Goto, T. Osakabe, K. Kakurai, Y. Uwatoko, A. Oosawa, H. Tanaka
1-2-67 Neutron Elastic Scattering in Quantum Spin System NH4CuCl3
T. Ono, K. Goto, Y. Kubota, H. Tanaka, N. Metoki, F. Honda, K. Kakurai－ 10 －

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1-2-68 Magnetic Structure of Co2TeO3Cl2
T. Kashi, Y. Yasui, T. Moyoshi, M. Sato, N. Igawa, K. Kakurai
1-2-69 Spherical Polarization Analysis of Artificially Confined Spin-Density Waves in
Cr/Sn Multilayers
M. Takeda, M. Nakamura, K. Kakurai, K. Mibu, E. Leli`evre-Berna
1-2-70 Neutron Scattering Study of Metamagnetic Phase Transition in HoRhIn5
Compounds
N.V. Hieu, S. Jonen, T. Takeuchi, K. Sugiyama, R. Settai, Y.Onuki, T.D. Matsuda,
Y. Haga, N. Metoki
1-2-71 Measurements of the Magnetic form Fators of α -Fe and CoFe Powder
by Polarized Neutron Deffractometry
S. Oitani, Y. Ishii, M. Takeda, K. Kakurai,Y. Sasaki, M. Kishimoto, Y. Nishihara
1-2-72 Magnetic-field Induced Magnetic Phase Transitions in Multiferroic Compound of
ErMn2O5
H. Kimura, S. Wakimoto, Y. Noda, K. Kaneko, N. Metoki, K. Kakurai, K. Kohn
1-2-73 Temperature and Electric Field Dependences of Spin Chirality in Multiferroic
Compound of HoMn2O5
H. Kimura, S. Wakimoto, K. Nishihata, Y. Noda, M. Takeda, K. Kakurai, K. Kohn
1-2-74 Magnetic Structure and Phase Diagram of NpIn3 Studied by Neutron Scattering
under Magnetic Field
F. Mizuno, T. Sugai, N. Metoki, Y. Haga, D. Aoki, Y. Homma, Y. Siokawa
1-2-75 Magnetic Ordering Process in the Layered Triangular Lattice System
LuFe2O4 in Applied Field
K. Kakurai, M. Matsuda, K. Yoshii, N. Ikeda, Y. Ishii, H. Kito, Y. Yamada－ 11 －

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No.
1-3-1
1-3-2

1-3-3
1-3-4
1-3-5

1-3-6
1-3-7
1-3-8

1-3-9
1-3-101-3-11
1-3-12
1-3-131-3-141-3-151-3-16

1-3-171-3-181-3-19
1-3-201-3-21
1-3-22「 Title 」
Neutron Scattering - Strongly Correlated Electron SystemsIncommensurate Magnetic Order in the Pressure-Induced Superconductor CeRhSi3
N. Aso, H. Miyano, H. Yoshizawa, N. Kimura, T. Komatsubara, H. Aoki
Evolution of commensurate magnetic state in the heavy-fermion superconductor
CeRh0.6Co0.4In5
M. Yokoyama, N. Oyama, S. Oinuma, I. Kawasaki, K. Tenya, H. Amitsuka, T.J. Sato,
M. Matsuura, K. Hirota
Ferromagnetic and antiferromagnetic orders in CaRu1−x Mnx O3
M. Yokoyama, H. Miyagawa, A. Noguchi, N. Oyama, Y. Nishihara, H.Kawanaka
Magnetic excitations of high TQ compound YbAl3C3
M. Kosaka, Y. Kato, H. Nowatari, K. Ohoyama
Antiferromagnetic Phase Transition in the Kondo Semiconductor CeOs4Sb12
K. Iwasa, S. Itobe, M. Kohgi, C. P. Yang, K. Kuwahara, H. Sugawara, H. Sato
N. AsoMagnetic Excitation in the Antiferro-Type Multipolar Ordering Phase of PrFe4P12
K. Iwasa, L. Hao, K. Kuwahara, M. Kohgi, H. Sugawara, Y. Aoki, H. Sato, T. D. Matsuda
Inelastic Neutron Scattering from the Heavy-Electron System NdFe4P12
K. Iwasa, L. Hao, H. Sugawara, H. Sato
Thermoelectric properties and crystal structures of chemically-modified layered
thermoelectric materials
H. Nakatsugawa, H. M. Jeong, R. H. Kim, N. Gomi
Spin Dynamics of Rare Earth Antiferroquadrupolar Ordering Compound HoB2C2
K. Ohoyama, H. Onodera, E. Matsuoka
Magnetic structure study of the multi-step metamagnet CeIr3Si2
Y. Muro, K. Motoya, K. Shigeto, T. Takabatake
Investigation of the magnetic excitations in high-T C cuprates Bi2.1Sr1.9CaCu2O8+δ
M. Matsuura, K. Hirota, H. Eisaki, N. Kaneko, Y. Yoshida, A. Iyo, C.-H. Lee
Evolution of spin gap structure in underdoped LSCO
M. Kofu, M. Fujita, K. Yamada
Concurrent Measurements of Neutron Diffraction and AC Susceptibility in thePressure-Induced Superconducting Ferromagnet UGe2
N. Aso, S, Ban, Y. Uwatoko, Y. Homma, Y. Shiokawa, N. K. Sato
Magnetic order and magnetic excitations in the Kondo-semiconductor CeOs4Sb12
M. Kohgi , K. Iwasa, K. Kuwahara, N. Aso
Spin correlations in electron-doped antiferromagnetic ordered phase of
Pr1-xLaCexCeO4
M. Fujita, M. Nakagawa, K. Yamada
Spin fluctuations in high-temperature-tetragonal phase of
La1.70Sr0.24Ce0.06CuO4
M. Fujita, M. Enoki, K. Yamada
Spin correlations in electron-doped antiferromagnetic ordered phase of
Pr1-xLaCexCeO4
M. Fujita, M. Nakagawa, K. Yamada
A phase transition between the itinerant and the localized f-electron states in theheavy fermion antiferromagnet Ce(Ru0.9Rh0.1)2(Si1-yGey)2
Y. Tabata, R. Yamaki, C. Kanadani, S. Ohya, S. Kawarazaki
Charge and magnetic order in La2-xSrxCoO4
K. Horigane, T. Uchida, H. Hiraka, K. Yamada, J. Akimitsu
Rattling in filled-skutterudite compounds
K. Kaneko, N. Metoki, H. Kimura, Y.Noda, T. D. Matsuda, M. Kohgi
Magnetic structures of PrA2Mn2O7 (A=Ca, Sr)
Y. Tokunaga, M. Uchida, T.J. Sato, T. Arima, Y. Tokura
Crystalline Electric Field Excitations in Pr3Pd20Ge6
H. Amitsuka, T.Wakabayashi, I. Kawasaki, M. Yokoyama, N. Aso－ 12 －

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1-3-23 High-Pressure Effects in Strongly Correlated 5f Electron Systems
H. Amitsuka, K. Matsuda, I. Kawasaki, K. Tenya, M. Yokoyama, N.Tateiwa, T.C. Kobayashi
S. Kawarazaki, H. Yoshizawa
1-3-24 Neutron scattering study of Pr0.5Sr0.5CoO3
Y. Oohara, M. Kubota, J. Takeuchi
1-3-25 Role of the electronic spins in a novel superconductor CeCoIn5
H. K.Furukawa, S. O. Kawamura, A. Yoshida, H. Shishido
1-3-26 Flux Line Lattice in CeCoIn5
H. K.Furukawa, A. Yoshida, S. O.Kawamura, H. Shishido, K.Shirahata, S. Konno
1-3-27 Flux Line Lattice Symmetry in MgB2-type Superconductor CaAlSi probed by
Small Angle Nuetron Scattering
S. Kuroiwa, Y. Sugiyama, T. Muranaka, H. K.Furukawa, J. Akimitsu
1-3-28 Order Parameter of Phase IV in (Ce,La)B6
K. Kuwahara, K. Iwasa, N. Aso, M. Sera, F. Iga
1-3-29 Neutron diffraction study of PrFe4P2 under high pressure
K. Kuwahara, T. Osakabe, D. Kawana, K. Iwasa, M, Kohgi, D. Kikuchi, H. Sugawara
Y. Aoki, H. Sato
1-3-30 Magnetic and electronic nature of shandite-type type metallic ferromagnet
Sn2Co3S2 and its related compounds with Kagome lattices
M. Matoba, A. Umetani, E. Nagoshi, T. Kubodera
1-3-31 Mn-substitution effect on spin correlations in La1.90Sr0.10CuO4
M. Fujita, M. Enoki, K. Yamada
1-3-32 Magnetism and Superconductivity in RE Ni2B2C
H. K.Furukawa, N. Adachi, S. O. Kawamura, H. Yoshizawa, N. H. Andersen, H. Takeya
1-3-33 Low-energy magnetic excations in a heavy fermion superconducting
antiferromagnet CeRhIn5
N. Aso, H. Miyano, H. Yoshizawa, G. F. Chen, N. K. Sato
1-3-34 Crystal structure in a non-centrosymmetric pressure-induced superconductor
CeRhSi3
N. Aso, H. Miyano, H. Yoshizawa, N. Kimura, T. Komatsubara, H. Aoki
1-3-35 Neutron scattering study of Nd0.25Sr1.75MnO4
Y. Oohara, M. Kubota, H. Kuwahara－ 13 －

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「 Title 」

Neutron Scattering -Amorphous ・ LiquidNeutron Diffraction Study on the Local Structure around Chloride Ions in Anion
Exchange Resins
Y. Kameda, K. Yamanaka, Y. Amo, T. Usuki
Dynamics
of Meso-scale fluctuations in liquid chalcogens near the metal-nonmetal
1-4-2transition
Y.Ohmasa, K.Fujii, T.Hoshino, M.Yao
1-4-3 QENS Studies of Fast Molecular Reorientations in Isotropic, Cholesteric, Glassand Crystalline Phases of 5*CB
H. Suzuki, N. Sakisato, J. Krawczyk, A. Inaba, T. Kikuchi, O. Yamamuro
1-4-4 Visualization of Density Fluctuation of Supercritical Carbon Dioxide Using Reverse
Monte Carlo Simulation
T. Sato, M. Sugiyama, M. Misawa, K. Hamada, K. Itoh, K. Mori, T. Fukunaga
1-4-5 Concentration fluctuations of DMSO-water mixtures
K. Ueki, T. Fujinaga, S. Nakamura, K. Yoshida, T. Yamaguchi
1-4-6 Temperature Dependence of water dynamics in nano-porous material FSM
S. Takata, T. Otomo, S. Setoyama, Y. Fukushima, Y. Inamura, O. Yamamuro
1-4-7 Quesielastic and Inelastic Neutron Scattering Study of Ionic Liquid bmimI
Y. Inamura, O. Yamamuro, S. Hayashi, H. Hamaguchi
1-4-8 Quasi-elastic neutron scattering study on diffusion dynamics of water molecules intert-butyl alcohol-water mixture
M. Misawa, M. Nakada
Dynamicsof Water and Methanol Molecules in Binary Liquid Mixture Confined in
1-4-9
Mesopores of MCM-41.
S. Takahara, S. Kittaka
1-4-10 Wide-q Observation of the Self-Assembled Fractal Porous Silica by
Ultra-small-angle Neutron Scattering
D. Yamaguchi, H. Mayama, S. Koizumi, K. Tsujii, T. Hashimoto

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No.
1-5-1

1-5-2

1-5-3

1-5-4
1-5-5

1-5-6

1-5-7
1-5-8
1-5-9

1-5-101-5-11

1-5-12

1-5-131-5-141-5-151-5-16
1-5-171-5-181-5-19

1-5-20「 Title 」
Neutron Scattering - Polymer Evaluation of Membrane Lipid Dynamics by Time-Resolved Small-Angle Neutron
Scattering
M. Nakano, M. Fukuda, T. Kudo, H. Endo
Surface and Interface Structure of (Deuterated Polystyrene with Silsesquioxane
End Group/Polystyrene) Blend Thin Films
K. Miyamoto, N. Hosaka, M. Kobayashi, A. Takahara
Structure Analyses of Ultra-Hydrophilic Zwitter-ionic Polymer Brush at Water
Interface by Neutron Reflectivity
M. Kobayashi, K. Miyamoto, N. Hosaka, A. Takahara
Structural Formation Process of Polymers under Shear Flow
G. Matsuba, K. Nishida, T. Kawai, T. Kanaya
Structural Formation of Uni-Lamellar Vesicles in a Mixture System
of Long- and Short-Chain Lipids
N. L. Yamada, N. Torikai, S. Okabe, N. Osaka, M. Shibayama
Surface Segregation in Miscible Polymer Mixtures of Block Copolymer /Homopolymers
D. Kawaguchi, N. Torikai, M. Hino, A. Takano, Y. Matsushita
Dynamic anisotropy of polymer thin films
R. Inoue, T. Kanaya, K. Nishida, I. Tsukushi
Dynamics of diblock polymer in the form of lamellar structure
R. Inoue, T. Kanaya, H. Ogawa, K. Nishida, I. Tsukushi, O. Yamamuro
Investigation on nanostructure in a block copolymer film having sulfonic acidgroupsK. Matsumoto, S. Kage, H. Matsuoka
Structural analysis of a dilatancy solution
T. Kume, H. Kawada, T. Matsunaga, S. Miyazaki, N.Osaka, S. Okabe, M. Shibayama
Small-Angle Neutron Scattering Study on Strain-Induced Crystallization andNonuniformity of Natural Rubber
M. Shibayama, T. Karino, Y. Yasuda, Y. Ikeda, S. Kohjiya
Small-Angle Neutron Scattering Study on the Miscibility and Concentration
Fluctuation of Hydrogen Bonding Polymer Blends
O. Urakawa, H. Ikuta, T. Shikata
Micellization behavior of non-surface active amphiphilic block copolymer
containing fluorine in aqueous solutions
H. Matsuoka, S. Kage, P. Kaewsaiha, Y. Suetomi, S. Hara, H. Chen, K. Matsumoto
Microstructure Analysis of Weakly-charged Gels Having Different Spatial
Distribution of Charged Groups ～pH Dependence～
T. Suzuki, T. Karino, F. Ikkai, M. Shibayama
Analysis of Aggregation States in Ultrathin Polymer Blend Films Confined
Between Solid Substrates
Y. Fujii, K. Tanaka, T. Nagamura, M. Hino
Concentration fluctuation for polymer blend thin film close to critical
H. Ogawa, R. Inoue, T. Kanaya, K. Nishida
Effects of Temperature on the Shear-Induced Structural Transition in the Lamellar
Phase of Nonionic Surfactants
Y. Koasaka, M. Ito, Y. Kawabata, T. Kato
Pressure-Induced Phase Separation of Block Copolymers in Aqueous Solution
N. Osaka, T. Karino, S. Okabe, M. Nagao, M. Shibayama, A. Sasai, S. Aoshima
Rheo-SANS behavior of Entangled Polymer Chains with Local Label Under Fast
Shear Flow
H. Watanabe, T. Kanaya, Y. Takahashi
Dynamics of aromatic molecules entrapped in the clathrate phase of syndiotactic
polystyrene
F. Kaneko, T. Kawaguchi, K. Ute－ 15 －

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1-5-21 Mobility of Polymer Chain in Clathrate Phase of Syndiotactic Polystyrene
T. Kawaguchi, F. Kaneko
1-5-22 Sol-gel transition of methylated polyrotaxane
T. Karino, Y. Okumura, M. Shibayama, K. Ito
1-5-23 Neutron spin echo studies on bending modulus of bilayer membrane in
DGI/SDS/D2O system
H. Mayama, X. -J. Chen, M. Nagao, H. Seto, K. Tsujii
1-5-24 Structural study for Thermoplastic Elastomer Consist of Carboxyl-terminatedTelechelic Poly(ethylene-butylene) and Stearylamine
Y. Takahashi, A. Takada
1-5-25 Thermal transition of viscoelasticity and association structure of small molecule
gelator with metal ions
A. Takada, Y. Takahashi
1-5-26 Structure Analysis of Silicon Nanosheets Synthesized from Layered Compounds
M. Harada, Y. Matsushita
1-5-27 Mesoscopic structure in near-critical mixtures of D2O and 3-methylpyridine withsalts
K. Sadakane, H. Seto, H. Endo, M. Kojima
1-5-28 The ”swollen phase” and the ”anomalous swelling” in DPPC aqueous solution
with ethanol
H. Seto, M. Hishida, K. Sadakane, N. L. Yamada
1-5-29 In -situ and Real-time Observation of Simultaneous Living Anionic
Copolymerization Process and Polymerization-Induced Self-Assembly by SANS,
UV-vis, GPC and NMR
Y. Zhao, N. Miyamoto, S. Koizumi, T. Hashimoto
1-5-30 In Situ Observation of the Formation of Actin and Polycation Complexes
T. Masui, K. Shikinaka, H. J. Kwon, S. Koizumi, T. Hashimoto,H. Iwase, A. Kakugo, J. P. Gong

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No.
1-6-1

1-6-2

1-6-3

1-6-4
1-6-5
1-6-6

1-6-7

1-6-8

1-6-9

1-6-101-6-11

1-6-12

1-6-131-6-14「 Title 」
Neutron Scattering - Biology Diversity of protein dynamic structure observed by solution inelasitic neutron
scatttering
H. Nakagawa, Y. Joti, O. Yamamuro, I. Tsukushi, K. Shibata, M. Kataoka
Solvent effect on structure and dynamics of beta-lactoglobulin in alcohol-water
mixturesK.Yoshida, T. Yamaguchi
Small-Angle Neutron Scattering Study on Hydrated Short Lamellar Structure in
Mammal’s Skin Stratum Corneum
H. Takahashi, N. Kunizawa, Y. Obata, N. Ohta, I. Hatta
Analysis of F-actin dynamics
S. Fujiwara, F. Matsumoto, N. Takahashi, H. Nakagawa, T. Oda
Structural evolution of human αB-crystallin on UV irradiation
M. Sugiyama, N. Fuji, Y. Morimoto, S. Kurabayashi, T. Sato, K. Itoh, K. Mori, T. Fukunaga
Defect Study of Protein Crystals by Neutron Topography
H. Koizumi, N. Ohya, M. Koishi, N. Kitajima, Y. Mukohbayashi, M. Tachibana, K. Kojima,
K. Kurihara, R. Kuroki
A Neutron Crystallographic Analysis of 2Zn-Insulin
W. Iwai, T. Yamada, Y. Ohnishi, Y. Kobayashi, I. Tanaka, K. Kurihara, R. Kuroki
N. Niimura
The State of Cryptobiosis of Larvae of Polypedilum Vandezplanki Studied by
Incoherent Inelastic Neutron Scattering
H. Nakagawa, T. Okuda, Y. Joti, M. Kataoka
Hydration Water Dynamics at Protein Dynamical Transition by Quasi-Elastic
Neutron Scattering
H. Nakagawa, M. Kataoka
Neutron Diffraction Study of Porcine Pancreatic Elastase with Its Inhibitor
T. Kinoshita, T. Tamada, T. Ohhara, K. Kurihara, T. Tada, R. Kuroki
Single Crystal Neutron Structure Analysis of a [NiFe]hydrogenase Model Complex
S. Ogo, R. Kabe, K. Uehara, B. Kure, T. Nishimura, S. C. Menon, R. Harada,
S. Fukuzumi,Y. Higuchi, T. Ohhara, T. Tamada, R. Kuroki
Contrast Variation Measurements of Hen Egg White Lysozyme
Amyloid Protofilaments
S. Fujiwara, F. Matsumoto, H. Nakagawa
Hierarchical Structure for Red Blood Cells Observed by Small-Angle Neutron
Scattering with Solvent Contrast Variation
H. Iwase, S. Koizumi
The Structure of 4-Repeat Tau and 3-Repeat Tau Monomer and theirSelf-Assembled Clusters
S. Naito, H. Mochizuki, T. Yasuda, Y. Mizuno, M. Furusaka,
S. Ikeda, M. H. Shimizu, J. Suzuki, S. Fujiwara－ 17 －

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1-7-1
1-7-2

1-7-3
1-7-4
1-7-5

No.
1-8-1

1-8-2
1-8-3
1-8-4
1-8-5

1-8-6

1-8-7
1-8-8

1-8-9

1-8-101-8-11
1-8-12

1-8-131-8-141-8-151-8-16「 Title 」
Neutron Scattering - Fundamental Physics ・ Neutron Optics Development of beam splitting etalons for pulsed neutrons
M. Kitaguchi, T. Seki, K. Taketani, H. Funahashi, M. Hino, H. M.Shimizu
Preliminary masurement of hydrogen content absorbed in Pd using neutroncomposite mirror
S.Taski, T.Wakita, M.Hino
Observation of roughness at iron-surface by neutron reflectometry
K. Inoue, T. Hirayama, T. Uno, T. Ebisawa, S. Tasaki, M. Hino
Development of a neutron focusing device with an ellipsoidal supermirror
K. Ikeda, H. Sato, K. Hirota, K. Mishima, T. Shinohara
A Development of the Neutron Beta Decay Experiment with Superconducting
Tunnel Junction (STJ)s
K. Mishima, H. Sato, S. Yamada, T. Shinohara, T. Oku, J. Suzuki, H. M. Shimizu「 Title 」
Neutron Scattering - Instrument Development of a Neutron Focusing Guide for High Q-Resolution Triple-Axis
Spectrometer HQR (T1-1)
S. Yamada, T. Oku, T. Shinohara, J. Suzuki, M. Nishi
Development of resonance spin flipper with high frequency
M. Kitaguchi, M. Hino, Y. Kawabata, H. Hayashida, S. Tasaki, T.Ebisawa
Development of fine-pixel detector for UCN
T. Sanuki, M. Hino, S. Komamiya, S.Kawasaki, S. Sonoda, H.Shimizu
A new layer structure for large-m polarizing neutron supermirror
M.Hino, M.Kitaguchi, H.Hayashida, Y.Kawabata, T.Ebisawa, T. Kume, S. Tasaki
A test of MIEZE-Reflectometer for study of surface and interface
M.Hino, M.Kitaguchi, H.Hayashida, Y.Kawabata, S.Tasaki, D.Yamazaki,
R.Maruyama, T.Ebisawa, K.Tanaka, N.Torikai, T.Kanaya
Development of miniaturized McWhan type high pressure cell for elastic andinelastic neutron scattering experiments
T. Fujiwara, Y. Uwatoko, H. Yamamoto, N. Aso, M. Nishi, K. Hirota, H. Yoshizawa
Bent Perfect Silicon Crystal Monochromator for Cold Neutrons
M. Furusaka, T. Satoh, K. Tanabe, P. Mikula, K. Koyama, F. Fujita, A.Homma
Development of High Performance Neutron Supermirrors
with Ion Beam Sputtering Technique
R. Maruyama, D. Yamazaki, T. Ebisawa, M. Hino, K. Soyama
Feasibility Tests on the Pressure-transmitting Media for Single-crystal
Magnetic Neutron Diffraction Experiments
T. Osakabe
Performance Test of Neutron Detector for Engineering Diffractometer in J-PARC
K. Sakasai, T. Nakamura, M. Katagiri, A. Birumachi, T. Hosoya, K. Soyama, S. Satoh,E. Shooneveld, N. Rhodes
Measurement of Energy Spectrum of Neutron Beam at MUSASI PortK. Sakasai, N. Metoki, H. Matsue
Development of High Quality Neutron Mirrors with Upgrading
Cold Neutron Bender System
I. Tamura, D. Yamazaki, R. Maruyama, K. Yamamoto, K. Nakamura, K. Soyama
Upgrading Cold Neutron Bender System
I. Tamura, R. Maruyama, K. Yamamoto, K. Nakamura, K. Aizawa, K. Soyama
3
Test of Prototype He PSDs and Related Electronics for New Spectrometers at
J-PARC
K. Nakajima, T. Yokoo, S. Satoh, M. Nakamura, N. Kaneko, Y. Kobayashi, R. Kajimoto
Development of a Neutron Polarizing Device Based on a Quadrupole Magnet
and Evaluation of Its Polarizing PowerT. Oku, S. Yamada, T. Shinohara, J. Suzuki, H. M. Shimizu
Profile of a Neutron Reflectometer SUIREN at C2-2, JRR-3
D. Yamazaki, A. Moriai, I. Tamura, R. Maruyama, T. Ebisawa, K. Soyama,
M. Takeda, M. Hino

－ 18 －

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No.
1-9-1

1-9-2

No.
1-10-1

1-10-2

1-10-3

1-10-4
1-10-5No.
1-11-1

1-11-2
1-11-3
1-11-4
1-11-5「 Title 」
Neutron Scattering - Superconductivity Polarized Neutron Inelastic Scattering Study of Spin Fluctuation in
La2-x (Sr,Ba)x CuO4
S. Wakimoto, K. Kakurai, M. Takeda, M. Matsuda, M. Fujita, K. Yamada
J.M. Tranquada
Magnetic Excitations in Lightly-Doped La2-x SrxCuO4
M. Matsuda, S. Wakimoto, M. Fujita, K. Yamada, J. M. Tranquada「 Title 」
Neutron Scattering - Residual Stress Intergranular Strain Pole Figure Measurement for
ECAPed Al by Neutron Diffraction
T. Suzuki, T. Ishibashi, Y. Tomota, H. Suzuki, T. Saito, S. Ryufuku
Quantitative Evaluations of Microstructural Factors by Neutron Diffraction
for Cold Rolled austenitic Stainless Steels
H. Suzuki, T. Saito, J. Y. Tomota, T. Suzuki, P.-G. Xu, S. Ryufuku
Attempt of Residual Stress Measurements in
Multi-Purpose Thermal Neutron Application and Science (MUSASI)
S. Machiya, A. Moriai, H. Suzuki, N. Metoki, Y. Akiniwa, Y. Morii
Performance Test of Radial Collimator Basic Performance Test
S. Harjo, S. Torii, A. Moriai, K. Shirakihara
Performance Test of Radial Collimator Application Test on PSZ Material
K. Shirakihara, S. Harjo, A. Moriai「 Title 」
Neutron Scattering - Others Hydration Properties of Low Heat Portland Cement
K. Mori, Y. Inamura, O. Yamamuro, K. Oishi, K. Kimura, T. Sato, K. Itoh, M. Sugiyama, M. Kawai
T. Fukunaga
Advanced KINKEN Triple-Axis Neutron Spectrometer, AKANE
H. Hiraka, K. Ohoyama, Y. Yamaguchi, K. Yamada
Kinken Powder Diffractometer HERMES
K. Ohoyama
Present Status of Tohoku University Triple-Axis Spectrometer TOPAN (6G)
K. Iwasa
Detection of Hydrogen Trapped by Nano-scale Carbide by SANS
M. Ohnuma, F.G. Wei, K. Tsuzaki, J. Suzuki－ 19 －

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JAEA-Review 2008-067

No.
2-1
2-2

2-3
2-4
2-5
2-6
2-7

2-8

No.
3-1
3-2

3-3

3-4

「 Title 」
Neutron Radiography
Development of a Dynamic Neutron Computer Tomography System
M. Kureta, H. Kumada, E. Kume, S. Someya, K. Okamoto
Neutron Tomography Analysis of Metal Hydride Canisterwith/without Hydrogen Charging and Discharging Cycle
Y. Fujita, T. Ebisawa, H. Iikura, M. Matsubayashi
Development of Neutron Imaging Techniques for PEM Fuel Cells (II)M. Matsubayashi, H. Iikura, R. Yasuda
Evaluation Research for Long Term Stability of Metal
M. Matsubayashi, H. Iikura, H. Yishikawa
Analysis of the water statement in plant tissue
T. Nakanishi
Thermochronological studies of orogenic belts
H. Hyodo, T. Itaya, C. Gouzu
Development of Digital Neutron Radiography Using Pulse Neutron Beam
M. Tamaki
Development of Dy-IP for Neutron Imaging for Nuclear Materials under
Realistic Conditions
M. Tamaki「 Title 」
Prompt Gamma-ray Analyses
Determination of Cadmium in Polymer Samples by MPGA
Y. Toh, M. Oshima, M. Koizumi, A. Kimura, K. Sushida, M. Sato
Neutron-induced prompt gamma ray analyses of volcanic and sedimentary rocks
T. Hasenaka, M. Miyoshi, T.Nasu, H. Uemura, Y. Takae, M. Shimono, T. Edamura
K. Yatuda, M. Morinaga, Y. Sekiguchi, T. Fukuoka, Y. Fukushi, Y. Sugiuchi
Y.Hoshi, H. Kusuno, T. Shindo, T. Sano, H. Shinjoe
Prompt gamma-ray analysis of Antarctic meteorites
M. Ebihara, Y. Oura, Y. Karouji, N. Shirai, J. Kuwayama, M. Takeda, Y. Koiwa
T. Takda, S. Yamazaki
Neutron-induced prompt gamma-ray analysis of solid environmental
samples and geochemical samples
M. Matsuo, A. Kuno, M. Kataoka, K. Shozugawa, A. Hasegawa, M. Tanoshima
A. Nakamura, D. Moromachi, M. Hoshino, T. Yamano－ 20 －

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JAEA-Review 2008-067

No.
4-1
4-2
4-3
4-4
4-5
4-6
4-7

4-8
4-9
4-10
4-11
4-12
4-13

4-14

No.

「 Title 」
Neutron Activation Analyses
Development for Measurement of Thermal Neutron Capture Cross Section by JRR-3
S. Nakamura, M. Ohta, Y. Hatsukawa, H. Harada
40
39
Revealing volcanotectonic history of Philippine Sea region using Ar/ Ar dating method
O. Ishizuka
Ratio of chemical forms of tritium generated in mercury
K. Manabe, S. Yokoyama
Concentration ratio of Vanadium(V) to Aluminium(Al) in the atmospheric coarse aerosol particles
N. Ito, A. Mizohata
Characterization of Aerosol in Kanto Air Basin (XXVI)S. Naito, S. Yonemochi
Estimation of soil ingestion in livestock by neutron activation analysis
K. Nishimura, N. Kihou
Development of the method for deciding soil-plant transfer coefficient to evaluate inorganic
element accumulation ability of crops
N. Kihou, K. Nishimura, H. Fujiwara, Y. Sakurai, N. Yamaguchi
Neutron Activation Analysis of Cr and Co in Ceramics
T. miura, Y. Kuroiwa, K. Chiba, H. Matsue
Influence of geological characteristics on the chemistry of river water
K. Anazawa, H. Sakamoto, K. Arima
Elemental analysis of plants and soils
T.Nakanishi
Activation analysis of major element in overland and marine aerosols
H. Nagai, T. Saito, T. Yamagata, T.Yoshida
53
Determination of Mn in Iron Meteorites by Neutron Activation Analysis
Y. Oura, F. Hashidume
Geoenvironmental assessment by INAA analysis of chromium and arsenic for a large
number of stream sediments
T. Itoh, T. Tanaka, M. Mimami, K. Yamamoto, Y. Asahara, K. Mimura, M. Takeuchi
S. Shibata, H. Kojima
Investigation on elemental concentrations of aquatic insect larvae in river in relation towater quality by INAA with k0 standardization method
N. Momoshima, T. Toyoshima, A. Fukuda, K. Hibino「 Title 」

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Others
5-1

Application of fission track method to particle analysis of environmental sample for safeguard
C. G. Lee, K. Iguchi, J. Inagawa, D. Suzuki, F. Esaka, M. Magara, S. Sakurai, N. Shinohara, S. Usuda,

433

5-2

Improvement of DAP plastic detector for fission track dating (Part 3)
H. Iwano, T. Danhara, H. Kobayashi, T. Tsuruta
Collaboration between SOF detector and JCDS system in Boron Neutron Capture Therapy
M. Ishikawa
Observation of the ultra small amount boron in various steel materials by
α particle track etching method
K. Asakura, C. Nagasaki, T. Koseki
Development of boron nano capsules for BNCT
H. Nakamura, M. Ueno, H. S. Ban, J. D. Lee, W. Nabeyama, K. Nakai, K. Turuta, A. Matsumura
Y. Kaneda
Development of boron drug localization measurement method inside biological cellsby neutron-induced alpha track mapping technique
M. Nakasawa, K. Amemiya, K. Fujita, H. Takahashi, M. Eriguchi, H. yanagiei, T. Hisa, Y. Nakagawa
N. Nishizawa, S. Nagasaka, T. Majima, N. Yasuda
Boron neutron capture therapy without craniotomy for malignant brain tumors
T. Toudou, Y. Inou, M. Tanaka, S. Miyatake, A. Matsumura

435

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5-4

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5-6

5-7

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JAEA-Review 2008-067－ 23 －

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JAEA-Review 2008-067

1-1-1

Low-Energy Phonon Anomaly and Electron-Lattice Interaction in the Pr-Filled
Skutterudites
K. Iwasa1 , Y. Mori1 , L. Hao1 , Y. Murakami1 , M. Kohgi2 , H. Sugawara3 , H. Sato2
Tohoku Univ.1 , Tokyo Metropolitan Univ.2 , The Univ. of Tokushima3
The rare-earth ﬁlled skutterudites
RT4 X12 (R = rare earth, T = transition
metal, X = pnictogen) have been studiedin terms of the anomalously anharmonic
lattice properties, as well as the various
strongly correlated electron phenomena
involving 4 f electrons. The ﬁlled ions arelocated within the icosahedral X cage, andvibrate with large amplitude detected as
the large effect of the Debye-Waller factors.
Ultrasonic measurements of PrOs4 Sb12
revealed dispersion of elastic constants
indicative of anomalous Pr-ion motion
within the Sb cage (T. Goto et al.: PRB 69(2004) 180511). Recent inelastic x-ray scattering experiment of Sm-based compounds(S. Tsutsui et al.: Physica B 383 (2006) 142,
JMMM in press) and inelastic neutron
scattering experiment of CeRu4 Sb12 (C. H.
Lee et al.: JPSJ 75 (2006) 123602) revealed
lower-frequency ﬂat phonon branches corresponding to the motion of ﬁlled atoms.
We have reported anomalous softening ofphonon due to Pr vibration with decreaseof temperature in PrOs4 Sb12 (K. Iwasa etal.: Physica B 378-380 (2006) 194). Suchvibration has been expected to produce
strong electron-phonon coupling that may
relate with the electronic phenomena.
We have investigated the low-energy
phonon spectra of PrOs4 Sb12 andPrRu4 Sb12 using the triple-axis spectrometers TOPAN (6G) and HER (C1-1).
The left ﬁgure shows phonon spectra of
PrRu4 Sb12 measured at the reciprocal lattice point Q = (0 3 3). It shows distinct
softening of excitation energy by 17% withdecreasing temperature from 300 down to
12 K. By the measurements in the Brillouinzone around Q = (0 3 3), this mode was
conﬁrmed to be less dispersive like an optical mode. We measured phonon spectra also at Q = (6 ζ ζ ), as shown in theright ﬁgure. The spectrum measured atζ = −0.4 is composed of the peak “R”
around 4 meV which exhibits softening behavior similar to the less-dispersive optical mode at Q = (0 3 3) and that around
6 meV ascribed to the transverse acoustic(TA) one which has no softening behavior.
The temperature dependence of the integrated intensity of the 4 meV peak is explained by the phonon state dominated by
the Pr-ion vibration, so that the low-energy
optical mode is given by the large Pr-ion
motion “rattling” inside the Sb cage. The
spectrum at the zone center Q = (6 0 0)
is unexpectedly quasielastic, whose tail extends beyond 4 meV. Such overdamped response can be attributed to a relaxation
phonon due to additional interaction. We
will compare the experimental data withthe phenomenological phonon susceptibility based on the mode coupling.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 22－ 25 －

JAEA-Review 2008-067

1-1-2

Split H-site model in synthetic Al-for-Ga substituted germanate-muscovites: FTIRand neutron powder diﬀraction studies
Kiyotaka Ishida, Yasuhiko Kato($), Yukinobu Kawakita($), Shinichi Takeda($)
Graduate School of Social and Cultural Studies, ($)Institute of Sciences, Kyushu University
FTIR and powder neutron diffraction studies of synthetic deuterated aluminogallogermanate muscovites have been madeat ambient temperature. More than three
infrared OH/OD-stretching bands wereanalyzed both OH- and OD-form s micas.
A neutron powder diffraction Rietveld
analyses for two germanate-micas of thecompositions KAl1.5Ga1.5Ge3O10(OD)2and KGa3Ge3O10(OD)2,
up to threehydrogen sites were derived, reﬂecting acrescent or horseshoe-like H/D distribution sitting on the (1-10) plane with various
angles from the (001) plane; their site occupancies and the angles from the (001) plane
are 0.36(-3.9), 0.45(29.2), and 0.18(80.8) in
the former mica, 0.28(-18.7), 0.45(15.4), and0.26(62.4) in the latter, respectively. The
higher wavenumber infrared OH/ODstretching bands ascribed to the higher
angle H/D from the (001) plane. These
split H/D-sites are derived mainly by the
local negative charges which occur by
the short range order of the tetrahedral
tetravalent and trivalent cations.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 43－ 26 －

JAEA-Review 2008-067

1-1-3

Possible structural transformation in the Eu-Ag-In 2/1 approximant and its
relation to the Cd-Yb quasicrystals
T. J. Sato1,2 , C. P. Gomez2,3 , A. P. Tsai3,2

1 NSL, ISSP, University of Tokyo, Tokai, Ibaraki 319-1106, Japan
2 SORST-JST, Kawaguchi Saitama 332-0012, Japan

3 IMRAM, Tohoku University, Sendai 980-8577, Japan

necessary to record single diffraction pattern. Shown in Fig. 1 are the observed powder diffraction patterns at the room temperature and the lowest temperature T =4 K. There is an apparent change of thelattice constant, resulting in the change of
the Bragg peak positions in consistent way.
In addition, some new peaks appear at
the lowest temperature; most notable one
is marked by a red arrow. This indicatesa possibility of magnetic/structural transition between the two temperatures. Detailed analysis of the diffraction patterns isin progress.
Note: the experiment approved by PAC
was on the Cd-Yb approximant itself, however, because of the unexpected UK airline
confusion due to the terrorism possibility
happened just a few days before the assigned HERMES beamtime, the sample delivery was delayed. Thus, we instead performed the most similar experiment withthe samples in hand.
300

RT
T=4K

Eu-Ag-In 2/1 approximant
HERMES

250
Intensity (counts/90min)

Quasicrystals are characterized by sharp
Bragg reﬂections with a point symmetrythat is forbidden in a periodic lattice, suchas the ﬁve-fold symmetry. For understanding of the formation and stabilization of
the quasiperiodic structure, a key fact may
be existence of approximant phase near
the quasiperiodic compound in phase diagram. An approximant is a periodic crystal which has similar or identical atomic
cluster in a ﬁnite length scale. For the binary Cd-Yb quasicrystal, there are two approximant phases are known to date; the1/1 and 2/1 phases. The 2/1 phase hasmuch larger atomic cluster in common to
the quasicrystalline phase and thus is intriguing for the elucidation of the stabilization mechanism of the quasicrystalline
phase. Recently, a 2/1 approximant phase
was observed in the Eu-Ag-In alloy, which
is supposed to be isostructural to the 2/1
Cd-Yb approximant. In a magnetic susceptibility study an abrupt change of theinverse-susceptibility slope was observed
around 70 K, indicating change of electronic state of Eu ions at the temperature.
Thus, the anomaly may possibly infer existence of certain structural distortion in the
2/1 approximant. To clarify this point wehave performed neutron powder diffraction study using the IMR-HERMES powder diffractometer.
Powder samples of the Eu-Ag-In alloys
were prepared by melting constituent elements in a standard manner. Because of
the high absorption of the Eu, Ag, andIn atoms, we have used an annular sample cell with the sample thickness of t =0.5 mm. Nevertheless, the diffraction wasvery weak due to the absorption, and thus
unusually long data acquisition time was

200

150

100

50

0
10

20

30

40

50

60

70

Two-theata (deg.)

Fig. 1. Neutron powder diffraction patterns at T =4 K (red) and RT (green) obtained at IMR-HERMES.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 44－ 27 －

JAEA-Review 2008-067

1-1-4

Neutron scattering study of phonon dynamics on type-1 clathrate cagecompounds (Ba,Sr)8Ga16Ge30
C. H. Lee(A), H. Yoshizawa(B), I. Hase(A), M. A. Avila(C), T. Takabatake(C)(A) AIST, (B) ISSP, (C) Hiroshima Univ.
Large vibration of an atom in an oversized atomic cage, so called rattling, has attracted a great interest since it can be theorigin of some exotic physical properties.
For example, the rattling can be responsible for an extremely low thermal conductivity. Electronic properties could also beaffected via electron-phonon coupling. To
clarify the relation between the rattling motion and exotic physical properties in materials having oversize atomic cages, it is very
important to understand the nature of therattling.
(Ba,Sr)8Ga16Ge30 is one of compounds
that has large Ga and Ge atomic cages
ﬁlled with Ba or Sr guest atoms. In thecompounds, the guest atoms are considered to behave as rattlers in the oversized atomic cages. To clarify the vibrational motion of ﬁlling atoms, we haveconducted neutron scattering measurements on (Ba,Sr)8Ga16Ge30 compounds
using the 3-axis spectrometers, GPTAS,TOPAN, HQR and AKANE, at JRR-3M reactor of Japan Atomic Energy Agency inTokai. Sample vomules of Ba8Ga16Ge30
and Sr8Ga16Ge30 single crystals used forthe measurements were about 1cc and 2cc,
respectively.
Fig. 1 shows the phonon dispersion of
Ba8Ga16Ge30 with propagation vector of[100]. The optical phonon mode observed
at E = 4.5 meV corresponds to a guest
mode, in which Ba atoms vibrate largely.
The guest mode shows anti-crossing behavior with acoustic phonon mode aroundq=(0.5,0,0). The low phonon energy indicates that Ba atoms bound loosely with surrounding atoms consistent with the previous expectation. On the other hand, theanti-crossing behavior indicates that theguest mode mixes strongly with the acoustic mode. Although the energy depen-

dence is weak, the guest mode is still dispersive suggesting the existence of Ba-Ba
interaction. In Sr8Ga16Ge30, on the other
hand, the energy dependence of the guest
mode is weaker and energy gap between
the guest and the acoustic mode is smaller
than in Ba8Ga16Ge30. It seems that theguest mode in Sr8Ga16Ge30 becomes more
Einstein-like mode than in Ba8Ga16Ge30.
In Sr8Ga16Ge30, the guest atoms tend to
split from the center position of atomic
cages, whereas in Ba8Ga16Ge30 they are located on the center. The results show thatthe guest mode is more Einstein-like in asample where the atomic splitting is larger.

Fig. 1. Phonon dispersion curves of transverse
phonon modes with propagation vector [100] in
Ba8Ga16Ge30.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 45－ 28 －

JAEA-Review 2008-067

1-1-5

Neutron scattering study of phonon dynamics on La3Pd20Ge6
C. H. Lee(A), H. Yoshizawa(B), I. Hase(A), T. Watanabe(C), Y. Nemoto(C), T. Goto(C)(A) AIST, (B) ISSP, (C) Niigata Univ.
Large vibration of an atom in an oversized atomic cage, so called rattling, has attracted a great interest since it can be theorigin of some exotic physical properties.
For example, the rattling can be responsible for an extremely low thermal conductivity. Electronic properties could also beaffected via electron-phonon coupling. In
beta-pyrochlore compound KOs2O6, it has
been proposed that rattling may assist theappearance of superconductivity [1]. Clarifying the nature of the rattling motion is
now a very important issue.
La3Pd20Ge6 is one of compounds thathas large Ge and Pd atomic cages ﬁlledwith La guest atoms. Ultrasonic measurements show that the elastic constant C44
of La3Pd20Ge6 exibits a Debye-type dispersion of around T=20K [2]. It is proposed that the phenomenon is originatedfrom rattling motion of La atoms. However
the relationship between the rattling and
Debye-type dispersion is still controversial.
In the present work, we study phonon dynamics of La3Pd20Ge6 and try to understand the reason of the Debye-type dispersion as well as the nature of the rattling.
Neutron scattering measurements werecarried out using the triple-axis spectrometer, TOPAN and GPTAS, at the JRR-3M
reactor of JAEA at Tokai. The ﬁnal neutron energy was ﬁxed at Ef = 14.8 meVusing a pyrolytic graphite monochromator and an analyzer. The sequences of
the horizontal collimators were 40’-40’-S40’-40’ or 40’-60’-S-60’-60’, where S denotes
the sample position. Total sample vomule
of La3Pd20Ge6 single crystals used for themeasurements was about 1.3cc.
Figure 1 shows typical phonon spectraof La3Pd20Ge6 at Q=(8.4,0,0). Peaks at E
= 3 and 6 meV correspond to an opticalmode where La guest atoms on 4c sites vibrate largely and an acoustic mode. Com-

parable intensity is due to mixture of bothphonon modes. Phonon peaks above E =8 meV correspond to optical modes wherelattice cages vibrate mainly. As other cagecompounds, clear anti-crossing behaviour
is also observed in La3Pd20Ge6. Analysis
in details is now in progress.
[1] S. Yonezawa et al., J. Phys.: Condens.
Matter 16 (2004) L9[2] T. Goto et al., Phys. Rev. B 70 (2004)
184126

Fig. 1. Energy spectra of longitudinal acoustic andoptical phonon peaks with propagation vector [100]in La3Pd20Ge6. The solid lines are the results ofGaussian ﬁts.

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Modulated structure of ion-exchanged Ca0.4 CoO2
Y. Miyazaki, D. Igarashi, Y. Hasegawa and T. Kajitani
Department of Applied Physics, Tohoku University
We have prepared a single-layered cobalt
oxide Cax CoO2 through the solid-state ionexchange method to interrogate the structural difference with the Na-analogue. The
ion-exchange was performed by mixing theNa0.7 CoO2 phase and Ca(NO3 )2 ·4H2 O andﬁred the mixture at 310 ◦ C for 48 h.
Neutron powder diffraction patterns
were collected at several temperaturesfrom 296 K down to 17 K using HERMES
diffractmeter. The crystal structure wasdetermined using the Rietveld reﬁnement
program PREMOS [1]. We assumed the superspace group of Cmcm( p10)000 and assigned the [CoO2 ] part as subsystem 1 and[Ca] part as subsystem 2. The p parameter is deﬁned as p = aCoO2 /aCa = a1 /a2 .
The compound consists of two orthorhombic subsystems of [Ca] and [CoO2 ] with b= 4.8798(9) Å c = 10.8946(10) Å and two aaxes of a1 = 2.8208(5) Å and a2 = 7.2552(5)Å at 296 K, yielding an irrational p value of
p = x = 0.389(1). The ﬁnal R-factor was RWP= 0.082.
On the basis of the adopted superspacegroup, the modulated structure has beensatisfactorily revealed, by considering up
to second order modulation amplitudes.
The zig-zag arrangement of the Ca ionsis realised perpendicular to the b-axis andthe zig-zag chains stack in an anti-parallelmanner along the c-axis. A markedly distorted arrangement of the Co ions in the
CdI2 -type CoO2 layer is also revealed. Fig.
1 shows the temperature evolution of the
Co-O bond distances plotted against internal coordinate t� . In the present compound,t’ is deﬁned as -px1 + x4 ∼ -0.389x2 + x4 .
The coordinates x1 and x4 respectively correspond to the x coordinate in the subsystems 1 and 2. Although, overall shape does
not change very much for all the temperatures, the Co-O distances signiﬁcantly varyfrom 1.7 to 2.0 Å which would relate to

the highly electrical insulating behaviour,even at room temperature, relative to theSr-analogue which exhibits metallic behavior down to 10 K. On the basis of the CoO distances, we evaluated the bond valence sum on the Co ions and we observed
a one-dimensionally (1D) charge-separated
stripe pattern perpendicular to the zigzag
arrangement of Ca ions. The 1D pattern
is somewhat similar to that observed in
Na0.5 CoO2 , but the charge is not fully separated to Co3+ and Co4+ . In addition, thenominal valence state of Co is around +3.5
at the positions where the zigzag chains of
Ca are not connected.
References [1] A. Yamamoto: Acta Crystallogr. A 49 (1993) 831.

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In-situ observation of the tetragonal-cubic phase transition in the CeZrO4 solid
solution
Takahiro Wakita, Masatomo Yashima, Yoshiaki Ando, Takayuki Tuji, Qi Xu, Toshikazu
Ueda, Yoichi Kawaike and Roushown Ali*
Department of Materials Science and Engineering, Interdisciplinary Graduate School of Scienceand Engineering, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama,226-8502; * National Institute for Materials Science, Sengen 1-2-1, Tsukuba, 305-0047
Yashima et al. [1,2] investigated the temperature and compositional dependenceof the axial ratio in the CeZrO4 solid
solution by ex-situ x-ray, synchrotron xray and neutron diffraction measurementsof quenched samples at room temperature. They reported the existence of threemetastable tetragonal forms of t, t’ andt”. The three tetragonal forms belong to
the P42/nmc space group. However, as
no high-temperature in-situ studies of thecrystal structure or cubic?tetragonal phasetransition have been conducted for the
CeZrO4 solid solution, the temperature dependence of the oxygen displacement andatomic displacement parameters remains
an unresolved issue. In this study, we investigated the temperature dependence ofthe crystal structure of the CeZrO4 solid
solution through in-situ neutron diffraction
measurements at high temperatures.
A CeZrO4 solid solution was preparedby co-precipitation method. The Ce(NO3)3and ZrO(NO3)2 aqueous solutions wereprepared, which contained 20 mass% CeO2
and 25 mass% ZrO2, respectively. Each solution was mixed with ion-exchanged water so that 1 mass% of CeZrO4 is contained. The mixed solution was put into a
5 mass% ammonia aqueous solution. Hydroxides precipitated at this stage. After
sucking ﬁltration and washing of the resultant precipitates, the precipitate was calcined at 800 oC for 3 h. The CeZrO4 powders thus obtained were pressed into pellets, and they were sintered at 1700 oC
for 5 h, and then they were annealed at
800 oC for 24 h. The cylindrical product of
19mm in diameter and of 76 mm in height
was obtained after the sintering. Neutron

diffraction measurements were performed
in air with a 150-detector system, HERMES, installed at the JRR-3M reactor inJapan Atomic Energy Agency, Tokai, Japan.
wereNeutrons with wavelength 1.8143
obtained by the (311) reﬂection of a Ge
monochromator. Diffraction data were collected in the 2? range from 5? to 150? inthe step interval of 0.1?, from 296 K to 1829
K. A furnace with MoSi2 heaters [3] wasplaced on the sample table, and used forneutron diffraction measurements at hightemperatures. Sample temperatures were
kept constant within ?1?C during each datacollection. The diffraction data were analyzed by the Rietveld method with a computer program RIETAN-2000 [4].
Rietveld analysis of the CeZrO4 solid solution was carried out by the tetragonal
structure with the P42/nmc space group at
296-1543 K. Data at 1829 K were analyzed
assuming the cubic ﬂuorite-type structurewith space group. The calculated proﬁle isin good agreement with the observed data
(Fig. 1).
The unit-cell parameters a t and ct of the
CeZrO4 solid solution increased with temperature, coinciding between 1523 K and1829 K due to the t -c transformation.
The axial ratio of the metastable t -CeZrO4
decreased from 1293 K to 1523 K. The axial ratio became unity between 1523 K and1829 K, corresponding to the t -c phasetransition. The oxygen displacement d(O)from the regular 8c position of the cubic
ﬂuorite-type structure can be estimated by
the equation d(O) = c[0.25 ? z(O)]. Thed(O) value of CeZrO4 decreased to 0.0
between 1523 K and 1829 K, corresponding to the t -c phase transition (Fig. 2).

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The isotropic atomic displacement parameters of Ce and Zr atoms B(Ce,Zr) and oxygen atoms B(O) increased with temperature (Fig. 3). B(O) was larger than B(Ce,Zr),suggesting the higher diffusivity of oxygenions (Fig. 3).
In the present study we have conﬁrmedthat the CeZrO4 solid solution transforms
from the tetragonal t form to the cubic
phase between 1543 K and 1829 K. The cto-t phase transition of CeZrO4 is accompanied by oxygen displacement along the caxis and the increase of the c/aF axial ratio
from unity.
References[1] M. Yashima et al., J. Am. Ceram. Soc. 76(1993) 2865-2868.
[2] M. Yashima et al., Appl. Phys. Lett. 72(1998) 182-184.
[3] M. Yashima, J. Am. Ceram. Soc. 85(2002) 2925-2930.
[4] F. Izumi and T. Ikeda, Mater. Sci. Forum.
321-324 (2000) 198-203.

Fig. 1. Rietveld pattern (1829 K) (a), temperature dependence of oxygen displacement (b) and thermal
parameters (c) of CeZrO4.

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1-1-8

Crystal structure and the structural disorder of ceria
M. Yashima (A), S. Kobayashi (A), T. Yasui (B)(A)Department of Materials Science and Engineering, Interdisciplinary Graduate School of
Science and Engineering, Tokyo Institute of Technology, (B)Daiichi Kigenso Kagaku Kogyo
Ceria (cerium dioxide, CeO2)-based compounds are attractive materials for potential use as electrolytes in solid oxide
fuel cells (SOFCs) and gas sensors, because the materials have a higher oxideion (O2-) conductivity than that of stabilized zirconia and a lower cost comparing with lanthanum gallate-based phases.
Other promising applications of ceriabased materials include the SOFCs anodematerials, solid-electrolyte oxygen pumps,
and mixed-conducting membranes for oxygen separation and partial oxidation of hydrocarbons. The ceria-based materials arewidely used as automotive catalysts. The
development of the ceria-based materials
requires a better understanding of the conduction mechanism, and crucial to this is
the knowledge of the structural disorderof mobile ions at high temperatures where
the materials work efﬁciently. The crystal
structure of the CeO2 at high temperatures
has been investigated by some researchers.
In the present work [1-3], we have reanalyzed the structure with a split-atom model
leading to a better ﬁt, because the oxideions have an anisotropic thermal motion as
described below.
Neutron powder diffraction experiments
were carried out in air in the temperature
range from 40o to 1497oC. Neutron powder
diffraction measurements were conductedin air with a 150-detector system, HERMES,
installed at the JRR-3M reactor in Japan
Atomic Energy Research Institute, Tokai,
Japan. Neutrons with wavelength 1.8207
were obtained by the (311) reﬂection of a
Ge monochromator. The experimental data
were analyzed by a combination techniqueof Rietveld analysis, the maximum-entropy
method (MEM), and the MEM-based pattern ﬁtting.
Rietveld analysis was carried out assum-

ing two structural models with the Fm3m symmetry. One was the ideal ﬂuoritetype structured model where the Ce andO atoms were put at 4a 0,0,0 and at 8c
1/4,1/4,1/4, respectively. The other was a
split-atom model where the O atoms were
distributed at the 8c 1/4,1/4,1/4 and at
the 32f x,x,x positions (x=1/4+delta). The
isotropic atomic displacement parameters
were used for all the atoms. The Rietveld
analysis with the split-atom model yieldeda better ﬁt than that with the ideal ﬂuorite
model. The unit-cell parameter increased
with an increase of temperature. The positional parameter x of oxide ion at the 32f
site x(O2) varied little with temperature.
With increasing of temperature the occupancy of oxide ion at the 32f site g(O2) did
not change much between 40o and 703oC,
while the g(O2) increased above 703oC.
The increase of g(O2) indicates an increaseof the disorder of oxide ions at the 8c and
32f sites. Both the isotropic atomic displacement parameters for the Ce atom B(Ce) andfor the O atom B(O) also increased withtemperature. At higher temperatures the
B(O) was larger than the B(Ce), suggestinga larger diffusion coefﬁcient of oxide ions.
MEM analysis was carried out using thestructure factors obtained in the Rietveld
analysis with the split-atom model. Number of structure factors derived in the analysis was 11. The present results reveal thatthe oxide ions in the CeO2 have a complicated disorder and spread over a wide area,
comparing with Ce ions. The spatial distribution of oxide ions is larger at higher
temperatures (Figs. 4 and 5), corresponding to the larger displacement parameters
and larger occupancy g(O2). Bulges in the
1/4-delta, 1/4-delta, 1/4+-delta directions(delta >0) are clearly seen in Figs. 4 and
5, indicating anisotropic thermal motions

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JAEA-Review 2008-067

around an ideal 8c position. The directionof bulges of oxide ions is opposite side of
the Ce ion and the oxide ions shift to theposition of the cavity at 1/2,1/2,1/2 position. The bulges are attributable to therepulsion between the Ce and oxide ions.
Other small bulges in the 1/4-delta, 1/4delta, 1/4+-delta directions (delta >0) canbe seen at the lower density level, whichmight be due to the experimental error. The
bulges in the 11/4-delta, 1/4-delta, 1/4+delta directions indicate a possible diffusion mechanism where the oxide ions movethrough a face of the surrounding Ce tetrahedron to the octahedral cavity and thenre-entering a neighboring anion site).
References[1]Masatomo Yashima, Daiju Ishimura,Yasuo Yamaguchi, Kenji Ohoyama, Katsuhiro Kawachi, ”High-temperature neutron powder diffraction study of cerium
dioxide CeO2 up to 1770 K ”, Chemical
Physics Letters, 372 [5-6] 784-787 (2003).
[2] M. Yashima and S. Kobayashi, Positional Disorder of Oxygen Ions in Ceria at
High Temperatures , Appl. Phys. Lett., 84[4] 526-528 (2004).
[3] M. Yashima, S. Kobayashi and T. Yasui,
Crystal structure and the structural disorder of ceria from 40 to 1497oC , Solid State
Ionics, 177 [3-4] 211-215 (2006).

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1-1-9

Diﬀusion path of oxide ions in the yttria-doped ceria
M. Yashima (A), S. Kobayashi (A), T. Yasui (B)(A) Department of Materials Science and Engineering, Interdisciplinary Graduate School of
Science and Engineering, Tokyo Institute of Technology, Nagatsuta-cho 4259-J2-61, Midori-ku,
Yokohama-shi, 226-8502, Japan; (B) Daiichi Kigenso Kagaku Kogyo Company,
Hirabayashi-Minami 1-6-38, Suminoe-ku, Osaka-shi, 559-0025, Japan.
Abstract
Scattering amplitude distributionof an yttria-doped ceria material(Ce0.93Y0.07O1.96, space group: Fm3m) has been investigated between 23 oC
and 1434 oC by the maximum-entropy
method (MEM) combined with the Rietveld analysis using neutron powder
diffraction data. The reﬁned unit-cell andatomic displacement parameters increased
with an increase of temperature. The
results of the MEM analysis reveal thatthe oxide ions have a positional disorderspreading over a wide area. One possible
diffusion path of the oxide ions lies on
the tie line along the <100> directions.
The other pathway of the oxide ions canbe seen along the <110> directions. The
curved feature in the diffusion path would
be common in various ionic conductors.
(1) Introduction
Atomic transport in solids is one of thecentral themes in contemporary solid statescience and technology. Crystalline ionic
conductors have extensively been studied
by numerous researchers because of their
many applications in solid oxide fuel cells(SOFCs), sensors, catalysts, and batteries.
The development of better electrolyte materials requires a better understanding of
the mechanism of ionic conduction, andcrucial to this is a comprehensive knowledge of the crystal structure. Therefore,
many researchers have studied the crystal structure and diffusion path of theionic conductors. It is well known thatthe ionic conductor has a positional disordering for the mobile ions. To describe
the spatial distribution and disorder ofthe mobile ions, various techniques suchas the split-atom model, the anharmonic
thermal motions, the probability density
function, the Fourier synthesis have been
applied. Recently the maximum-entropy
method has been developed for the determination of accurate structural features
through the electron and nuclear density
distribution in the crystalline materials. In
the present work we focus on an oxideion conductor, yttria-doped ceria solid solution, Ce0.93Y0.07O1.96 [1].
(2) Experiments
A
ceria-yttria
solid
solution
Ce0.93Y0.07O1.96 sample was preparedfrom a precursor carbonate including Ceand Y atoms. The precursor carbonate
was calcined at 1200 oC and then crushed
and ground by a ball-milling technique.
The Ce0.93Y0.07O1.96 powders thus obtained were pressed into pellets, and thensintered at 1500 oC for 3 h in air. The
sintered product was cylindrical with thesize of 19 mm in diameter and 30 mm inheight. These pellets were used for thehigh-temperature neutron diffraction measurements. Neutron powder diffraction
experiments were carried out in air in thetemperature range from 23 oC to 1434 oCNeutron powder diffraction measurements
were conducted in air with a 150-detector
system, HERMES, installed at the JRR-3M
reactor in Japan Atomic Energy Agency,
Tokai, Japan. Neutrons with wavelength
were used. The neutron diffrac1.82035
tion data were analyzed by a combination
technique of the Rietveld analysis and the
maximum-entropy method (MEM).
(3) Results and discussion
All the reﬂections in the neutron powder

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diffraction patterns of Ce0.93Y0.07O1.96 in
the whole temperature range of 23 oC to1434 oC were indexed by a single phasewith the cubic ﬂuorite-type structure. Rietveld analysis was carried out assuming
the ﬂuorite-type structure with the symmetry where the cation (Ce4+ and Y3+)
and anions (O2- and its vacancy) were put
at 4a 0,0,0 and at 8c 1/4,1/4,1/4, respectively. The isotropic atomic displacement
parameters were used for all the atoms.
The calculated proﬁle agreed well withthe observed data. The reﬁned crystallographic parameters and the reliability factors in the Rietveld analyses are shown in
Table 1. The unit-cell parameter increased
with an increase of temperature. Both theisotropic atomic displacement parameters
for the cations B(CY) and for the anions
B(O) also increased with temperature. The
B(O) was larger than the B(CY), suggestinga larger diffusion coefﬁcient of oxide ions.
These features are consistent with the previous results in Rietveld analyses for the
non-doped and doped ceria materials.
Maximum-entropy method (MEM) analyses were carried out using the structure
factors obtained in the Rietveld analysis.
Number of structure factors derived in theanalysis was 11. In the MEM calculations
we used the 111 peak intensity at the lowest 2theta position that is the most important information for the MEM analysis. The MEM map provided much information on the positional disorder of oxide ions, comparing with the structuralmodel obtained in the Rietveld analysis.
The conventional simple models consistedof atom spheres are no longer appropriate
to describe the positional disorder of oxide ions at high temperatures. The present
results reveal that the oxide ions in theCe0.93Y0.07O1.96 have a complicated disorder and spread over a wide area, comparing with cations. The spatial distribuC was larger
tion of oxide ions at 1434
than that at 23
C, corresponding to
the larger atomic displacement parameters.
There were two types of bulges in the MEM
distribution map. The other exists along the<110> directions. These directions of oxide ions are opposite side of the Ce and Y
cations. The bulges are attributable to therepulsion between the cations and oxideions. Such anisotropic feature in the neutron scattering amplitude have been observed in the ceria materials.
Reference[1] Masatomo Yashima, Syuuhei Kobayashi
Positional disorand Tadashi Yasui,
der and diffusion path of oxide ions in
the yttria-doped ceria Ce0.93Y0.07O1.96 ,Faraday Discussions, 134, 369-376 (2007).

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1-1-10

Crystal Structure Analysis of (Ga0.93Zn0.07)(N0.90O0.10) Oxynitride
Photocatalyst
Masatomo Yashima (1), Kazuhiko Maeda (2), Kentaro Teramura (2), Tsuyoshi Takata(2), and Kazunari Domen (2)(1) Department of Materials Science and Engineering, Interdisciplinary Graduate School of
Science and Engineering, Tokyo Institute of Technology, Yokohama, 226-8502, Japan; (2)Department of Chemical System Engineering, School of Engineering, The University of Tokyo,
Tokyo, 113-8656, Japan
Abstract

Galliumzinc
oxynitride(Ga0.93Zn0.07)(N0.90O0.10) is a new
type of photocatalyst that is capable of overall water splitting undervisible light. The crystal structure ofthe(Ga0.93Zn0.07)(N0.90O0.10)
was
reﬁned by Rietveld analyses of neutron powder diffraction data. The(Ga0.93Zn0.07)(N0.90O0.10) was conﬁrmed to have a Wurtzite-type structure(space group: P63mc). The present work
demonstrates that oxygen substitutes fornitrogen in the crystal structure, and may
be responsible for the desirable opticalproperties of (Ga0.93Zn0.07)(N0.90O0.10)
as a photocatalyst for visible light-driven
overall water splitting. The neutron scattering amplitude distribution throughthe maximum-entropy method (MEM)
and MEM-based pattern ﬁtting revealed that the crystal structure of the(Ga0.93Zn0.07)(N0.90O0.10) is free ofinterstitial sites and large disorder.
(1) Introduction
Overall water splitting using a photocatalyst can supply the clean and recyclable hydrogen energy. Maeda et al. reported the gallium zinc oxynitride (Ga1xZnx)(N1-xOx) as a new type of photocatalyst. This is the ﬁrst example of photocatalyst that is capable of overall water splitting
under visible light. The (Ga1-xZnx)(N1xOx) photocatalyst was identiﬁed by x-ray
powder diffraction to be a single phasewith a wurtzite-type structure. The x-ray
diffraction peak positions changed withcomposition x in the (Ga1-xZnx)(N1-xOx),

suggesting the formation of solid solution(Ga1-xZnx)(N1-xOx). However, the position and occupancy of nitrogen and oxygen atoms have not yet been known yet,probably due to the difﬁculty in distinguishing the nitrogen atoms from oxygen
atoms through X-ray diffraction method.
On the contrary, neutron diffraction candistinguish them from each other, because
the neutron scattering length of nitrogen
atom (9.36 fm) is different from that of oxygen atom (5.803 fm).
The present work [1] reports a neutron powder diffraction study of the(Ga0.93Zn0.07)(N0.90O0.10), which was
determined in the previous study1) to be an
active composition for overall water splitting.
(2) Experiments and Data Processing
Powders of (Ga0.93Zn0.07)(N0.90O0.10)
were prepared by solid-state reaction under NH3 gas ﬂow. A mixture of Ga2O3(High Purity Chemicals, 99.9%) and ZnO(Kanto Chemicals, 99%) powders washeated under NH3 ﬂow (250 mL/min)at 1123 K for 5.4 × 104 s to afford the(Ga0.93Zn0.07)(N0.90O0.10) photocatalyst
as a yellow powder.
For neutron diffraction measurement, the(Ga0.93Zn0.07)(N0.90O0.10) powder wasplaced in a ?10 mm × 50 mm vanadium
cylinder. Neutron diffraction data were collected at 299 K using a multi-detector ﬁxedwavelength powder diffractometer (HERMES) of the Institute of Materials Research,
Tohoku University, which is installed at the
JRR-3M research reactor of the Tokai Research Laboratories, Japan Atomic Energy

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JAEA-Review 2008-067

Agency. A neutron beam with wavelengthof 0.18207 nm was obtained using the (331)plane of a germanium monochromator.
The crystal structure of the(Ga0.93Zn0.07)(N0.90O0.10)
powder
was reﬁned by Rietveld analysis of theneutron diffraction data using the computer program RIETAN-2000 with neutron
scattering lengths of Ga, 7.288; Zn, 5.60;
N, 9.36; and O, 5.803 fm. Scattering amplitude distributions were obtained by amaximum-entropy method (MEM) for the
structure factors obtained in the Rietveld
analysis.
(3) Results and Discussion
The (Ga0.93Zn0.07)(N0.90O0.10) photocatalyst was conﬁrmed to achieve
overall water splitting to H2 and O2
under irradiation with visible light.
Chemical analysis indicated the average composition of the powder to be
Ga0.933(1)Zn0.0670(3)N0.896(1)O0.104(0)where the values in parenthesis are standard errors. Neutron diffraction data
for the (Ga0.93Zn0.07)(N0.90O0.10) weresuccessfully analyzed assuming a single
hexagonal wurtzite-type phase with spacegroup P63mc. In a preliminary analysis,
we reﬁned the occupancy factors of Ga
atom g(Ga) and Zn atom g(Zn) with aconstraint g(Ga)+g(Zn)=1. The reﬁned
g(Ga) and g(Zn) agreed with those obtained in the chemical analysis. In anotheranalysis, we reﬁned the z coordinate of
Ga atom z(Ga) and z(Zn) independently.
The reﬁned z(Ga) agreed with the reﬁnedz(Zn). Therefore, we ﬁxed the occupancy
factors: g(Ga)=0.933 and g(Zn)=0.067,
and used a constraint: z(Ga)=z(Zn) in
the ﬁnal analysis. The reﬁned unit cellparameters were a = 0.31900(2) and c =0.51835(2) nm, and the reﬁned fractional
coordinate z for the (Ga,Zn) cation in(Ga0.93Zn0.07)(N0.90O0.10)(0.3782(2))
is in good agreement with that in GaN(0.377(1)). The (Ga,Zn) cation is coordinated with four anions (N,O) to form a(Ga,Zn)(N,O)4 tetrahedron. The interatomic distance between the cation andanions is in the range of 0.19473?0.1960
nm. The estimated quadratic elongation
and angle variance6) are 1.000 and 0.35
(deg2), respectively, indicating that the(Ga,Zn)(N,O)4 tetrahedron is regular.
The reﬁned occupancies of N and O atoms
determined by Rietveld analysis are g(N)= 0.89(2) and g(O) = 0.11(2), where theconstraint g(N) + g(O) = 1.000 was assumed. The corresponding chemical formula Ga0.93Zn0.07N0.89(2)O0.11(2) agrees
well with that determined by chemical
analysis (Ga0.93Zn0.07)(N0.90O0.10), indicating that oxygen substitutes for nitrogen in this material. In the previous study,
the variation of the x-ray powder diffraction proﬁle and diffuse reﬂectance spectrawith x in (Ga1-xZnx)(N1-xOx) suggested
this substitution. The present results thus
provide direct evidence of the substitutionof oxygen for nitrogen in this structure.
The validity of the reﬁned crystal
structure and the possible disorder in(Ga0.93Zn0.07)(N0.90O0.10)
were
investigated by calculating the scattering
amplitude distribution using a maximumentropy method (MEM) and MEM-based
pattern ﬁtting (MPF). The MEM equicontour map reproduces the atomic positions
determined by the Rietveld analysis, butdoes not indicate any interstitial sites.
This result conﬁrms the validity of thereﬁned crystal structure. The MEM density
map also indicates that the structure is
free of large positional disorder. Since all
the atoms are localized near the stable
position and do not exhibit large positional
disorder, the reliability factors in the MPF
analysis are nearly equaled to those in the
Rietveld analysis.
Reference[1] M. Yashima, K. Maeda, K. Teramura, T.
Takata and K. Domen, ”Crystal Structure
Analysis of (Ga0.93Zn0.07)(N0.90O0.10)
Oxynitride Photocatalyst”, Mater Trans., 47[2] 295-297 (2006).

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1-1-11

Phonons in NaNbO3
I. Tomeno, Y. Tsunoda,(1) M. Nishi,(2) and K. Oka (3)Faculty of Education and Human Studies, Akita University, (1)School of Science andEngineering, Waseda University, (2) ISSP, The University of Tokyo, (3)Nanoelectrics
Research Institute, AIST
dra becomes unstable. The zone-boundary
phonon softening roughly explains resultsfor diffuse X-ray scattering in the cubic
phase.[3-4] Further experiments are necessary to investigate the lattice dynamics of
cubic NaNbO3.
References[1] C. N. W. Darlington and K. S. Knight,
Physica B266 (1999) 368.
[2] W. Zhong and D. Vanderbilt, Phys. Rev.
Lett. 74 (1995) 2587.
[3] F. Denoyer, R. Comes and M. Lambert,
Solid State Commun.8 (1970) 1979.
[4] F. Denoyer et al., Solid State Commun.18 (1976) 441.
[5] F. Gervais et al., Solid State Commun.41(1982) 345.
NaNbO3 T = 933 K

25

20

15
E (meV)

Sodium niobate NaNbO3 has a simple cubic perovskite structure above 913
K. NaNbO3 shows a complicated sequenceof phase transitions as a function of temperature.[1] First, the cubic to a tetragonal phase transition takes place at 913K.
Next, three distinct orthorhombic phases
are found in the intermediate range between 643 and 848K. Then an antiferroelectric monoclinic phase exists in the range
between 193 and 643 K. Below 193 K,
NaNbO3 has a ferroelectric orthorhombic
structure. First-principles calculations havepredicted the coexistence of zone-centerand zone-boundary instabilities in cubic
NaNbO3.[2]Diffuse X-ray and neutron scatteringexperiments for NaNbO3 strongly suggest
the zone-boundary phonon instability.[3-4]In addition, infrared reﬂectivity measurements show that the frequency of zonecenter TO phonon in the cubic phase decreases gradually on cooling.[5] Unfortunately, there is no data for the phonon dispersion relations. Here we report preliminary results for cubic NaNbO3.
Inelastic neutron scattering measurements were performed using the triple-axis
spectrometer T-11 (HQR) at JRR-3M. Figure 1 shows the TA phonon dispersion relation along the [111] direction determinedat 933 K. The essential feature is the R-point
softening in the cubic phase. The measurements up to 1223 K indicate that the frequency of the R-point TA phonons in cubic
NaNbO3 increases gradually with increasing temperature. In addition, we found out
the M-point softening of the TA phonons
along the [110] direction with the polarization parallel to the [1 -1 0] direction. The
softening at the R and the M points suggests that the rotation of the oxygen octahe-

10

5

0
0.0

0.1

0.4

0.5

Γ

Reduced wave vector [ ξ ξ ξ ]

R

0.2

0.3

Fig. 1.
Phonon dispersion relations for cubic
NaNbO3 along the [111] direction.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-1-12

Phonon dipsersion relations in PbTiO3
I. Tomeno, Y. Tsunoda,(1) M. Nishi,(2) Y. Ishii,(3) and K. Oka(4)Faculty of Education and Human Studies, Akita University, (1)School of Science andEngineering, Waseda Unisersity, (2) ISSP, The University of Tokyo, (3) Neutron Science
Research Center, JAEA, (4) Nanoelectrics Research Institute, AIST
rane, Phys. Lett. 84 (2000) 5216.
[3] I. Tomeno, S. Shimanuki, Y. Tsunoda,
and Y. Ishii, J. Phys. Soc. Jpn.70 (2001) 1444.
[4] I. Tomeno, Y. Ishii, Y. Tsunoda, and K.
Oka Phys.Rev.B73 (2006) 064116.
T= 520C

PbTiO3

Counts/10min200
E= - 6meV
150
100
50

Counts/10min

0
250
200

E= - 4meV

150
100
50

Counts/5min

0150
E= - 3meV
100

50

0
150
E= - 2meVCounts/3min

Lead titanate PbTiO3 undergoes onlya single ﬁrst-order transition at Tc=490
C from a cubic paraelectric to a tetragonal ferroelectric phase. PbTiO3 is also
the end member of relaxor ferroelectrics(1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZNPT) and (1-x)Pb(Mg1/3Nb2/3)-xPbTiO3(PMN-PT). In the 1970s, Shirane et al.
[1] have reported the phonon dispersion
relation along the [100] direction in cubic
PbTiO3. They revealed the existence of thewell-deﬁned soft mode. Recently, phonon
dispersion relations have been studied
extensively for relaxor ferroelectrics. [2-3]We have studied the lattice dynamics oftetragonal PbTiO3. [4] Here we report on
the phonons in the cubic phase.
The inelastic neutron scattering measurements were performed on the triple-axis
spectrometer T-11 (HQR) at JRR-3M. Figure 1 plots typical constant-E scans acrossthe TO branches along the [1 1 0] direction. The zone-center TO phonon energy
is found to be approximately 4meV at 520
C. The present data is roughly consistent
with the value reported by Shirane. [1] The
TO phonon curve along the [100] direction up to q=0.1 is almost the same as the
TO phonon curve along the [110] direction. This suggests the isotropic nature of
TO phonon dispersion relations around thezone center. Results for TA phonons along
the [100] and the [110] directions also suggest the isotropic nature. Further experiments are necessary to determine the latticedynamics of cubic PbTiO3.

100

50

0
1.8

1.9

2.0

2.1

2.2

Reduced wave vector [ 2−ζ, 2+ζ, 0 ]Fig. 1. Constant-E scans for cubic PbTiO3 measured
at 520 C.

References[1] G. Shirane, J. D. Axe, J. Harada, and J. P.
Remeika, Phys. Rev.B2 (1970) 155.
[2] P. M. Gehring, S.-E. Park, and G. ShiActivity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-1-13

Low temperature neutron diﬀraction studu of (La0.8Sr0.2)ScO3-δ perovskite
K. Nomura (A), H. Kageyama (A), K. Kakinuma (B), M. Yashima (C)(A) AIST, (B) Kanagawa University, (C) Tokyo Institute of Technology

Recently, strontium doped LaScO3-based
perovskites, (La1-xSrx)ScO3-δ have been
investigated as the electrolyte materials ofhydrogen sensors, etc., because of the relatively high proton conductivity and highchemical stability against CO2. Of these,x = 0.2 compound, (La0.8Sr0.2)ScO3-δ
(LSS82) shows the highest proton conductivity of 6 × 10-3 S/cm at 873K [1]. However, the detailed crystal structure and theproton conduction mechanism of this compound are not clear. In this study, we measured the low-temperature neutron diffraction data of LSS82 between 3 and 297K, andinvestigated the crystal structure and thesite occupation of proton.
High purity LSS82 powder was prepared by a solid-state reaction method.
Obtained LSS82 powder was hold in anelectric furnace at 923K for 30 hrs under wet 21%O2-79%Ar gas ﬂow condition. The absorbed H2O content was evaluated by using a TG-MASS analyzer, andthe ﬁnal chemical composition was determined as (La0.8Sr0.2)ScO2.9885H0.177(LSS82-H2O). The LSS82-H2O powder
packed in a vanadium cell was set in a He
gas circulating refrigerator (4K-cryo). Neutron diffraction measurements were performed with HERMES installed at JRR-3M
in JAEA (Tokai) [2]. Neutron wavelength
was 1.81963(4)A. Diffraction data were collected in the 2 θ range from 20 to 153 degin the step interval of 0.1 deg, between 3
and 297K. The diffraction data obtained
were analyzed by using a computer program RIETAN-2000 [3] and a maximumentropy method (MEM)-based pattern ﬁtting. MEM calculation was carried out using a computer program PRIMA [4].
All the reﬂections of LSS82-H2O between
3 and 297K were indexed by an orthorhombic symmetry (Pnma). Figure 1 shows
the crystal structure of LSS82 at 3K andthe speculated six hydrogen positions. Of
these, the most plausible sites were H3 andH6 positions.
References[1] K. Nomura et al., Solid State Ionics, 175,553 (2004).
[2] K. Ohoyama, T. Kanouchi, K. Nemoto,
M. Ohashi, T. Kajitani, and Y. Yamaguchi,
Jpn. J. Appl. Phys., 37, 3319 (1998).
[3] F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324, 198 (2000).
[4] F. Izumi and R.A. Dilanian, in: Recent
Research Developments in Physics, vol.3,
Transworld Research Network, Trivandrum, 2002, p.699.

Fig. 1. The crystal structure of LSS82 at 3K and thespeculated hydrogen sites. The most plausible positions: H3 and H6.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 59－ 41 －

JAEA-Review 2008-067

1-1-14

Low temperature neutron diﬀraction study of Ba(Zr0.8Y0.2)O3-δ perovskite
K. Nomura (A), H. Kageyama (A), K. Kakinuma (B), M. Yashima (C)(A) AIST, (B) Kanagawa University, (C) Tokyo Institute of Technology

Since the discovery of proton conductionin acceptor-doped BaZrO3 by Iwahara etal. [1], BaZrO3-based perovskites, such as
Ba(Zr1-xYx)O3-δ (0<=x<=0.3), have been
attracting attention, because they have highproton conductivity and chemical stability. However, the detailed crystal structures of these compounds are not yet
clear. In this study, we measured the lowtemperature neutron diffraction data ofBa(Zr0.8Y0.2)O3-δ (BZY82) between 3 and299K, and investigated the crystal structure.
High purity BZY82 powder was prepared by a solid-state reaction method. The
BZY82 powder obtained was hold in anelectric furnace at 773K for 20 hrs underwet 21%O2-79%Ar gas ﬂow condition. The
BZY82 powder packed in a vanadium cell
was set in a He gas circulating refrigerator(4K-cryo). Neutron diffraction measurements were performed with HERMES installed at JRR-3M in JAEA (Tokai) [2]. Neutron wavelength was 1.81638(2)A. Diffraction data were collected in the 2 θ range
from 20 to 153 deg in the step interval of
0.1 deg, between 3 and 299K. The diffraction data obtained were analyzed by using
a computer program RIETAN-2000 [3].
Figure 1 shows the diffraction patternsof BZY82 at 3, 76, and 299K. Super lattice
peaks appeared at around 2 θ = 42, 56, 79,
and 111 deg, which cannot be indexed asa cubic perovskite phase (Pm-3m, NO.221).
These peaks were not observed by X-ray
diffraction measurement at 298K. All the
peaks of BZY82 could be indexed hypothesizing a trigonal perovskite phase (R-3c,
NO.167). The intensity of super lattice
peaks decreased with increasing temperature, and the peaks almost disappeared at
299K. In a previous study, the similar superlattice peaks were observed for LaGaO3based perovskite-type oxide-ion conduc-

tor, (La0.8Sr0.2)(Ga0.8Mg0.15Co0.05)O3-δ
at high temperatures above 1273K [4].
References[1] H. Iwahara, T. Yajima, T. Hibino, K.
Ozaki, and H. Suzuki, Solid State Ionics, 61,
65 (1993).
[2] K. Ohoyama, T. Kanouchi, K. Nemoto,
M. Ohashi, T. Kajitani, and Y. Yamaguchi,
Jpn. J. Appl. Phys., 37, 3319 (1998).
[3] F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324, 198 (2000).
[4] M. Yashima, K. Nomura, H. Kageyama,
Y. Miyazaki, N. Chitose, and K. Adachi,
Chemical Physics Letters, 380, 391 (2003).

Fig. 1. Neutron diffraction patterns of BZY82 at 3,76, and 299K. The arrows show the position of super lattice peak.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 60－ 42 －

JAEA-Review 2008-067

1-1-15

Martensitic transformation of Heusler-type Ni2 MnGa shape memory alloy
K. Inoue A , Y. YamaguchiB , H. HirakaB , Y. IshiiC , H. YamauchiC
A Fac. of Science and Tech., Ryukoku University, B IMR, Tohoku University, C Quantum Beam
Science Section, JAEA
Process of a thermally induced martensitic transformation of a Heusler-type offstoichiometric Ni2 MnGa single crystal wasinvestigated. A triple-axis neutron spectrometer, AKANE, was used. The composition of the alloy was Ni2.16 Mn0.78 Ga1.06 ,having a martensitic transformation temperature around room temperature (293 K)
coincident with a Curie temperature. It isferromagnetic in the martensitic phase andparamagnetic in the mother phase and is
expected as a magnetic ﬁeld-induced shapememory alloy. Change of a cubic (020)
peak on (hk0) reciprocal-plane (h=-0.36 0.36, k=1.76 - 2.36), where the cubic structure is in the mother phase, was observedwith decreasing temperature from 293 K
to 100 K. The result was compared withmagnetic ﬁeld dependence of the patternmeasured by TAS-2, where the ﬁeld waschanged up to 10 T at 293 K. The diffraction
patterns projected on (hk0)-plane at typical temperatures, 279 K and 100 K, underno magnetic ﬁeld and the pattern under 10
T at 293 K are shown in Fig. 1. At 279
K peaks belonging to orthorhombic structure in the martensitic phase1) , are seen.
Two peaks near k=2.1 due to orthorhombic(002), a peak at k=2.0 due to orthorhombic(020) and two peaks near k=1.9 due to orthorhombic (200) are observed. Other fourpeaks on the corner of the (hk0)-plane, theintensity of which are very weak, indicatethat there are some long period in the orthorhombic structure. The origin of thislong period is not yet analyzed. Peaks near
(0 2.3 0) and (0 1.72 0) were found to be thefoot of (0 2.3 ± 0.3) and (0 1.72 ± 0.26). At
100K the structure changed to a tetragonal
structure in the martensitic phase1) . Peaks
near k=2.12 belong to tetragonal (200) andthe peaks near k=1.78 belong to tetragonal(002). Under the magnetic ﬁeld of 10 T at

293 K, the observed orthorhombic structure
was quite similar to that at 279 K under noﬁeld. It is suggested that temperature decrease of 14 K in this alloy causes the same
effect of magnetic ﬁeld of 10 T. The magnetic ﬁeld as high as 10 T is not enough tocause the tetragonal structure, which is theequilibrium martensitic structure at low
temperature. However, these experimental
results show that magnetic ﬁeld-induced
shape memory effect becomes promising,
because we already know that the additionof small amount of boron to the alloy ormaking a foil of the alloy improve the brittleness of the material and make the transformation easier.
1) K. Inoue, Y. Yamaguchi, et. al.: Materials
Transactions 46 (2005) pp.1425-1432.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 65－ 43 －

JAEA-Review 2008-067

1-1-16

Measurement of Thickness of Thin Lubricant Film at Solid-Solid Interface by
Neutron Reﬂectometry
Tomoko Hirayama1 , Tomoki Uno1 , Kazuko Inoue2 , Seiji Tasaki3 , Masahiro Hino4 , Toru
Ebisawa5
1 Doshisha Univ., 2 Ryukoku Univ., 3 Kyoto Univ., 4 KURRI, 5 JAEA
Tribological phenomena usually occur ata solid-solid interface, where the presenceof a lubricant greatly contributes to low
friction. A lack of lubricant causes substantial wear and even seizure of two bodies under severe conditions. However, anin-situ observation is difﬁcult to perform
if some lubricant is present at a solid-solidinterface because any common rays, suchas X-rays and visible rays, cannot penetrate into metals. A neutron beam, on
the other hand, is well known to be able
to penetrate into almost all metals. Thus,
we propose to apply a neutron scattering
method to judge whether or not a lubricant is present at a metal interface. Reﬂectometry is generally recognized as a useful
method to analyze vertical structures precisely on a target surface. In this study, we
try to measure a thickness of thin lubricant
ﬁlm formed between two silicone blocks byneutron reﬂectometry. The instrument weused was ’MINE’, which is a neutron reﬂectometer, in JAEA. First, some basic samples
with periodic surface roughness were prepared; a grating thin ﬁlm made of nickel
was formed on one of the silicone blocks byphoto-lithographic technology as part of asimple roughness model. In addition, theother plane silicone block was covered on
the grating surface, resulting in our being
able to obtain an ’interface model’ with awell-deﬁned clearance between the two silicone blocks. The clearance was set at about
100, 50, and 10 nm and was ﬁlled by air or
two kinds of lubricants: water or base oil.
As a result, we obtained different reﬂectivity proﬁles depending on each medium at
the interface. In addition, the thickness of
the lubricant ﬁlm could be estimated by intervals of the interference fringes of the reﬂectivity proﬁles. We conclude that neu-tron reﬂectometry is a useful method to estimate lubricants quantitatively, even at a
metal interface.

Fig. 1. Reﬂectivity proﬁle of lubricant ﬁlm at interface of two silicone blocks

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 90－ 44 －

JAEA-Review 2008-067

1-1-17

Phase Transition and Debye-Waller Factor of KDP
H. Mashiyama, T. Asahi, H. Kasano and T. Miyoshi
Faculty of Science, Yamaguchi University
The mechanism of the phase transition
in KDP (KH 2PO 4) has been interested
widely. The isotope effect could be explained by the famous proton tunnelingmodel[1] for long years. But the replacing
proton by deuteron changes atomic distance, which could also present the characteristic isotope effect.[2]With using neutron diffractometry, detailed structural studies were performed
in a quarter century ago, and the orderdisorder picture of proton distribution was
revealed.[3] However, the analysis was limited above 127K, so the temperature range
should be expanded to discuss the proton
motion deﬁnitely.
A single crystal of KDP was set ina cryostat mounted on a diffractometer(FONDER) installed at JRR3M reactor in
JARERI, Tokai.
First sample was used in the paraelectricphase P (tetragonal I-42d). In the ferroelectric phase F (orthorhombic Fdd2), dc
bias ﬁeld was applied to make the second sample single. Diffraction data up to
2theta<156 (neutron wave length 1.2452A)
were collected at two and four temperatures in phase P and F, respectively. Absorption and extinction correction was performed by using RADIEL. Atomic parameters were reﬁned by least-squared calculations. Nuclear density was estimated by
PRIMA and visualized by VEND.[4]Figure shows the nuclear density images at 150K. The elongated ellipsoids indicate the disordered protons. In the phase
F below 122K, the proton distribution isordered and atoms move along the z-axis
with a deformation of PO 4 tetrahedrons.
The temperature dependence of the DebyeWaller factor U’s is plotted in Figure. The
split atom method is applied for protons in
the tetragonal phase, where the factor becomes smaller than the phase F. Our results

are consistent with the previous one.[3]However, since the samples were different,
the direct comparison between the phase P
and F should be reserved currently.
The values of U at T=0 indicate that nucleus have a ﬁnite width corresponding totheir wave functions. The detailed analysis will predict the local potential in which
each atom is constrained.
References[1] R. Blinc, J. Phys. Chem. Solids 13 (1960)
204. [2] M. Ichikawa et al, Phys. Rev. B 36
(1987) 874. [3] R. J. Nelmes et al, J. Phys. C
15 (1982) 59. [4] F. Iizumi, Japan J. Crsytalography. 44 (2002) 380.

Fig. 1. Nuclear density at 150K in the tetragonalphase (top) and the temperature dependence of thethermal parameters (bottom). In the bottom, theprevious results after ref. 3 are shown by brokenlines.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 96－ 45 －

JAEA-Review 2008-067

1-1-18A coupling between an acoustic phonon and the diﬀuse scattering in the relaxor
ferroelectric（1-x)Pb(Mg1/3 Nb2/3 )O3 -xPbTiO3 near morphorobic phase boundary
M. Matsuura and K. Hirota
Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106
Relaxor ferroelectrics are a class of disordered crystals showing extremely high,broad and frequency dependent peak indielectric susceptibility. It is widely believed that the polar nanoregions (PNR)
play an important role in relaxor behavior occurring at temperatures much
above Tc , the so-called Burns temperature
Td [1]. Neutron scattering measurements
by Naberezhnov et al. on the typical relaxorPb(Mg1/3 Nb2/3 )O3 (PMN) revealed the onset of strong diffuse scattering at or very
near Td [2], indicating a close connection
between the PNR and the diffuse scattering. A solid solution of PMN and ferroelectric PbTiO3 (PT) exhibits a maximum
dielectric susceptibility near PMN-30%PT,
the boundary between the rhombohedralphase and the tetragonal one, which isthe so-called morphorobic phase boundary(MPB). Last year, we investigated PMN34%PT which locates on the tetragonal sideof the MPB and reported that the Q-patternof the diffuse scattering changes from ellipsoid elongating along �110� direction in the
cubic phase to cross elongating along �100�
direction in the tetragonal phase. This year,
we report an overdamped acoustic phonon
coupled with the diffuse scattering.
Figures 1 show constant Q scan spectraat (0.944 1.056 0) and (0.92 1 0) taken at T =440 and 410 K. At T = 440 K (cubic), thediffuse scattering extends along the [11̄0]
direction; the diffuse scattering is strong at(0.944 1.056 0) but weak at (1.021 1 0). We
found the acoustic phonon at (0.944 1.056 0)
is overdamped while that at (1.021 1 0) is
underdamped, as shown in Fig.1(a) and(b). At T = 410 K (tetragonal), the overdamped phonon becomes underdamped
concomitantly with the disappearance ofthe diffuse scattering at (0.944 1.056 0). On
the other hand, at (1.021 1 0), the well-deﬁned phonon peak observed in the cubic
phase disappears presumably due to overdamping. These results indicate a coupling
between the acoustic phonon and the diffuse scattering. Similar damped acoustic
modes were observed in PMN by Stock et
al. [3] and the authors successfully simulated the phonon spectra by Michel-Naudts
model which takes into account a coupling
between a phonon mode and a relaxation
mode [4]. From their model, an acoustic
mode is overdamped and peak at E = 0
appears when a characteristic relaxationalfrequency is less than or nearly equal tophonon frequency. The current results indicate slow relaxation mode may exist along
the particular direction at which the diffuse
scattering is strong.
References[1] G. Burns and F. H. Dacol, Solid. State Commun. 48, 853 (1983).
[2] A. Naberezhnov et al. , Eur. Phys. J. B, 11,
13 (1999).
[3] C. Stock et al. , J. Phys. Soc. Japan, 74, 3002
(2005).
[4] K. H. Michel and J. Naudts, J. Chem. Phys.
68 216 (1978)

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 109－ 46 －

JAEA-Review 2008-067

1-1-19Investigation of the local crystal distortion in the relaxor ferroelectric(1-x)Pb(Mg1/3 Nb2/3 )O3 -xPbTiO3 (0.0 ≤ x ≤ 0.40) using extinction eﬀect
M. Matsuura and K. Hirota
Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106
Relaxor ferroelectrics of the form
PbBB� O3 are receiving a great deal ofscientiﬁc attention as a result of the extremely high piezoelectric response over awide temperature range. The key concept
to understand the relaxor behavior isbelieved to be the so-called polar nanoregions (PNR) at temperatures much above
Tc . However, these clusters cannot be
detected from the proﬁles of the X-ray
and neutron diffraction Bragg peaks dueto their extremely small size. In a nearly
perfect crystal, the scattering intensityof a strong Bragg peak becomes smaller
than the calculated value due to scattering
by various crystallites, which is called
secondary extinction. To elucidate theevolution of the PNR in the relaxor system,
we investigated the thermal variations of
Bragg peaks in the relaxor ferroelectric(1-x)Pb(Mg1/3 Nb2/3 )O3 -xPbTiO3 (PMNxPT; x = 0.0, 0.10, 0.20, and 0.40) which
could be associated with the thermalvariation of the local crystal distortion by
the secondary extinction effect. Neutron
scattering experiments were performedon the triple-axis spectrometers PONTA
installed at the JRR-3 Reactor of the JAEA.
Figure 1 (a) shows the temperature dependence of the integrated intensity at the(200) Bragg peak for PMN-10%PT. The
peak intensity increases sharply at T = 615
and 280 K, which could be explained bya release of the secondary extinction effectdue to the tilt of the crystal mosaics. Figure 1 (b) shows zero ﬁeld phase diagramof PMN-xPT. Open circles denote the valueof the local TC at which a structural phasetransition was observed by x-ray diffraction, but not by neutron diffraction. A bulk
structural phase transition, however, wasobserved for x ≥ 0.27, shown by closed
circles. The higher temperature of therapid increase in the (200) Bragg (Td extinction: open rectangles) corresponds to theonset of the diffuse scattering, which canbe associated with an appearance of PNR.
The lower one (Tc extinction: open triangles) matches the structural phase transition temperature, which could be associated with an ordering of PNR. Both temperatures increases with PT substitution. In
addition, the difference between these temperatures becomes small with x, which is
expected to be zero at PbTiO3 .

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 110－ 47 －

JAEA-Review 2008-067

1-1-20Damped acoustic phonon in the relaxor ferroelectric Pb(Mg1/3 Nb2/3 )O3M. Matsuura and K. Hirota
Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106
Relaxor ferroelectrics have gained greatinterest recently due to their promising application as piezoelectric devices.
Pb(Mg1/3 Nb2/3 )O3 (PMN) is a typical relaxor which shows a broad and frequency
dependent peak in dielectric susceptibility. It is widely believed that the polar
nanoregions (PNR) occurring at temperatures much above Tc , the so-called Burns
temperature Td , play an important role insuch relaxor behavior. Neutron scattering
measurements by Naberezhnov et al. on
PMN revealed the onset of strong diffuse
scattering at or very near Td ∼ 600 K [1],indicating a close connection between the
PNR and the diffuse scattering. The lattice dynamics in PMN are characterized
by a soft, zone center, transverse optic(TO) mode observed below Td . Thus, it
is expected that the local crystal distortionin PNR is driven by the soft TO. However, recently, the soft TO mode was observed in the normal ferroelectric PMN40%PT [2], which casts doubt on the softmode concept of the PNR. To elucidate thelattice dynamics in PNR, we investigated
the acoustic phonon and low energy excitations in PMN. Neutron scattering experiments were performed on the triple-axis
spectrometers HER installed at the JRR-3
Reactor of the JAEA.
Figures 1 show the constant Q spectraat (1.1 1.1 0) and (1.1 0.9 0) taken at T =650, 500, and 400 K. At T = 650 K (≥Td ), a well-underdamped transverse acoustic (TA) phonon and longitudinal one (LA)shown by dotted lines were observed at
2.67 ± 0.03 and 3.57 ± 0.15 meV, respectively. At T = 500 K, the TA mode becomes
overdamped and a resolution-limited peakat E = 0 (central peak: dotted line) develops at (1.1 0.9 0), while the LA moderemains underdamped and no enhancement of the central peak was observed at(1.1 1.1 0). The central peak corresponds
to the (110) diffuse scattering which elongates along the transverse directions. In
addition, a quasielasctic scattering (dottedand broken line) appears below T = 500 K.
The central peak and quasielastic scatteringdevelops especially at (1.1 0.9 0) with decreasing temperature. The overdamped TA
mode coupled with the strong diffuse scattering and quasielastic scattering indicatesa coupling between TA mode and PNR,
which is consitent with the uniform phaseshift concept proposed by Hirota et al. [3]On further cooling, the underdamped TA
mode recovers and the quasielastic scattering disappears below Tc ∼ 213 K at
which PMN becomes ferroelectric on electrical ﬁeld-cooling.
References[1] A. Naberezhnov et al. , Eur. Phys. J. B, 11,
13 (1999).
[2] C. Stock et al. , Phys. Rev. B, 73, 64107(2006).
[3] K. Hirota et al. , Phys. Rev. B, 65, 104105(2002).

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 112－ 48 －

JAEA-Review 2008-067

1-1-21The diﬀuse scattering in the relaxor ferroelectric compound
H. Iida1 , M. Matsuura1 , K. Hirota1 , Y. Noguchi2 , and M. Miyayama2
1 Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106
2 Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo

153-8505

direction, suggesting a close connection between the diffuse scattering and soft transverse optical mode.
References[1] J. Suchanicz and J. Kwapulinski, Ferroelectrics 165 249 (1995).
[2] G. Burns and F. H. Dacol, Solid. State Commun. 48, 853 (1983).
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Relaxor ferroelectrics have attracted considerable attention since the discovery of
giant piezoelectricity in relaxor-based single crystals. (Na0.5 Bi0.5 )TiO3 (NBT) forms
perovskite structure with two different ions
Na+ and Bi3+ at the A site of ABO3 . Temparature anomalies in dielectric properties of and two structural phase transitions
have been investigated since 60’s: the structural symmetry is lowered from cubic totetragonal phase at T = 813 K and fromtetragonal to rhombohedral phase at approximately 533 K [1]. Recently, NBT regains attention as promising applications
to piezoelectric devices containing no toxic
lead. NBT exhibits extremely high andbroad peak in the dielectric susceptibility
which is very similar to that in typical relaxors. It is widely believed that the polar nanoregions (PNR) play an importantrole in relaxor behavior occurring at temperatures much above Tc . the so-called
Burns temperature Td [2]. The purposeof the present work is to study the Qstructure and thermal variations of the diffuse scattering to clarify nature of PNR in
NBT. Neutron scattering experiments were
performed on the triple-axis spectrometers
PONTA installed at the JRR-3 Reactor of
the JAEA.
Figure 1 shows intensity contours of the
diffuse scattering near (110) and (100) measured at T = 440 K. The diffuse scattering was observed in the rhombohedralphase, which is elongated along the [100]and [010] directions transverse to the wave
vector. Such �100�-type diffuse scattering
indicates a short-ranged atomic shift withtetragonal symmetry in the matrix withrhomboheral one. In addition, the diffuse
scattering has more intensity along transverse direction than that along longitudinal

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Fig. 1. Intensity contours of the diffuse scattering
near (a) (110) and (b) (100) measure at T = 400 K.

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JAEA-Review 2008-067

1-1-22Crystal structural change of Ba-doped-tricalcium phosphate
Yoichi Kawaike (A), Masatomo Yashima (A), T. Wakita (A), T. Tsuji (A), R. Ali (B), Y.
Matsushita (B)(A) Department of Materials Science and Engineering, Interdisciplinary Graduate School of
Science and Engineering, Tokyo Institute of Technology, Yokohama, 226-8502, Japan, (B)National Institute for Materials Science
Abstract
Crystal structural change of bariumdoped-tricalcium phosphate (TCP) has
been investigated using high-temperatureneutron powder diffraction and Rietveld
method. The alpha-alpha’ phase transition
temperature decreased with an increase of
Ba composition x in Ca3(1-x)Ba3x(PO4)2.
Structural reﬁnement of Ba-doped-TCP
was successfully performed by P21/a.
Temperature dependence of unit cellparameters was determined around thealpha-alpha’ phase transition point. Unitcell parameter a discontinuously changed
at the alpha-alpha’ transition temperature,indicating that the transition is of ﬁrst
order.
(1) Introduction
Tricalcium phosphate [TCP: Ca3(PO4)2]
has increasingly been used as a biocompatible material for bone replacement or
for the coating of bone prostheses. There
are many studies to investigate doped
TCPs. Although many researches for crystal structure of doped-TCP have been reported for ?-phase, crystal structure ofalpha-type doped-TCP has been insufﬁciently understood and studied, probably
due to their complicated crystal structures.
In this study, we investigated the crystal
structural change of Ba-doped-TCP using
high-temperature powder neutron diffraction analysis.
(2) Experiments and Data Processing
High-purity alpha TCP was prepared bysolid-state reactions from beta Ca3(PO4)2and Ba3(PO4)2. Stoichiometric amounts ofhigh-purity CaHPO4 (99.6% purity, Kyowa
Chemical Industry, Takamatsu, Japan) andCaCO3 (99.99% purity, Kojundo Chemical Lab. Co., Ltd., Sakado, Japan) powders were mixed for about 3.0 h in an
agate mortar. The mixture was pressed
into pellets under a uniaxial pressure of
150 MPa. The pellets were sintered for 12
h at 1000?C to obtain single phase beta
TCP. Ba3(PO4)2 was obtained after sintering BaCO3 and NH ４ H2PO4 mixture at1000 C deg. for 12 hours. The sintered pellets of beta Ca3(PO4)2 and Ba3(PO4)2 wereground and mixed (Ca/Ba atomic ratio=95/5). And the mixtures were sintered at
1400 C deg. for 6 h. The resultant products
were used for neutron powder diffraction
study.
To investigate the temperature dependence of the crystal structure of Ba-dopedTCP, neutron powder diffraction experiments were carried out at high temperatures in air with a 150-detector system,HERMES, installed in the JRR-3M reactor
at the Japan Atomic Energy Agency, Tokai,
Japan. Neutrons with a wavelength of 0.182
nm were obtained by the (3 1 1) reﬂection ofa Ge monochromator. The diffraction data
were collected in the 2 theta range from 3
deg. to 153.9 deg. in a step interval of 0.1
deg. in the temperature range from 24 to1533 C deg. A furnace with MoSi2 heaters
was placed on the sample table, and used
for the neutron diffraction measurements
at the high temperature. The unit-cell andstructural parameters of the Ba-doped-TCP
were reﬁned by Rietveld analysis using
the RIETAN-2000 computer program. The
diffraction patterns were ﬁtted with a Pearson VII type function.
(3) Results and Discussion
Figure 1 shows the temperature depen-

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JAEA-Review 2008-067

dence of the neutron diffraction pattern for
5 mol% Ba doped TCP. Closed and open
circles in Fig. 1 denote neutron diffraction peaks of high-temperature alpha and low-temperature alpha-phases, respectively. At 1449.9 C deg., the pattern exhibited both peaks of the alpha (closed circles in Fig. 1) and alpha’ (open circles inFig. 1) phases, indicating the alpha and alpha phases co-existed at this temperature. The characteristic peaks of the alphaphase (closed circles in Fig. 1) disappeared
between 1425.9 and 1474.8 C deg. Therefore, the alpha-TCP transforms into alpha’phase between 1425.9 and 1474.8 C deg.
Structural reﬁnement was successfully performed by a monoclinic structure, spacegroup P21/a. The reliability factors wereRwp = 5.32%, S = 2.05, RI = 0.40%,
RF = 0.19%. The unit-cell parameters obtained from the Rietveld analysis were a =1.2936(3), b = 2.7540(3), c = 1.5252(4)nm, alpha = beta = 90 deg., gamma = 126.66(1)deg.
We successfully determined the temperature dependence of the unit-cell parameters a for TCP around the alpha? alphaphase transition point. Thus we were able
to clearly indicate that the alpha? alphaphase transition is of ﬁrst order.

Fig. 1. Neutron powder diffraction patterns of
5mol% Ba-doped-TCP at different temperatures.
Closed and open circles denote neutron diffraction peaks of high-temperature alpha’- and lowtemperature alpha-phases, respectively.

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1-1-23Magnetic ﬂuctuation in ternary alloy CuFePt6
Miwako Takahashi1 , Ejaz Ahmed1 ,, Toetsu Shishido2 and Ken-ichi Ohshima1
1 Institute of Materials Science, University of Tsukuba, 2 Institute for Materials Research,

Tohoku University

necessary to understand the magnetic behavior in the alloy.
References[1] A. K. Das, R. Nakamura, M. Takahashi, H.
Iwasaki, T. Shishido, K. Ohshima : J. Phys.
Soc. Jpn. 75 (2006)024604.
[2] M. Takahashi, E. Ahmed, A. K. Das, Y. Fujii, H. Iwasaki and K. Ohshima : J. Alloy.
Comp. in print.

Intensity / 1000K (~5 min.)

(a)

400

0 1/2 1/2

CuFePt6
7K

300

0 11
2 meV

200

3 meV
100

5 meV
0
0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
k in 0 k k

(b)
250

0 1/2 1/2
Intensity / 1000K (~5min.)

The ternary alloy CuFePt6 is one of aseries of the newly found ternary alloys
CuMPt6 (M is 3d metal). It has a single phase at this stoichiometric composition and forms a Cu3 Au type ordered structure below the order-disorder transition
temperature 1313 K [1]. In the magnetization measurements, a transformation to
ferromagnetic order is observed at TC =210 K in the alloy with the Cu3 Au type order. Magnetic moment per one CuFePt6
molecule estimated from the value of magnetization at 5T is 4.1 µB for 5 K [2]. In the
weak magnetic ﬁled of 0.01 T, on the other
hand, magnetic susceptibility of ZFC process shows further phase transition with
anti-ferromagnetic-like cusp at TN = 100 K,
though no anomaly has been found forthat of FC process. In the pulsed-neutron
diffraction measurements, magnetic reﬂection appears at Γ point below TC , and at Mpoint below TN with keeping the intensityof Γ point reﬂection unchanged. These results indicate an existence of strong ﬂuctuation in the magnetic structure of CuFePt6 .
In order to understand the origin of themagnetic ﬂuctuation in the alloy, inelastic
scattering measurements were performed
at 5G (PONTA). Figure 1 shows inelastic scattering line proﬁles along [011] axis
passing through 0 1/2 1/2 ( M point ) and 0
1 1 (Γ point ) RLP at 7 K. The inelastic intensities spread along this axis with a strong
peak at 0 1/2 1/2 over an energy of 5 meV.
It has been found from the measurements
along [100] axis that the inelastic intensities also spread along this axis. In Fig. 2,line proﬁles for 2 meV inelastic scattering
are shown for 7 K and 145 K (above TN ).
The 0 1/2 1/2 inelastic peak persists above
TN with higher intensity, indicating that themagnetic ﬂuctuation arises from a temperature far above TN . Further investigation is200

CuFePt6
E = 2 meV

7K
145K

150

011

100
50
0
0.5

1.0
k in 0 k k

Fig. 1. (a)Inelastic scattering line proﬁles of 2, 3,
5 meV obtained at 7 K . (b)Inelastic scattering line
proﬁles of E = 2meV obtained at 7 K and 145 K.

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1-1-24Structure and phase transition in a lead-based inorganic-organic perovskites
M. Takahashi1 , K. Kawasaki1 , K. Kataoka1 , Y. Fujii1 and M. Watanabe2
1 Institute of Materials Science, University of Tsukuba,2 Institute of Multidisciplinary Research

for Advanced Materials,Tohoku University

The structure and phase transitionin the one-dimensional semiconductor
C5 H10 NH2 PbI3 has been investigatedby using neutron and x-ray single crystal diffraction methods. C5 H10 NH2 PbI3
has a lead-based inorganic-organic perovskites structure consisting of semiconducting parts which are composed of
one-dimensional chains of face-sharing
lead-iodide octahedra and barrier parts
composed of C5 H10 NH2+ molecules. It
has been shown by Raman scattering thatthe structure undergoes successive phasetransitions below the room temperature
which involves rotational/orientational
ordering of the organic C5 H10 NH2+ parts[1]. However, its precise structure has
not been determined even for the room
temperature. The aim of the present study
is to clarify the structural change and its
effects on the electronic state in the phasetransitions of C5 H10 NH2 PbI3 by combining
the data obtained by neutron and x-ray
single crystal diffraction.
The neutron data were obtained at T2-2,
FONDER at room temperature (R.T.), andanalyzed by using program SHELXL with
199 unique reﬂections. In the reﬁnement,
positional parameters for Pb and I are ﬁxed
to the values previously obtained by x-ray
structural analysis [2]. Positional information for nitrogen and hydrogen atoms
which were not taken into account in the
x-ray data analysis is obtained with R =0.09. The nitrogen atom in the C5 H10 NH2+
molecule tends to occupy C1 and C2 carbon
sites, which are closer to the lead-iodide
chain than the C3 site. The occupancies
of nitrogen atoms at C1 and C2 sites arefound to be 0.42 and 0.58, respectively. The
hydrogen atoms are found as CH2 groups
with the distances of the hydrogen bonds
being 0.8769 Å from C1, 1.0687Å from C2

and 1.1403Å from C3. Figure 1 shows the
structure of the organic C5 H10 NH2+ part at
R.T. obtained from the neutron data. In theﬁgure, C3 site obtained from the x-ray datais shown together as C3� for a comparison.
The structure of the molecule obtained by
the neutron data clearly shows a chair form
which has grater strain than that obtainedby the x-ray data. It is expected that thetwisting motion between the two identicalchair conformers is present in the moleculeand plays an important role in the phasetransitions.
References[1] A. Masui et al.: Phys. Stat. Sol. (b) 223(2001)501.
[2] G. V. Gridunova et al.: Doklady Akademii
Nauk 278 (1984)656.

Fig. 1. Structure of the organic C5 H10 NH2+ part obtained from neutron data. C3� site is positional dataobtained from x-ray data.

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JAEA-Review 2008-067

1-1-25Diﬀusion Path of Oxide Ions in a Fast-ion Conductor La0.64(Ti0.92Nb0.08)O3
with a Double Perovskite-type Structure
Roushown Ali(A,B), Masatomo Yashima(B), Fujio Izumi(A)(A) Quantum Beam Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba,
Ibaraki 305-0044; (B) Department of Materials Science and Engineering, Interdisciplinary
Graduate School of Science and Engineering, Tokyo Institute of Technology, Nagatsuta-cho
4259-J2-61, Midori-ku, Yokohama-shi, 226-8502, Japan.
Materials with high oxide-ion conductivities have received special attention inrecent years owing to the potential applications of such materials in batteries
and solid-oxide fuel cells. Information on
the diffusion path and positional disorder of mobile oxide ions at high temperatures, where the materials work most efﬁciently, is indispensable for developing better oxide-ion conductors.
The lanthanum titanate solid solution
La(2+-x)/3(Ti1-xMx)O3 (M = Al or Nb,
0.05<x<0.20) has an A-site deﬁcient double perovskite-type structure and exhibitshigh oxide-ion conductivity at high temperature. Yoshioka [1] studied the electricalproperties of La(2+-x)/3(Ti1-xNbx)O3 (x =0.05-0.15) and reported that a sample withx = 0.10 displayed the highest ionic conductivity (10-2 S cm-1 at 700 C deg.) of thesamples examined. In this study, we haveexamined the crystal structure and pathway of oxide-ion diffusion in A-site deﬁcient layered double perovskite-type oxide,
La0.64(Ti0.92Nb0.08)O3, at high temperature.
Neutron powder diffraction data forLa0.64(Ti0.92Nb0.08)O3 were collected at
496 C deg., 1008 C deg. and 1358 C deg. using powder diffractometer HERMES witha furnace [2] to heat the sample. The sample temperature was maintained within +1.5 C deg. during each measurement. Incident neutron wavelength was 0.18143 nm.
The diffraction data were analyzed by the
Rietveld method followed by applicationof MPF [3] using the computer programs
RIETAN-2000 [4]. The MEM calculations
were performed with the unit cell divided
into 64 X 64 X 128 pixels. To reduce thebias imposed on the nuclear density by
the simple structural model adopted in the
Rietveld analyses, an iterative procedure
called the REMEDY cycle was employedfollowing MEM analyses.
All reﬂections in the neutron
powderdiffraction
patternsforLa0.64(Ti0.92Nb0.08)O3 at 496 C deg.,1008 C deg., and 1358 C deg. were indexedon the basis of a tetragonal P4/mmm
cell. Reﬁnements of anisotropic atomic
displacement parameters (Uij) for cations
resulted in no signiﬁcant improvement in
the reliability (R) factors. Therefore, Uij
were reﬁned only for oxygen sites in subsequent Rietveld reﬁnements. The oxygen
atoms located at 4i site displayed large
anisotropy in the atomic displacement
parameters, suggesting a directionality inthe movements of oxide ions around thestable positions.
At 496 C deg., the O3 atoms are localized near the stable 4i site (1/2, 0.0,
0.234). The O3 atoms display small bulges
in the [101] direction which become larger
at 1008 C deg. and 1358 C deg. The probability density of an O3 atom is connectedwith that of nearest-neighbor O3 atoms,
indicating diffusion along a pathway following the [100] and [010] directions. The
O3 atoms migrate to the nearest-neighbor4i site through a triangle formed by adjacent La1, La2, and (Ti,Nb) atoms. At theintermediate points, the densities of thecoherent-scattering lengths of oxide ions (4isite) are 0.13 fm ?ˆ(-3) at 1358 C deg., 0.10
fm ?ˆ(-3) at 1008 C deg., and 0.03 fm ?ˆ(3) at 496 C deg. Such an increase in the density of oxide ions with increasing temperature is consistent with the higher conduc-

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JAEA-Review 2008-067

tivity at higher temperatures.
The O3 atom migrates following a curvedroute so as maintain a relatively constantdistance from (Ti,Nb) atoms rather than adirect linear path. Yashima et al. [5] in theirstudy of the nuclear density distribution of
an ideal cubic perovskite-type compound(La0.8Sr0.2)(Ga0.8Mg0.15Co0.05)O2.8
found similar curved migration pathways.
The oxide-ion conductor with an ideal
perovskite-type structure exhibits diffusion paths along the [100], [010] and [001]directions to form a three-dimensional
network of equivalent diffusion pathways,
as shown by Yashima et al. [5]. On thecontrary, in the present double perovskitetype La0.64(Ti0.92Nb0.08)O3, a twodimensional diffusion pathways is present,by which O3 atoms migrate along the [100]and [010] directionsThis two-dimensionalfeature is attributable to the layered structure of the La0.64(Ti0.92Nb0.08)O3, which
consists of La-occupied La1-O1, (Ti,Nb)-O,
and La-deﬁcient La2-O2 layers.
References[1] Yoshioka, H. J. Am. Ceram. Soc. 85(2002) 1339.
[2] M. Yashima, J. Am. Ceram. Soc. 85(2002) 2925.
[3] F. Izumi and R. A. Dilanian, Recent Res.
Dev. Phys., 3 (2002) 699.
[4] F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324 (2000) 198.
[5] Yashima et al. Chem. Phys. Lett. 380(2003) 391.

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1-1-26

Crystal Structure of Apatite-type La9.7(Si5.7Mg0.3)O26.3
Roushown Ali(A), Masatomo Yashima(B), Fujio Izumi(A), Hideki Yoshioka(C),Yoshitaka Matsushita(A), Takahiro Wakita(B), Takayuki Tsuji(B), Yoichi Kawaike(B),Takafumi Komatsu(B) and Yong Phat(B)(A)Quantum Beam Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba,
Ibaraki 305-0044; (B)Department of Materials Science and Engineering, Interdisciplinary
Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259
Nagatsuta-cho, Midori-ku, Yokohama, 226-8502; (C)Hyogo Prefectural Institute of Technology,
3-1-12 Yukihira-cho, Suma-ku, Kobe 654-0037, Japan
Solid materials with high oxide-ion diffusivity are of vital interest in materials science due to their potential applications ofsuch materials in batteries and solid-oxide
fuel cells. It is important to understand theionic transport behavior of the solids andto relate their crystal structure to ionic conductivity in order to design and develop
new oxide ion conductors. Lanthanum silicates La10-xSi6O26+d having apatite-type
structure are one of the promising groups
exhibiting signiﬁcant oxide ion conductivity. Two kinds of conduction pathways, a
direct linear path through the hexagonal[0,0,z] channel and a non-linear sinusoidallike path through interstitial oxide ion site
have been proposed for the apatite-type
structure [1]. But the understanding of the
conduction mechanism in this structure remains subject to uncertainties. Here, wehave investigated the crystal structure anddiffusion pathway of oxide ions in apatitetype compound La9.70Si5.7Mg0.3O26.25 at
1558 C deg.
The neutron powder diffraction data
were collected at 1558 C deg. on HERMES installed at the JRR-3M reactor. Incident neutron beams with a ﬁxed wavelength of 1.8265 were obtained by a vertically focusing (331) Ge monochromator.
A furnace [2] with an MoSi2 heater wasused to heat the sample and the sample
temperature was maintained within +-1.5
C deg. during the measurement. The resulting diffraction data were analyzed by the
Rietveld method with RIETAN-FP [3] andwhole-pattern ﬁtting approach based on
the maximum-entropy method (MPF) [4].

The MEM calculation was done with theunit cell divided into 100 X 100 X 80 pixels
and whole-pattern ﬁtting using RIETANFP.
The Rietveld reﬁnement was performed
with neutron powder diffraction data of
La9.7(Si5.7Mg0.3)O26.3 measured at 1558
C deg. on the basis of hexagonal P63/m.
The calculated pattern agreed will withthat of observed pattern. The reﬁnement
was carried out with anisotropic thermal
displacement parameters for all the cations
and anions. The thermal displacement parameters of oxygen O3 atoms showedstrong anisotropic along the a-axis withlarge U11 value (0.00135(5) nmˆ2) whilethat of O4 showed stronger anisotropic
along the c-axis with larger U33 value(0.0044(3) nmˆ2). The reliability values obtained from the reﬁnement were Rwp =2.96 %, Rp = 2.23 %, RI = 1.29 % RF = 0.73 %and S = 3.30. The Rietveld reﬁnement suggested an interstitial oxygen atom site (O5)at the periphery of the c axis accompanied
by a slight improved proﬁle ﬁtting results.

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JAEA-Review 2008-067

1-1-27

Crystal structure and the structural disorder of yttrium tantalate
T. Tsuji (A), M. Yashima (A), T. Wakita (A), Xi Qu (A), T. Ueda (A), Y. Kawaike (A) T.
Komatsu (A), Y. Phat (A), R. Ali(B), Y. Matsushita(B)(A) Department of Materials Science and Engineering, Interdisciplinary Graduate School of
Science and Engineering, Tokyo Institute of Technology, (B) National Institute for Materials
Science
Yttria-tantalum oxide system has various phases such as defect-ﬂuorite, webertite phase and cubic phase. Defect-ﬂuorite
type structure has high diffusion coefﬁcient of oxide ions. On the other hand, theweberite-type structure exhibits lower diffusion coefﬁcient. In this study, we prepare
defect-ﬂuorite-phase Y0.79Ta0.21O1.7 andinvestigate the crystal structure and positional disorder of oxide ions through MEM(Maximum Entropy Method) analysis ofneutron powder diffraction data measured
at RT and at high temperatures
Neutron powder diffraction experiments were carried out in air in the temperature range from 298 K to 1824(3) K.
Neutron powder diffraction measurements
were conducted in air with a 150-detector
system, HERMES, installed at the JRR-3M
reactor in Japan Atomic Energy Agency,
Tokai, Japan. Neutrons with wavelength
0.18207 nm were obtained by the (311) reﬂection of a Ge monochromator. The experimental data were analyzed by a combination technique of Rietveld analysis, themaximum-entropy method (MEM), andthe MEM-based pattern ﬁtting.
Rietveld analysis was carried out assuming the ideal ﬂuorite-type structure wherethe (Y,Ta) and O atoms were put at 4a 0,0,0
and at 8c 1/4,1/4,1/4 sites of Fm-3m symmetry, respectively. The isotropic atomic
displacement parameters were used for all
the atoms. At higher temperatures the B(O)
was larger than the B(Y,Ta), suggesting alarger diffusion coefﬁcient of oxide ions.
MEM analysis was carried out using thestructure factors obtained in the Rietveld
analysis. Number of structure factors derived in the analysis was 11. The spatial distribution of oxide ions is larger at higher

temperatures and it seems to have disordering along <1 0 0> directions, indicating
the diffusion path. (Figures (a), (b) and (c)).

Fig. 1.

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JAEA-Review 2008-067

1-1-28

Dependence of thermodynamic stability and crystal structure on substisution and
Li content of Lix(Mn,Ni,Co,M)O2 as a cathode active materila for Li secondary
battery
Yasushi Idemoto, and Takaaki Matsui
Tokyo University of Science
Many lithium-intercalated transition
metal oxides have been studied as positiveelectrode materials in high energy density
rechargeable batteries. In recent years, thelayered-structured
LiNixCo1-2xMnxO2
has been extensively studied as a candidate
to replace the LiCoO2 cathode materials.
But, it is not clear that relationship between thermodynamic stability, structurestability and cycle performance. We had
been reported that the relationship between thermodynamic stability, structurestability and cathode performance ofLiMn2-yMyO4 (M=Cr, Al, Mg, Co, Ni,
Zn), LixMn1-yMyO2 (M=Mn, Al, Cu).
In this study, LiNi1/3Co1/3Mn1/3O2,
LiMn0.3Co0.3Ni0.3M0.1O2 (M=Al,Ti,Fe)
and
LiMn1/3Co1/3-0.1Ni1/3Al0.1O2
were prepared by the solid-state andsolution reaction. We investigated therelationship between the thermodynamic
stability, crystal structure, properties,
and electrode performance depend on
synthesis method, substitution and Li
content.
The samples were prepared by two
methods. The samples synthesized bysolid-state reaction using each simple oxide as starting materials. Another samples synthesized by solution reaction using each metal acetate dissolved in distilled water and mixed with aqueous solution of citric acid. Li+ extraction from
LiMni1/3Co1/3Ni1/3O2 were carried out
0.5mol ??dm-3 (NH4)2S2O8 solution bya batch method. Li content was controlled by immersing time. The heat ofdissolution was measured by a twin-type
multi-calorimeter. The enthalpy change permole of atoms for the formation reaction,??HR, were calculated from the heatof dissolution by applying Hess ??law.
We considered a similar experiment about
Li+ extraction samples. The crystal structure was determined by powder neutron
diffraction using HERMES of IMR at the
JRR-3M. The data were reﬁned using the
Rietan-2000. The nuclear densities determined by powder neutron diffraction andthe electron densities determined by powder XRD were calculated by MEM using
the PRIMA.
All samples were determined to single phase with a well-deﬁned layer structure (R-3m, 166) by XRD. The intensity ratio of (003) and (104) peaks in the XRD
patterns is greater than 1.2 and there isa clear splitting of the (006) and (102),(108) and (110) doublet peaks in the allcompounds, which conﬁrms there is little cation mixing in the layered structure.
The lattice parameter, a, decrease and c
increase with the decreasing Li content.
LiMn1/3Co1/3Ni1/3O2, which obtainedby solution reaction, was more high discharge capacity and good cycle ?? performance than that obtained by solidstate reaction. ??One of these factors controlled cycle performance, we investigated
the thermodynamic and structure stability. From the crystal structure analysis,
the cation mixing was little change withdecreasing Li content. The bond lengthsof Li-O increased and M-O {M=(Mn, Co,Ni)} decreased with decreasing Li content. From the results of electronic andcrystal structure, the change of covalentbond and cation mixing were small by
substitution. The chemical diffusion coefﬁcient of Li+ was little change by each

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JAEA-Review 2008-067

synthetic method. The enthalpy change
per mole of atoms for formation reaction,??HR, of LixMn1/3Co1/3Ni1/3O2 obtained by each synthetic method is linearlychanged with Li content. It is thought that
there is not structure changes (0.4<x<1.0),
and it corresponds to the crystal structure analysis. From the results, the hoststructure is structurally and thermodynamically stable of the all amounts of Li content. Moreover, ??HR of the sample bysolution reaction decreased compared tothat of the sample by solid-state reaction. ??HR increased with decreasing Li
content and LixMn1/3Co1/3Ni1/3O2 andLixMn1/3Co1/3-0.1Ni1/3Al0.1O2, whichobtained by solution reaction, was more
thermodynamically stable than that obtained by solid-state reaction. It was suggested that these factors should provide aneffective cycle performance.

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JAEA-Review 2008-067

1-1-29Magnetic Structure of Prx Y1−x Mn6 Sn6 Alloys
T. Hori and H. Shiraishi
Shibaura Institute of Technology, Saitama-City, 337-8570
Ternary YMn6 Sn6 alloys have the hp13
type (MgFe6 Ge6 type) layer structure. It
should be noticed that Mn atom layers
on 6i (1/2, 0, z2 ) and (1/2, 0, −z2 ) sites
are well separated by Sn atom layers on
2c (1/3, 2/3, 0), 2d (1/3, 2/3, 1/2) and 2e(0, 0, z1 ) sites and Y atom layer on 1a(0, 0, 1/2) site. This alloy shows an inhomogeneous helical antiferromagnetism
with the Néel temperature TN = 333 K
and the paramagnetic Curie temperatureθ P = 394 K.
Recently, we have made magnetization
measurements on YMn6 Sn6 alloy, and obtained interesting results; the magnetization approaches saturation around 11
T at 77 K; the saturated magnetization
corresponds to the magnetic moment of
2.0µ B /Mn atom.[1]We have found that Prx Y1− x Mn6 Sn6 (0 ≤x ≤ 0.4) alloys have the hp13 type structure, and carried out neutron diffraction experiments using HERMES.
Figure 1 shows neutron diffraction pattern for Pr0.1 Y0.9 Mn6 Sn6 alloy at 10 K.
There are several magnetic reﬂections inaddition to the nuclear Bragg reﬂections.
These magnetic reﬂections are the satellite
reﬂections of the nuclear ones with propagation vector q = (0, 0, 19 ) as indexed inFig. 1. It is remarkable that there are only
ﬁrst order satellite reﬂections and there isno higher order satellite reﬂection.
We supposed the helical structure propagating along c-axis. The magnetic moments
on Mn atom layers in c-planes at z = z2
and z = 1 − z2 , µMn (= 2.3 µ B ), and on
Nd atom layer in a c-plane at z = 1/2,
µPr (= 3.2 µ B ), are ferromagnetic arrangement each other, where z is parallel to thec-axis in unit of the lattice constant c. In
other words, a ferromagnetic slab is composed by in a set of these three magnetic
layers, and lay in the c-plane. The direc-

tion of the magnetic moments change theirorientation by an angle, θ, of 80˚ between
the adjacent ferromagnetic slabs along thec-axis.
The Pr0.2 Y0.8 Mn6 Sn6 alloy also show thehelical structure with propagation vector q= (0, 0, 16 ) and the angle θ = 60˚ .
The Pr0.4 Y0.6 Mn6 Sn6 alloy shows a simple ferromagnetic arrangement. The direction of magnetic moment is perpendicular
to c-axis.
It is likely that the magnetic momentsµMn and µPr keep constant values of 2.3µ B / Mn atom and 3.2 µ B / Pr atom respectvely, and lay in the c-plane in whole
composition (0 < x ≤ 0.4).
We have also carried out the magnetization measurements with an extraction
method using a 18T-SM super conducting
magnet up to 18 T at the High Field Laboratory of Tohoku University. The magnetic moments obtained from the saturated magnetizations, µS , linearly increase
with increasing x in the whole composition(0 < x ≤ 0.4) as expressed by a formulaµS = 12.82 + 2.91 x (µ B /f.u.); suggesting
the magnetic moments of Mn and Pr atoms,µMn and µPr , are µMn = 2.14 µ B /Mn atom
and µPr = 2.91 µ B /Pr atom. This result is
consistent with the neutron data.
References[1] Y. Shigeno et al, J. Magn. Magn. Mater. 26230 (2001) 1153.

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1-1-30Magnetic excitation spectrum in the frustrated magnet CuFe1-xAlx02
M.Yamada(A),K.Igarashi(A),S.Mitsuda(A),T.Nakajima(A),N.Terada(B)(A) Department of Physics, Tokyo University of Science, (B)RIKEN/SPring8
CuFeO2 with delafossite crystal structure has been extensively studied as one ofmodel materials of geometrically frustrated
triangular lattice antiferromagnets (TLA).
The magnetic properties in CuFe1-xAlxO2
are highly sensitive to nonmagnetic Al3+
impurity; quite small amount of nonmagnetic Al3+ impurity successively induces
ferroelectric incommensurate (FEIC) state(0.014<x<0.030) and the oblique partiallydisordered (OPD) state (x>0.030) from the
4-sublattice (4sub) ground state of CuFeO2[1]. Such dramatic changes due to nonmagnetic Al3+ impurity can be found also
in the signiﬁcant difference between themagnetic excitation spectrums of 4sub and
FEIC magnetic orderings; while higher energy (HE) branch is insensitive, lower energy (LE) branch is quite sensitive.[2,3]The magnetic orderings in OPD phaseis also very curious in the viewpoint ofthermodynamics, because, even in the lowest temperature, the length of the magnetic
moment is modulated owing to the thermal
ﬂuctuation. In present study, in order to investigate the magnetic excitation spectrum
for OPD state, we have performed inelastic neutron scattering on the sample with
x=0.05(344mg) using GPTAS (Kf=2.67[A1], 40-80-PG-40-40) for high-energy regionand HER (Ki=1.25[A-1], Open-Open-Be-8080) for low-energy region at JRR-3M. Notethat we have also measured TA phonons
for both x=0.015 and x=0.05 samples so as
to quantitatively compare the magnetic excitation spectrums for OPD with these obtained previously for FEIC states.
As shown in the inset of Fig.1, in the typical constant-Q scan for HE branch, spinwave spectrum of the x=0.05 sample can beseen as is for the x=0.015 sample, suggesting that the HE branch still remains for
OPD state. On the other hand, as is clearlyseen in the typical constant-delta E scan forthe x=0.05 sample shown in Fig.1(b), welldeﬁned four spin wave peaks seen in the
x=0.015 sample disappears and only diffusive magnetic response can be seen in the
low energy region where LE branch for the
x=0.015 sample exists.
References[1] N. Terada et al, JPSJ 74, (2005) 2604
[2] N. Terada et al, JPCM(in press)[ a proceeding paper of Highly Frustrated Magnetism 2006][3] N. Terada et al, J.Magn. and Magn.
Mater. 272-276 Supplement 1 E997-E998(2004)

Fig. 1. (a)Spin wave dispersion relation for FEIC
state, inset :Typical constant-Q scan proﬁles forhigher branch, (b) Typical constant-dE scan proﬁles
for lower branch

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JAEA-Review 2008-067

1-1-31

Crystal Structure and Origin of Polarization of Hydrogen-Bonded Organic
Ferroelectrics Composed of pi-Condugated Supramolecules
R. Kumai(A), Sachio Horiuchi(A), H. Sagayama(B), T. Arima(B,C), M. Watanabe(B), Y.
Noda(B), and Y. Tokura(A,C)(A)CERC, AIST, (B)IMRAM, Tohoku Univ., (C)ERATO-SSS, JST
Ferroelectrics have been motivated not
only by basic science but also by application because of those various utilizations
for electronics. Recently we have developed new ferroelectrics by using a molecular solid with supramolecular structure,
the cocrystal of phenazine (Phz, C12H8N2)
with chloranilic acid (H2ca, C6H2O4Cl2)
or bromanilic acid (H2ba, C6H2O4Cl2), in
which nonpolar pi-conjugated molecules
are connected by the intermolecular OH...N hydrogen bonds. Here, we report the
low-temperature crystal structure of PhzH2ca and Phz-H2ba [1] obtained by theneutron diffraction in order to make clear
for the origin of polarization.
Figure 1a shows the crystal structure of ferroelectric phase of Phz-H2ba at 110 K obtained by a neutron crystal structure analysis. Lattice parameters, space group (P21),
and atomic coordinates except for hydrogen atoms, agree with those obtained by
the X-ray diffraction experiments. The O-Hbond in the hydrogen-bonded site is clearlyobserved, suggesting that both molecules(Phz and H2ca or H2ba) are neutral evenin the ferroelectric phase, which is consistent with the infrared spectra. The molecular structure of H2ba at paraelectric phase(300 K) and ferroelectric phase (110K) are
shown in Figs. 1b and 1c. One can ﬁnd
a highly elongated thermal ellipsoid of
one hydrogen atom in the low-temperature
structure, which implies disordering of thehydrogen atom position. A similar situation is observed in the ferroelectric phaseof Phz-H2ca.
Figure 1d is summarized interatomic distances between O-H (a, b) and N...H (c, d)and N...O (e, f) related with the hydrogenbonding in the paraeletric and ferroelectric phases of the Phz-H2ca and Phz-H2bacrystals obtained by the present neutron
study. As can be seen from the asymmetric OH bond, the two hydrogen-bondedsites are not equivalent in the ferroelectricphase. This asymmetry in the hydrogenbond chain is the origin of the polarizationin the Phz-H2xa (x=Cl, Br) system.
AppendixPhz-H2ca 300K: C18H10Cl2N2O4, Z = 2,
Monoclinic P21/n, a = 12.422(6) A, b =3.849(6) A, c = 16.981(12) A, beta= 107.83(4)deg., V = 772.9(14) A3, R = 0.0531 for 725
independent reﬂections (|Fo| > 4 sigma).
Phz-H2ca 160K: C18H10Cl2N2O4, Z = 2,
Monoclinic P21, a = 12.423(4) A, b = 3.788(8)A, c = 16.914(6) A, beta = 107.89(3) deg.,
V = 757.5(17) A3, R = 0.0488 for 919 independent reﬂections (|Fo| > 4 sigma). PhzH2ba 300K: C18H10Br2N2O4, Z = 2, Monoclinic P21/n, a = 12.386(5) A, b = 3.908(5)A, c = 17.433(7) A, beta = 107.86(3) deg.,
V = 803.1(12) A3, R = 0.0460 for 685 independent reﬂections (|Fo| > 4 sigma). PhzH2ba 110K: C18H10Br2N2O4, Z = 2, Monoclinic P21, a = 12.371(4) A, b = 3.845(3) A, c
= 17.342(5) A, beta = 107.74(2), V = 785.8(7)A3, R = 0.0387 for 1314 independent reﬂections (|Fo| > 4 sigma).

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1-1-32

Investigation of drag reduction phenomena in a surfactant solution by a surfactant
solution by neutron refrectometer
N.Takenaka1, H.Suzuki2, Y.Nakanishi1, R.Nakamura2, T.Nishimura1, H.Watanabe2
1 Dept. Mechanical, 2 Chemical Engineering, Kobe University
It is known that turbulent frictional pressure drop of a liquid ﬂow in a tube is reduced much by solving long-chain polymer or surfactant in the liquid after Thom’s
discovery in 1949. The effect is called dragreducing (DR) effect or Thom’s effect. Recently it is used in intermediate heat exchanger systems for saving pump power.
However, no standard physical model has
not been established on this effect. Somemodels have been reported that the long
chain polymers or rod-like micelles of thesurfactant suppress the turbulence of the
ﬂow over the tube or near the wall of the
tube.
This study is based on the model that therod-like micelles suppress the turbulenceof the ﬂow near the wall. The neutron reﬂection rate measurement was conducted
to investigate the micelle behavior near the
inner surface of the wall made of monocrystal Silicon. The solution ﬂew in a rectangular tube, 1 mm x 30 mm in cross section. Water solution of surfactant, Esogard,
4000 ppm in concentration with counter
ions, salicylic acid, 50 in mole rate wastested.
Preliminary experiments were carried out
on the reﬂection rate measurement on thetest section without liquid, with water, withthe stagnant solution and with the ﬂowing
solution where the DR effect was observed.
The results were compared with theoretical values by one-dimensional Schrodinger
Equation. The measured reﬂection rate
without liquid, i.e., with air, agreed wellwith the theoretical ones within the standard derivation. It was shown that themeasurement was accurately conducted.
The measured values with water wereslightly smaller than the theoretical ones
and were well predicted by the theoretical ones with surface roughness of about

3 nm. It was expected that the wettabilityof the solution and the Silicon wall caused
the decrease of the reﬂection rate at theirinterface. Those with the stagnant solution
were also smaller than the theoretical ones
and were predicted well with the surface
roughness of about 1.9 nm. The measured
values with the ﬂowing solution were apparently smaller than those with the stagnant solution. The difference of them wasmore than two times of the standard deviation. Assuming the surface roughness of
1.9 nm for the ﬂowing solution, it was estimated that the concentration of the surfactant at the wall was about 5200 ppm, higher
than the averaged concentration of 4000
ppm by 1200 ppm. It was expected that themolecular structures near the wall were different for the stagnant and the ﬂowing solution and the difference might cause theDR effects. It can be shown that the reﬂection measurement was available for the investigation of the DR effect. More experiments were required to discuss physicalmodels of the DR effect.

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JAEA-Review 2008-067

1-1-33

Successive Magnetic Transitions and H-T Phase Diagram of Kagome Staircase
Compound Co3V2O8
Y. Yasui, Y. Kobayashi, T. Moyoshi, M. Soda, M. Sato and K. Kakurai*
Dept of Phys., Nagoya Univ., *JAEA
Co3V2O8 is an insulating system with
Co2+ spins (ﬁctitious spin S=1/2) arranged
in a kagome staircase structure or in a buckled kagome plane. It is interesting to investigate the magnetic behavior of this twodimensional spin system at low temperature T, because it has the geometrical frustration inherent in its crystal structure. Another interesting view point of this system is their dielectric properties, because
for the iso-structural system Ni3V2O8, themultiferroic behavior has been reported,that is, magnetic and ferroelectric transitions take simultaneously at a critical temperature.[1] Theoretically, the mechanismsof the multiferroic behavior are proposed
to be expected in system with the transverse spiral order.[2] The magnetic structure of Co3V2O8 has also been investigatedby neutron diffraction study. The detailed
results and discussions are reported in ref.
3.
We have carried out the magnetization,
speciﬁc-heat and dielectric measurements
on single crystal samples Co3V2O8 in various magnetic ﬁelds along three crystallographic axes up to 5 T. Neutron measurements on a powder sample as well as a single crystal with magnetic ﬁeld along c havebeen carried out down to 2 K. Neutron
measurements on a single crystal were carried out at T1-1 (HQR), where the double
axis condition was adopted. In zero magnetic ﬁeld, the system exhibits three transitions at temperatures Tc1˜11.2 K, Tc2˜8.8 K
and Tc3˜ (6.0-7.0) K, where the last transition has the co-existence region of T due toits ﬁrst order nature. No evidence for ferroelectric transitions has been observed in
the measurements of the dielectric constantwith the electric ﬁelds along three crystallographic axes, a, b and c.
On the basis of the results of the neu-tron scattering study, detailed magnetic
structures are proposed in zero magnetic
ﬁeld. The ordered moments have the sinusoidal nature with the modulation vector (0,delta,0) in the antiferromagnetic
phases (Tc3<T<Tc1), and the single crystal data present clear evidence for the noncollinear nature of the magnetic structuresin all magnetically ordered phases. The
transverse spiral state does not exist in
Co3V2O8, which is in a clear contrast withthe case of the multiferroic Ni3V2O8. It isconsistent with the fact that no evidence forthe occurrence of the ferroelectric transition
has been found in the dielectric data, thatis, the difference between Co3V2O8 andNi3V3O8 can be understood by the existing theories. Only small dielectric anomalies closely connected with the magnetic
phase transitions have been found.
We have constructed detailed ﬁeld (H)temperature (T) phase diagrams for theﬁelds parallel to the three crystallographic
directions a, b and c as shown in the ﬁgure. The abbreviations P, ICAF, CAF and CF
represent paramagnetic, incommensurateantiferromagnetic, commensurate- antiferromagnetic and commensurate- ferromagnetic phases, respectively. The delta value
is estimated from the position of the 02delta 0 magnetic reﬂections. Solid symbols are the transition temperatures determined by the magnetization and speciﬁcheat data. The phase boundaries plotted by
the open symbols are determined by theneutron scattering studies in the magnetic
ﬁeld H(//c). The dotted lines are drawn toconnect the crosses deﬁned as the inﬂexion
points of the M-T curves, and may not correspond to the phase boundaries. In the Tregion below these inﬂexion points, the relatively large ferromagnetic component is
induced by the applied magnetic ﬁeld. The

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JAEA-Review 2008-067

phases stabilized by the external ﬁeld arevery sensitive to the strength of the ﬁeld.
In the magnetic ﬁeld H along c, the magnetically ordered phases with delta =1 anddelta =2/3 have been found in the H-regionof H > 1 T. The existence of various phases
can be considered to be due to the geometrical frustration.
References[1] G. Lawes et al.:Phys. Rev. Lett. 95 (2005)
087205.
[2] for example; M. Mostovoy.:Phys. Rev.
Lett. 96 (2006) 067601, H. Katsura etal.:Phys. Rev. Lett. 95 (2005) 057205.
[3] Y. Yasui et al.:to be published in J. Phys.
Soc. Jpn. 76 (2007) No3.

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


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


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

Fig. 1. The H-T phase diagrams of Co3V2O8 forthe magnetic ﬁelds H along (a)H//a, (b)H//b and(c)H//c.

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1-1-34

Phonon Dispersion of Martensitic Material showing 2nd-order-like Transformation
Takuya OHBA and Daichi KITANOSONO
Department of Materials Science, Shimane University
Martensitic Transformation is known to be
typical ﬁrst-order transformation. TiNi(Fe)alloy system, some of Ni atoms were replaced by Fe, has been studied for longtime from fundamental point of view andapplication point of view. Alloy composition close to Ti50Ni47Fe3 was used
for the studies of the martensitic transformation mechanism because of small hysteresis. Recently, high Fe composition alloy was reported that the alloy shows
second-order-like transformation in resistivity measurements and calorimetric measurements. The alloy Ti50Ni44Fe6 wasstudied previously and reported that diffuse scattering appeared around 1/3 of(110) (incommensurate) at 200 K and approached to commensurate position withlowering temperature (180 K). Electricalresistivity showed minimum value at 209
K. Inelastic neutron scattering measurements were performed on this composition alloy and showed minimum phonon
energy at 200 K. On the other hand, thealloy Ti50Ni42Fe8 studied in this experiment showed incommensurate transformation and does not show commensuratetransformation on further cooling. This behavior may relate to the martensitic transformation and immediate study was required.
Ti50Ni42Fe8 alloy was grown by ﬂoatingzone method. The single crystal sample
was obtained by heat treatment at 1283K
for 24 h and quenched. Electrical resistivity of this alloy shows minimum temperature at 179 K. Inelastic scattering experiments were performed at the triple-axis
spectrometer 5G-PONTA. Initial energy ofneutron was 14.7meV and collimators usedwere 40 -40 -sample-40 -40 . Measured
phonon mode was [zz0]TA2 at various
temperatures. Figure shows E-const measurements at q=(0.25, -0.25, 0) around (120)reﬂection at various temperatures. The
phonon energy decreases with lowering
temperature. Approaching to z=1/3 andabove, phonon peaks became broader, thatis, over-damping was occurred. It is notclear the reason of the over-damping. The
precise analyses have been undertaken for
obtaining relationship between the phonon
and transformation behavior.

Fig. 1. Phonon Energy at q=(0.25, -0.25, 0) at various
temperatures.

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JAEA-Review 2008-067

1-1-35

Dependence of ferroelectric performance and crystal structure on composition andheat treatment of (Bi,M)4(Ti,Si)3O12(M=La,Nd) ferroelectric oxide
Yasushi Idemoto, and Eiji Iso
Tokyo University of Science
1. Bi rich (Bi,La)-Ti-Si-O Ferroelectric Material
The La-substituted (Bi4-xLax)Ti3O12 is
an attractive lead-free material for ferroelectric random access memory (FeRAM)
applications because of its relatively large
remanent polarization and fatigue-freecharacteristics. The bulk materials of
Bi3.25+xLa0.75Ti3O12(x=0, 0.15, 0.25)[BLT] and Bi4Si3O12 (BSO) at speciﬁccompositional ratio were prepared forferroelectric materials and some of samples annealed under the vacuum or highWe inoxygen partial pressure(Po2).
vestigated the relationship between thephysical properties, crystal structure andferroelectric performance of the sample
before and after various heat treatments
and changing composition.
From the results, Pr increases with increasing BSO content, but Pr decreased
with increasing Bi content. Moreover, Pr
decreased and Ec increased by heat treatment in the most of samples. On the other
hand, the dielectric constant (ε s) at Tc
of BLT remarkably increased by adding
BSO. From the crystal structure analysis,
the bond length and the bond angles of TiO are changed. Consequently, the changeof distortion in Ti-O6 octahedra will effectof the change of ferroelectric performance,such as Pr.

From the results, the remanent polarization (Pr) of Bi4-xNdxTi3O12 (x=0.75,
0.85, 1.2) samples increased by adding
BSO. On the other hand, Pr of Bi4xNdxTi3O12(x=1.0) sample shows a maximum, but Pr decreased by adding BSO.
Moreover, Pr decreased by heat treatmentin the most of samples. The dielectric constant (ε s) at room temperature and Tc
of BSO added Bi4-xNdxTi3O12 remarkably
increased by adding BSO. Tc and ε s at
Tc decreased and the dielectric loss (tan δ)
at Tc remarkably decreased by heat treatment. From the results of neutron diffraction analysis, the bond length of Bi1(Nd)O6 shows the maximum of BSO added
Bi2.8Nd1.2Ti3O12, and it shows the minimum for BSO added Bi3NdTi3O12. The
bond length of Bi1(Nd)-O6 increased withdecreasing of Nd content, x, of BSO added
Bi4-xNdxTi3O12(x<1.0). The total calculated spontaneous ferroelectric polarization(Ps) along a-axis shows a maximum at
BSO added Bi3NdTi3O12. The similar tendency was obtained of no BSO addition
sample. It was found that the Ps is related
to the Pr. Moreover, the bond length ofBi1(Nd)-O6 changes by heat-treatment andit affects to Pr.

2. (Bi,Nd)-Ti-Si-O Ferroelectric Material
We synthesized the new ferroelectric bulk
materials of Bi4Si3O12 (BSO) added Bi4xNdxTi3O12(x=0.75,0.85,1.0,1.2). We investigated the dependence of ferroelectric performance and crystal structure on content
and heat treatment for Bi4Si3O12 added
Bi4-xNdxTi3O12.
Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-1-36

Magnetic excitations in La2-xCaxCoO4
K. Horigane, T. Uchida, H. Hiraka*, K. Yamada* and J. Akimitsu
Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara 229-8558;*Institute for Materials Research, Tohoku University, Sendai 980-8577
Layered transition metal oxides have attracted much attention due to their wide
variety of magnetic, electrical and structural properties. In some of the doped transition metal compounds, there is a real
space ordering due to the charge carriers
in a certain carrier concentration, resulting in an orbital ordering (OO) and sometimes a charge ordering (CO). In a recent
neutron scattering study, Zaliznyak et al.
observed a checkerboard charge order of
Co2+/Co3+ and Co2+ magnetic order inthe half-doped cobaltate La1.5Sr0.5CoO4[1]. From the analysis of the magnetic andcharge order scattering, they concluded acheckerboard arrangement of Co2+ andnon-magnetic Co3+ ions in the CoO2 plane.
On the other hand, Y. Moritomo et al. reported the drastic change of effective moment μ eff in La2-xSrxCoO4(0.4<x<1.0),
suggesting a spin-state transition of Co3+
ions from the high-spin to intermediate
spin state[2]. Our purpose of this study is
to clarify the exchange interaction between
Co spins, spin and charge conﬁgurations of
CoO2 plane and to observe the intermediate spin state.
Single crystal of La2-xCaxCoO4 (0.3 ≦ x ≦0.8) was grown by the TSFZ method. The
sample volume was about 1.0 cc each and it
was mounted in a cryostat with the b-axis
vertical, allowing the wave vector transfers in the (h0l) reciprocal lattice plane.
The crystal structure remains in the tetragonal phase (space group I4/mmm) even at
the lowest temperature. However, to index
the superlattice peaks it is convenient tochoose a unit cell as twice as the primitive
unit cell, corresponding to a space group
F4/mmm. The neutron scattering experiments were carried out on the 3-axis spectrometer TOPAN (6G).
In order to clarify the exchange interac-tion, we have performed the inelastic neutron experiments. Spin wave dispersion at
Q=(h, 0, 3) are shown in Fig.1-(a). This spinwave is seen up to 16meV, in contrast to
50meV in La1.5Sr0.5NiO4. This indicates amuch weaker exchange interaction in thecobaltates than that in nickelates. We haveobtained the magnetic dispersion curves
for the different Ca concentrations and its
spin excitations are basically same. These
results suggest that magnetic interaction is
not changed by Ca substitutions. To solve
this strange phenomena, we examined thehole-doping dependence of magnetic correlation in a wide carrier-doping range of
0.3<x<0.8.
Fig.1-(b) shows Ca dependence of magnetic correlation lengths. From the holedoping dependence, the in-plane correlation lengths of spin order are found to
give a maximum at x=0.5 and spin ordered peaks exist in the entire x range.
From the results, unchanged magnon dispersion can be understood as existing thelong ranged magnetic order in a wide holedoping range.
Moreover, we discovered the Ca dependence of two types of magnetic peaks
for a different Ca concentration. In thelower doping samples (x<0.5), we only observed the l=half-integer (type 1 stacking)patterns, while we observed the l=integer(type 2 stacking) patterns in higher doping samples(x>0.5). This result is consistent with the Larochelle s result of perovskite manganites[3]. From this point ofview, La2-xCaxCoO4 can be explained by
the two-type of stackings and CE-type spinand charge conﬁguration was clearly observed in this system.
Reference[1]I. A. Zaliznyak et al., Phys. Rev. Lett. 85

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JAEA-Review 2008-067(2000) 4353
[2]Y. Moritomo et al., Phys. Rev. B 55 (1997)
14725[3]S. Larochelle et al., Phys. Rev. B 71,
024435 (2005)

Fig. 1. (a) Ca dependence of magnon dispersion at
Q=(h, 0, 3) and (b) Ca dependence of magnetic correlation lengths in La2-xCaxCoO4.

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1-1-37

Preliminary experiments of D2O scattering for MIEZE spectrometer with AGNES
S.Tasaki, Y.Abe, Y.Edura, M.Hino, T. Ebisawa
Dept. of Nucl. Eng., Kyoto Univ., KURRI, JAEA
Mieze spectrometer is a modiﬁed version
of NSE spectrometer, in which echo condition (cancellation of Larmor precession
phase) is realized when the distance between the detector and the last p/2-ﬂipper
is adjusted and hence, contrast of NSE signal depends on the distance. Since the sensitivity on the distance is proportional tothe energy resolution of the Mieze spectrometer, the thickness of the detector andthe size of the sample should be small (lessthan a few millimeter) for high resolution.
Since besides the other NSE spectrometer,no spin analyzer is required between thesample and the detector in Mieze spectrometer, new types of experiments suchas inelastic or quasi-elastic scattering withneutron spin ﬂip is measurable with Mieze.
We intend to construct Mieze spectrometer as one of the three NSE spectrometers. In order to reduce the sensitivity on
the detector position, the energy resolutionof the Mieze spectrometer is conﬁned tothat of the conventional inelastic scattering
spectrometers. The advantage of the Mieze
comparing to the inelastic scattering spectrometer is the compactness of its size andthe beam intensity at the sample position.
In order to check the properties of Mieze,
it is important to measure standard samples and compare the measured data to thatof some conventional spectrometer. For
this purpose, we measured the inelastic
scattering of D2O (as the standard sample)
using the inelastic scattering spectromter
AGNES (as reference spectromter).
D2O is contained in a Al-cell and themeasurements were performed at various
temperatures under normal pressure. An
example of the results for the temperatureof 4 degree is shown in Fig.1. Coherent
scattering in the low Q region is obviously
observed. Scattering intensity in high Q region (over 1.5 Å−1 ) is much reduced when

the sample temperature rises. Due to theimprovement of AGNES spectromter, S/Nratio is much improved especially when
the count rate is low. These data will be
used for calibration of Mieze spectrometer.
Experiment
Lorentzian
Pseudo-Voigt
Teixeira

S(Q, hw) [arb. unit]

0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0

0.5

1
Q [1/AA]

1.5

2

2.5

3 -5

0

5

15
10
hw [meV]20

Fig. 1. The result of neutron inelastic scatterin from
D2O at 4 degree.

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JAEA-Review 2008-067

1-1-38The Ordering Structure of Water Molecules in The Superconductor
NaxCoO2.yD2O and The Magnetic Excitation in Na0.5CoO2
Taketo Moyoshi, Minoru Soda, Yukio Yasui, Masatoshi Sato and Kazuhisa Kakurai*
Dept. of Phys., Nagoya Univ.,* JAEA
Na0.3CoO2.1.3H2O exhibits the superconducting transition at 4.5 K[1]. Because
strong magnetic ﬂuctuation expected forcorrelated electrons on the 2-dimensional
triangular lattice may play an importantrole in realizing superconductivity, the hydrated Co oxide, which may have suchelectrons have attracted much interest. We
are also intersted in roles of the water intercalation in realizing the superconductivityof this system.
In the present work, two kind of neutron
scattering studies have been carried out
on aligned single crystals of Na0.5CoO2
and NaxCoO2.yD2O. First, we have investigated the intensity of magnetic excitation in Na0.5CoO2 which exhibits themagnetic transition at 87 K to compare
to that in superconductor. Second, we
have investigated the D2O ordering pattern in NaxCoO2.yD2O. This crystal contains superconducting phase (bilayer system, y˜1.3) and non-superconducting phase(non-deuterated system). The volume fractions of these systems were estimated to be
80% and 20%..
Neutron measurements were carried out
using the spectrometer 5G with the tripleaxis condition installed at JRR-3 in Tokai.
The aligned crystals of Na0.5CoO2 wereused with the [100] and [001] axes inthe scattering plane. The crystal of NaxCoO2.yD2O was used with the [100] and[001] axes and [110] and [001] axes in the
scattering plane.
In Na0.5CoO2, we carried out inelastic
scattering along (h, 0, 3) and (1/2, 0, l) at
90 K for some transfer energies (E) between
2.5 and 15 meV. As the result, we observed
peaks at Q = (1/2, 0, 3) which is the magnetic Bragg position. The E-dependenceof spectral weight kai (Q, E) shows thatthese peaks are due to the magnetic ﬂuc-

tuation. In the neutron inelastic scatteringon aligned crystals of NaxCoO2.yD2O withhalf of the molar number of Na0.5CoO2,
no evidence has been found in the search
for the ferromagnetic ﬂuctuations in the superconducting phase [2]. These results indicate that magnetic ﬂuctuations in NaxCoO2.yD2O are rather weak, if they exist.
It can be said especially for ferromagnetic
ﬂuctuations and is consistent with the results of the NMR Knight shift reported by
the present authors group[3, 4].
In NaxCoO2.yD2O, in the elastic scansalong (1/2, 0, l), (3/2, 0, l) and (1/2, 1/2, l)at room temperature, we have observed asigniﬁcant diffuse scattering contribution,
which has an intensity modulation with aperiodicity of c* of the bilayer system. The
ordering is short-ranged along the c direction, while the in-plane correlation of D2O
or the correlation length within a layer isalmost inﬁnite (at least more than 300 A),
judging from the widths of the 1/21/20
reﬂection in the scan along (h, h, 0). Analyzing these data, we can ﬁnd that scatterings originate from the intercalated D2O
molecules. The ordering pattern is basicallysimilar to the model proposed by Argyriou
et al.[5]. Recently, it is shown that the transition temperature (Tc) changes with time
for about 1000 hours after sample preparation by Barnes et al.[6]. We think that it
is important to study the relationship between details of the D2O ordering pattern
and Tc to clarify possible roles of the waterintercalation in realizing the superconductivity of this system.
Reference[1]K. Takada et al.: Nature 422 (2003) 53.
[2]T. Moyoshi et al.: J. Phys. Soc. Jpn. 75(2006) 074705.
[3]Y. Kobayashi et al.: J. Phys. Soc. Jpn. 74

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JAEA-Review 2008-067(2005) 1800.
[4]Y. Kobayashi et al.: J. Phys. Soc. Jpn. 75(2006) 074717.
[5]D. N. Argyriou et al.: J. Phys. Condens.
Matter 17 (2005) 3293.
[6]P. W. Barnes et al.: Phys. Rev. B 72 (2005)
134515.

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1-1-39Phonon Measurements on Protonic Conductor K3 H(SeO4 )2Fumihito Shikanai, Keisuke Tomiyasu, Susumu Ikeda and Takashi Kamiyama
Institute of Materials Structure Science, High Energy Accelerator Research Organization
K3 H(SeO4 )2 undergoes ﬁrst-order phasetransition at 390 K (TC ). The crystal shows
remarkable high protonic conductivity inthe high-temperature phase (phase I), andferroelastic in the room-temperature phase(phase II). The crystal belongs to the rhombohedral system with the space group R3̄min the phase I, and monoclinic system withthe space group C2/c in the phase II. Superlattice reﬂections expressed as (h k/2 l) are
observed in the phase II, that is, the crystal
structure in the phase II is super structureof phase I. It suggest that the phase transition may be caused by a zone boundarymode with k = 12 g2 , and the phase transition is improper ferroelastic type.[1]Inelastic neutron scattering (INS) measurement was carried out using a highenergy resolution triple-axis spectrometer(C1-1 HER) installed at JRR-3M reactor,
Japan Atomic Energy Agency, Tokai, Japan.
Incident energy Ei was ﬁxed at 5 meV. The
measurement was performed from (0 2 0)
to (0.5 2 0 ) zone with the energy transfer
range form -10.0 meV to -0.4 meV.
Figure 1(a) shows INS spectra at vicinity of Γ -point, (0.1 2 0), obtained at 413
K and 388 K. A large peaks correspond totransversal acoustic (TA) mode were observed at -1.6 meV. As sown in the ﬁgure,no abnormally accompanied by the phasetransition was found on the TA-mode. The
result is consistent with the nature thatthe phase transition is improper ferroelastic type. Figure 1(b) exhibits INS spectra at
L-point, (0.5 2 0), obtained at 413 K, 388 K
and 363 K. Diffuse scatterings are observed
around 0 meV in the phse I and near thephase transition temperature TC . It is considered that the spectra are caused by aover-dumped phonon or structural ﬂuctuations of local structure. In order to makeclear the phase transition mechanism andproton conduction mechanism, further de-tailed measurements of the zone-boundarymode are needed.
References[1] S. Yokota, Y. Makita and Y. Takagi : J. Phys.
Soc. Jpn. 51 (1982) 1461.

Fig. 1.
Inelastic neutron scattering spectra ofK3 H(SeO4 )2 obtained at: (a) vicinity of Γ -point (0.1
2 0), (b) L-point, (0.5 2 0).

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1-1-40

Powder Neutron Diﬀraction of Ta- and Al-doped Zn2TiO4
S. Takai, H. Okada, T. Esaka
Faculty of Engineering, Tottori University
When the tantalum ions are partly
substituted in stead of titanium ions in
Zn2TiO4 accompanied by the deﬁciency ofzinc, Zn2-x/2Ti1-xTaxO4, oxide ion conduction appears at elevated temperatures[1,2]. From the powder density measurements and TOF neutron diffraction, thistype of substitution was found to form thecation vacancies at the octahedral site of theinverse-spinel structure, contributing to theoxide ion conduction [3].
Recently, it was found that in addition totantalum, aluminum substitution which reduces the cation deﬁciency also forms thesolid solution, and any obvious enhancement of oxide ion conduction was not observed when equimolar tantalum and aluminum ions are substituted [4]. However,structural investigation of both Ta- and Aldoped Zn2TiO4 was not made and eventhe position of aluminum was uncertain.
In the present study, neutron diffraction
experiments were carried out on x = 0.15
of Zn2-x/2Ti1-xTaxO4 (ZTT) and Zn2Ti12xTaxAlxO4 (ZTTA) up to 500 K to clarify
the conduction mechanism.
Samples of ZTT and ZTTA were prepared by conventional solid-state reaction
method started from ZnO, TiO2, Ta2O5 andAl2O3. The calcining and sintering temperatures were selected as 1000 and 1200℃, respectively. About each 10 g of thecrushed samples were charged in vanadium cells, which were mounted in thehigh-temperature CTI. Neutron diffraction
experiments were carried out 300, 400 and
500 K on the multi-counter type diffractometer HERMES installed in the JRR-3M
reactor of JAEA [5]. The wavelength of theneutron beam was 1.8265 A. Structure reﬁnement was performed using Rietveld reﬁnement program RIETAN-2000 [6].

The reﬁned structure of ZTT at room temperature essentially agrees with that of previous one obtained by TOF neutron diffraction; the tantalum substitution and vacancy
formation were made at octahedral siteof the inverse-spinel type structure. On
heating, any apparent structural change,e.g. symmetry or occupancy of each site,
was not detected. The diffraction data of
ZTTA can be also reﬁned with relatively
worse Rwp values, although additional
diffraction peaks caused by ZnO were detected. Multi-phase analysis suggested theamount of ZnO was estimated as about 5% in weight. While the tetrahedral site
was occupied only by zinc ions, octahedral
one was by zinc, tantalum and aluminumions. When the Rietveld ﬁtting was carriedout assuming all the cations were stuffed
and allowing the occupation factor of oxide ion to vary, the deduced occupancy ofoxide ion was g(O) = 1.015(12). This indicated that, although small amount of vacancy might be introduced in the cation
site, any signiﬁcant deﬁciency was not supposed to be occurred.
The lattice parameters, interatomic distances between cation-oxide ions, andisotropic temperature factors of oxide ionswere plotted versus temperature in Fig.
1, all of which essentially grew larger
with temperature. While the tetrahedral
cation-oxide ion lengths show similar values (Fig. 1(b)), octahedral ones represent
some discrepancy (Fig. 1(c)). This is consistent with the result of the cation distribution that tetrahedral site was occupied
by Zn without deﬁciency in both systems
whereas the octahedral position contains
different species between these two systems. While isotropic temperature factors
become larger with temperature in both
systems, ZTTA shows apparent enhancement at 500 K comparing with ZTTA. This

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JAEA-Review 2008-067

also consistent with the fact that cation deﬁcient ZTT shows oxide ion conduction atelevated temperatures while stuffed ZTTA
was not. High temperature experiment
was expected to show more apparent behavior. In addition, further precise investigation would reveal the oxide ion motion and oxide ion conduction mechanismof ZTT.
The authors thank Dr. K. Ohoyama for
the instruction and set-up to use HERMES.
This research was partially supported by
Ministry of Education, Science, Sports andCulture of Japan, Grant-in-Aid.
1. T. Esaka, T. Ikebe and M. Kamata, Denki
Kagaku 61 (1993)749.
2. T. Esaka, T. Ikebe and M. Kamata, Solid
State Ionics 76 (1995)237.
3. S. Takai, T. Shinohara, A. Hoshikawa,
S. Harjo, K. Oikawa, T. Ishigaki, T.
Kamiyama, T. Esaka, (in preparation).
4. H. Okada, S. Takai, T. Esaka, (unpublished).
5. K. Ohoyama, T. Kanouchi, K. Nemoto,
M. Ohashi, T. Kajitani and Y. Yamaguchi:
Jpn. J. Appl. Phys. 37 (1998) 3319.
6. F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324 (2000) 198.

Fig. 1. Temperature dependence of (a) lattice parameters, (b) tetrahedral cation-oxide ions and (c) octahedral cation-oxide ion interatomic distances and(d) isotropic temperature factors of oxide ions. ●:ZTT and ○: ZTTA.

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1-1-41

Phonon Dispersions in Hexagonal BaTiO3
H. Shigematsu(A), T. Miyoshi(B), Y. Akishige(A)(A) Department of Physics, Faculty of Education, Shimane University, (B) Faculty of Science,
Yamaguchi University
Hexagonal BaTiO3 is one of the twopolymorphic forms of BaTiO3: the otheris the well known perovskite type (cubic
BaTiO3). Hexagonal-BaTiO3 undergoes astructural phase transition from the hexagonal phase (space group P63/mmc) to theorthorhombic phase (C2221) at T0 = 222
K . This phase transition is believed tobe caused by freezing of a soft E2u silent
mode at the zone center. Below T0, the E2umode becomes two Raman-active soft optical mode, Omega1 and Omega2. With further decreasing temperature, it undergoes
a ferroelectric phase transition related to ac66 soft acoustic mode at TC = 74 K.
We have studied in order to clarify the mechanism of the phase transitions in hexagonal BaTiO3 and differencein physical property between hexagonaland cubic-BaTiO3. As the ﬁrst step, we performed inelastic neutron scattering experiments on the hexagonal BaTiO3 by using the triple-axis spectrometers (4G andT1-1) at JRR-3M in JAERI (Tokai). Single
crystals were grown from the molten BaTiO3. A crystal with the dimensions of 5× 5 × 6 mm was used for the neutron experiment. The data collections were carriedout in the h0l and hhl scattering planes.
The measurements of phonon dispersion
were performed along the lines 006-106,006-116, where the indices are referred tothe unit cell of the hexagonal phase, and soon.
Figure 1 shows the phonon dispersion curves at 300 K in the major symmetry directions M-K-Gamma-A. The E2u
soft mode was clearly conﬁrmed at about
3 meV around Gamma point and showsa weak softening as the temperature approaches T0 from above. It was difﬁcult toobserve the whole branches, because someparts of branches were so broad and weak.

On the other hand, the presence of E2u softmode has not been clearly conﬁrmed in the
major symmetry directions M-Gamma-A.
The Bragg reﬂections at the position hhl:
l=odd appeared at T0 and increased in intensity with decreasing temperature. Data
analysis is now in progress.

Fig. 1. Phonon dispersion curves at 300 K in the major symmetry directions M-K-Gamma-A. Peak positions of the clearly observed peaks are plotted.

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1-1-42

Structural change of a zirconia-scandia solid solution
Toshikazu Ueda, Masatomo Yashima, Yoshiaki Ando, Qi Xu, Takayuki Tsuji, Yoichi
Kawaike, Kenji Ohoyama* and Katsuhiro Kawachi**Department of Materials Science and Engineering, Interdisciplinary Graduate School of Scienceand Engineering, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama,226-8502; * Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku,
Sendai, 980-8577; **Daiichi Kigenso Kagaku Kogyo, Hirabayashi-Minami 1-6-38, Suminoe-ku,
Osaka, 559-0025
Zirconia-scandia solid solutions are someof the highest oxygen ion conductors in thezirconia-based materials. Here, we report
the crystal structure and the nuclear density distribution of a zirconia-scandia solid
solution using the high-temperature neutron powder diffraction data.
Neutron-diffraction
measurements of a zirconia solid solution(Zr0.81Sc0.19O1.905) were performed
in air with a 150-detector system, HERMES, installed at the JRR-3M reactor inJapan Atomic Energy Association, Tokai,
Japan. Neutrons with wavelength 0.18142
nm were obtained by the (311) reﬂectionof a Ge monochromator. Diffraction data
were collected in the 2 theta range from 5
deg to 150 deg in the step interval of 0.1
deg. A furnace with MoSi2 heaters [1] wasplaced on the sample table, and used forneutron-diffraction measurements from
267 to 495.3+-0.6 C deg. The diffraction
data were analyzed by Rietveld methodwith a computer program RIETAN-2000.
All the neutron diffraction
peaks of the zirconia solid solution(Zr0.81Sc0.19O1.905) sample measured
from 267 to 495.3 C deg were indexedwith a trigonal cell. Rietveld analysis was
performed with the trigonal structure.
Calculated proﬁle agreed well with theobserved data. Figure 1 shows the temperature dependence of (a) unit-cell parametera, (b) cell parameter c and (d) unit-cell volume. The a increased with temperature.
The c parameter did not change largely.
The unit-cell volume of the trigonal phaseincreased with temperature.

Fig. 1.

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1-1-43

Neutron Diﬀraction Analysis of Hydrogen-Bonding Networks of the Inosine
5’-Monophosphate Hydrate Stable in Medium Humidity Range II
S. Yamamura A , Y. Sugawara A , H. KimuraB , Y. NodaB
A School of Science, Kitasato University
B Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
Disodium inosine 5� -monophosphate(Na2 IMP) hydrates undergo phase transitions depending on temperature andrelative humidity conditions. We havecarried out a series of neutron diffraction
analyses [1], and clariﬁed reconstruction ofhydrogen-bonding networks accompaniedby the phase transitions. Besides, nuclear
distributions of oxygen and hydrogenatoms indicated ﬂuctuating ﬁgures ofcrystal water molecules which are hydrated to biomolecules. In the case of
the heptahydrate, which is stable in therelative humidity range 40 - 60 %, there
were uncertain sites of a part of sodium
ions and water molecules [2]. Under suchcircumstances, we reinvestigated neutron
diffraction analysis of the heptahydrate.
A crystal with approximate dimensions
11.4 × 7.7 × 1.4 mm3 was sealed in aquartz tube. The crystal volume was about
2.5 times larger than that of the previous experiment. Data collection was carried out using a four-circle diffractometer,
FONDER, at T2-2 of JRR-3 in JAERI (Tokai).
With the neutron wavelength of 1.24 Å,
1563 unique reﬂections up to 0.76 Å resolution (2θ = 110 ◦ ) were measured at room
temperature. Two crystal settings wereused due to the limitation of the diffractometer. There remained inconsistency inintensities of a few reﬂections after the absorption correction.
Initial difference Fourier maps were calculated based on non-hydrogen atoms of
IMP molecule determined by X-ray analysis. In a series of full-matrix least squares
reﬁnement cycles ﬁxing non-hydrogenatoms of IMP molecule followed by difference Fourier syntheses, sodium ions, O andH atom sites of water molecules were as-signed and reﬁned. Then the sites of IMP
molecule and those of sodium ions andwater molecules were reﬁned alternatively.
All hydrogen atoms of the IMP moleculeand 13 hydrogen sites of seven crystal water were determined (Fig. 1). The R factor is
0.075 for 1385 observed reﬂections ( | Fo | >4σ( Fo ) ) at the present stage. The crystal
structure is essentially the same to that ofthe previous study except the atomic displacement parameters of the uncertain sitesof sodium ion (Na3) and water molecule(W7).
References [1] Sugawara et al., ISSPNSL Research Highlights 2005, 38-39(2005).
[2] Sugawara et al., ISSP Activity Reporton Neutron Scattering Research, 10, 8687(2003).

Fig. 1. Crystal structure of Na2 IMP.7H2 O viewed
along the a axis.

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JAEA-Review 2008-067

1-1-44Pr-site ﬁlling fraction in the ﬁlled skutterudite PrFe4Sb12 synthesized under highpressure
K. Kuwahara(1), K. Tanaka(1), Y. Kawahito(1), D. Kikuchi(1), H. Aoki(1), Y. Aoki(1), H.
Sato(1), H Sugawara(2)(1) Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, (2) Faculty ofIntegrated Arts and Sciences, Tokushima University, Tokushima 770-8592
The ﬁlled skutterudite compounds RT4X12(R: rare earth or actinide, T: transition
metal, X: pnictogen) crystallize in the bodycentered cubic space group Im-3, in which
R ion is surrounded by a cage of 12 X
ions. These compounds show a wide variety of thermal, magnetic and transport
properties due to strong c-f mixing effects
and a rattling motion of R ion resulting
from the unique crystal structure. Amongthem, PrFe4Sb12 has been much interest
because of the drastic effect of Pr-site ﬁlling fraction on the magnetic properties. On
the physical properties of PrFe4Sb12 prepared under ambient pressure, three independent groups have reported different
magnetic ground states below 5 K; ferromagnetic [1], antiferromagnetic [2], and ferrimagnetic ordering [3]. Moreover, different crystal-ﬁeld (CF) level schemes are proposed; the triplet ground state with the singlet ﬁrst excited state in ref. [2] and thetriplet ground state with the non-Kramers
doublet ﬁrst excited state in ref. [3]. Such adisagreement may be partly ascribed to theﬁlling fraction of Pr ions. In fact, the ﬁlling
fractions of Pr ions were reported to be 73%
and 87% in refs. [2] and [3], respectively.
Recently we have succeeded in synthesizing the ﬁlled skutterudite PrFe4Sb12 underhigh pressure [4]. In this crystal, no magnetic transition has been conﬁrmed down
to 0.15 K. From the temperature dependence of magnetic susceptibility and speciﬁc heat, furthermore, the CF ground stateis estimated as a singlet with ﬁrst excitedstate of a triplet above 20 K. This singlet
ground state differs completely from thetriplet ground state proposed in refs. [2,3],
but is the same as that in other Pr-based
ﬁlled skutterudite compounds.

In order to clarify the origin of the big
difference of magnetic properties between
the crystals prepared under ambient pressure and high pressure, it is necessary toestimate the Pr-site ﬁlling fraction of thecrystal synthesized under high pressure exactly. Therefore, we have performed thepowder neutron diffraction experiments
by using the multicounter diffractometer HERMES. Figure 1 shows the diffraction pattern at room temperature. From
the Rietveld analysis using the software
RIETAN-2000, the Pr-site ﬁlling fractionof the PrFe4Sb12 synthesized under highpressure has been estimated as 97% +- 2%.
References[1]M.E. Danebrock et al., J. Phys. Chem.
Solids 57, 381 (1996)[2]E. Bauer et al., Phys. Rev. B 66, 214421(2002)[3]N. P. Butch et al. Phys. Rev. B 71, 214417(2005)[4]K. Tanaka et al., Physica B 378-380, 213(2006)

Fig. 1. Neutron powder diffraction pattern of
PrFe4Sb12 at room temperature.

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1-1-45

Crystal Structure Reﬁnement of visible-light driven photocatalyst
H. Ishikawa, T. Matsumoto, K. Uematsu, K. Toda, M. Sato
Niigata University
In recent years, photocatalytic materials
that function under visible light have beenstudied extensively in an attempt to improve solar energy conversion and reduce
the environmental impact of energy production. Overall water splitting using aheterogeneous photocatalyst is an attractive solution for the production of H2 asa clean and recyclable energy source. The
overall water splitting reaction has alreadybeen well established in many wide gap
oxide semiconductors in the early 1980s.
These oxides absorb only the UV region
photons. The response to visible light is,however, desired for photocatalytic water
splitting from the view point of efﬁcientsolar energy conversion. In this study, we
reported the crystal structure of yellow(Hf,Zr)V2O7 with V 3d electron.
The samples were prepared by a conventional solid state reaction. Starting materials were stoichiometric mixtures of HfO2,
V2O5 and ZrO2 powders. The mixture waspressed into a pellet and heated in a platinum boat at 973 K for 4 h in air. The
completion of the reaction and the phase
purity of the samples were conﬁrmed bypowder X-ray diffraction methods. We performed neutron powder diffraction experiments on the Kinken powder diffractometer for high efﬁciency and high resolution
measurements, HERMES with 0.18196 nm
wavelength, of Institute for Materials Research(IMR), Tohoku University, installedat the JRR-3M reactor in Japan Atomic Energy Research Institute (JAERI), Tokai. The
ﬁne powder sample was sealed in a vanadium cylinder. Rietveld structure reﬁnement was carried out with the program RIETAN2000.
Crystal structures of HfV2O7 were ﬁrst
reported by Turquat et al. They reﬁned
HfV2O7 on the basis of a cubic systemwith space group Pa-3 (a = 0.87530 nm)

However, since these structures were deduced only from the electron and powder
X-ray diffractions, the information on lightelements, especially for oxygen atom, wasquite poor. To investigate the substance Zr
for Hf, the powder neutron diffraction data
were collected from the single phase samples with x = 0.5.
The crystal structure of (Hf,Zr)V2O7 canbe considered as related to the NaCl structure, with the (Hf,Zr)ZrO6 octahedron centered at the ideal Na site and the bridging
oxygen of the V2O7 group at the ideal Na
site and the bridging oxygen of the V2O7
group (O3V-O-VO3) at the Cl site. All of
the diffraction peaks were well indexed on
cubic system Pa-3(0.8742(1)nm). A good ﬁtting proﬁle were obtained with Rwp = 8.33%.

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1-1-46Structure Determination of Ordered Perovskite-type Oxides, Ca2MTeO6 (M =Mn, Co) by Neutron Diﬀraction
Yue Jin Shan, Keitaro Tezuka, Yoko Kanai, Shogo Hosokawa, Hideo Imoto
Kenji Ohoyama
The B site of the perovskites can accommodate two kinds of metal ions. The generalformula of such a system is given as A2B
B O6, while the B and B ions are either
in an ordered or a disordered arrangement.
Many researches including two kinds ofmagnetism ions, such as Sr2FeMoO6, havebeen carried out. However, there were
few researches on high-oxidation cation of
Te6+ in the B site. Ordered perovskitetype oxides, Ca2MTeO6 (M = Mn, Co), belonged to space group P21/n and were
insulators at room temperature. However, their electronic conductivities tended
large gradually with a rise of temperature.
Ca2MnTeO6 and Ca2CoTeO6 showed antiferromagnetism, and their Neel temperatures were 10 K and 7 K, respectively. The
effective magnetic moment of manganese
ion was 5.8 B while its valence was bivalence in Ca2MnTeO6.
Neutron diffraction measurements were
performed above (50 K) and below (3 K)
TN to determine the changes in the crystal and magnetic structures of Ca2MTeO6(M = Mn, Co). Powder neutron diffraction patterns were recorded using the highefﬁciency and resolution powder diffractometer, HERMES, of Institute for Materials Research, Tohoku University, installedat the JRR-3M Reactor in JAEA (Tokai).
The wavelength of a neutron incident is1.82646(6) . The crystal and magnetic
structures were analyzed using the Rietveld analysis program, RIETN2000.
The neutron diffraction patterns of two
samples at 50 K were well ﬁtted witha space group P21/n (No. 14) by Rietveld analysis. The lattice parameter ofCa2MnTeO6 and Ca2CoTeO6 were determined to be a = 5.4917(3) , b = 5.6678(3), c = 7.8371(5) , β =90.251(4), and a =5.4448(2) , b = 5.5899(2) , c = 7.7196(3), β = 90.269(3), respectively. The lattice
parameters became smaller with decreaseof an ion radius in order of M = Mn, Co.
At 3 K, some additional Bragg peaks wereobserved indicating the magnetic ordering
for two samples. Fig. 1 shows the case of
Ca2CoTeO6. These magnetic peaks could
be indexed on the same crystallographic
unit cell, the neutron diffraction patternsof Ca2CoTeO6 at 3 K were reﬁned with aspace group P-1 (No. 2). As a result, a direction of magnetic moment seems to turnto the direction deviated from c-axis. However, the reﬁnement for Ca2MnTeO6 did
not succeed.
References[1] Y.J. Shan, Yoko Kanai, Keitaro Tezuka
and Hideo Imoto, Advances in Science andTechnology 45 2572 ? 2575 (2006).

Fig. 1. Powder neutron diffraction patterns of
Ca2CoTeO6 at (a) 3 K and (b) 50 K. Indices for magnetic reﬂections are based on crystallographic unit
cell.

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1-1-47In situ experiment of magnetic scattering, dielectric constant and electric
polarization of ErMn2 O5 and TmMn2 O5
Y. Noda( A) , M. Fukunaga( A) , H. Kimura( A) , K. Nishihata( A) and K. Kohn( B)( A) IMRAM Tohoku Univ., ( B) Waseda Univ.
We have performed in situ experimentof neutron magnetic scattering, dielectric measurement and D-E hysteresis measurement of ErMn2 O5 and TmMn2 O5 at
FONDER.
The system shows complicated magnetic
and dielectric phase transitions due to alarge magneto-electric coupling, and called
as multiferroic system. Preveous works wehave performed reveled that all of transition temperature of magnetic and electric
properties are coincide each other. However, the experiments were performed at
off-line, that is, dielectric measurements
were performed at laboratory system sothat the transition temperature are not so
precisely consistent.
New measurement system was constructed on this work, and in situ measurements of magnetic scattering, dielectric constant and electric polarization are
now available. We have performed suchin situ measurements of ErMn2 O5 andTmMn2 O5 . In addition, new cryostat introduced at FONDER gives 2.7K, far below we
could achieve. Then new measurements
at very low temperature were also performed. The results were somehow slightly
controversial, and the interpretation of the
2D-ICM to 1D-ICM transition and 1D-ICM
to CM transition temperature against thedielectric transition of ErMn2 O5 must bechanged. Further, we have newly foundthat the lowest phase, LT-1DICM phase,is long-range stable phase. This phase
was considered that rapid quench treatment down to 8K could create as a shortrage ordering state. However, the experiment down to 2.7K revealed that long rage
1D-ICM with the propagation vector (1/2,0, qz ) is stable. Not only that this phaseshows drastic decrease of electric dipole
moment without anomaly of dielectric con-stant. The results of in situ experiment of
ErMn2 O5 are summarized in Figure. Magnetic propagation vector qx and qz , intensity of magnetic peak, electric polarizationand dielectric constant are shown as a function of temperature near the transition temperature around 2D-ICM to 1D-ICM to CMphase, and around CM to LT-1DICM phase.
These new evidence will give slightly different scenario we had, and the detail analyses is required.

Fig. 1. The results of in situ experiment of ErMn2 O5 .
Magnetic propagation vector qx and qz , intensity ofmagnetic peak, electric polarization and dielectric
constant as a function of temperature.

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1-1-48Structure Analysis of P-type Icosahedral Zn-Mg-Ho Quasicrystal
H. Takakura1 , T. Moriwaki1 , A. Yamamoto2 , T. J. Sato3 , H. Kimura4 and Y. Noda4
1 Division of Applied Physics, Graduate School of Engineering,
Hokkaido University, Sapporo 060-8628, Japan.
2 National Institute for Materials Science, Tsukuba 305-0044, Japan
3 Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106
4 Institure of Multidisciplinary Research for Advanced Materials,
Tohoku University, Sendai 980-8577, Japan.
Since the ﬁrst discovery of icosahedral
quasicrystals (i-QCs) in 1984 [1], structure determination of these exotic materials remains a challenging problem. The pZn75 Mg16 Ho9 belongs to a series of i-QCs
known as p-Zn-Mg-R (R = rare earth elements) that was found in 2002 [2]. It is
known that three large occupation domains(ODs, or atomic surfaces) in a unit cell characterize its six-dimensional (6D) structureby an x-ray diffraction study [3]. In addition, a triacontahedral cluster that is considered as an extended icosahedral clusterof Bergman type has been identiﬁed as oneof the fundamental building units for the
structure description [3]. Although, the 3D
structure can be understood as an aperiodic arrangement of such triacontahedralclusters, its detailed atomic structure is still
undetermined, since p-Zn75 Mg16 Ho9 is aternary alloy and the location of the lightest element, Mg, is not easy to determineby x-ray diffraction. In order to obtaincomplementary structural information to
x-ray diffraction technique for determining
a structure model of the p-Zn75 Mg16 Ho9 ,we have performed a neutron scattering experiment on this i-QC.
The neutron four-circled diffractometer
FONDER installed by Tohoku University
at the beam line T2-2, JRR-3M in JAERI
was used for the experiment. The neutron
wave length of 1.24 Å(Ge 311 monochromator) was used. The volume of single
crystal sample used was 66 mm3 . The intensity data of selected strong 544 Bragg
reﬂections (2θ < 150◦ ) were measured and324 reﬂections were observed at room temperature.

Using the present neutron diffraction
data, together with the structural phasesfrom a model by x-ray diffraction, nuclear
densities in the 6D space have been reconstructed (ﬁgure 1). The reconstructed nuclear densities exhibit ODs in which contribution from Mg atoms is enhanced compared with the electron densities that wereobtained by x-ray diffraction data [3]. In
particular, an extra small OD, which was
not recognized in the previous study, wasfound as indicated by the ellipse in Fig.1.
Structure reﬁnment based on a detaieldstructure model of p-Zn75 Mg16 Ho9 is now
under way.
References[1] D. Shechtman et al.: Phys. Rev. Lett. 53(1984) 1951.
[2] R. Sterzel et al.: Philos. Mag. Lett. 82 (2002)
443.
[3] H. Takakura et al.: Philos. Mag. 86 (2005)
621.

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1-1-49Phonon modes of beta-Na0.33V2O5
T.Kajitani, D.Abe, D.Igarashi, and Y.Miyazaki
Department of Applied Physics, Graduage School of Engineering, Tohoku University
Introduction
Vanadium bronze,beta-Na0.33V2O5, wasrecently found to undergo superconducting phase transition at 8K under 8Gpa by
Yamaguchi, Ueda and Mori1). Since then,doped vanadium bronze, beta-AxV2O5
with A=Na, Ka, Sr, Cu, Ag etc. and x=0.20.6, have been identiﬁed as a group ofn-type ceramic superconductors in a lowtemperature range under high pressure.
These materials exhibit relatively high negative Seebeck coefﬁcient, e.g., about 100microV/K at 380K for A=Cu and x=0.602).
The unit cell of beta-AxV2O53) consists ofthree different 1D VOn (n=5 or 6) sublattices extended parallel to b-axis, namely,
two leg ladders, two rows of corner shared
VO6 octahedra and zigzag VO5 squarepyramids, respectively. Doped cations sit
at roomy interstitial sites situated adjacent to the zigzag VO5 square pyramids.
Present neutron inelastic scattering measurment was aimed to elucidate phonon
spectra, i.e., DOS and low energy modes
related with the spin/charge ordering andstructural instabilities which could haveconnections with 2kf-CDW, superconductivity as well as high Seebeck effect being
observed for the doped vanadium bronzes, beta-AxV2O5.
Experimental Procedures
Beta-Na0.33V2O5 powder sample wasprepared by the solid sate reaction method.
Mixture of appropriate molar ratio of
Na2V2O7, V2O3 and V2O5 powders was
mixed in an agate mortar, then pelletizedand ﬁred at 650 celsius deg. for 12hrs in
vacuum. Same pellets were pulverized ,mixed and sintered at 650 celsius deg. fora couple of times. Neutron scattering experiment was carried out by the use of acold neutron spectrometer JRR3M-AGNES
at room temperature, 100K, and 10K. For
comparison, room temperature run was

carried out for the V2O5 reference powder
sample. Neutron inelastic intensities observed by 328 He3 gas counters were addedin an appropriate way then DOS curves
were calculated. Pulsed cold neutron rawas utilized
diation with lambda=4.22
through out the experiment.
Results
Figure 1 shows phonon-DOS spectra ofV2O5, Ca0.26V2O5, and Na0.33V2O5 samples obtained from the anti-Stokes side, i.e.,
the neutron energy gain side of the inelastic
scattering intensities. Phonon-DOS curvesof V2O5 and Ca0.26V2O5 were obtained
previously. Observed inelastic scattering
intensities are mostly due to the vibrationof vanadium atoms because of their verylarge incoherent scattering cross section, σi=5.08 barn, relative to oxygen and calcium
atoms. Discontinuity of DOS curves from
24meV to 36meV is due to the contamination of lambda/2 incident neutron beam.
There are obvious differences in the three
DOS curves in the range from 7 to 20meV.
V2O5 sample shows a peak intensity at
9meV but the DOS curves of Ca0.26V2O5and Na0.33V2O5 shows rather ﬂat features.
In Na0.33V2O5, some softening feature isseen at around 10meV relative to the calcium system.
References
1)T.Yamauchi, Y.Ueda and N.Mori; Phys.
Rev. B 29 (2002) 57002.
2)D.Abe; Master Thesis, Grad. School Eng.,
Tohoku Univ. 2007.
3)A.D.Wadsley;
Acta
Crystallogr.8(1955)695

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Fig. 1. Observed phonon density of states curves of
V2O5, Ca0.26V2O5, and Na0.33V2O5.

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1-1-50

Phonon Dispersions in the Thermo-electric Material of Bi0.88Sb0.12
M. Nishi, S. Tomiyoshi(A) and O. Yamashita(A)ISSP-NSL Univ. Tokyo, (A)Facul. Engineer. Ehime Univ.
Bi0.88Sb0.12 is known as a thermoelectricmaterial with a high cooling power under magnetic ﬁelds due to high mobility ofelectrons and holes [1] and from that it isalso inferred that the heat conduction byphonons may be affected by the application of strong magnetic ﬁelds [2]. So in thepresent experiments we try to investigate
this problem by measuring phonon dispersions without magnetic ﬁelds ﬁrst.
Single crystals of Bi0.88Sb0.12 were obtained with the brigeman method andthe mosaic width of the crystal used in
the present experiments was good enough(about 0.1 deg.) for phonon measure- ments
and the crystal was conﬁrmed to be consisted mostly with a single grain. A triple
axis neutron spectrometer of 4G was usedwith collimators of 40’-40’-40’-40’ and thesingle crystal sample was cooled to 77K byusing a refrigerator. Bi0.88Sb0.12 is a disordered alloy with the trigonal symmetry(R m) containing two atoms in a unit cellwhich usually indexed as a hexagonal cell.
Figure 1(a) shows acoustic branch ofphonon dispersions measured along thetrigonal axis (the c-direction in the hex.
cell). Along with our data Smith’s data ofpure Bi measured at 75K were inserted tocompare to our Sb added Bi data. Acoustic
branches of Bi0.88Sb0.12 almost agree withthat of Bi for longitudinal and transversal
modes, however, for longitudinal scans abranch which appears below TA mode wasobserved, which is not identiﬁed at present.
The branches along the c-direction suggestthat the force constants along the c-planes
are not much altered by the addition of Sb
atoms .
Figure 1(b) shows acoustic branches measured along the a-axis, which appear abovethat of pure Bi. This suggests that the addition of Sb makes the bonding between
atoms fasted in the c-plane. This is consis-

tent with the improvements of the thermoelectric properties for directions in the cplane by the addition of Sb in Bi.
References[1]R. Wolfe and G. E. Smith, Appl. Phys.
Lett. 1,5(1962).
[2] O. Yamashita, private communication.
[3] D. B. Smith, Unpublished Thesis, Los
Alamos Scientiﬁc Report No. LA- 3773
(1967).

Fig. 1. 1 (a) Phonon dispersions of Bi0.88Sb0.12
along the c-direction as a function of the wave vector q. The data of pure Bi [1] are shown. (b) Phonon
dispersions of Bi0.88Sb0.12 along the a-axis.

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1-1-51

In situ neutron diﬀraction study of formation and decomposition process inclathrate hydrate
Akinori Hoshikawa, Hiroshi Fukazawa, Hiroki Yamauchi, Naoki Igawa and Yoshinobu
Ishii
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
The neutron diffraction measurements
were carried out on HERMES installedat JRR-3. A single-crystal sapphire cell
was used as a high-pressure sample cell.
The Bragg peaks of the sapphire cell were
excluded by Cd Blade of HERMES.
Figure 1 (a) shows time resolved diffraction
patterns of methane hydrate (MH). Eachmeasurement was done for 14 min. Analysis was based on the previous crystal structure data [1, 2]. The temperature and pressure dependence of mass fraction was obtained as shown in Figure 1 (b).
The CH4 gas was gradually applied D2O
ice until 6 MPa at 216 K as isothermal process. The diffraction peaks of MH were observed in this condition and the mass fraction of MH was 0.05. The pressure was kept
at ca. 6 MPa for 18.5 hours. However, themass fraction of MH did not change. Wechanged temperature from 216 K to 240 K
and then the pressure increased to 6.7 MPa.
The CH4 gas was applied until 7 MPa at
240 K. And the pressure was kept at ca. 7
Pa for 18.5 hours. The mass fraction of MH
slightly increased to 0.07. Following, temperature increased to 260 K and the pressure changed to 7.5 MPa. The mass fractionof MH increased until 0.13.
Next, we released the pressure and decrease temperature. The mass fraction of
MH decreased to 0.07. We repeated tochange temperature in the same way although the pressure was only applied up
to 6 MPa at a maximum. In this case, themass fraction of MH increased until 0.1 at
240 K. Here, 0.13/7.5*6=0.104. Accordingly,
it is clariﬁed that the mass fraction of MH
was proportional to the CH4 gas pressure.
Finally, temperature was increased at 6
MPa as isobaric process. The D2O ice did
not melt at 277 K. When temperature in-creased to 282 K, the D2O ice melted andthe Bragg peak of MH grew rapidly. There
was no Bragg peak of D2O ice (Ih) at 282 K.
However, when temperature decreased to240 K, the Bragg peak of D2O ice appeared
and the mass fraction of MH was 0.6. Accordingly, methane hydrate covered D2O
ice and D2O water did not ﬂow out. In addition, it is proposed that unreacted waterremained because we used coarse-grained
powder of D2O ice (<400 micrometer).
As a result, it is clariﬁed that the growthrate depends on the pressure of CH4 gas,
although we considered that the growthrate didn t depend on the pressure under
the sufﬁcient pressure for the growth.
References
1) A. Hoshikawa, N. Igawa, H. Yamauchi,
and Y. Ishii: J. Phys. Chem. Solid., 66, 18101814 (2005).
2) A. Hoshikawa, N. Igawa, H. Yamauchi,
and Y. Ishii: J. Chem. Phys., 125, 034505(2006).

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1-1-52

Structural analysis and Observation of Spin-Gap
in Vanadium Oxide V4 O9
S. Yamazaski A , M. NishiB , M. Isobe A , H. Ueda A , K. OhoyamaC and Y. Ueda A
A Material Design and Characterization Laboratory, ISSP, University of Tokyo, Kashiwa
277-8581, JapanB Neutron Science Laboratory, ISSP, University of Tokyo, Tokai 319-1106, Japan
C Institute for Materials Research, Tohoku University, Sendai 980-8577
Among various binary systems, a number of binary vanadium oxides are reported. They have been searched for andextensively studied for a long time. However there remains one binary vanadiumoxide whose crystal structue is not known
yet. Obviously, its physical properties are
not reported. That compound is V4 O9 .
Here, we present the crystal structure andphysical properties of V4 O9 .
V4 O9 is unstable at high temperature.
Hence, it is impossible to obtaion single
crystals. Using V4 O9 powder samples
we started structural analysis by meansof transmission electron microscopy(TEM)and powder X-ray diffraction(XRD). And
then, we determined lattice constants andpositions of vanadium atoms. But it was
difﬁcult to identify the positions of oxygen atoms, since the diffraction intensity ofoxygen atom is too weak in XRD. To get the
information about oxygen positions, powder neutron diffraction measurements(ND)
were carried out on the Kinken powder
diffractometer for high effciency and highresolution measurements, HERMES (T1-3)
at JRR-3M of JAERI in Tokai with wave
length 1.82646(6) Å. In the result of the experiment, oxygen atomic position was improved. Furthermore, it was clariﬁed that
previous our estimation of the space groupand the unit cell is wrong. Combined with
TEM and ND, we reassingned the spacegroup to Cmcm with a doubled unit cell.
The precise structural analysis of V4 O9 is
now in progress.
Temperature dependence of magnetic
susceptibility of V4 O9 indicates spin-gap
behavior. To elucidate details of spin-

gap nature, inelastic neutron scattering
mesasuremets were carried out on the
ISSP-PONTA triple axis spectrometer (5G）
at JRR-3M of JAERI in Tokai. The obtained
spin-gap energy is 8.3 meV (see Fig. 1)
which is consistent with the χ measurement. Constant-Q scan at 2.3 K with a peakat Q=1.2 Å−1 can be ﬁtted by dimer model.
From structural point of view , our V4 O9model can be regarded as an isolated dimer
system. The result is reasonable with ourV4 O9 model.

Fig. 1. Neutron scattering proﬁles at Q=1.2 Å−1 atseveral tempertures.

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JAEA-Review 2008-067

1-1-53Phase transition mechanism of KTaO3 doped with Li by neutron quasi-elastic
scatterings
Y.Uesu, H.Yokota, S.Asanuma, Y.Tsunoda
Faculty of Science & Engineering, Waseda University
Quantum paraelectrics KTaO3 becomes arelaxor when Li ions are doped in K+ site.
KTaO3:Li (KLT) is a new class of relaxor inwhich A-sites are occupied with two kindsof isovalent ions (K+ and Li+). Therefore,
the structure is much simpler thanthat of widely investigated relaxors ofPb(B1,B2)O3 compounds, and could give a
new approach to the general understanding of relaxor nature and its origin.
In this investigation, we performed neutron diffuse scattering experiments to conﬁrm the appearance of polar nano-regions(PNR) in the temperature range which
we have recently found using second
harmonic generation microscopic observations and high-presision X-ray diffraction
studies.
The results are still preliminary, nevertheless interesting for further investigations.
The neutron diffuse scattering distribution(DSD) of KLT-7% at 85K around the reciprocal point (110) is shown in Fig.1.
When we subtract the DSD at room temperature, we obtain the rod-like distribution stretching along [100] and [010] directions.
We also measured the temperature dependence of DS and found that it exhibits a
sharp increase at Tc. This phenomenon indicates that DS of KLT-7% consists of thecritical diffuse scattering (critical opalescence ) and that originating from PNRs.

Fig. 1. Neutron diffuse scattering of KLT-7% around(110) reciprocal lattice point at 85K.

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1-1-54

Colloidal Complexes obtained from Charged Diblock Copolymer and Oppositely
Charged Surfactant
Masahiko Annaka, Kanae Morishita
Department of Chemistry, Kyushu University
During the past decade, there has beena widespread interest for the design andsynthesis of polymer-based colloidal particles of high stability in aqueous solutions.
Among these particles, colloidal complexes
have emerged as a new type of microstructure with potential applications in drug delivery. The block copolymer is the key feature of the electrostatic self-assembly. The
overall size and the stability of the colloid
depend on the nature of the electrostatic
charges, on the molecular weight, and on
the ﬂexibility of the chains.
We report on the formation colloidal complexes resulting from the electrostatic selfassembly of polyelectrolyte-neutral diblock
copolymers and oppositely charged surfactant. In the diblock/surfactant system, thepolyelectrolyte block is negatively charged
poly(sodium acrylate) and the neutral
block is poly(N-isopropylacrylamide). The
copolymer is studied in aqueous solution
in the presence of cationic surfactant dodecyltrimethylammonium bromide (DTAB).
Using light and neutron scattering experiments, and ﬂuorescence spectroscopy,
the diblock copolymer associate with oppositely charged surfactant into colloidal
complex that have core-shell microstracture. For surfactant/polymer charge ratio Z lower than a threshold (Zc ˜ 0.4),
the complexes are single DTAB micelle
attached by few copolymers. Above thethreshold, the formation of hierarchicalcore-shell structure takes place. The coreof typical radius 15-17 nm is composedof densely packed surfactant micelles
connected to polyelectrolyte blocks. The
corona of the colloidal complex is constituted from poly(N-isopropylacrylamide).
Typical hydrodynamic radius of the complex is around 30 nm. Due to the LCSTtype thermosensitive property of poly(N-isopropylacrylamide) corona, the complexes form larger aggregates with the hydrodynamic sizes ˜ 300 nm. We have also
investigated the colloidal stability under
the different degree of neutralization andthe presence of salt.

Fig. 1. SANS proﬁles for 0.4wt% PNIPAM-bPANa/DTAB in D2O at various temperature andschematic illustrations of complexes.

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1-1-55
New-Type Phase Transition of Honeycomb Lattice System Li2 RuO3
Y. Miura, Y. Yasui, M. Sato, N. Igawa1 and K. Kakurai1
Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Li2 RuO3 has layers of the honeycomb lattice of edge-sharing RuO6 octahedra witha LiO6 octahedron at the corner of eachhexagon of RuO6 . The Ru valence is +4
and the four electrons exist in the 4d t2g orbits. Li atom layers are between the honeycomb layers. For this system, we have founda phase transition at temperature T = Tc ∼540 K.1) With decreasing T , the electrical resistivity exhibits an anomalous increase at Tc ,suggesting the “metal-to-insulator”-like transition, and the magnetic susceptibility also
shows a sharp decrease.
To clarify the mechanism of the transition, powder neutron diffraction measurements were carried out at room temperature(RT) and 600 K using a high resolution powder diffractometer (HRPD) installed at JRR3 of JAEA in Tokai, and Rietveld analyses
were carried out using RIETAN-2000. Although the space group at RT was previously reported to be C2/c2, 3) , several superlattice peaks which cannot be explained by
C2/c were observed. To reproduce these reflections, we adopt the space group P 21 /m.
The result of the Rietveld fitting with P 21 /m
is rather well. As the possible space groupat 600 K, we have adopted C2/m, the minimal non-isomorphic supergroup of P 21 /m,
because this space group allows the secondorder transition at Tc . (From the experimental data, it is not easy to definitely distinguish
if it is the second-order one or the first-orderone.)
At 600 K, Ru atoms form an almost ideal
honeycomb structure. At RT, a significant
reduction (by ∼ 13 %) of the bond lengths
was found between two of the six Ru-Ru pairsof the hexagon (figure (right panel)). To answer why such drastic changes take place, we
consider the coupling of the lattice distortion
with the formation of the molecular orbits of
原子炉：JRR-3

装置：HRPD(1G)











Figure 1: The distortion pattern of Ru-honeycombskeleton at RT (left) and the energy levels of themolecular orbits of Ru4+ -Ru4+ pairs (right) below Tc .
The electrons in these levels are shown by the arrows
presenting the spin directions.

the t2g electrons of Ru4+ -Ru4+ of edge sharing RuO6 octahedra. The energy levels of thebonding and corresponding antibonding orbits are shown in the Figure 1(right), where
we can see that the nonmagnetic electron configuration is realized below Tc .
Although transitions accompanied with thesignificant anomalies of the electrical resistivity and the magnetic susceptibility similar to those of the present system have beenreported for La4 Ru2 O10 with corner-sharing
RuO6 octahedra and for Tl2 Ru2 O7 with a pyrochlore structure, their microscopic mechanisms are different from that presently proposed. Li2 RuO3 with edge-sharing RuO6 octahedra is considered to present, as far as weknow, a new type of phase transitions associated with the structural distortion inducedby the molecular-orbit formation of the d electron states.
References
1) Y. Miura, et al., J. Phys. Soc. Jpn., 76, 033705(2007).
2) J. F. Durac, C. R. Acad. Sc. Paris Ser. B, 270,
223(1970).
3) A. C. W. P. James and J. B. Goodenough, J. Solid
State Chem., 74, 287(1988).

分野：中性子散乱（構造）－ 91 －

JAEA-Review 2008-067

1-1-56
Magnetic Microstructure of LaMnO3+δ Nanocrystals in Mesoporous Silica
H. Kira, H. Tamura, Y. Murakami, T. Shinohara1 and J. Suzuki1
Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578
1Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195

We have synthesized a perovskite-type
manganite LaMnO3+δ (LMO) with an average size of 20 nm to study the characteristic electronic states in nanocrystals1, 2) .
The magnetization, susceptibility and neutron diffraction measurements have revealed
that the ferromagnetism (FM) with TC =260 K coexists with the antiferromagnetism(AFM) with TN = 90 K. It is reasonable for
us to assume that LMO nanocrystals of large
AFM core with a short correlation length of∼ 5 nm were coated with a thin FM shell.
We performed small-angle neutron scattering(SANS) measurements at SANS-J at JRR-3
so as to confirm the core-shell magnetic microstructure of the LMO nanocrystals.

q range 0.1 nm−1 < q < 1 nm−1 . Thus
it is considered that the observed magnetic
SANS spectrum in this q range originatesfrom the intra-particle contributions and theq dependence of the magnetic SANS spectrum changes into q −4 in q > 1 nm−1 . Thenthe thickness of the FM shell is estimated tobe less than 1 nm, which is consistent withour core-shell model. It is considered that
the FM state occurs through the double exchange mechanism owing to the hole doping
near the surface with the excessive oxygen.
The hole-doped bulk LMO with a rhombohedral structure shows only ferromagnetism but
no antiferromagnetism. Thus the rhombohedral AFM phase newly appeared is ascribedto the size effect.

We used an average wavelength (λ = 0.4nm) with a relative wavelength spread ∆λ/λ
∼ 10% at sample to detector distances of 2.5
and 10 meter, respectively, to cover a magnitude of the wavevector transfer range 0.02
nm−1 < q < 2 nm−1 . The measured intensities were normalized by the intensities
of a standard aluminum sample. The magnetic SANS intensity I(q) was obtained bysubtracting the nuclear scattering obtained at
300 K from the total SANS intensity obtained
at 9 K with applied field of 1 T (Fig. 1).
We have found a definite ferromagnetic contribution in the magnetic SANS spectrum.
A characteristic change in the slope of thescattering curve around q = 0.1 nm−1 is associated with the size of LMO nanocrystals,
and the q −2 dependence in the q range q <0.1 nm−1 is attributed to the effect of interparticle scattering. In the high q region, I(q)is generally expected to decrease according
to a function of q −4 , which is well known
as Porod’s law, however, the magnetic SANS
spectrum exhibits a q −3.5 dependence in the
原子炉：JRR-3

装置：SANS-J(C3-2)

Figure 1: Ferromagnetic SANS spectrum of LMO
nanocrystals in mesoporous silica.

References
1) H. Kira, et al., AIP Conference Procedings, 850,
1157(2006).
2) H. Kira, et al., J. Magnetism Magnet. Mater.,
310, 2480(2007).

分野：中性子散乱（構造）－ 92 －

JAEA-Review 2008-067

1-1-57
Crystal Structure Analysis of LiGa5 O8 by Neutron Powder Diffraction
H. Yamauchi, T. Suzuki1 and Y. Ohishi1
1

Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Optical Functional Materials Laboratory, Toyota Technological Institute, Nagoya, Aichi 468-8511

Recently, many researchers have developeda type of glass-ceramic composites in whichnanosize crystalline phase including Ni ionswere frozen in the glass matrices. Transition
metal-doped glasses are generally not applicable to gain media for laser and optical amplifiers, since nonradiative decay processes dominate the relaxation of the excited state intransition metals and the quantum efficiency
is very low in glasses. However, transition
metals can have sufficiently large quantum efficiency in single crystals, though it is very difficult to fabricate single crystal fibers. Glassceramics have the advantage of both crystalline and glass materials.
Nickel stably takes the divalent state in almost all the hosts and shows the broadband
near-infrared emission from Ni2+ ions. It is
expected that the Ni2+ ions occupy the octahedral site of spinel oxides in crystalline
phases from the absorption and emission spectrum. Transparent Li2 O-Ga2 O3 -SiO2 glassceramics embedding Ni-doped nanocrystals
are very attractive as a host matrix for Nidoping 1) . If Ni2+ ions are incorporated into
the LiGa5 O8 nanocrystals in glasses, highpotential glass-ceramics can be synthesized.

In this study we performed neutron powder
diffraction experiments in order to clarify the
crystal structure of LiGa5 O8 .
The neutron diffraction experiments werecarried out on the high resolution powder
diffractometer HRPD (λ = 0.18229 nm), using
a powder sample synthesized by the conventional solid state reaction. The horizontal
collimation was 12 - (monochromator) - 40 (sample) - 6 - (detector). The crystal structure was determined by the Rietveld analysis
using the program RIETAN-2000 2) .
Figure 1 shows the observed diffraction
pattern (plus marks) and calculated intensity after Rietveld refinement (solid line) of
LiGa5 O8 . The diffraction pattern was satisfactorily explained by the cubic type structurewith a space group P 43 32. This symmetry
type structure has an octahedral 12d site likethe octahedral 16d site in spinel oxides. Basedon this result, next diffraction experiments for
Ni: LiGa5 O8 are under contemplation.
References
1) T. Suzuki, et al., Appl. Phys. Lett., 86, 131903(2005).
2) F. Izumi, et al., Mater. Sci. Forum, 321-324, 198(2000).

3

Intensity (counts/1100 mon.)

25x10

20

LiGa5O8

15

obs.
calc.

10
5
0
10

20

30

40

50

60

70

80

90

100

110

120

130

140

Scattering angle (deg.)
Figure 1: The high resolution neutron powder diffraction pattern of LiGa5 O8 at room temperature.

原子炉：JRR-3

装置：HRPD(1G)

分野：中性子散乱（構造）－ 93 －

150

JAEA-Review 2008-067

1-1-58
Neutron Diffraction Study on Successive Structural Phase Transitions of
TlCoCl3
Y. Nishiwaki, A. Oosawa1 , K. Kakurai2 and T. Kato3
Department of Physics, Tokyo Women’s Medical University, Shinjuku-ku, Tokyo 162-8666
1
Department of Physics, Sophia University, Chiyoda-ku, Tokyo 102-8554
2
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
3
Faculty of Education, Chiba University, Inage-ku, Chiba 273-8522

Here we closely investigated q-scan profiles
on the (h h 2) line of TlCoCl3 and found asmall but definite peak at ( 61 16 2), which appeared only in phase IV (68 K< T <75 K).
The representative profiles of (h h 2) fromh = 0.1 to h = 0.4 at 86.4 K (phase III),71.7 K (phase IV) and 60.0 K (phase V) are
shown in Fig.1(a). The temperature dependence of the height of ( 16 61 2) peak is shownin Fig. 1(b). The temperature dependenceof ( 13 13 2) and ( 14 41 2) peaks that characterize phases III (75 K< T <165 K) and V(T <68 K), respectively, were also measured.
As a result, we confirmed that the phase IV
原子炉：JRR-3

装置：TAS-2(T2-4)

structure was characterized by the ( 61 61 2)
peak. We proposed√possible√crystal structuresof phase IV with 2 3a × 2 3a × c unit cells.
11

TlCoCl3
hh2
86.4K

10
Neutron Counts (/20s)

9

10

7

10

71.7K

5

10

3

60.0K

10

(a)

1/4

1/6

1

10

0.15

0.20

0.25
h (r.l.u)3

16x10
Neutron Counts (/30s)

Successive structural phase transitions of
TlCoCl3 are studied through single-crystal
neutron diffraction measurements. The measurements were performed with the tripleaxis spectrometer TAS-2.
TlCoCl3 is
one of the KNiCl3 family compounds.1–3)
The KNiCl3 family compounds are distorted from the CsNiCl3 -type structure (spacegroup P 63 /mmc) through successive structural phase transitions. Each structural phaseis labeled as I, II, III, IV or V, from the hightemperatures. The CsNiCl3 -structure has a-NiCl3 - chain along the c-axis, and the chainsform a triangular lattice on the c-plane. The
lattice deformation of the KNiCl3 family compounds is characterized by upward or downward shifts of the chains along the c-axis.
The crystal symmetries of phase II, III andV structures of TlCoCl3 were reported to be
P 63 /mmc, P 63 cm and P bca, respectively4) .
The chain shift along the c-axis of the P 63 cm
and P bca structures was arranged in an upup-down and up-up-down-down manner in aunit cell, respectively. However, the phase IV
structure was not determined.

12

Tst4

0.35

Tst3

cooling

10
8
6
4

heating

20(b)

TlCoCl3(1/6 1/6 2)

14

1/3
0.30

60

65

70
75
Temperature [K]80

Figure 1: (a) Neutron diffraction intensities of
TlCoCl3 scanned parallel to (h h 2) directions at T
= 86.4 K (phase III), 71.7 K (phase IV) and 60.0 K(phase V) with deliberately shifted base lines. (b)Temperature dependence of ( 16 16 2) peak height.

References
1) D. Visser, G. C. Verschoor and D. J. W. Ijdo,
Acta Crystallogr. B, 36, 28(1980).
2) K. Yamanaka, Y. Nishiwaki, K. Ito, T. Mitsui,
T. Tojo and T. Atake, J. Therm. Anal. Calorim.,
70, 371(2002).
3) Y. Nishiwaki, K. Iio and T. Mitsui, J. Phys. Soc.
Jpn., 72, 2608(2003).
4) Y. Nishiwaki, T. Kato, Y. Oohara, A. Oosawa,
N. Todoroki, N. Igawa, Y. Ishii and K. Ito, J. Phys.
Soc. Jpn., 75, 034707(2006).

分野：中性子散乱（構造）－ 94 －

JAEA-Review 2008-067

1-1-59Location of Deuterium Atoms in BaSn0.5 In0.5 O2.75
by Neutron Powder Diffraction at 77-473 K
T. Nagasaki1 , T. Ito2 , K. Iwasaki2 , M. Yoshino2 , N. Igawa3 and Y. Ishii3
EcoTopia Science Institute, Nagoya University, Nagoya 464-8603
Department of Materials, Physics and Energy Engineering, Graduate School of Engineering,
Nagoya University, Nagoya 464-8603
3
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
12

attributable to deuterium atoms is almost independent of temperature and basically thesame as that at 10 K4) , indicating that thedeuterium atoms are located at or very close
to the 12h site with an O-D distance of 1.0 Å
at these temperatures. This is the first determination by neutron diffraction of hydrogen
position in a proton-conducting oxide at elevated temperatures. On the other hand, wecannot find any features suggesting diffusion
paths of deuterium atoms or disorder of otheratoms in the scattering length density distributions.

Aliovalently-doped perovskite oxides often
show significant proton conductivity in ahumid atmosphere at high temperatures1) .
While several computational approaches2)
have yielded consistent results with respect tothe hydrogen site in these materials, none of
the neutron diffraction studies3) had verified
the results until our latest study4) revealed
that the deuterium atoms in D2 O dissolved
BaSn0.5 In0.5 O2.75 at 10 K are located at orvery close to the 12h site of the perovskite
structure (space group Pm 3̄m) with an O-D
distance of 1.0 Å.
In the present study, we measure neutron
diffraction patterns of BaSn0.5 In0.5 O2.75 withand without dissolved D2 O at higher temperatures. The diffraction data, especially whenanalyzed by the maximum entropy method(MEM), might be able to visualize the diffusion paths of hydrogen atoms and/or dynamic
disorder (momentary displacement) of otheratoms associated with hydrogen diffusion.
The BaSn0.5 In0.5 O2.75 samples with andwithout dissolved D2 O were prepared by thesame procedure as before.4) The deuterium
concentration in the “wet” sample was evaluated to be 0.21 D/Ba by thermogravimetry. The neutron powder diffraction data
(λ =1.823 Å) of the samples were collected
at 77 K, room temperature and 473 K using a high resolution powder diffractometer(HRPD). The data were analyzed by the
maximum entropy method (MEM, program
PRIMA) as well as the Rietveld method (program RIETAN-2000)5, 6) .
Figure 1 shows the distribution of neutron
scattering length density in the “wet” samples obtained by the final MEM analysis after the REMEDY cycle5, 6) . The distribution
原子炉：JRR-3

装置：HRPD(1G)



















Figure 1: Scattering length density distributions on
the (100) plane of D2 O-dissolved BaSn0.5 In0.5 O2.75 at(a) 77 K, (b) RT and (c) 473 K determined by the
MEM analysis7) .

References
1) H. Uchida, et al., Solid State Ionics, 34, 103(1989).
2) For example, M. Yoshino, et al., Solid State Ionics, 162-163, 127(2003).
3) For example, N. Sata, et al., Phys. Rev. B, 54
15795(1996).
4) T. Ito, T. Nagasaki, et al., Solid State Ionics, 178,
13(2007).
5) F. Izumi, et al., Mater. Sci. Forum, 321-324,
198(2000).
6) F. Izumi, et al. :“Recent Research Developmentsin Physics”, Transworld Research Network,
Vol. 3, Part II, 699(2002).
7) T. Ito, T. Nagasaki, et al., Solid State Ionics, 178,
607(2007).

分野：中性子散乱（構造）－ 95 －

JAEA-Review 2008-067

1-1-60Observation of CO2 Molecule in Clathrate Hydrate by Maximum Entropy
MethodN. Igawa, T. Taguchi, H. Fukazawa, H. Yamauchi and Y. Ishii
Quantum Beam Science Directorate, JAEA, Tokai-mura, Ibaraki-ken 319-1195

Clathrate hydrates consist of two typesof cages (called “large” and “small” cages)
formed by water molecules and traps encaging
gas molecules inside each cage. The aimof this study is the precise crystal structural analysis of CO2 hydrate focused on the
motion behaviors of the inclusion CO2 gas
molecule in the cages. The neutron diffraction
patterns of CO2 hydrate were measured byusing a high resolution powder diffractometer(HRPD) in the temperature range from 10 K
to 200 K. A neutron wavelength of 0.1823 nm
was used and diffraction data were collectedin the 2θ range from 20◦ to 165◦ with a stepangle of approximately 0.05◦ . The obtained
diffraction patterns were analyzed by the Rietveld method using the program “RIETAN2000”1) . After the Rietveld analysis, the Maximum Entropy Method (MEM) analysis was
carried out using the program “PRIMA”2) .

Figure 1: Scattering length density map of CO2 hydrate at 10 K.

Figure 1 shows the scattering length density map of CO2 hydrate at 10 K analyzed
using MEM. Two unit cells are shown in thisfigure. The small cage is located at the cornerand center of the unit cell and the large cage islocated at the faces of the unit cell. Carbon of
the CO2 molecule is observed in the small cage
though oxygen is not observed. It is indicatedthat the CO2 molecule spins freely around its
原子炉：JRR-3

装置：HRPD(1G)

carbon atom. This behavior is independent of
temperature from 10 K to 200 K. Both carbon and oxygen, however, are observed in thelarge cage: oxygen is distributed around thecarbon on the parallel plane to the hexagonal facet of the large cage. Figure 2 shows
the temperature dependence of the scattering length density map of the large cage. Although the motion of CH4 in the large cage of
methane hydrate is drastically changes from10 to 116 K3) , the motion of CO2 in those of
CO2 hydrate is independent of temperature.

Figure 2: Temperature dependence of the scattering
length density map of the large cage of CO2 hydrate.

References
1) F. Izumi and T. Ikeda, Mater. Sci. Forum, 198,
321(2000).
2) F. Izumi and R. A. Dilanian: “Recent Research
Developments in Physics”, Transworld Research
Network, 3, 699(2002).
3) A. Hoshikawa, N. Igawa, H. Yamauchi and Y. Ishii,
J. Phys. Chem. Sol., 66, 1810(2005).

分野：中性子散乱（構造）－ 96 －

JAEA-Review 2008-067

1-1-61
Neutron Study Suggests Ferroelectric Ice in the Universe
H. Fukazawa, H. Yamauchi, N. Igawa and Y. Ishii
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

In the Galaxy, ice is one of the major solid
components in low temperature environment.
Ice grains have been identified by infrared
spectra in interstellar molecular clouds and ingaseous clouds around low-temperature stars.
Big icy planets have been discovered beyond
our solar system. Huge ice mass exists onplanets and moons, such as Neptune, Uranus,
Pluto and Charon, in our solar system. Smallbodies like Saturn’s rings and comets are also
composed of icy grains.

Figure 1: Ice XI with proton-ordered arrangement has
small circles that show fully occupied protons. Since
water molecules are aligned along c-axis (vertical direction), ice XI has ferroelectricity.

Below 200 MPa, crystalline ice becomes a
structure, which named as ice I (one) or ice XI(eleven). Whether ice in the Universe exists
as ice XI, is an attracted question, because ice
XI is ferroelectric (Fig.1). Long-range electrostatic forces, caused by the ferroelectricity,
might be an important factor for planet formation. Furthermore, the grains may play
important roles in chemical evolution includ原子炉：JRR-3

装置：HRPD(1G)

ing the formation of prebiotic organic materials. However, in astronomical observations to
identify an icy object, it is not clear whether
ice XI exists or not on the surface. Features of
the infrared spectrum of ice XI are unknown
because of the difficulty in creating perfect ice
XI in the laboratory.
We have studied the conditions required
for the formation of ice XI. In 06’ we measured diffraction profiles of ice with manykinds of dopants using a high resolution powder diffractometer (HRPD). We carefully created samples of ice that contained impurities,
which assisted the ice XI conversion process acatalyst. The results indicate that ice with an
ionized defect (OH− ) transforms to an enoughice XI after several hundred hours. We studied an irradiated ice. The gamma- and UVirradiation also creates OH− . The detailed
analysis is in progress.
Normal ice naturally has a small amountof the defect. Thus, without adding the impurity compound, it would take 10,000 years
for normal ice to transform into ice XI. While
this time scale is much longer than what canbe measured in a laboratory, it is not too longin the astronomical time scale. Furthermore,cosmic rays assist the formation. Thus, we expect that ice XI exists in the Universe1) . We
reported this research in the press and it was
taken up by the mass media2) . We hope that
it would spur astronomers to find frerroelectric ice XI in the future.
References
1) H. Fukazawa, et al., Astrophys. J. Lett., 652, 57(2006).
2) Science, 315, 18(2007).; Physorg.com,
http://physorg.com/news83862687.html.;
Japanese newspapers (Joyo shimbun, 1/12, (2007).;
Kagaku shimbun, 1/19, (2007).; Asahi shimbun,
2/22, (2007).).

分野：中性子散乱（構造）－ 97 －

JAEA-Review 2008-067

1-1-62Analysis of Crystal LiMn2 O4 Size in Composite Sample by Neutron Scattering
K. Basar, Xianglian, S. Siagian, K. Ohara, T. Sakuma, H. Takahashi1 , O. Abe2 , N. Igawa3
and Y. Ishii3
1

Institute of Applied Beam Science, Ibaraki University, Mito 310-8512, Japan
Institute of Applied Beam Science, Ibaraki University, Hitachi 316-8511, Japan
2
Faculty of Engineering, Ibaraki University, Hitachi 316-8511, Japan
3
Japan Atomic Energy Agency, Tokai 319-1195, Japan

Lithium metal transition compounds arepromising materials for cathodes in lithiumion batteries. In this group of materials,
LiMn2 O4 is an attractive and important material because it is relatively cheaper and lesstoxic. We report the use of a neutron scattering experiment to analyze the anneal temperature effect on the crystalline size of composite LiMn2 O4 .
The sample was prepared by dry mixingof LiOH and MnO2 then milled for 3 hours
at frequency of 2 Hz to perform a groundproduct. After that, the mixture was heatedat temperature 200◦ C for 16 hours. To analyze the anneal temperature effect on the
crystalline size of LiMn2 O4 in the composite samples, we divided the whole sample into
three parts: sample A annealed at 400◦ C for
3 hours, sample B annealed at 500◦ C for 3
hours and sample C annealed at 800◦ C for 3
hours. Neutron scattering measurements atroom temperature have been performed forsamples A, B and C by HRPD. The data werecollected in the 2θ range from 20◦ to 150◦ withstep angle of 0.05◦ .
Figure 1 shows the neutron scattering intensity of powder LiMn2 O4 composites forsamples A, B and C. Rietveld analysis has
been performed on the neutron scattering
intensities of samples A, B and C using
RIETAN-20001) . The crystal of LiMn2 O4 isassumed to belong to cubic type structurewith a space group Fd3m2) . The full-widthof half maximum of Bragg lines of LiMn2 O4
in the samples A, B and C shows a tendency to decrease with increasing the annealing temperature. The average crystallite sizesof LiMn2 O4 were calculated using Scherrer
equation. The obtained average size of a crys原子炉：JRR-3

装置：HRPD(1G)

tal LiMn2 O4 in the composite samples areabout 5, 20 and 130 nm for samples A, B
and C, respectively. In a former report of
LiNiO2 , the temperature dependence of diffuse scattering intensity decreases drasticallywith increasing annealing temperature. The
strong diffuse scattering intensity was related
to the amount of starting material LiOH in
the composite samples3) . However, in the caseof LiMn2 O4 , the diffuse scattering intensity
does not change so much in samples A, B and
C. The amount of starting material LiOH isvery small even in sample A.

Figure 1: Neutron scattering intensities of powder
LiMn2 O4 composites at room temperature.

References
1) F. Izumi and T. Ikeda, Mater. Sci. Forum, 321-324,
198(2000).
2) K. S. Yoo, N. W. Cho and Y. J. Yo, Solid State
Ionics 113-115, 43(1998).
3) K. Basar, Xianglian, H. Honda, T. Sakuma, H. Takahashi, O. Abe, N. Igawa and Y. Ishii: “Proceedings of the 10th Asian Conference on Solid State
Ionics, Kandy, Sri Lanka 2006, eds B. V. R. Chowdari, et al.”, World Scientific, 121(2006).

分野：中性子散乱（構造）－ 98 －

JAEA-Review 2008-067

1-1-63Ferroelectric Phonon Mode in Relaxor K1−x Lix TaO3
S. Wakimoto, G. A. Samara1 , R. K. Grubbs1 , E. L. Venturini1 , L. A. Boatner2 , G. Xu3
and G. Shirane3
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
2
Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
3
Brookhaven National Laboratory, Upton, New York 11973, USA
4
Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
1

We have performed neutron scattering experiments at the TAS-2 triple axis spectrometer to study the FE mode in the KLT (x =0.10) sample which shows the ferroelectrictransition at 110 K with an intent to confirm
the phonon contribution to the dielectric behavior in KLT.
Dielectric measurements indicate the ferroelectric transition of the x = 0.10 sample
at Tc = 110 K. This has been confirmed by
the neutron scattering measurements showing that the nuclear Bragg peak width andintensity increase rapidly below 110 K, suggesting a transformation of the lattice into alower symmetry due to the ferroelectric transition. However, the crystal structure probed
by the neutron scattering with a tight collimation sequence, 15’-10’-20’-10’, is cubic inaverage even below Tc , implying that only a
原子炉：JRR-3

装置：TAS-2(T2-4)

small portion of the sample is ferroelectricallytransformed.
The FE mode has been measured with thecollimation sequence of 15’-80’-80’-open. Figure 1 shows the phonon the energy squared asa function of temperature for KLT x = 0.10
and 0.05. We have found that the x = 0.10
sample exhibits an additional phonon mode
which hardens below Tc as shown by the open
squares. We assign this as an FE mode originating from the ferroelectrically ordered region. Such hardening of the FE mode below
Tc has been observed in the displacive ferroelectic materials such as PbTiO3 , and relaxors, PMN and Pb(Zn1/3 Nb2/3 )O3 (PZN).
We have detected the hardening of the FE
mode below Tc in the relaxor KLT for the firsttime. Combined with similar results for therelaxors PMN and PZN, it is shown that the
FE mode has an important role in the perovskite relaxors.
200

150

KLT : Li 10%

ω02 ( meV2 )Relaxor K1−x Lix TaO3 (KLT) shows richdielectric properties. The system is quantum paraelectric at x = 0. With substitution of a small amount of K+ ions with
Li+ the system shows relaxor behavior, andthen further substitution triggers ferroelectric transition. Although the relaxor behavior is expected to arise from the relaxational
behavior of the off-center Li ions, the roleof the zone-center transverse-optic ferroelectric (FE) mode is not well understood yet.
Last year, we have studied the diffuse scattering and the FE mode in the relaxor KLT
with x = 0.05 and found atomic displacements arising from the condensation of the
FE mode superimposed on the uniform phaseshift, same as the case of Pb(Mg1/3 Nb2/3 )O3(PMN), indicating the contribution of the ferroelectric mode.

100

KLT : Li 5%

50

0

50

100

150

200

250

300

Temperature (K)Figure 1: Squared phonon energy of the zone-centertransverse optic phonon as a function of temperaturefor KLT10 % (open symbols) and KLT5 % (black circles).

分野：中性子散乱（構造）－ 99 －

JAEA-Review 2008-067

1-1-64
Assessment of Vanadium Alloys
A. Hoshikawa, S. Kakei1 , H. Yoshinaga1 , T. Ishigaki and T. Kamiyama2
J-PARC Center, Tokai, Ibaraki 319-1195
Ako Laboratory, Taiyo Koko Co., Ltd., Ako, Hyogo 678-0232
2
Institute of Materials Structure Science, KEK, Tsukuba, Ibaraki 305-0801
1

A sample holder is necessary for neutron
powder diffraction measurements. Vanadiumis usually used as the sample holder. Since thecoherent scattering length of vanadium is notzero but a small negative value (-0.443 fm),
Bragg peaks from the sample holder cannot
be neglected in the future. In the Japan Proton Accelerator Research Complex (J-PARC)
project, high-intensity neutron beams are going to be produced with MW-class high power
pulsed proton beams. Therefore, it is important to develop materials for the sample
holder. Recently, a metal with a positive coherent scattering length is mixed with vanadium and some new vanadium alloys are synthesized (V-Al, V-Cr, V-Fe and V-Ni alloys).
It is necessary to check these vanadium alloys. Therefore, we investigated these vanadium alloys using a high resolution powder
diffractometer (HRPD) at JRR-3.
Measured samples were V, V-Al, V-Cr, VFe, V-Ni and V-Nb alloys. For the control experiment, we prepared V, which is pure vana-dium, and V-Nb alloy confirmed as a ‘null alloy’. Here, ‘null alloy’ is an alloy whose coherent scattering length is zero. These samples were supplied by Taiyo Koko Co., Ltd.
(Japan). We used bulk samples and typical sample dimensions were 23×23×5 mm3 .
These samples are rotated during measurement. The 1st collimator before the Ge
monochromator was opened because of highintensity. Each sample was measured for a
day and data were collected over the 2θ rangeof 2.5–160◦ because of ascertaining the presence of impurity phase.
Neutron powder diffraction patterns areshown in Fig.1. Tick marks in the figure
show the peak positions of vanadium. Some
Bragg peaks are clearly observed for V. In
powder diffraction patterns except V, there isno vanadium peak and no other Bragg peak.
Accordingly, we confirmed that these vanadium alloys were ’null alloy’. Next, we should
investigate workability for the sample holder.

JRR-3 HRPDCounts/a.u.

λ = 1.8237Å

40

60

80

100

120

140

2θ / °

Figure 1: Neutron powder diffraction patterns of vanadium alloys.

原子炉：JRR-3

装置：HRPD(1G)

分野：中性子散乱（構造）－ 100 －

JAEA-Review 2008-067－ 101 －

This is a blank page.

JAEA-Review 2008-067

1-2-1

Magnetic structure of single-crystalline RRhGe (R=Tb, Dy) compounds
G. Nakamoto(A), Y. Ueda(A), M. Kurisu(A), Y. Andoh(B), T. Tsutaoka(C)(A)Japan Advanced Institute of Science and Technology, Ishikawa 923-1292, Japan, (B)Facultyof Regional Sciences, Tottori University, Tottori 680-8551, Japan, (C)Graduate School of
Education, Hiroshima University, Hiroshima 739-8524, Japan
RTX (R: rare earths, T: transition metals,
X: metalloids) compounds crystallize in thee-TiNiSi-type orthorhombic structure. The
magnetic property is characterized as follows:
3

TM

DyRhGeH = 1000 Oe

2

TN

1

(a)
0
0

10

20
30
40
Temperature (K)

50

2500
Al
Intensity (counts / 90 sec.)

Recently, it has been revealed that RRhGe(R=Tb and Dy) compounds also possess
successive magnetic transitions below the
Neel temperature from magnetic and speciﬁc heat measurements.
The purpose of this study is to determine the magnetic structures of magnetically ordered phases for RRhGe (R=Tb andDy) compounds.
Single-crystalline samples were grown bya Czhoralski method using a tetra-arc furnace in puriﬁed Ar atmosphere. The magnetic and speciﬁc heat measurements were
performed by a SQUID magnetometer anda PPMS. The neutron diffraction measurements were performed at T1-1:HQR spectrometer installed at JRR-3M, JAEA.
Figure 1(a) shows the magnetization of
DyRhGe compound as a function of temperature. It is found that antiferromagnetic
ordering takes place at 22 K. The powder neutron diffraction patterns of DyRhGe
compound at 3 K and 30 K are displayedin Fig. 1(b). The magnetic reﬂections areclearly observed at 14.6 and 26.8 deg at 3 K.
Detailed analysis of the magnetic structure
is now in progress.

Magnetization (emu/g)

1. succesive magnetic transitions below
Neel temperature.
2. multi-step metamagnetic transitions in
the ordered state along the easy magnetization b-axis.
3. incommensurate magentic structure.

M
M

2000

1500

DyRhGe
T=3 K
T=30 K

1000
0

10
20
30
Scattering angle (deg.)(b)
40

Fig. 1. Magnetization as a function of temperature(a) and powder neutron diffraction patterns at 3 K
and 30 K (b) for DyRhGe compound.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 27－ 103 －

JAEA-Review 2008-067

1-2-2

Critical behavior of S=1/2 triangular antiferromagnet Cs2CuBr4
T. Ono A , K. Goto A , Y. Kubota A , H. Tanaka A , N. MetokiB , F. HondaB , K. KakuraiBA Dept. of Phys. Tokyo Inst. of Tech., B ASRC, JAEA
using this power law. Obtained exponent,
β = 0.346 ± 0.010, agrees well with that ofconventional n = 2 (XY) universality class,
β = 0.346 (Guillou 1977). The value of βseems to deviate from the value which ispredicted in the “chiral” universality scenario (β = 0.253 for n = 2 and 0.300 for n =3). This fact indicates that the chiral degeneracy should be lifted by DM interaction
between Cu2+ -ions on the strongest bonds.
Since the a-axis component (perpendicular
to the bc-plane) of the D-vectors point tothe same direction, the direction of the spinrotation within the triangular plane is determined uniquely. The value of the critical exponent β consequently demonstrates
that the DM interaction plays a key rolein determining the spin arrangement. At
present, it is not clear the reason why no
diffuse scattering was observed just above
the transition temperature.
60

Counts/Monitor [arb. units]

In Cs2 CuBr4 , the magnetic Cu2+ -ionsform the distorted triangular lattice within
the bc-plane. For the isostructural compound Cs2 CuCl4 , the magnetic properties are described by a quasi-2D distorted triangular antiferromagnet withsmall Dzyaloshinsky-Moriya (DM) interaction between Cu2+ -ions. Since Cs2 CuBr4
has the same crystal structure, it is expectedthat the magnetic behavior of Cs2 CuBr4
should be described by the same Hamiltonian obtained for Cs2 CuCl4 . Below the ordering temperature TN = 1.45 K, the magnetic structure is helical incommensurate
structure with the ordering vector Q =(0, 0.575, 0) (Ono et al. 2003). The helical spin structure has the “chiral” degeneracy which comes from the direction of thespin rotation. It is predicted that the additional degeneracy lead the anomalous critical behavior which belong to the new n =2 and 3 chiral universality classes (Kawamura 1998). In order to check the criticalbehavior of Cs2 CuBr4 , we have performed
the elastic neutron scattering experiments.
Single crystal of Cs2 CuBr4 was grownby the slow evaporation method from theaqueous solution of CsBr and CuBr2 . Neutron elastic scattering was performed at
HER triple axis spectrometer. A single crystal with ∼ 0.4 cm3 was used for this measurement. The sample was cooled down to
T = 0.7 K using the 3 He refrigerator.
Figure 1 shows the temperature dependence of the magnetic Bragg peak intensity
at Q = (0, 0.575, 0). The Néel temperature was determined as TN = 1.47 K. The
solid line is the result of least squares ﬁt
to a power law in the reduced temperature
given as Intensity ∝ [( TN − T )/TN ]2β +Background. Since the magnetic Bragg
scattering intensity is proportional to thesquare of the sublattice magnetization, we
can roughly estimate critical exponent β by50

β = 0.346 ± 0.010
40
30
20

TN

Cs2CuBr410
Q = (0, 0.575, 0)
0
0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

T [K]

Fig. 1. Temperature variation of the magnetic Bragg
peak intensity measured at Q = (0, 0.575, 0). Solidline is the result of a ﬁt to a power law describedin the text with β = 0.346 ± 0.010 and with TN =1.47 K.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 28－ 104 －

JAEA-Review 2008-067

1-2-3

Magnetism of S=1/2 Square-Lattice Antiferromagnets (CuX)LaNb2O7 (X=Cl,Br)
Kageyama H., Tsujimoto Y., Ajiro Y., Yoshimura K., Nishi M.(A), Hirota K.(A)Department of Chemistry, Graduate School of Science, Kyoto University, (A)ISSP, Universityof Tokyo
Magnetic systems usually achieve longrange order of spins at low temperatures.
However, completely different behaviors
can be seen in low-dimensional antiferromagnetic (AFM) quantum spin systems.
Due to quantum ﬂuctuations, the systems
may not order long range even at 0 K.
A characteristic of the spin liquid groundstate is an energy gap in the magnetic excitation spectrum. Among them, the S = 1/2
frustrated square lattice AFM system is of
special importance in the light of Anderson’s resonating valence bond (RVB) concept to explain high-Tc superconductivity
in doped cuprates [1].
We discovered that a double-layered DionJacobson phase (CuCl)LaNb2O7 can be avery good candidate for the 2D quantum
square lattice system. As shown in Fig. 1,
the crystal structure is tetragonal (spacegroup P4/mmm), where 2D Cu square lattices are well separated with each otherby nonmagnetic double perovskite slabs.
Our bulk susceptibility and zero-ﬁeld inelastic neutron scattering experiments revealed that this system indeed provides a
new class of two-dimensional (2D) Heisenberg spin systems that has a spin-singlet
ground state with a ﬁnite energy gap of
2.3 meV [2, 3]. The magnetic susceptibilityof (CuBr)LaNb2O7 is also prepared fromtopotactic ion-exchange reactions. In contrast to the spin-liquid behavior in the Cl
sample, the Br sample shows an antiferromagnetic ordering at 32 K [4], despite
nearly identical structural parameters. The
neutron diffraction experiment demonstrated that the magnetic structure is described by a stripe ordering or a collinear
ordering with a propagation vector of q
= (1/2 0 1/2). This observation implies
that the next-nearest bond (J2) is dominant

over nearest-neighbor bond (J1), as theoretically suggested for the square-lattice J1J2 model. This is the 4th experimental example of the stripe ordering. Mixed ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor interactions are of comparable strength (J1/kB= 35.6 K and J2/kB= 41.3 K), placing the system in a more frustrated region of the stripe(collinear) phase than ever reported.
In order to reveal the origin of the anomalous critical ﬁeld, we have performed in2005 and 2006 neutron scattering measurements on the copper chlorine system withﬁelds up to 5 T, using the C1-1 spectrometer installed at the guide hall of JRR-3M
and the 5 T superconducting magnet. The
scattering intensity as a function of energy
transfer shows that the 2.3 mode splits into
three mode. This is the ﬁrst direct experimental observation of the softening of thetriplet excitation in this compound. The
subsequent experiment at higher magnetic
ﬁeld performed on the DCS at the NCNR
further supported this view.
We successfully obtained the solid-solution
series between (CuCl)LaNb2O7 and(CuBr)LaNb2O7, (CuCl1-xBrx)LaNb2O7(0<x<1), which allows us to investigate
the phase diagram between the spin
liquid state and collinear ordered state.
Inelastic neutron scattering experimentson the 5%-Br substitute sample, i.e.,
CuCl0.95Br0.05)LaNb2O7
were carriedout on the ISSP-PONTA triple-axis spectrometer installed at a 5G beam port of
JRR-3M at the Japan Atomic Energy Research Institute. A powder sample of 12.6 g
was put into an aluminum cylinder. Mostof the data were collected using a ﬁxed
ﬁnal energy Ef of 14.7 meV (kf = 2.67 Å-1)
and a horizontal collimation of open-40’-

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 32－ 105 －

JAEA-Review 2008-067

S-80’-80’ in combination with a pyrolytic
graphite (PG) ﬁlter placed after the sample
to eliminate higher-order beam contaminations. As shown in Fig. 1, the neutron
diffraction evidences the long-range magnetic ordering of the collinear type. Itmeans that 5% Br substitution for the Clsite is enough to induce the long rangeordering. A similar impurity-induced antiferomagnetic order from the spin-singlet
ground state has been observed in the
1D spin-Peierls system CuGeO3 and 1D
spin-ladder system SrCu2O3, suggestingthat this phenomena is a universal behavior, occurring not only for 1D but also 2D
system.
This work has been supported by Grantsin-Aid for Young Scientists (A) (No.
17684018) and Science Research on Priority
Area (No. 16076210) from MEXT of Japan,
and by the 21st Century COE Program, Kyoto University Alliance for Chemistry.
References[1] P. W. Anderson, Science 235, 1196 (1987).
[2] H. Kageyama et al., J. Phys. Soc. Jpn. 74,
1702 (2005).
[3] H. Kageyama et al., J. Phys. Soc. Jpn. 74,
3155 (2005).
[4] N. Oba et al., J. Phys. Soc. Jpn. 75, 113601(2006).
01 (2006).

Fig. 1.
Neutron diffraction patterns for(CuCl0.95Br0.05)LaNb2O7, suggesting the magnetic reﬂection at (1/2 0 1/2) at low temperature
below 8K.

－ 106 －

JAEA-Review 2008-067

1-2-4

Magnetic Structures of (MX)LaNb2O7 (M=Cu, Mn...; X=Cl, Br)
Kageayma H., Ajiro Y., Yoshimura K., Tsujimoto Y., Watanabe T., Baba Y., Kitada A.,
Nishi M.(A), Hirota K.(A)Department of Chemistry, Graduate School of Science, Kyoto University, (A)ISSP, Universityof Tokyo
In recent years, much attention has been
given to low-dimensional antiferromagnetic (AFM) quantum spin systems thathave a ground state with no long-range
magnetic order and an energy gap in
the magnetic excitation spectrum. Amongthem, the S = 1/2 frustrated square lattice AFM system (J1-J2 model) is of special importance in light of Anderson’s
resonating valence bond (RVB) concept
to explain high-Tc superconductivity in
doped layered cuprates. Low-temperature
topotactic strategies such as intercalation/deintercalation offer effective routes
for the design and construction of new twodimensional (2D) magnetic materials.
Topochemical ion exchange reaction
has been employed to obtain a doublelayered Dion-Jacobson phase such as(CuCl)LaNb2O7 starting from a nonmagnetic mother compound RbLaNb2O7 [1-4].
As shown in Fig. 1 (a), the structure consists of magnetic [CuCl] planes having an
S = 1/2 square lattice arrangement that are
widely separated by nonmagnetic double
perovskite slabs. Thus it can be a very
good candidate for the 2D quantum squarelattice system. In 2004, we performed
inelastic neutron scattering experiments on(CuCl)LaNb2O7 using the ISSP-PONTA
triple-axis spectrometer installed at a 5G
beam port of JRR-3M at the Japan Atomic
Energy Research Institute. It has been revealed that this system indeed provides a
new class of two-dimensional (2D) Heisenberg spin systems that has a spin-singlet
ground state with a ﬁnite energy gap of
2.3 meV [5, 6]. Quite recently, we preparedisostructural compound (CuBr)LaNb2O7
using a method similar to that to obtain(CuCl)LaNb2O7. In spite of the fact thatthe lattice parameters are almost the same,the magnetic properties of the copper
bromine system is completely different
from the spin-liquid state observed in
the copper chlorine system. In contrast
to the spin-gapped behavior in the Cl
sample, the magnetic susceptibility of theBr sample shows the gapless behavior withan antiferromagnetic ordering at 31 K. In
order to reveal the magnetic structure, we
demonstrate the powder neutron diffraction proﬁles measured at 3 K and 45 K.
We found two magnetic peaks centered at
2 θ = 15 ° and 20 ° that can be indexedas (1/2 0 1/2) and (1/2 0 3/2), respectively, indicating the so-called collinear
type (or stripe) ordering, where arraysof ferromagnetic chain along [100] alignin an antiferromagnetic manner in thesquare lattice (see Fig. 1(a)). The collinear
ordering is expected to occur when themagnitude of the next-nearest-neighborexchange interaction is greater than that of
the nearest-neighbor interaction. To date,
only three examples have been reported
to exhibit collinear ordering among S =1/2 square lattice systems. Therefore, itwould be interesting to examine the natureof the collinearly ordered state and tocompare with the spin liquid state in theisostructural (CuCl)LaNb2O7.
To further understand the nature of
the unusual ground states observed in(CuCl)LaNb2O7 and (CuBr)LaNb2O7, it
would be quite interesting to compare
these compounds with other related materials. Thus, in this study, we performed
powder neutron diffraction experimentson the isostructural (MCl)LaNb2O7(M=Co, Cr, Mn), using the IMR-HERMES
diffractometer (T1-3). Neutrons with awavelength of 1.81386(7) Å were obtainedby the 331 reﬂection of the Ge monmochro-

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 33－ 107 －

JAEA-Review 2008-067

mator, and the 12’-blank-sample-18’
collimation was employed. A powder
sample of 4 g was put into a vanadium
cylinder. Figure 1(b) demonstrates the neutron diffraction proﬁles of (CoCl)LaNb2O7
obtained at 8 K and 100 K. The lower temperature data have additional magnetic
reﬂections characterized by the propagation vector (pi, 0, pi), indicating thecollinear type of magnetic ordering. The
magnetic ordering temperature is obtained
to be 55K by measuring the intensity of(1/2, 0, 1/2). The manganese analogue
also exhibits the collinear order but atslightly higher temperature, while the neutron diffraction proﬁle of the chromium
analogue may indicate incommensurate
magnetic structure at low temperatures.
This work has been supported by Grantsin-Aid for Young Scientists (A) (No.
17684018) and Science Research on Priority
Area (No. 16076210) from MEXT of Japan,
and by the 21st Century COE Program, Kyoto University Alliance for Chemistry.
[1] T. A. Kodenkandath et al., J. Am. Chem.
Soc. 121, 10743 (1999).
[2] L. Viciu et al., Inorg. Chem. 2002, 3385
(2002).
[2] H. Kageyama et al., J. Phys.: Condens.
Matter 16, S585 (2004).
[3] H. Kageayma et al., Prog. Theo. Phys.
Suppl. 159, 39 (2005).
[4] H. Kageyama et al., J. Phys. Soc. Jpn. 74,
1702 (2005).
[5] H. Kageyama et al., J. Phys. Soc. Jpn. 74,
3155 (2005).
[6] N. Oba et al., J. Phys. Soc. Jpn. 75, 113601(2006).

Fig. 1.
(a) Crsytal and magnetic structure of(MX)LaNb2O7. (b) Neutron diffraction patterns for(CoCl)LaNb2O7 measured at 8 K and 100 K, demonstrating the collinear (pi, 0) type of magnetic longrange ordering.

－ 108 －

JAEA-Review 2008-067

1-2-5

Magnetic ordering and excitations in the Zn-Fe-Sc-RE (RE: rare-earth) icosahedral
quasicrystals
T. J. Sato A,B , S. KashimotoC , C. MasudaC , T. OnimaruB,A , I. Nakanowatari A , K. Iida A , R.
Morinaga A , and T. IshimasaC
A ISSP-NSL, University of Tokyo, B SORST-JST, C Department of Applied Physics, Hokkaido
University
netic Bragg reﬂections at the lowest temperature. We also checked existence of themagnetic Bragg reﬂections in several samples with RE = Ho and Tm, with a few
different RE concentration, however, all ofthem gives negative results. Further exploratory study on the magnetic quasicrystal with higher magnetic ion concentrations
is in progress; neutron diffraction study on
those materials is obviously necessary todetect deﬁnite long-range signal.

p-Zn-Fe-Sc-Ho7% powder
GPTAS 2axis
ki = 2.56 40-80-80-Open

35000
30000

1000

T = 3.8K
T = 30K
Temp diff

500

25000
20000

0

15000
10000

-500

5000
0

Intensity difference (counts/30sec)

40000

Intensity (counts/30sec)

Quasicrystals are characterized by sharp
Bragg reﬂections with a point symmetrythat is forbidden in a periodic lattice, suchas the ﬁve-fold symmetry. For magnetic
quasicrystals, non-trivial ordering of spins
arranged on a quasiperiodic lattice may be
expected in theory. Nevertheless the longrange order has not been observed yet inany magnetic quasicrystals, despite continuous efforts to ﬁnd the magnetic longrange order made to date. The recently
discovered Zn-Fe-Sc-RE (RE: rare-earth)quasicrystals has been expected to havethe highest possibility to show magnetic
long-range order, since it has highest magnetic ion concentration among magnetic
quasicrystals reported to date. In addition,
the combination of the 3d and 4 f moments
may provide longer inter-spin interactions,
resulting in the likely situation for the longrange order. Here, we report ﬁrst neutron scattering study on the new magnetic
quasicrystals Zn-Fe-Sc-RE (RE =Ho andTm). Experiments have been performedat the triple-axis spectrometer 4G-GPTAS
with incident energy Ei = 13.7 meV. Datashown here were taken with a double-axis
mode. A powder sample of Zn-Fe-Sc-RE
was prepared by melting constituent elements and heat-treated in an appropriatemanner.
Shown in Fig. 1 are powder diffraction
patterns taken at the two temperatures T =3.8 and 30 K. The difference between the
two-temperature data sets is also shown by
the blue triangles. As the nuclear Bragg
reﬂections are clearly seen in the ﬁgure atboth the temperatures, the temperature dependence shows very ﬂat behavior, excluding possibility for appearance of the mag-

-1000
0

0.5

1

1.5

2

2.5

3

3.5

4

Q (invA)

Fig. 1. Neutron powder diffraction patterns at T =3.8 (red) and 30 K (green) obtained at ISSP-GPTAS.
Temperature difference [I (3.8 K) − I (30 K)], as amagnetic scattering contribution, is also shown by
the blue triangles.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 34－ 109 －

JAEA-Review 2008-067

1-2-6

Uniaxial pressure induced ﬁrst-order phase transition in Pt3 Fe alloy
R. Matsui, Y. Tsunoda
Waseda University
The ordered Pt3 Fe alloy has an
L12 (Cu3 Au)-type structure, in which
the corner sites are occupied by Fe and theface center sites by Pt, respectively. Since Pt
atoms carry no magnetic moments, Pt3 Fe
alloy is considered to be a simple cubic antiferromagnet. Below the Néel temperature(TN ∼ 180 K), Pt3 Fe alloy undergoes an
AF-AF phase transition at TS (TS ∼ 80 K).
At the high temperature phase, magnetic
structure is a (1/2 1/2 0)-type, but atthe low temperature phase, the (1/2 0 0)
Bragg peak coexists with decreasing of the(1/2 1/2 0) Bragg peak intensity.
Among simple cubic antiferromagnetic
structure, both (1/2 1/2 0)-type and (1/2
0 0)-type structure have ferromagnetic andantiferromagnetic nearest neighbor spin
couplings, suggesting existence of spin
frustration. Then, we can expect strong effect for the magnetism of Pt3 Fe alloy by an
external perturbation ﬁeld. To study thespin correlations in simple cubic antiferromagnet, we carried out the neutron scattering experiments on a single crystal specimen of Pt3 Fe alloy under uniaxial pressure.
The uniaxial pressure was applied along
the [0 0 1] axis using a hard coil spring,which destroys the cubic symmetry of thelattice. The measurements were performedat the T1-1 triple axis spectrometer, JRR3M.
We ﬁrst measured the temperature dependence of the (1/2 1/2 0) Bragg peakintensity and obtained the results that theNéel temperature increases with increasing uniaxial pressure, indicating that the(1/2 1/2 0)-type magnetic structure is stabilized by uniaxial pressure. Further, weobserved that the phase transition at TN under the high uniaxial pressure looks likeof the ﬁrst-order. In order to conform theﬁrst-order phase transition at TN , the temperature dependence of the (2 0 0) Bragg

peak intensity was carefully studied at theslightly off point (1.994 0 0). Results are
given in Fig. 1 together with the data for
free state. The data clearly shows the lattice expansion at TN with decreasing temperature under the uniaxial pressure, indicating that the magnetic ordering accompanies with the lattice deformation, thus, theﬁrst-order phase transition. The lattice expansion at TN is estimated to be 1.3×10−4
using the linear thermal expansion coefﬁcient of Pt (8.9×10−6 at RT)

Fig. 1. Temperature dependence of the intensities
studied at (1.994 0 0) Bragg peak position

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 37－ 110 －

JAEA-Review 2008-067

1-2-7

Magnetic excitation in the Ni4 magnetic cluster
Kazuki Iida, Yiming Qiu A , Seunghun LeeB , Taku J Sato
ISSP, A Univ. Maryland, B Univ. Virginia
neic origin for these peaks was conﬁrmed
by measuring their temperature and Q dependence. Applying the magnetic ﬁeld, thepeak at 0.6 meV becomes broad, the peakat 1.3 meV shifts to the lower energy side,
though the peak at 1.6 meV exhibits negligible change. These chagnes can hardly be
explained consistently by the Zeeman effect.
We have also performed inelastic neutron scattering experiments using the DCS
spectrometer at NIST Center for Neutron
Research. Combining the all S( Q, h̄ω ) obtained at the two spectrometers, we are
now working on the determination of thespin Hamiltonian in this system.
[1] A. Muller it et al., Inorg. Chem. bf 39(2000) 5176.
5000

Intensity ( counts / 750 seconds )V O (µ The molecular magnet [Mo1230 2OH)10 H2 {Ni I I (H2 O)3 }4 ]·14H2 O (Ni4 ) has
four magnetic Ni2+ (S = 1) ions forming an isolated tetrahedral cluster. Earlier macroscopic experiment suggests dominant antiferromagnetic intracluster interactions between the Ni2+ spins, with negligible single-ion anisotropy [1]. Thus theNi4 was expected to be a good realization of Heisenberg antiferromagnet withstrong geometrical frustration effect due
to tetrahedral spin arrangement. Owing
to the small S, small number of spins involved, and the geometrical frustration,strong quantum effects may be expected in
the Ni4 magnetic cluster.
Two grams of deuterated powder sampleof Ni4 was prepared following the prescription given in the earlier report [1]. The neutron inelastic scattering experiments were
performed at the cold-neutron triple-axis
spectrometer ISSP-HER installed at JRR-3,
JAEA, Tokai. Superconducting magnetic
was used to apply vertical magnetic ﬁeld
up to 5 T. The lowest attainable temperature was 1.5 K. A brand-new horizontally
focusing analyzer was used with all sevenblades operational, and a Be ﬁlter is placedin front of the sample to remove the higher
order harmonics. Several ﬁnal energies
were used to collect the inelastic spectra depending on the contradicting necessity forthe energy resolution and intensity; typically Ef = 4.5 meV.
Figure 1 shows inelastic neutron scattering spectra at Q = 0.6 Å−1 under the various magnetic ﬁelds. (Each spectrum isshifted by 400 counts to increase visibility.)
In a zero ﬁled spectrum, there is a peak ath̄ω = 0.6 meV appearing as a sholder ofthe huge elastic peak due to the incoherent scattering of the remaining hydrogen.
Also seen is a peak at 1.3meV accompanied
by a sholder peak at 1.6 meV. The mag-

H=0T
1T
2T
2.5T
3T
4T

4000

3000

2000

1000

0
0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Energy transfer (meV)Fig. 1. Inelastic spectra of Ni4 under various magnetic ﬁeld observed at ISSP-HER. See text for details.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-2-8

Magnetic correlation and excitation in triangle and hexagonal magnetic molecules
Kazuki Iida, Keisuke Hukaya A , Hiroshi Ishikawa A , Gou Kamohara A , Toshihiro
Yamase A , Taku J Sato
ISSP, A Tokyo Institute of Technology
Q = 0.6 Å−1 are shown in Fig. 1. Dataacquisition durations for each point were
20 minutes in the V3 experiment, 4 minutes in the Mn6 Sb, 6 minutes in Mn6 As, 8
minutes in Cu6 As, respectively. In the ﬁgure, the spectrum of V3 is shifted by 800
counts, Mn6 Sb by 800 and Mn6 As by 400.
In the V3 spectra there appears a peak ath̄ω = 0.8 meV at the lowest temperature.
It is found that the peak intensity decreases
as Q becomes large, and that it disappears
at the high temperature T = 30 K. These results indicate that this peak has a magnetic
origin. There also appears an slight shoulder at h̄ω = 0.4 meV, although it is difﬁcult
to conclude due to insufﬁcient statistics.
For Mn6 Sb, we only observed a symmetricpeak around the elastic position, and thus
it most likely originates incoherent elastic
scattering of hydrogen or a nuclear bragg
peak. The spectrum of Mn6 As exhibits a
broad shoulder in an energy range of 0.2 <h̄ω < 0.5 meV. Its temperature dependence
suggests that this shoulder has also a magnetic origin. The spectrum of Cu6 As shows
only incoherent scattering from hydrogen.
A continuous study is apparently necessary to elucidate their spin Hamiltonians.
In future, we will focus on V3 and Mn6 As
where existence of the magnetic scattering
was suggested in the present results.
2500

V3
Mn6Sb
Mn6As
Cu6As

2000

I n t e n s it ySingle molecular magnets attract special attention recently, as they provide a
new playground for studying isolated (orweakly coupled) quantum systems. Here,
we have investigated four molecular magnets, V3 , Mn6 Sb, Mn6 As and Cu6 Sb using
inelastic neutron scattering. These experiments are rather preliminary, as we look
for systems of which spin Hamiltonian
may be determined by inelastic neutron
scattering. Chemical formulae of thosesystems are K11 H[(VO)3 (SbW9 O33 )2 ] ·27H2 O and K12 [(VO)3 (BiW9 O33 )2 ] · 29H2 O,[nBuND3 ]12 [Mn6 Cl6 (SbW9 O33 )2 ] · 6D2 O,[nBuNH3 ]12 [Mn6 Cl6 (AsW9 O33 )2 ] · 6D2 O
and [nBuNH3 ]12 [Cu6 Cl6 (AsW9 O33 )2 ] ·6D2 O respectively. V3 forms a triangle
cluster, whereas hexagonal cluster geometry was realized in the other systems.
From the bulk magnetic susceptibility
measurements, V3 and Mn6 Sb were foundto be anitferromagnetic, whereas physicalproperties of other systems have not beenreported to date.
Powder samples of 0.71 g V3 , 0.34 g
Mn6 Sb, 0.36 g Mn6 As, and 0.24 g Cu6 As
were used in the neutron experiments. The
neutron inelastic scattering experiments
were performed at the cold-neutron tripleaxis spectrometer ISSP-HER installed at
JRR-3, JAEA, Tokai. A brand-new horizontally focusing analyzer was used with allseven blades operational, and a Be ﬁlter isplaced in front of the sample to remove thehigher order harmonics. Several ﬁnal energies were used to collect the inelastic spectra depending on the contradicting necessity for the energy resolution and intensity;
typically Ef = 3 meV. The V3 experiment
was performed at 0.9 K using the 1 K refrigerator, whereas the other experiments weredone at 4 K using the Orange cryostat.
Inelastic spectra from the four samples at

1500

1000

500

0
-0.5 -0.4 -0.3 -0.2 -0.1

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.91

1.1 1.2 1.3 1.4 1.5

Energy transfer (meV)Fig. 1. Inelastic spectra of V3 , Mn6 Sb, Mn6 As, andCu6 As observed at ISSP-HER. See text for details.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-2-9

Spin excitations in chormite spinel
Keisuke Tomiyasu
Neutron Science Laboratory, High Energy Accelerator Research Organization
We are very attracted to the microscopic
origin of the beautiful diffuse pattern along
the Brillouin zone boundary in the magnetic geometric frustration systems. Some
Reversed Monte Carlo simulations and theparamagnetic spin ﬂuctuation theory with
RPA well reproduce the patterns in theseveral frustrated systems. However, weare questioning the context to study theparameters of exchange interactions andanisotropy energy only from the paramagnetic scattering. The microscopic origin of
frustration is unresolved.
On the other hand, the spin excitationsin the ordered phase directly give the interactions in the Hamiltonian. For example,
the partial frustration system CoCr2O4 andthe usual frustration system MgCr2O4 andZnCr2O4 exhibit magnetic long-range order in the lowest temperature phases. In
CoCr2O4, the spiral component of spins
forms short-range order at the lowest temperature, but the ferrimagnetic component of spins form long-range order. It is
worth investigating the relation between
the spiral component and the ﬂuctuationof the ferrimagnetic component. MgCr2O4
and ZnCr2O4 exhibit the antiferromagnetic long-range order described by several
propagation vectors. By daring to select theordered phases in those frustrated systems,
we can investigate the spin dynamics andthe interactions.
In this year (2006), we performed
the inelastic scattering experiments below TN=13 K on the single crystal of
MgCr2O4. MgCr2O4 is suitable comparedto CoCr2O4, because the former is described by 4 sublattices of spins and lessthan the 6 sublattices in the latter. In spiteof the antiferromagnetic order, the same
Q-dependence characterizing the geometric frustration was observed at the ﬁnite energy around 4.5 meV. We observed otherexcitation modes by the three instruments,
and will also continue the experiments inthe next year to measure the overall pictureof S(Q,E).

Fig. 1. Fig. Q-dependence of magnetic inelastic scattering in MgCr2O4 The upper and lower data were
measured at T=20 K and E=1 meV and t T=6 K and
E=4.5 meV, respectively. The horizontal focusing analyzer was used.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 62－ 113 －

JAEA-Review 2008-067

1-2-10Inelastic neutron scattering in the antiferroquadrupole material, PrPb3
T. Onimaru1,2,3 , T. Sakakibara3 , N. Aso4 , T.J. Sato4 , H. Yoshizawa4 and H.S. Suzuki5
1 Graduated School of Advanced Sciences and Matter, Hiroshima University,
Higashi-Hiroshima
2 SORST, Japan Science and Technology Agency, Kawaguchi
3 Institute for Solid State Physics, The University of Tokyo, Kashiwa
4 Neutron Science Laboratory, Institute for Solid State Physics, The University of Tokyo, Tokai,
Ibaraki
5 National Institute for Materials Science, Tsukuba
The rare-earth compound PrPb3 crystallizes in the AuCu3 -type structure and the
crystalline electric ﬁeld (CEF) ground stateis a Γ3 non-Kramers doublet.[1] The Γ3
doublet carries quadrupolar moments O20
and O22 , and it actually exhibits a secondorder transition at TQ =0.4 K.[2] In ourwork, we performed neutron diffraction
experiment in magnetic ﬁeld and revealed
the distribution of ﬁeld-induced magnetic
moments with the propagation vectorsof k1 =[1/2±δ, 1/2, 0] and/or k2 =[1/2,1/2±δ, 0] (δ∼1/8).[3] The ﬁeld-induced
magnetic moments are aligned with a sinusoidal (incommensurate) structure below TQ , suggesting that the quadrupoles
be aligned with the same structure. In inelastic neutron scattering experiments, theCEF excitations were observed, however,it was found that the CEF excitation has astrongly dispersive relation with no temperature dependence.[4]In the present work, we performed inelastic neutron scattering experiments on
PrPb3 at temperatures ranging from 1.3 K
to 30 K. The experiments were performed
using the HER(C1-1) with E f =3.6 meV. We
used a single crystalline sample with highquality grown by the Bridgman method.
Fig. 1 shows the constant−Q spectrum
at Q=(5/8 1/2 0) at the temperatures of
1.3 K≤ T ≤30 K. At T =1.3 K, inelastic peaks
were observed at E=1.4, 1.7 and 2.4 meV.
Surprisingly, the spectra at 1.3 K and 4.2 K
show almost no change. In addition, we
had found that the the spectra would notchange at all even below TQ in another experiment. These behavior probably showsthat the inelastic peak would not result
only from the CEF, since the number of thepeaks should be inconsistent with the one
expected from the CEF levels reported by
Gross et al.[1] Moreover, increasing temperatures, the intensity of the peaks at E=1.4
and 2.5 meV apparently decreases. On theother hand, the peak at E=1.7 meV still remain even at T =30 K. These temperaturedependence of the intensity can not be explained by the CEF levels.
References[1] W. Gross et al., Z. Phys. B 37 123(1980).
[2] E. Bucher et al., J. Low Temp. 2 322 (1972).
[3] T. Onimaru et al., Phys. Rev. Lett. 94, 197201(2005).
[4] M. Niksch et al., Helv. Phys. Acta 55, 688(1982).

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 71－ 114 －

JAEA-Review 2008-067

1-2-11

Magnetic Field Dependence of Two Kinds of Magnetic Correlations in Random
Magnet Fe65(Ni0.78Mn0.22)35
K. Motoya, Y. Muro and T. Igarashi
Department of Physics, Faculty of Science and Technology, Tokyo University of Science
In a previous neutron scattering study, we
found that the short-range ferromagnetic
and antiferromagnetic correlations coexist in wide concentration and temperature ranges of a random magnet system
Fe65(Ni1-xMnx)35 [1] . This result showedthat the magnetic phase diagram determined by macroscopic measurements does
not properly represent the magnetic stateof a competing magnetic interaction system. In order to clarify the microscopic
magnetic state of the competing magnetic interaction system, we observed themagnetic ﬁeld dependence of the neutron
scattering patterns arising from ferromagnetic and antiferromagnetic correlations in
Fe65(Ni0.78Mn0.22)35.

The ﬁeld variations of these parametersindicate that the magnetic clusters disappear sequentially from larger size with increasing magnetic ﬁeld. The present resultshows that the ferromagnetic and the antiferromagnetic clusters coexist separately inthis alloy.
[1] K. Motoya and K. Hioki, J. Phys. Soc.
Jpn. 72 (2003) 930.
[2] M. Shiga et al. J. Mag. Mag. Mater. 51(1985) 345.
[3] K. Motoya and Y. Muraoka, J. Phys. Soc.
Jpn. 62 (1993) 2819.

According to the reported magnetic phase
diagram, the alloy of this compositiontransforms from a paramagnetic phase toa spin-glass phase around 80K[2]. Spinwave excitations with ferromagnetic character have been observed in the temperature range 10-300K[3].
As reported in ref.1, the magnetic
diffuse scattering pattern arising fromferromagnetic correlation is composedby a Lorentzian (LOR) and a squared
Lorentzian (SQL) components. On theother hand, signals from antiferromagnetic correlation is well traced only by a
LOR function. As increasing magnetic
ﬁeld, the diffuse scattering pattern fromferromagnetic
correlations
decreases,
whereas the change of the signal from
antiferromagnetic correlations is small.
Figure 1 shows the ﬁeld variations of theamplitude and the width of the SQL component of the ferromagnetic diffuse signal
which is the major part of scattering signal.

Fig. 1. Magnetic ﬁeld variations of the amplitude and the width of a squared Lorentzian scattering function arising from ferromagnetic correlation
measured at various temperatures.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 72－ 115 －

JAEA-Review 2008-067

1-2-12Magnetic Structure of RPdSn(R=Tb ,Dy and Ho) Compounds
Y. Andoh(A), Z. Ingjie(B), M. Kurisu(C), G. Nakamoto(C), T. Tsutaoka(D)(A)Faculty of Regional Sciences, Tottori University,(B)Graduate School of Education, Tottori
University,(C)JAIST,(D)Graduate School of Education, Hiroshima University
Ternary equiatomic rare-earth compounds, RPdSn (R = Tb, Dy and Ho), crystallize in the orthorhombic (Pnma) TiNiSitype structure. TbPdSn and HoPdSn exhibit a multi-step metamagnetic transition at low temperatures[1]. In the present
work, we have carried out the neutron
diffraction studies to reveal the magnetic
structure of TbPdSn, DyPdSn and HoPdSn.
The single crystals were grown by the
Czochralski method using a tri-arc furnace. The neutron diffraction measurements were made using the HQR spectrometer of JRR-3M of JAEA at Tokai.
Figure 1(a) shows the contour maps of thediffraction intensity around the (0 0.26 3)
Bragg position in the rotated plane from thereciprocal b*-c* by seven degrees aroundthe b*-axis at T=9.5 K and T=14.5 K, respectively of TbPdSn. The propagation vector determined by the powder diffraction
data.The obtained propagation vectors k =(0.004, 0.266, 0.003) at 16 K and the k =(0.005, 0.266, 0.107) at 3.5 K are in good
agreement with those reported by Andre etal[2].
Figure 1(b) shows neutron diffraction
data for HoPdSn in the b*-c* reciprocal
plane at 1.8 K. The weak magnetic reﬂections appear at the at the Bragg positions(0 1.5 l) and (0 2.5 l) for l = 2n+1. The ﬁrst
magnetic scattering is given by (1/3, 1/2,
1/3) and is corresponding to powder neutron results well if it is assumed that thesepeaks are the third harmonic scattering.
Figure 1(c) shows the powder neutron
diffraction pattern of DyPdSn at 1.6 K and
14K. There are three magnetic reﬂections
at 1.6 K. With increasing temperature thesemagnetic reﬂections vanish at Tt = 4.8 K.
However, the magnetic reﬂection is notfound in the reciprocal a*-b*, a*-c* and b*-c*

planes for DyPdSn single crystal.
REFERENCES[1] Y. Andoh et al., Meeting Abstract ofPhys. Soc. Jpn. 54 Part 3 (1999) 365.
[2] G. Andre et al., J. Magn. Magn. Mater.,
125 (1993) 303.
[3] A. Szytula et al., J. Alloys Compounds
370 (2004) L14

Fig. 1. (a) the contour maps of TbPdSn, (b) neutron
diffraction data of HoPdS and (c) the powder neutron diffraction pattern of DyPdSn

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 74－ 116 －

JAEA-Review 2008-067

1-2-13

Neutron Diﬀraction Studies on a Dy7Rh3 Single Crystal
T. Tsutaoka(A), A. Tanaka(A), Y. Andoh(B), Zgy Ingjie(B), G. Nakamoto(C)andand M. Kurisu(C)(A)Graduate School of Education, Hiroshima University, Hiroshima 739-8524, Japan(B)Faculty of Regional Sciences, Tottori University, Tottori 680-8551, Japan(C)Japan
Advanced Institute of Science and Technology, Ishikawa 923-1292, JapanThe rare earth compound Dy7Rh3 crystallizes in the hexagonal Th7Fe3 type structure with the space group P63mc. From themagnetic measurements, it was shown thatthe compound possesses the two magnetically ordered states, an antiferromagnetic
one between TN = 59 K and TC = 34 K
and a ferrimagnetic or canted one below
TC[1]. We have also determined the magnetic propagation vector of k = (0 0 0.366)
in the ferrimagentic phase by the powder
neutron diffraction[2]. In this study, moredetailed neutron diffraction measurements
have been carried out on a Dy7Rh3 single
crystal in the a* - c* reciprocal plane using the HQR spectrometer of JRR-3M in thetemperature range from 10 to 70 K.
Fig.1(a) shows the magnetic and nuclear
reﬂections in the a* - c* reciprocal planeat 10 K. The magnetic reﬂections appear
at the positions indexed by the propagation vector k = (0 0 0.375). Since a small
spontaneous magnetization was observed
both along the c-axis and in the c-plane, theconical or canted magnetic structure is proposed. Fig.1(b) shows the integrated intensity of the magnetic reﬂection (0 0 0)+ andthe z component of the propagation vector k as a function of temperature.The integrated intensity shows a peak at about
20 K and an anomaly at TC, while the kz
is almost constant with temperature up to
TN. In the intermediate antiferromagentic
state above TC, the positions of magnetic
reﬂections are almost the same as that in
the lower temperature phase. The absenceof magnetic component at the nuclear positions may be explained by the fact thatthe spontaneous magnetization is only 0.1
Bohr magneton below TC. Magnetic structure analysis for the two magnetic phases isin progress using a Rietveld method.
[1]T. Tsutaoka et al., J. Phys. Soc. Jpn. 70(2001) 199.
[2]T. Tsutaoka et al., Activity Report on
Neutron Scattering Research Vol. 13 (2005).

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 87－ 117 －

JAEA-Review 2008-067

1-2-14Zero-Field Random-Field Eﬀect in Diluted Triangular Lattice Antiferromagnet
CuFe1-xAlxO2Taro Nakajima, Setsuo Mitsuda and Takeshi Komiya
Tokyo University of Science
Delafossite compound CuFeO2 is oneof the model materials of triangular lattice antiferromagnet (TLA), and its magnetic properties were extensively investigated in the last ﬁfteen years. Recent
studies on the diluted system CuFe1xAlxO2 (x<0.050) revealed that various
magnetically ordered phases are inducedin the low-Al3+-concentration region, owing to partial release of spin frustration.[1] In contrast, in the high Al3+concentration region of x>0.040, only theoblique-partially-disordered (OPD) state,whose local spin structure is a sinusoidally
amplitude-modulated structure with incommensurate wave number, shows up,
and the local magnetic structure does notchanges depending on the amount of nonmagnetic impurity.[2] However, our preliminary neutron diffraction measurements
revealed that the width of the diffraction
proﬁle broadens with increasing Al3+ concentration. We thus investigate how thespin correlation in CuFe1-xAlxO2 is modiﬁed depending on amount of nonmagnetic impurity, by high-Q resolution neutron diffraction measurements.
In present experiments, we performed
neutron diffraction measurements using
the single-crystal CuFe1-xAlxO2(x=0.10)
at the triple-axis spectrometer HQR(T11) installed at JRR-3M, The incident neutron wavelength is 2.44[A] and collimation open-’40-’40-’60 was employed. We
ﬁrstly obtained the diffraction proﬁles of(qOPD,qOPD,1.5) and (qOPD,qOPD,4.5)
magnetic reﬂections with qOPD˜0.19 along
six directions illustrated in Fig.1 (e). Next,
we numerically calculated the diffraction
proﬁles for these directions by convoluting a functional form of S(q) with themeasured resolution function, and ﬁtted
them to the measured proﬁles simultane-

ously. Trying several functional form of
S(q), we found that the scattering function of the magnetic reﬂection is describedas the sum of a Lorentzian term and a
Lorentzian-squared term with anisotropic
widths. The Lorentzian-squared term dominating at low temperature is indicativeof the domain state in the prototypicalrandom-ﬁeld Ising model. Taking accountof the magnetic structure in OPD phase,
we conclude that the effective random ﬁeld
arises even at zero-ﬁeld, owing to the combination of site-random magnetic vacancies and the sinusoidal magnetic structure.
The details of the present study will be seenin the coming paper.[3][1] N. Terada et al.: JPSJ 74 (2005)2604.
[2] T. Nakajima et al.: ISSP-NSL Activity
Report Vol. 13 (2006)[3] T. Nakajima et al.: JPCM (in press)[a proceeding paper of ’Highly Frustrated
Magnetism 2006’]

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 88－ 118 －

JAEA-Review 2008-067

1-2-15Magnetic Structure in the Multiferroic Phase of Frustrated Magnet CuFe1-xAlxO2Taro Nakajima(A), Setsuo Mitsuda(A), Shunsuke Kanetsuki(A), Hiroyuki Kimura(B)and Yukio Noda(B)(A)Tokyo University of Science, (B) Tohoku University
Geometrically frustrated triangular lattice
antiferromagnet CuFeO2 has been extensively studied for last ﬁfteen years. Recently, Kimura and co-workers has discovered the spontaneous electric polarization in the low-temperature ﬁeld-induced
phase of CuFeO2, and argued that CuFeO2
provides an opportunity to study a newclass of multiferroic materials.[1] To understand the microscopic mechanism of
the multiferroic nature, detailed magnetic
structure in the ferroelectric(FE) phaseis indispensable. Quite recently, we performed neutron diffraction measurementswith a horizontal ﬁeld cryomagnet at HMI,
and revealed that the magnetic structurein the FE phase is a proper helical structure propagating along <110> axis.[2,3]This measurements is, however, restricted
to the (hhl) zone, in which the proper helical structure cannot be distinguished fromthe sinusoidal structure with the moments
canted by 45[deg] from the c axis toward<1-10> direction.[4] Thus, the information
beyond the (hhl) zone is indispensable to
conﬁrm the proper helical structure.
Fortunately, the small magnetic reﬂections corresponding to the magnetic
ordering of the FE state were foundto coexist with the four-sublattice(upup-down-down) magnetic state in the
ground state of the slightly diluted sample CuFe1-xAlxO2(x=0.012), owing to aslight macroscopic inhomogeneity of the
Al-concentration. We thus surveyed thethree-dimensional hkl-dependence of themagnetic structure factor of the FE state inzero ﬁeld, using the x=0.012 sample andfour-circle diffractometer FONDER(T2-2)
installed at JRR-3M. The incident neutron
wavelength is 1.24[A] and the closed-cycle
He-gas refrigerator is used to provide
access to the temperature down to T=2.5K.

From observed magnetic structure factors,
we estimated the Spin Orientation Factors(SOF), and found that the hkl-variationof observed SOF is well explained by theproper helical model, even beyond (hhl)zone, as shown in Figs. 1(b)-(e).
A naive application of the theory for ferroelectricity in noncollinear magnets[5] to theproper helical structure does not lead to aﬁnite uniform electric polarization. Nevertheless, the present results imply that a spin
noncollinearlity is relevant to the multiferroic nature in CuFe1-xAlxO2.
[1] T. Kimura et al.:PRB 73(2006)220401R[2] T. Nakajima et al.: BENSC Experimental
Report 2006
[3] T. Nakajima et al.:(submitted JPSJ)[4] N. Terada et al.:JPSJ 74 (2005) 1561
[5] H. Katsura et al.: PRL 95(2005)057205

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-2-16The magnetic ﬁeld eﬀect of ZnCr2O4
T.Arai and Y.Tsunoda
Waseda University
ZnCr2O4 is a three-dimensional geometrical spin frustration system with a normal spinel structure, in which magnetic
Cr3+ ions occupy the B-site and the nearest neighbor Cr3+ spins couple antiferromagnetically. ZnCr2O4 undergoes the ﬁrst
order phase transition to an antiferromagnetic phase accompanied by a tetragonal lattice distortion of the order of 0.2%
at 12.5K. The magnetic structure in the
ground state of ZnCr2O4 was studied byseveral authors in the past in the aspect ofa fundamental magnetic system. However,
the results are not clear due to the complex magnetic structure. Last year, we have
performed the neutron scattering measurements with a ZnCr2O4 single crystal specThe (hh0) (h= n/2, n= odd)
imen. [1]series magnetic Bragg peaks disappeared
when the magnetic ﬁeld was applied along
the [111] axis. It means that the magnetic
structure turns into a new structure withhigher symmetry than that in the groundstate under a small magnetic ﬁeld. In orderto obtain further knowledge of the magnetic structure of ZnCr2O4 in the groundstate, we performed the neutron scattering
using isotropic powder ZnCr2O4 specimen
under a magnetic ﬁeld.
A powder sample was prepared bysolid state reaction between stoichiometricamounts of ZnO and Cr2O3 in air. Experiments were performed on the T1-1 triple
axis spectrometer installed at JRR-3M witha vertical magnetic ﬁeld.
In elastic neutron scattering experiments,
ﬁeld cooled (FC) and zero ﬁeld cooled(ZFC) states were measured. Figure showsthe (2 1 1/2) magnetic Bragg peak obtainedwith and without magnetic ﬁeld (H=4.5T).
As a result, the disappearance of a magnetic Bragg peak was not observed in any
series of indices. For the single crystal specimen, since the (hh0) magnetic peaks com-pletely disappeared under the magnetic
ﬁeld, present data indicate that the (111)plane has a special meaning for the magnetic structure under the magnetic ﬁeld.
In inelastic neutron scattering experiments, Q-dependence was measured by
the constant E mode at E=2.5meV and4.5meV. At E=2.5meV, dispersion was observed around the strong magnetic Bragg
peaks. At E=4.5meV, however, dispersion
was not observed. In addition, inelastic
diffuse peak shifted towards the low angle side when the temperature was raised.
From these experiments, we can conclude
that the spin axis inclines gradually underthe magnetic ﬁeld and the magnetic structure with higher symmetry is stabilized.
Reference[1] Y. Tsunoda, H. Suzuki, S. Katano, K. Siratori, E. Kita and K. Kohn: J. Phys. Soc. Jpn.
75. 064710 (2006)

Fig. 1. The magnetic Bragg peak at (2 1 1/2) in elastic neutron scattering.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 93－ 120 －

JAEA-Review 2008-067

1-2-17

Thermodynamic anomaly speciﬁc to PD phase of spin frustration system CuFeO2
S. Mitsuda(A), T. Nakajima(A), T. Fujii(A), N. Terada(B),(A) Department of Physics, Tokyo University of Science, (B) RIKEN/SPring8
heating process starting from T˜11.65 K, thepoint q(T) moves horizontally, meets andfollows the T-increasing-Guide-line on T-qplane. In such a way, we measured the trajectory of the point q(T) on q-T plane up
to 3rd temperature-cycle for various temperature width dT and conﬁrmed that the
trajectory of the point q(T) extracted fromknee-points in the temperature response of
the sample in the speciﬁc heat measurement with the relaxation technique is wellcoincide with that from present neutron
diffraction measurements. From these results, we concluded that extra heat absorption and heat generation in the PD phaseoccur for decreasing and increasing of the
propagation wave number q, respectively,
suggesting a kind of Devil’s Staircase for
the PD state of CuFeO2.
References[1] S. Mitsuda et al, JPSJ 67, 4026 (1998).
[2] T. Fujii et al, ISSP-NSL Activity Report
Vol.13

0.208

starting point of
1st thermal cycle

q [r. l. u.]

0.209

q [r. l. u.]

Delafossite compound CuFeO2 has been
extensively investigated as one of model
materials for triangular lattice antiferromagnets (TLA). Although CuFeO2 is considered to be a Heisenberg spin TLA
with S=5/2 of orbital singlet Fe3+, a sinusoidally amplitude-modulated magnetic
state with a temperature dependent incommensurate magnetic propagation vector (q, q, 3/2) is thermally induced from 4sublattice ground state as a partially disordered (PD) state characteristic to Ising spin
TLA.[1]
We have reported anomalous thermal behavior speciﬁc to the PD phase and suggested that changes in microscopic magnetic state with variation of the propagation wave number q is accompanied byadditional latent heat in the PD phase.
[2] In present study, to investigate accurately how change in the propagation wave
number q reﬂecting the microscopic magnetic state correlate with extra heat absorption and generation during thermal cycles
found in the speciﬁc heat measurement, we
performed neutron diffraction experimentswith varying the temperature as was in
the speciﬁc heat measurement, using HQR
spectrometer at JRR3M in JAERI (Tokai)
for single-crystal sample of CuFeO2. The
incident wavelength of neutron is 2.44[A]and collimation of open-’40-’40-open is employed.
As shown in Fig.1, starting 1st-heatingprocess from T˜11.65 K, variation of the
wave number q well follows the Tincreasing-Guide-line shown in the inset
of Fig.1. In subsequent1st-cooling process,with decreasing the temperature from thehighest temperature ˜11.85 K, the point
q(T) depicted by blue cricle moves horizontally on the wave number q v.s. Temperature (q-T) plane, meets and follows the Tdecreasing-Guide-line. In subsequent 2nd-

T-Increasing
Guide-Line

0.21
0.2
0.19
11

T-Decreasing
Guide-Line

12

13

T [K]

14

T-Increasing
Guide-Line

0.207

NeutronSpecific Heat

T-Decreasing
Guide-Line

0.206
11.60 11.65 11.70 11.75 11.80 11.85 11.90

Temperature [K]Fig. 1. Trajectory of the wave number q for
temperature-cycles with the temperature width of
dT=0.20 K. [inset] Tempetature dependence of themagnetic propagation wave number q in PD state,.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-2-18Phase Stability and Site Occupancy for the L21-type phase in Co2YGa (Y = Ti,
V, Cr, Mn and Fe) Alloys
K. Kobayashi (a), R. Y. Umetsu (b), R. Kainuma (b), K. Ishida (a), K. Ohoyama (c) and Y.
Yamaguchi (c)(a) Graduate School of Engineering, Tohoku Univ., (b) IMRAM, Tohoku Univ., (c) IMR,
Tohoku Univ.
Many Co2YZ L21 (full-Heusler)-type
half-metallic ferromagnets (HMFs) havebeen extensively studied from both theoretical and experimental points of view
due to their potential applications in spindependent devices such as magnetic random access memories (MRAMs). From therecent studies [1-3] on Co-, Ni-, and Cubased X2YZ L21-type alloys, it has been
conﬁrmed that the phase stability of L21type alloys strongly depends on the kind ofelements occupying the Y (4a) site and thatthe order-disorder transition temperaturefrom the L21 to B2-type phase Tt(B2/L21)
tends to decrease with increasing electron number of the Y element in the periodic table, except for in the case of Cr.
The Tt(B2/L21) of Co2CrGa is the lowest
among the Co2YGa (Y = Ti, V, Cr, Mn andFe) alloys. In the present study, the site occupancy in the L21-type phase of Co2YGa
alloys was investigated to clarify the correlation between the phase stability and thesite occupancy.
The specimens were prepared by induction melting under an argon atmosphere. After alloying, each ingot wasannealed at 1373 K for 72 hours andquenched in ice water. Powdered specimens were additionally annealed at 773
K for 2 hours. Neutron powder diffraction experiments were carried out using the
Kinken powder diffractometer, HERMES[4], of the Institute for Materials Research(IMR), Tohoku University, installed in the
JRR-3M reactor at the Japan Atomic Energy
Agency (JAEA), where the wavelength was
0.182646 nm. The neutron diffraction data
were analyzed with the Rietveld method
using the RIETAN2000 program [5].
Figure 1 shows the observed and calcu-

lated neutron diffraction patterns and theirdifferences between them at 300 K in theparamagnetic state for the Co2TiGa alloy
which has a Curie temperature at TC=137
K. It was conﬁrmed from the Rietveld analysis that the lattice constant a = 0.5858 nm,
that the 8c site is entirely occupied by Co
atoms, and that the 4a site is occupied by
the Ti atoms with the site occupancy g =0.96. In order to simplify this analysis, we
introduced an assumption that the Co (8c)site is not occupied by Ga atoms [6], which
is supported by the thermodynamic calculation based on the Bragg-Williams-Gorsky(BWG) approximation [7]. The high site occupancy obtained for the L21-type phasein the Co2TiGa alloy is consistent with thehigh phase stability that is suggested by
the fact that the order-disorder transition
temperaturefrom the L21 to B2-type phase
Tt(B2/L21) is very high at 2390 K [3].
The observed and calculated neutron
diffraction patterns and the difference betwen them at 573 K in the Co2CrGa alloy
are shown in Fig. 2; the TC of this alloy isknown to be 495 K [3]. Structural parameters including the site occupancy were reﬁned under the same assumption as thatfor the Co2TiGa alloy. We have obtained
the following results; the lattice constant a= 0.5805 nm, the 4a site is occupied by Cr
atoms with g = 0.86, the 4b site is occupied by Ga atoms with g = 0.88, and the 8csite is occupied by the Co atoms with g =0.99. It was conﬁrmed that while the site
occupancy of the 8c site by the Co atoms
in the Co2CrGa alloy as well as that in theCo2TiGa alloy is almost perfect, the site occupancies of the 4a and 4b sites are lower
than those in the Co2TiGa alloy.
According to the BWG approximation [6],Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

the Tt(B2/L21) of the stoichiometric X2YZ
alloy is simply indicated by the following
relation under the assumption that the occupancy of the 8c site by the X atoms is perfect at the ordering temperature Tt(B2/L21)[8]:
Tt(B2/L21) = 3W(YZ)/2k,
where W(YZ) is the interchange energy of
the Y-Z bond between the second nearest neighbors and k is the Boltzmann constant. The above equation means that there
is a linear relation between Tt(B2/L21)
and W(YZ). Therefore, it can be concluded that the difference of the site occupancy between Co2TiGa and Co2CrGa
can be attributed to the difference ofthe W(YZ), which can be evaluated fromthe Tt(B2/L12) of Co2CrGa (1056K) andCo2TiGa alloys (2390K) by Eq 1. Further
systematic quantitative analysis of the site
occupancy in Co2YGa (Y = V, Cr, Mn andFe) alloys is needed to clarify the relation
between the phase stability and the site occupancy.
In conclusion, the site occupancies of
the Co2TiGa and Co2CrGa alloys were investigated and it was found that for the
Co2TiGa alloy, the 4a, 4b and 8c sites arealmost entirely occupied by Ti, Ga and Co
atoms, respectively. On the contrary, for
the Co2CrGa alloy, the 4a and 4b sites areoccupied by the Cr and Ga atoms withg = 0.85 and 0.88, respectively. These results can be explained by the difference ofthe order-disorder transition temperatureTt(B2/L21) from L21 to the B2-type phasefor these two alloys.

Aoki and K. Ishida, J. Alloys Compds. 367(2004) 2.
[3] K. Kobayashi, K. Ishikawa, R. Y.
Umetsu, R. Kainuma, K. Aoki and K.
Ishida, J. Magn. Magn. Mater., in press.
[4] K. Ohoyama, T. Kanouchi, K. Nemoto,
M. Ohashi, T. Kajitani, Y. Yamaguchi, Jpn.
J. Appl. Phys. 37 (1998) 3319.
[5] F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324 (2000) 198.
[6] R.Kainuma, R.Umetsu and I. Ohnuma,
unpublished work.
[7] W. L. Bragg, E. J. Williams, Proc. Roy.
Soc. A 145 (1934) 699, A 151 (1935) 540.
[8] G. Inden, Z. Metallkde, 66 (1975) 577.

This work was supported by Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST).
References[1] K. Ishikawa, R. Kainuma, I. Ohnuma, K.
Aoki and K. Ishida, Acta Mater. 50 (2002)
2233.
[2] K. Ishikawa, I. Ohnuma, R. Kainuma, K.

－ 123 －

Fig. 1.

JAEA-Review 2008-067

1-2-19Magnetic Ordering of β-MnOs alloys

R. Y. Umetsu (a), A. Fujita (b), R. Kainuma (a), K. Fukamichi (a) and T. Hori (c)(a) IMRAM, Tohoku Univ., (b) Graduate School of Engineering, Tohoku Univ., (c) Shibaura
Institute of Technology.
It has been known that pure β-Mn has
no long-range magnetic ordering down to
the lowest temperatures [1]. In the βMn alloys, the alloying transition elements
are usually substituted for Mn atoms in
8c and/or 12d sites of the β-Mn structure (P4132) [2], and the magnetic properties signiﬁcantly depend on the substituted
site of the elements. For example, in the βMnFe, β-MnCo and β-MnNi alloys wheremost of the additional atoms occupy the 8csite, the magnetism has been determined
by NMR examination to be antiferromagnetic [3]. However, no experimental evidence for the long-range antiferromagnetic
ordering has been reported in the previous neutron diffraction study [4]. We havebeen investigated various physical properties of β-MnTM (TM =Os, Ru and Ir) alloys because the TM can be substituted fora wide concentration range in the β-Mn,almost up to 40 at. %. In the present investigations, we performed neutron powder diffraction (NPD) investigations for βMn1-xOsx alloys with x = 0.06 and 0.25 inorder to conﬁrmed existence or absence ofthe magnetic ordering.
The alloys were prepared by arc melting
and the obtained ingots were annealed at1273 K and then quenched in ice water. The
NPD experiments were carried out using
the Kinken powder diffractometer, HERMES [5], of Institute for Materials Research(IMR), Tohoku University, installed in the
JRR-3M reactor at the Japan Atomic Energy
Agency (JAEA), where the wavelength was
0.182646 nm. The obtained NPD data wereanalyzed with the Rietveld method using
RIETAN2000 program [6].
Figure 1 shows the NPD patterns measured at 8 K (a) and 200 K (b) and thedifference of them (c) for x = 0.25. The
diffraction pattern at 200 K can be simply

indexed as the nuclear peak of the basic βMn structure. It was conﬁrmed by the Rietveld analysis that the lattice constant is a
= 0.6486 nm, and that the site occupanciesof Mn atoms in the 8c and 12d sites are g= 0.37, and 0.93, respectively, i.e., most of
the Os atoms occupy in the 8c site. On theother hand, many additional peaks are observed in the diffraction pattern at 8 K (a).
According to our previous investigation,an anomaly in the thermo-magnetization
curve has been observed around 160 K.
This means that these additional peaks are
due to the magnetic ordering. From thismagnetic diffraction pattern, it would bethought that the magnetic structure is classiﬁed as a non-collinear-type in antiferromagnetic structures. The detailed magnetic structure is now under consideration.
Temperature dependence for the intensityof a large magnetic peak for x = 0.25, indicated by an arrow in the Fig. 1 (c), is shownin Fig. 2. It is evident that the magnetic
peak disappears at around 160 K almost coinciding with the temperature in which theanomaly was conﬁrmed in the magnetic
measurements. Therefore, it is concluded
that the anomaly is attributed to the Neeltemperature.
Figure 3 shows the NPD patterns at 4 K(a) and 50 K (b) and the difference of them(c) for x = 0.06. It was determined by the
Rietveld analysis that the obtained peaks
are indexed as the β-Mn structure with a= 0.6315 nm, and that the 8c and 12d sites
are occupied by the Mn atoms with g = 0.91
and 0.97, respectively. No magnetic peakis observed in the diffraction patterns obtained at 4 K (a), although an anomaly inthe magnetic measurements was detected
at around 40 K. These results are similar tothat of the β-MnCo alloy [4].
According to the theoretical calculations,

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JAEA-Review 2008-067

the magnetic moments for a Mn atom inthe 8c and 12d sites are completely different and evaluated to be about 0.2 and 1.25
mB/Mn-atom, respectively [7]. The absence of the magnetic ordering of the pureβ-Mn alloy is thought to be caused by thegeometrical frustration of the Mn atoms in
the 12d site forming a triangular lattice [8].
It would be concluded that the lattice expansion and/or the distortion of the triangular lattice given by the substituted alloys
in the 8c site bring about the long-range antiferromagnetic ordering.
References[1] Y. Masuda, K. Asayama, S. Kobayashi,
and J. Itoh, J. Phys. Soc. Jpn. 19 (1964).
[2] K. I. Kripyakevichi, Sov. Phys. Crystllogr. 5 (1960) 253.
[3] T. Kohara and K. Asayama, J. Phys. Soc.
Jpn. 37 (1974) 401.
[4] T. Hori, J. Phys. Soc. Jpn. 38 (1975) 1780.
[5] K. Ohoyama, T. Kanouchi, K. Nemoto,
M. Ohashi, T. Kajitani, Y. Yamaguchi, Jpn.
J. Appl. Phys. 37 (1998) 3319.
[6] F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324 (2000) 198.
[7] T. Asada, J. Magn. Magn. Mater. 140-144(1995) 47.
[8] H. Nakamura and M. Shiga, Physica B
237/238 (1997) 453.

Fig. 1.

－ 125 －

JAEA-Review 2008-067

1-2-20

Neutron Diﬀraction Studies on R7Rh3Dx
T. Tsutaoka(A), A. Tanaka(A), G. Nakamoto(B) and M. Kurisu(B), Y. Andoh(C)(A)Graduate School of Education, Hiroshima University, Hiroshima 739-8524, Japan(B)Japan Advanced Institute of Science and Technology, Ishikawa 923-1292, Japan (C)Faculty ofRegional Sciences, Tottori University, Tottori 680-8551 JapanThe rare earth intermetallic compounds
R7Rh3 crystallize in the hexagonal Th7Fe3
type structure with the space group P63mc.
They are easily hydrogenized to have
R7Rh3H30 with the Th7Fe3 type structure remained [1]. We have shown that themagnetic property of Tb7Rh3 is drastically
modiﬁed by the hydrogenation. Furthermore, electrical conduction changes fromsemimetallic to metallic by the hydrogenation. In this study, we have performed thepowder neutron diffraction measurements
on R7Rh3Dx (R=Dy and Ho) to investigate
the location of deuterium atoms and themagnetic structure of the deuteride. Deuterization of R7Rh3 samples was carriedout in the pressure up to 10 kbar at 25
and 100 degree Celsius in the high pressure
vessel [2]. The concentration of deuteriumin the deuterides was determined by thegas chromatography. The neutron diffraction measurements have been carried out
by using the HERMES spectrometer of JRR3M in the temperature range from 10 to 100
K. The neutron wave length was 0.18265
nm.
Figure 1(a) shows the powder neutron diffraction proﬁles of Ho7Rh3 andHo7Rh3D17 at 70 K. All the peaks in
Ho7Rh3 can be indexed on the basis of theTh7Fe3 type structure. In Ho7Rh3D17, thepeaks shift to lower angle side, indicatingthat the lattice expands by the deuterization. The structural determination for thehydrides is in progress. Figure 1(b) indicates the powder neutron diffraction proﬁles of Ho7Rh3 and Ho7Rh3D17 at 4 K. In
the Ho7Rh3 a strong magnetic reﬂection isobserved at the position of 2 theta = 6.4
degree. As we proposed an incommensurate helical structure with the propagation
vector k = (0 0 0.377) in the lower antifer-romagentic phase of Ho7Rh3 [3]; the observed proﬁle can be indexed with this helical structure.
On the other hand, in Ho7Rh3D17, only aweek peak is observed at 2 theta = 2.6 degree. This peak may be a magnetic reﬂection from the Ho7Rh3D17. The analysis of
the magnetic structures of R7Rh3Dx is alsoin progress.
[1] R. Sato, T. Tsutaoka, S.M. Filipek, J. Alloys Compd., (2007) to be published.
[2] B. Baranowski, S.M. Filipek, J. Alloys
Compd., 404-406 (2005) 2.
[3] T. Tsutaoka et al., Activity Report on
Neutron Scattering Research, Vol.8 (2001)
114.

Fig. 1. Powder neutron diffraction proﬁles of
Ho7Rh3 and Ho7Rh3D17 at 70 K (a) and 4 K (b).

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JAEA-Review 2008-067

1-2-21

Neutron Diﬀraction Experiments with 30T Pulsed Magnets
K. Ohoyama, N. Katoh, H. Nojiri, Y.H. Matsuda, H. Hiraka
Institute for Materials Research, Tohoku Univ.
(1,0,0) magnetic reﬂection. As shown in
Fig.1, the intensity of the (1,0,0) magnetic
reﬂection decreased when magnetic ﬁelds
over 10T were applied. Note that the intensity recovered when the magnetic ﬁeld
became lower than B=10T, indicating thatthe decrease of the intensity was not due tothe heating by the coil current. Thus, thisindicates that we succeeded in observing
the spin-ﬂop transition of MnF2 at B=10T.
We have also succeeded in observing magnetic reﬂection over 22T in CuFeO2 with
30T pulsed magnetic ﬁelds.
References:[1] M. Motokawa et al, Physica B 155 (1989)
39.
[2] S. Mitsuda et al., J. Phys. Chem. Solid 60(1999) 1249.
[3] Y. H. Matsuda, et al., J. Phys. Soc. Jpn. 75(2006) 024710.

CNT/ 400µsec / 100pulse

250

(100)
T=4.2K

200
150
100
50
0
20
Magnetic Field / T

Magnetic ﬁeld is an important parameter which can control magnetic moments
directly. On the other hand, neutron scattering provides a direct probe of space-timecorrelation of spins. Thus, neutron scattering under high magnetic ﬁelds is eagerly
anticipated.
Currently, the highest magnetic ﬁeld forneutron scattering experiments was B=25T
performed by Motokawa et al. using a repeating pulsed magnet in KENS in KEK,
Japan[1-2]. However, experiments over
B=10 T are still limited; easier and morediffusive techniques are ambition. Therefore, aiming at performing neutron scattering experiments under B=40T, we aredeveloping techniques for neutron scattering experiments with long pulsed magnets.
In 2006, we have succeeded in performing
neutron diffraction experiments under 30T
pulsed magnetic ﬁeld on AKANE.
One of the results is observation of spinﬂop transition at 10T in MnF2[4]. The magnet coil[3], in which the single crystalline
sample of MnF2 was ﬁxed, was set in a liquid He refrigerator. The scattering plane
was the a*-c* plane so that we could measure the (1,0,0) antifferomagnetic reﬂection
under magnetic ﬁelds applied along thec-axis. The wave length of the neutrons
was 2.0A; the collimation condition was GOpen-S-B-B. The detector was ﬁxed at thepeak top position of the (1,0,0) reﬂection.
During the pulsed magnetic ﬁelds experiments, neutrons counts and coil currents
were measured with an oscilloscope to resolve time structure. Fig.1 shows time dependence of neutron counts at the peak
top obtained after 100shots. Since the interval between each pulse of 17min. wasneeded, the actual measurements duration
was about 28hr. Since the background was
negligible small under the present conditions, the scattering in Fig.1 was due to the

15
10
5
0
0

5

10

15

Time / msec

Fig. 1. Time Dependence of neutron counts at thepeak top position of (1,0,0) magnetic reﬂection at
T=4.2K obtained after 100 shots (upper panel)

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JAEA-Review 2008-067

1-2-22

Electric Control of Spin Helicity in TbMnO3
Y. Yamasaki(A), H. Sagayama(B), T. Goto(A), M. Matsuura(C), K. Hirota(C), T.
Arima(B,D) and Y. Tokura(A,D)(A)Dept. Appl. Phys., Univ. Tokyo, (B)IMRAM, Tohoku Univ., (C)ISSP, Univ. Tokyo,(D)ERATO-SSS, JSTInamagnetoelectriccompound
TbMnO3 , a sinusoidal incommensurate antiferromagnetic ordering of the
Mn3+ moments takes place at TN = 42 K
with a magnetic wave vector with q ∼ 0.27.
The ferroelectric polarization along thec axis (Pc ) emerges upon the magnetic
phase transition from collinear to cycloid
spin structure at TC = 27 K. We report
here the quantitative elucidation of suchmagnetically induced ferroelectricity interms of the spin ellipticity as the orderparameter and show the successful electric
control between the clockwise (CW) andcounter-clockwise (CCW) spin helixes.
Spin polarized neutron diffraction measurements were performed with a tripleaxis spectrometer PONTA at JRR-3. A single crystal was mounted on a sapphire
plate in a closed-cycle helium refrigerator
and irradiated with a spin-polarized neutron beam with a kinetic energy of 36.0
meV. A Heusler monochromator was utilized to obtain the spin-polarized neutron
beam. The spin of the neutron beam could
be ﬂipped by a spin-ﬂipper, so as to be parallel or anti-parallel to the scattering vector
Qs with a guide-ﬁeld of about 10 gauss applied by a Helmholtz coil.
All the neutron diffraction measurements were performed without applicationof electric ﬁeld after cooling the sample
from 50 K in a poling ﬁeld. Peak proﬁles ofmagnetic satellite reﬂections (4 +q 1) and(4 −q 1) with q ∼ 0.27 were obtained by rotating the sample around the vertical axis,
which approximately corresponded to the
L scan in the reciprocal space.
Figure 1(a) shows the proﬁles of magnetic satellites at Qs = (4 ±q 1) for the ferroelectric state at 9 K after cooling in an electric ﬁeld of E = ±160 kV/m. In the case of

Pc > 0, the intensity of the satellite (4 +q 1)
is approximately 9 times as high with neutron spin (Sn ) anti-parallel to the scatteringvector Qs as that with parallel Sn . As forthe satellite (4 −q 1), the opposite relation isobserved. These behaviors are typical of aspiral magnet with a single helicity, where
the spiral plane is almost perpendicular tothe scattering vector. Here, it is to be notedthat the spiral plane of TbMnO3 is perpendicular to the a axis. When the directionof the cooling electric ﬁeld is reversed, it isclearly shown that the opposite helicity domain becomes dominant. In other words,
that the spin helicity can be successfully
controlled by a poling electric ﬁeld. The
revealed relation between the spin helicity
and electric polarization is depicted in Fig.
1(b).

Fig. 1. (a) Proﬁles of magnetic satellites (4 ±q 1) with
Pc > 0 and Pc < 0 at 9 K. (b) Relation between thespin helicity and the direction of electric polarization in TbMnO3 .

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JAEA-Review 2008-067

1-2-23A puzzling magnetic phase in HoCu2Si2
T. Shigeoka (A), M. Tanaka (A), M. Nishi (B)(A) Graduate school of Sci. and Engin. Yamaguchi Univ., (B) ISSP, Univ. Tokyo
The ternary compound HoCu2Si2, having
the tetragonal ThCr2Si2-type crystal structure (space group: I4/mmm), orders antiferromagnetically below TN=6.0 K [1]. An
additional magnetic transition has been recently observed at Tt=5.1 K from measurements of magnetic susceptibility andspeciﬁc heat [2]. The antiferromagnetic
structure, reported from powder neutron
diffraction study [3], is characterized by thewave vector k= (1/2, 0, 1/2), having Ho
moments parallel to the [100] direction. The
magnetic structure for Tt<T<TN has been,
however, unknown yet.
In order to investigate the magnetic structure for the intermediate temperature region Tt<T<TN, neutron diffraction studies
have been performed on a HoCu2Si2 single crystal using a double-axis mode of thetriple axis spectrometer HQR installed at
JAERI, Tokai, Japan. The a-axis of the single crystal was vertically oriented to obtain
the distribution of neutron intensities in the
a*-c* reciprocal plane.
The single crystal has been grown by
the tri-arc Czochralski method. The single
phase nature has been conﬁrmed by X-ray
powder diffraction
At low temperatures below Tt, an appearance of antiferromagnetic reﬂections
associated with the propagation vector
k1=(1/2, 0, 1/2) has been conﬁrmed. These
reﬂections disappear above Tt. In intermediate temperature region Tt<T<TN,
new antiferromagnetic reﬂections appear
around (1/2 0 1/2), indexed by (1/2+d1, 0,
1/2+d2) and (1/2-d1, 0, 1/2-d2) (d1=0.030,
d2=0.033). They are associated with the
propagation vector k2=(0.530, 0 , 0.533).
No higher order harmonics are observed,
suggesting that this magnetic structure is
not an anti-phase one but amplitude modulated one. The temperature dependenceof peak intensity for antiferromagnetic re-ﬂections is shown in Fig. 1. The (1/2 0
1/2) intensity rapidly decreases around Tt
with increasing temperature. On the other
hand, the (0.530 0 0.533) intensity develops
around Tt and disappears above TN. Thermal hysteresis is observed around Tt, indicating the transition at Tt is of the ﬁrst
order. An analysis for magnetic structureof the intermediate temperature is now inprogress.
References[1] D. Gignoux and D. Schmitt, Handbookof Magnetic Materials, 1997, 239[2] T. Shigeoka et. al., AIP conference proceedings (2006)1257[3] J. Leciejewicz et. al., J. Magn. Magn.
Mat. 53(1986)309.

Fig. 1. Temperature dependence of antiferromagnetic reﬂections in HoCu2Si2

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JAEA-Review 2008-067

1-2-24

Neutron Diﬀraction Study on La2-xCaxCoO4
K. Horigane, T. Uchida, K. Ohoyama*, K. Yamada* and J. Akimitsu
Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara229-8558; *Institute for Materials Research, Tohoku University, Sendai 980-8577
Perovskite Co oxide, La1-xAxCoO3(A=Ca,
Sr, Ba), has attracted considerable interest because their fascinating physicalproperties. F. Fauth et al reported thediffraction and transport properties of
La0.5Ba0.5CoO3 [1]. From the neutron andsynchrotron diffraction powder studies,
they have observed the Jahn-Teller (JT) distortion of the CoO6 octahedra below Tc.
The JT-effect is favored for the intermediate spin state (IS) conﬁguration, (t2g)5(eg)1.
Thus, they concluded that ferromagnetictransition and IS state are strongly correlated each other in La0.5Ba0.5CoO3.
Recently, we reported neutron diffraction experiments of La1.5Ca0.5CoO4 andCE-type spin and charge conﬁgurations
are probably realized. In the CE-type spin
conﬁguration, double-exchange interaction
between Co2+(HS) and Co3+(IS) is realized and it is expected that JT-distortionis formed below TN. In order to clarify
the JT effects in a half-doped material, we
performed neutron powder diffraction experiments using the diffractometer, HERMES, installed on T1-3 port of JRR-3M reactor. La1.5Ca0.5CoO4 has two-magnetic domains, so we use a single magnetic domainof La1.85Ca0.15CoO4.17 which is an almost
half doped material.
The
structure
analysisforLa1.85Ca0.15CoO4.17 at 7, 50 and 100K
concluded that its space group is P4/mmm
which corresponds to the isotropic oxygen
displacement model (√ 2atet ×√ 2atet ×c). Figure 1 shows the temperature dependence of Co-O apical oxygen distance. In
neutron experiments of La1.5Sr0.5CoO4 ,it s found that Co2+-O distance is longer
than Co3+-O distance [2]. We assumed
that the Co(1)-O(2) and Co(3)-O(5) distances correspond to that of Co2+-O andCo3+-O, respectively. As can be seen in

Fig.1, temperature dependence of theapical oxygen distortion coincides withthat of the antiferromagnetic order. This
result suggests that magnetic transition
and JT-distortion are also strongly related
each other in La-Ca system. Magnetic
diffuse peaks due to an antiferromagnetic
ordering of Co2+ are observed at (0.5,0, 0.5) and (0.5, 0, 2.5). These peaks areindexed in the crystallographic unit cell.
This indicates that the magnetic peaks are
two-dimensional Bragg diffraction becauseof the layered crystal structure.
References[1] F. Fauth, E. Suard and V. Caignaert,
Phys. Rev. B 65, 060401 (2001)[2] I. A. Zaliznyak, J. M. Tranquada, R.
Erwin and Y. Moritomo, Phys. Rev. B 64,
195117 (2001)

Fig. 1. Temperature dependence of Co2+(3+)-O
bond length

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-2-25

Anisotropic magnetic diﬀuse scattering in a helical magnet ErNi2Ge2
Yoshikzau Tabata, Ryota. Yamaki, Taichi Kido, Shuzo Kawarazaki
Graduate School of Science, Osaka University

In Ref.[1], they reported that ErNi2Ge2 hasa sinusoidal modulated structure with themagnteic wave vector k = (0,0,0.757) and its
magnetic moment forms an angle 64 deg.
with the c-axis. However, it is not consistent with our magnetization measurements
using single crystalline samples, which evidently indicate that the ab-plane is a magnetic easy plane and the magnetization
component along the c-axis is less than
1/10 of that in the ab-plane.

markable anisotropic nature, namely, thepeak proﬁle is broaden along the [1,0,0]and the [1,1,0]-axis, whereas it is sharp
along the c-axis enough to be considered
as a resolution limit. These results indicate that the antiferromagnetic order of
ErNi2Ge2 is composed of the long-range
and the short-range orders. And also, theysuggest that the short-range orders consist of one-dimensional long-range helices
along the c-axis.
[1] G. Andre et al., J. Alloys Comp. 224(1995) 253.
105
ErNi2Ge2
4

10

103

In order to resolve this inconsistency, we
have performed neutron scattering experiments using single crystalline samples on
the triple-axis spectrometer T11 installedat the JRR-3M. A quantitative analysis ofintensities of several magnetic reﬂections
indicates that the moments lie in the abplane, rather than forming an angle 64
deg. with the c-axis, and form the helicalmodulation, not the sinusoidal one. Thismagnetic structure is consistent with ourmagnetization measurements and our crystalline electric ﬁeld(CEF) analysis.
Furthermore, we found a characteristic
magnetic diffuse scattering, as shown in
Fig. 1. Below TN, the peak proﬁle is composed of a long-range sharp peak and ashort-range broad one. The broad one canbe ﬁtted with a Lorentzian. Interestingly,
this magnetic diffuse scattering has a re-

T=
1.45K

Intenisty (arb. units)

Magnetic frustration is one of the central
issue of the magnetism for decades. Origins of the magnetic frustration are roughlyclassiﬁed into two categories, the geometrical frustration and the frustration in theexchange couplings such as in the ANNNI
system. A rare-earth intermetallic compound ErNi2Ge2 is a latter type manget,
showing a long-periodic magnetic structure[1].

102

101

2.65K

101
3.05K
101

101

100
-0.03

3.66K

-0.02

-0.01

0

0.01

0.02

0.03

h in (h h 3.25) (r.l.u.)

Fig. 1. Temperature variation of the magnetic scattering of ErNi2Ge2. Black solid lines represent theﬁtting results. Blue ones are the Lorentzian components.

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JAEA-Review 2008-067

1-2-26

Neutron scattering in O2 adsorbent magnet
Takatsugu Masuda
International Graduate Schools of Arts and Sciences, Yokohama City University,
22-2 Seto, Kanazawa-ku, Yokohama, 236-0027
Oxygen molecule is a simple magnetic
element that carries S = 1 spin. While
metal ions are constituents of various
types of magnetic compounds, O2 basedmagnets has been restricted to monolayer
O2 molecule adsorbed on the surface ofseveral materials such as Aluminum orgraphite [1, 2]. The adsorbed O2 forms spinframework that reﬂects the surface structure of mother compound. For example
S = 1 trangular lattice is realized in theO2 adsorbed graphite. However the small
amount of the adsorbed spins makes themagnetic property measurement difﬁcult.
Hence the metal based compound has beenmajor substances for the study of magnetism.
Recently the adsorption of O2 moleculein the nanochannel of some microporouscompounds were reported [3]. In contrast
with the surface adsorption, the oxygen
molecules are intercalated deep inside thehost compound and the adsorption is realized in the bulk crystal. Hence the O2 basedmagnet with the bulk size is experimentallyrealized. In this pioneering work we observed the magnetic excitation of O2 S = 1
spins in the O2 adsorbed microporous compound [Cu(II)2 (bza)4 (pyz)]n (bza and pyz
are benzoate and pyrazine, respectively) by
neutron scattering technique.
Crystal structure analysis by x-ray
diffraction showed that the adsorbed
O2 molecule forms isolated trimer [3].
Preliminary magnetic susceptibility measurements is consistent with the spin
trimer model with J ∼ 2.0 meV [4]. If thisis the case a narrow band excitation would
be observed at h̄ω ∼ 2.0, 4.0, and 6.0 meVwith the intensity modulation in inelastic
neutron scattering (INS). [5]. Hence weperformed initial experiment at PONTA
spectrometor installed at 5G beamline.

However, we observed no intrinsic signal
in the energy transfer range between 1 meV
and 20 meV. This means that preliminarymodel is inconsistent with experiment.
Then we performed the second experiment
at HER spectrometer at C11 in guide hall.
We repeat the measurements for both O2
adsorbed and not adsorbed samples in thesame experimental conﬁguration.
Figure 1 shows a typical constant q scan.
Well deﬁned sharp peak was observed ath̄ω = 0.40 meV. We conﬁrmed the disappearance of the peak in not adsorbed sample. The peak position was independentof q. The intensity decrease with the increase of q gradually and monotonically.
The h̄ω = 0.4 meV mode is the only excitation that we observed in the energy rangeof 0.15 meV < h̄ω < 20 meV. Furthermore
we did not observe any sign for the intensity modulation.
The results mean that the observed peakis due to magnetic excitation from O2 spinsof S = 1. The q independence means thatthe spin system is isolated. The absence of
the intensity modulation means that the interaction between O2 spins is too weak to
be detected in INS. The only possible explanation for the excitation is that a single
ion anisotropy of an O2 spin of S = 1.
In summary we succeeded in the observation of the magnetic excitation in O2 adsorbent magnet.
References[1] L. N. Mulay and L. K. Keys, J. Am. Chem.
Soc. 86, 4489 (1964).
[2] Y. Murakami and H. Suematsu, Phys. Rev.
B 54, 4146 (1996).
[3] S. Takamizawa, E. Nakata, T. Saito, T. Akatsuka, and K. Kojima, CrystEngComm, 6,
197 (2004).
[4] S. Takamizawa, E. Nakata, and T. Akatsuka, Angew. Chem. Int. Ed. 45, 2216

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067(2006).
[5] U. Falk et al., Phys. Rev. B 35, 4893 (1987).

Intensity (counts/1min.)300
PYZ C11
guide-open-Be or PG - sample-HEA-open
250 Ef=2.5 meV-1
q=1A
200 T=1.5K
150
100
50
0
0.0

0.2

0.4

0.6

0.8

1.0

Energy (meV)Fig. 1.
Constant q scan in the O2 adsorbed[Cu(II)2 (bza)4 (pyz)]n .

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JAEA-Review 2008-067

1-2-27

Neutron scattering in Ba2 MnGe2 O7
Takatsugu Masuda
International Graduate Schools of Arts and Sciences, Yokohama City University,
22-2 Seto, Kanazawa-ku, Yokohama, 236-0027
Ba2 MnGe2 O7 is a 2D square-lattice antiferromagnet with Mn2+ spin of S =5/2. The crystal structure is tetragonalwith space group P − 421m, a = 8.4952 Å,and c = 5.5256 Å. The isostructural compound Ba2 CuGe2 O7 [1] is well known as
spiral magnet with Dzyaloshinskii-Moriya
and KSEA interaction. The remarkable difference is found in the energy scale of exchange constants J. In Ba2 MnGe2 O7 J ∼0.05 meV is estimated by magnetic susceptibility measurements. The boundary energy is calculateed to be 0.5meV from spinwave approximation. Hence the spin dispersion can be measured by cold neutron
scattering experiment. This exchange energy corresponds to the saturation ﬁeld of
about 9 T. This means that the spin dispersion can be fully tuned by the magnetic ﬁeld by using available superconducting magnet. To study the behavior ofspin wave in the strong magnetic ﬁeld [2],we planned to characterize the following
magnetic properties: (i) magnetic sturcture
analysis, (ii) inelastic cold neutron scattering in zero ﬁeld, and (iii) inelastic cold neutron scattering in magnetic ﬁeld.
We had grown good-looking single crystal of Ba2 MnGe2 O7 by ﬂoating zone furnaces. In prior to neutron experiment powder XRD was performed to conﬁrm the absence of impurity. We observed beautiful 4-fold axis in Laue picture. Rocking
curve with sharp line width was also obtained. After these careful sample characterization, we started neutron experiment
at PONTA spectrometer in 5G beamline
to collect magnetic Bragg diffractions. To
our surprise we found that the intensities
of fundamental nuclear Bragg peaks werevery weak. For example the intensity of(1 1 0) reﬂection, which is the 2nd strongest
peak, of the sample the dimension of 5 ×

5 × 5mm3 was only 2000 cps. Furthermore,
we found a few more (1 1 0) reﬂections
in arbitrary directions, even though eachrocking curves were in resolution limited.
Hence we had to conclude that our sample was multi-domain crystal even ghouth
the bulk sample seems to have good planeand beautiful Laue picture was obtainedby using x-ray. textbf The lesson that welearned is that preliminary crystal checkmust be done by using neutron beams. Xray diffraction is not enough to check the
big crystal for neutron use.
In the given maschine time we changed
our plan and we did the neutron scattering study in O2 absorbent magnet: the proposal ID 6459. Now we are trying to growthe single crystal of Ba2 MnGe2 O7 by using
different growth conditions.
References[1] A. Zheludev et al., Phys. Rev. B 54, 1563
(1997).
[2] Z. E. Zhitomirsky et al., Phys. Rev. Lett. 82,4536 (1999).

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JAEA-Review 2008-067

1-2-28

Neutron scattering in O2 adsorbed CPL-1
Takatsugu Masuda and A Kazuma Hirota
International Graduate Schools of Arts and Sciences, Yokohama City University,
22-2 Seto, Kanazawa-ku, Yokohama, 236-0027
A ISSP the University of Tokyo, 106-1, Shirane, Shirakata, Tokai, Ibaraki, 319-1106
In some metal-organic compounds O2
molecules are adsorbed in nano-scale microporous structure [1, 2]. Since S = 1 spinsare localized at O2 molecules, of which theelectronic structure is 3 Σ−
g , and the array of
the O2 molecules is determined by the geometry of microporous in host compounds,
O2 adsorbed microporous compound is a
new research ﬁeld for designing quantum
spin magnets. So far magnetism of artiﬁcially controlled oxygen molecules has
been restricted to surface adsorption ongraphite [3] or Aluminum. The amount ofoxygen is very small: monolayer or multilayer at best. In contrast in microporouscompound, bulk amount of adsorbed oxygen form bulk S = 1 quantum spin magnet. Here we report the observed spin dynamics of O2 molecules adsorbed in the
prototypical microporous compound CPL1 (C16 H12 Cu2 N6 O10 ) by thermal neutron
inelastic scattering technique.
The crystal structure of O2 adsorbed
CPL-1 is determined by x-ray powder
diffraction [2]. A saturated amount of adsorption of O2 molecules is two moles per
one mole of CPL1. Since O2 molecules
forms ladder structure, the spin-gap is expected in the O2 based magnet. Indeed themagnetic susceptibility [2] and magnetization measurements [4] suggests the spin
gap of 60 ∼ 88 K (5.2 ∼ 7.6 meV). Hence weutilize the thermal neutron scattering technique to study the spin dynamics.
20 g of the powder sample of CPL1 (protonated sample) was prepared by
Takamizawa et al. The sample is put in Al
can (φ 20 mm × 80 mm ) with specially designed sample probe for O2 adsorption experiment. The spacer of 10 mm height is
put in the bottom of Al sample can for the
extra O2 reservoir. The O2 pressure wasmaintained at 0.8 MPa down to 90 K forthe adsorption [2]. ORANGE type cryostat was used to achieve the temperature of
1.5 K. The neutron inelastic experiment was
performed at PONTA spectrometer at 5G
beam line in JRR3 in JAEA Tokai. The sollar collimation of open - 80’ - sample -radialcollimation - open with EF = 14.7 meV wasused. PG ﬁlter was put after sample andhorizontally focusing analyzer was used toobtain better statistics. We paid special attention to background subtraction. Since
we have large background due to protons
in the host compound, we performed theexactly same scans for both with and without O2 molecule. This means that it takes
two times as much as usual experiment.
Though large background with peak structure is observed in the constant q scan without O2 , the enhanced intensity is clealy observed in O2 adsorbed sample. Three peaks
are observed at 5meV ≤ h̄ω ≤ 16 meVin the subtracted data. Among them thepeaks at h̄ω ∼ 10.5 and 14 meV are supposed to be non-magnetic origin because
they are temperature independent. In contrast the sharp peak at h̄ω ∼ 8 meV is suppressed by the increasing temperature. In
addition, the peak position is q independent in wide q range and the peak intensity is suppressed with the increase of q.
These results mean that the 8 meV peak isdue to magnetic excitation of isolated spinclusters. Constant energy scan at h̄ω = 8
meV is shown in Fig. 1. The scan at 6meV
is used as background. There seems a maximum around 1.0 meV. In addition peakstructure around 3 meV probably exists but
seems smeared out due to poor statistics.
The most probable model for the observed spin cluster is S = 1 spin dimers
due to adsorbed O2 molecules. From crys-

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JAEA-Review 2008-067

tal structure consideration, the intradimer
distance is 3.206 Å [4] and the inter-dimer
distance is 4.688 Å. The empirical relation
between the spin exchange constant andinter-molecule distance of oxygen suggeststhat the latter is reasonably weak and canbe neglected. Hence we draw the spin
dimers neutron cross section including presumed O2 form factor (dashed-dotted line
in Fig. 1) [5]. In spite of rough calculation,
the curve reproduce maximum at q ∼ 1.0
Å−1 .
In summary we observed spin dynamics
of O2 molecules adsorbed in microporouscompound CPL-1.
References[1] S. Takamizawa, et al., Angew. Chem. Int.
Ed. 43, 1368 (2004).
[2] R. Kitagawa, et al., Science 20, 2358 (2002).
[3] Y. Murakami and H. Suematsu, Phys. Rev.
B 54, 4146 (1996).
[4] T. C. Kobayashi et al., Prog. Theor. Phys.
Suppl. 159, 271 (2005).
[5] Form factor of oxygen is extensively
studued in P.W. Stephens, Phys. Rev. B 31,
4491 (1985). In this memo I simply used exponential decay formula. Further analysis
will be done later.
open-80-CPL(O2)-PG-RadCol.-HFA-open
Ef=14.7meV(Const e scan at hw=8meV) - (Const e scan at hw=6meV)

Intensity (counts/4 min.)

4000

Const E scan
Const Q scan

3000

2000

1000

0

0

1

2

3

4

5

-1

q (A )

Fig. 1. Constant E scan.

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JAEA-Review 2008-067

1-2-29Magnetic and Neutron Diﬀraction Study on Ni2In type Mn65(Sn1-xTx)35
T=(Ga,Ge)
H.Shiraishi, T.Hori, N.Ohokubo(A) and K.Ohoyama(B)Shibaura Institute of Technology, The Physical Sscience Labolatory Nihon university(A),Institute Materials Research, Tohoku University(B)The hexagonal Ni2In type (P63/mmc)
Mn65(Sn1-xTx)35 T=(Ga,Ge) compoundshows a single phase in the range of
0.2?x?0.5 for T=Ga and 0?x?0.8 for T=Ge.
The sample of x=0 has a collinear ferrimagnetic structure showing glass-like phaseat lower temperature range. We madethe magnetization measurements and theac susceptibility χ ac measurements forMn65(Sn1-xTx)35 T=(Ga, Ge) compound.
The concentration dependence of lattice
constants a and c at room temperature isshown in Fig.1(a). The ferrimagnetic Curie
temperature increases monotonously for
Mn65(Sn1-xGax)35 system and decreases
for Mn65(Sn1-xGex)35 system.
In order to determine the distribution of
the atoms in the Ni2In type crystal structure, the neutron diffraction (ND) experiments were carried out for several samples at paramagnetic state and the data
was analyzed with the Rietveld reﬁnement
methods. The reﬁned pattern at T=295 K
for x=0.5 of Mn65(Sn1-xGax)35 system isshown in Fig.1(b). The determined distribution of atoms among the sublattice is asfollows; 2(a) site is occupied by Mn(1.0) ,2(d) site is occupied by Mn(0.64) and 2(c)site is occupied by Sn(0.50) and Ga(0.50).
Fig.1(c) shows the observed ND intensity
at T=20K for x=0.5 of Mn65(Sn1-xGax)35
system. In the lower angle of ND pattern,
the magnetic super lattice line (0 0 1/2), (1
0 1/2) is clearly observed in the low temperature, which means the existence of themagnetic unit cell with two times of thechemical one in the c direction. ND patternfor x=0.3 and x=0.5 of Mn65(Sn1-xGex)35
system showed only weak and broad magnetic reﬂection. In the temperature rangeof the cluster glass for Mn65(Sn1-xGex)35
system, large size and small size of ferri-magnetic and ferromagnetic clusters may
exist coupling each other. The nonmagnetic 2(c) site atoms play important rule
to formation of the magnetic super lattice in the hexagonal Ni2In type Mn65(Sn1xTx)35 T=(Ga,Ge) compound.

Fig. 1. Fig. １ (a) The concentration dependence oflattice constants a and c at room temperature forMn65(Sn1-xTx)35 T=(Ga, Ge) compound

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JAEA-Review 2008-067

1-2-30Inelastic Neutron Scattering Measurements on a Quadrupolar Ordering in Yb
monopnictides
A. Oyamada(A), K. Kuwahara(B), K. Ohoyama(C), K. Iwasa(D), M. Kohgi(B), S.
Maegawa(A)(A)Human and Environmental Studies, Kyoto Univ., (B)Department of Physics, Tokyo
Metropolitan Univ., (C) IMR, Tohoku Univ., (D) Department of Physics, Tohoku Univ.

The Γ 6 - Γ 8 excitation was observed around 17 meV using the triple axis
spectrometer 6G(TOPAN) with a ﬁxed kf.
The energy spectra were measured down
to 0.7 K including the quadrupolar ordering state. The energy spectra has almost
no change at 5 K, that is consistent withthe results of the molecular ﬁeld calculation assuming O20-type ordering. The energy spectra between 0 and 3.5 meV werealso measured by the triple axis spectrometer C1-1(HER). A strong q-dependence of
the intensity at 0.4 meV was observed below 5 K. The q-dependence is enhancedwith lowering the temperature. The qdependence is probably ascribed to the dispersion of the excitation in the quadrupolarordering state. Further studies at lower energy are required.
Now we turn to the experimental results
on a single crystal of YbAs.
Figure 1 shows the q-dependence of theenergy spectra of YbAs at 3.3 K. The measurements were carried out on the triple

axis spectrometer 6G(TOPAN) with a ﬁxed
kf. The structure in the ﬁgure shows thetransition between Γ 6 ground states andΓ 8 excited states.
The intensity at (2, 0, 0) is smaller than thatat (3, 0, 0). This means the intensity ofthe zone center is smaller than that of thezone boundary. This situation is similar to
PrOs4Sb12 that has a quadrupolar ordering. In the case of YbAs, the quadrupolarordering around 80 K is still controversial.
If there is no quadrupolar ordering around
80 K, our results indicate the importanceof the quadrupolar interactions between 4f
electrons. Further studies using the single
crystal of YbAs is promising.
The observed q-dependence suggeststhat the theoretical approach beyond themolecular ﬁeld approximation is requiredin order to understand the magnetic properties of Yb monopnictides.
[1] L. Keller et al.: Europhys. Lett. 26 (1994)
353.

1000
h = 3, k = 0
h = 2, k = 0

YbAs
800
Counts / 3200 Mon.

The compound YbSb is well-known as a
mixing-type quadrupolar ordering occurs
at 5 K. One of the most anomalous properties of Yb monopnictides (YbN, YbP, YbAs
and YbSb) is the unexpected splitting of theﬁrst excited states (Γ 8) of the crystal ﬁeld
splitting. Keller et al. proposed that the unexpected splitting is explained by the occurrence of a quadrupolar ordering around
80 K in YbN, YbP and YbAs.[1] In order to study the quadrupolar ordering in
Yb monopnictides, inelastic neutron scattering experiments on the powder samplesof YbSb and a single crystal of YbAs were
measured.

3.3 K
600
400
200
0

5

10

15

20

25

30

35

Energy (meV)Fig. 1. Energy spectra at Q = (3, 0, 0) and (2, 0, 0).

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JAEA-Review 2008-067

1-2-31

Successive magnetic phase transitions of DyB4
Takeshi Matsumura and Daisuke Okuyama
Department of Physics, Graduate School of Science, Tohoku University
A tetragonal rare-earth compound DyB4
has been attracting interest as a system
where the quadrupolar moment of Dy
might be ﬂuctuating because of the geometrical frustration, which is geometrically equivalent to the Shastry-Sutherlandmodel. The Dy lattice can be regarded as a
combination of square and triangular connections because the nearest neighbor andthe next nearest neighbor connections havealmost the same distance.
DyB4 interestingly exhibits two phase transitons at TN1=20.3 K and at TN2=12.7 K.
It is already established by neutron powder diffraction that an antiferromagnetic
order occurs at TN1 with magnetic moments align along the c-axis and propagate along the [100] direction. What is intriguing is that the entropy of Rln2 still
remain and that the elastic softening andabsorption are enhanced in the temperature region TN2 < T < TN1. These results indicate that the quadrupolar degeneracy still remains even below TN1. We
performed resonant x-ray scattering experiments and have revealed that the magnetic components within the ab-plane areshort range ordered in this intermediate
temperature region [1]. Below TN2, the inplane moments order with the corresponding quadrupolar moment <Ozx>, resulting in a uniform structural distortion fromtetragonal to monoclinic.
Observation of the short range ordering
by resonant x-ray scattering and the elastic softening suggests that the in-plane moments are ﬂuctuating in a relatively longtime scale; it looks ordered by x-ray but
paramagnetic by ultrasonic measurement.
By investigating this phenomenon by neutron diffraction, with intermediate timescale ˜THz, we expect that we could clarify
if the in-plane moments are really ﬂuctuating and its ﬂuctuation rate.

We have performed neutron diffraction experiment on a single crystalline DyB4. The
sample was grown by the ﬂoating-zone
method using 11-Boron isotope to avoid
absorption by 10-Boron in natural boron.
The experiment was performed using a
triple-axis spectrometer TOPAN, installedat the 6G port of JRR-3 in JAEA. The collimators of 15’-30’-30’-Blank was used with
PG ﬁlter at neutron energy of 30.5 meV.
Since the absorption by natural Dy is extremely large, the diffraction in this sample
occurs in a very thin region at the surface
less than 0.5 mm. Therefore the comparisonof the scattering intensity among different
diffraction peaks are impossible. Only the
relative variation with temperature are analyzed.
Calculated magnetic structure factor fromthe magnetic structure model shows thatthe relative contribution to the intensity by
the in-plane moment becomes large withincreasing the c-axis component of the scattering vector. The (200) reﬂection involves
no contribution from the in-plane component and reﬂects only the c-axis component. Then, we have measured the temperature dependences of (100), (101), (102),(103), and (200) reﬂections and analyzed
the results.
Figure shows the temperature dependences of the (200) and (103) reﬂections.
The (200) magnetic reﬂection arises only
from the c-axis component, while the 94%of the structure factor of the (103) magnetic
reﬂection is due to the ab-plane component. The lines in the ﬁgure are the calculated temperature dependences for each reﬂections, assuming the c-axis and ab-planecomponent illustrated in the bottom ﬁgure.
The experimental results are well reproduced. This result shows that the in-planecomponent is indeed very weak in the intermediate temperature region, and it is or-

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JAEA-Review 2008-067

dered below TN2. Unfortunatelly, because
the structure factor of the (103) reﬂection
contains contribution from c-axis component by 6%, we could not tell if the in-planecomponent in TN2 < T < TN1 is zero or
not although it is certainly less than 10%.
[1] D. Okuyama, T. Matsumura, H. Nakao
and Y. Murakami, J. Phys. Soc. Jpn., 74,2434, (2005).

Fig. 1. Temperature dependence of (200) and (103)reﬂections of DyB4. Lines are calculated temperature dependences. Bottom shows the c-axis (z) andab-plane (x) components of the magnetic moment
assumed for the calculations.

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1-2-32Chiral Helimagnetism in CuB2O4
Y. Kousaka1, K. Shimoda1, K. Hirota2, M. Nishi2 and J. Akimitsu1
1Department of Physics and Mathematics, Aoyama-Gakuin Univ., 5-10-1 Fuchinobe,
Sagamihara 229-8558; 2Institute for Solid State Physics, The Univ. of Tokyo, 106-1 Shirakata,
Tokai 319-1106
Helical magnet copper metaborate
CuB2O4 has been paid attention from theviewpoint of chiral helimagnetic ordering.
It shows various magnetic phase transitions at low temperature: paramagnetic
state above TN (= 20 K), commensurate
phase with weak ferromagnetic ordering in
the range of T* (= 10 K) < T < TN and incommensurate phase with helimagnetic ordering below T*. In the temperature close
to the incommensurate-to-commensuratetransition, neutron diffraction experiments
show higher order satellite, which is anevidence for the formation of magnetic
soliton lattice [1]. With increasing an applied magnetic ﬁeld perpendicular to thehelical c-axis, incommensurate phase II isobserved in the region which was supposed to be commensurate magnetic structure [2]. The magnetic property of CuB2O4
can be interpreted by the lattice chiral XY
model: commensurate-to-incommensuratetransition is understood by the formationof chiral magnetic soliton lattice [3]. In order to detect chiral helimagnetic ordering,polarized neutron diffraction technique ispowerful by comparing asymmetric magnetic satellite intensities between up-spin(+) and down-spin (-) neutron. Therefore,
we performed polarized neutron diffraction experiments in the incommensurate
phase.
The single crystal was grown by
the spontaneous crystallization technique;slow cooling of CuO, Li2CO3 and B2O3[3], using enriched 11B2O3 to avoid thelarge neutron absorption due to 10B. The
polarized neutron diffraction experiments
were performed at PONTA (5G), JRR-3M
reactor in JAEA (Tokai). The experimental
condition was 8 K under an applied magnetic ﬁeld parallel to the scattering vec-

tor, due to aligning the neutron polarization parallel to the scattering vector. We
observed incommensurate satellite peaks
around (0,0,2), indexed as (0,0,2+q) and(0,0,2-q). As shown in Fig.1, we observed
no difference between up-spin and downspin neutron intensities, which indicates nochiral magnetic ordering. However, symmetry operation based on its space group,
I-42d, allows antiferrochiral helimagnetic
ordering, which alternates right and left
handed screws. In case of the antiferrochiral helimagnetic ordering, observing(1,1,4+q) and (1,1,4-q) reﬂections, which is
not parallel to magnetic propagation vector (0,0,q), is needed. Therefore, in order toinvestigate antiferrochiral helimagnetic ordering, additional experiments are now inprogress.
References[1] B. Roessli et al.: Phys. Rev. Lett. 86 (2001)
1885.
[2] To be submitted.
[3] To be submitted.

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1-2-33Magnetic Structure Analysis in CuB2O4
Y. Kousaka1, K. Shimoda1, S. Yano1, Y. Noda2 and J. Akimitsu1
1Department of Physics and Mathematics, Aoyama-Gakuin Univ., 5-10-1 Fuchinobe,
Sagamihara 229-8558; 2IMRAM, Tohoku Univ., 2-1-1 Katahira, Aoba-ku, Sendai 980-8577
Helical magnet copper metaborate
CuB2O4 has been paid much attention because its strange behavior of magnetization can be interpreted by lattice chiral XY
model; magnetic properties are understoodby a formation of magnetic soliton lattice[1]. It shows various magnetic phase transitions at low temperature: paramagnetic
state above TN (= 20 K), commensurate
phase with weak ferromagnetic ordering in
the range of T* (= 10 K) < T < TN andincommensurate phase with helical magnetic ordering below T*. In the weak ferromagnetic phase, magnetic structure analysis with 4 circle diffractometer shows thecommensurate structure with the propagation vector k0 = (0,0,0) [2]. However, thedetermined structure is inconsistent with
NMR data [3] because of a few number ofreﬂections with long incident wavelengthof 2.36A. In order to argue the magnetic
structure of incommensurate phase, it isimportant to determine magnetic structureof commensurate phase, because the latticechiral XY model indicates that the strucureof the incommensurate phase reﬂects thatof the commensurate phase.
Last year, we performed the neutron
diffraction experiment at 4 circle diffractometer FONDER (T2-2), JRR-3M reactor
in JAEA (Tokai) with short incident wavelength of 1.24A. However, we did not observe any magnetic scattering because of asmall size of the sample, several magnetic
domains under zero ﬁeld and a small magnetic moment of Cu.
Therefore, in order to re-perform the experiments, we improved 2 points; 4 times
larger size of the sample and ﬁeld cooledmeasurement of 800 Oe along the <1,1,0> by sandwiching permanent magnets,
which were enough to saturate the spontaneous magnetic moment.

The single crystal, of which size was 5x 4 x 7 [mm3], was grown by the spontaneous crystallization technique; slow cooling of CuO, Li2CO3 and B2O3, using enriched 11B2O3 to avoid the large neutron
absorption due to 10B. The measurements
were performed at 10 K and 30 K. Subtracting the intensities of 30 K from that of 10 K,
we determined magnetic scattering intensities. We observed clear difference of scattering intensities between 10 K and 30 K. As
shown in Fig.1, comparing (1,1,0) and (1,1,0), magnetic scattering is observable onlyin (1,-1,0), which indicates that the magnetic domain of (h,h,0) reﬂection was well
suppressed by the applied magnetic ﬁeld.
Now we are analyzing the magnetic structure with observed 40 reﬂections.
References[1] To be submitted.
[2] M. Boehm et al.: Phys. Rev. B 68 (2003)
024405.
[3] M. Chiba et al.: Proceedings of NATO
Advanced Research Workshop, ”Smart
Materials for Ranging Systems” (2004) 1.

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1-2-34Magnetic Structure in the Shastry-Sutherland Lattice TmB4
F. Igaˆaˆ , A. Shigekawaˆaˆ, S. Michimuraˆaˆ, T. Takabatakeˆaˆ, S. Yoshiiˆbˆ, T.
Yamamotoˆbˆ, M. Hagiwaraˆbˆ, K. Kindoˆcˆ, K. Ohoyamaˆdˆ
a ADSM, Hiroshima Univ., Higashi-Hiroshima, Hiroshimna 739-8530, Japan bKYOKUGEN,
Osaka Univ., Toyonaka, Osaka560-8531, Japan cInstitute for Solid State Physics, Univ. ofTokyo, Kashiwa 277-8581, Japan d IMR, Tohoku University, Katahira, Sendai 980-8577, Japan
Rare-earth tetraborides RB4 have a tetragonal crystal structure with a space group
P4/mbm which is characterized by the 2dimensional orthogonal dimers in the cplane. Such dimer systems are equivalent
to the Shastry-Sutherland lattice (SSL) [1]
where nearest-neighboring dimers geometrically frustrated. The frustration effectin ErB4 manifests itself as a plateau in
the magnetization process M(B) at the halfof the full moment of 9 mB/Er for B//c
and B//a at 2 T and 10 T, respectively[2]. The frustration in DyB4 is caused by
not only magnetic interaction but also thequadrupolar interaction [3]. A magnetization plateau appears for B//c, but neither
magnetic plateau nor metamagnetic transition occurs for B//a. In order to investigate the origin in the magnetic anisotropy
and rare-earth dependence on the magnetic plateau for B//a, we have searchedother candidates with geometric frustration in magnetic or quadrupolar interaction among the RB4 series. The previous
study of TmB4 indicates an antiferromagnetic order at 11.7 K by the measurementsof temperature dependences of electricalresistivity and magnetic susceptibility [4].
We have studied the magnetization process
and phase diagram of TmB4.
High-quality single crystal TmB4 wasgrown by ﬂoating zone method using afour-xenon lamps image furnace [5]. Magnetic susceptibility c(T) from 2 K to 300 K
and M(B) up to 5 T in were measured bya Quantum Design-SQUID magnetometer.
Electrical resistivity was measured by a DC
4-probe method. Speciﬁc heat C(T) measurement was performed by a relaxation
method using a QD-PPMS system. Magnetoresistance R(B, T) was also measured byusing a AC- transport puck of PPMS system up to 14 T. High ﬁeld magnetization
within the c-plane (a-axis) was measured
by a long pulse magnet (pulse width ˜10ms) up to 50 T . From these experimental results, TmB4 exhibits three phase transitionsat TN1=11.7K, T*=11K and TN2=10K. The
phase transitions at TN1 and TN2 were already reported by Fisk et al. However, thephase transition at T* has been found by
our single crystal study. c(T) shows highly
anisotropic behavior for B//a and B//c.
The effective moment was close to that ofTm3+ free ion. However the paramagnetic
Curie temperature qP for B//c shows positive sign (+27.5 K) although those withinc-plane were negative (-146.5 K). This behaviour can be ﬁt by supposing the crystalﬁeld excited states at 20 K and 40 K, respectively. In viewing of the crystal structure where Tm-Tm dimers stack along thec-axis and orthogonally aligned along withthe [110] direction, antiferromagnetic correlation may be dominant within the cplane and ferromagnetic interaction dominant along the c-axis.
The M(B) for B//c has not only a 1/2
plateau at 2-3 T but also a 1/8 plateau at
1.7-1.4 T in the descending process. Thishysteresis for a 1/8 plateau was observedin the temperature range from 1.8 up to 8
K. This hysteresis region is named as phase
III hereafter. The phase III may be a statewith a long period modulation by magnetic
frustration for the phase III.
In order to clarify this prediction, we have
performed neutron powder diffraction on
the Kinken powder diffractometer for highefﬁciency and high resolution measurements, HERMES, of Institute Material Research, Tohoku University, installed at the

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JAEA-Review 2008-067

JRR-3 reactor in JAEA, Tokai. Neutrons
with a wavelength of 1.8265A were obtained by the 331 reﬂection Ge monochromator. The powder sample Tm11B4 ofabout 7 gram was ﬁlled in a vanadium
cylinder with a diameter of 7 mm. Furthermore this cylinder was sealed in the aluminum can cell with a helium gas atmosphere. The cell was cooled down to 3K
by using a closed cycle He gas refrigerator. The experiments were performed at 3K(antiferro-magnetic phase, IV), 10.7K (unknown phase, III), 11.7K (unknown phase,II) and 20K (paramagnetic phase, I).
Figure 1 shows the powder pattern for
the four phases of TmB4. The pattern at
30 K was used for the nuclear scattering standard. Phase IV shows simple antiferromagnetic pattern with a propagation vector k4=(1, 0, 0). This is consistent with the previous report. The Phase III
has been assigned with propagation vector
k4 and an additional long period modulation vector k3=(0.13, 0, 0). Furthermore,
the phase II was also indexed with the
k4 and k2=(0.012, 0.036, 0) and k2=(0.012,
0.012, 0). However, we have not succeededin obtaining complete ﬁtting parameter because some unknown peaks were observedat this experiment.
Magnetization process M(B//c) in TmB4
shows 1/8 and 1/2 plateaus at 1.7-1.4 T
and 2-3 T, respectively. M(B//a) shows a
1/2 plateau at 32 T. The anisotropy in thetransition ﬁeld is much higher than that in
ErB4. From the magnetization, magnetoresistance, and speciﬁc heat measurements, acomplex phase diagram in TmB4 was obtained. These characteristic behavior may
be originated from geometric frustration in
not only magnetic dipole interactions but
also electric multipole interactions.

[4] Z. Fisk et al., Solid State Commun. 39(1981), p. 1189.
[5] F. Iga et al., J. Magn. Magn. Mater. 177181 (1998) p.337.

Fig. 1. Fig. 1 Neutron powder diffraction patterns
for the four phases of TmB4. The bottom shows asimulation of powder diffraction only by the nuclear peaks.

References[1] B. S. Shastry and B. Sutherland, Physica
B & C 108B (1981), p. 1069.
[2] S. Michimura et al., Physica B (2006), inpress.
[3] R. Watanuki, et al., J. Phys. Soc. Jpn. 74(2005), p. 2169.

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1-2-35Competing magnetic correlations in the paramagnetic phase of HoB4
Takeshi Matsumura, Daisuke Okuyama, and Takuya Mouri
Department of Physics, Graduate School of Science, Tohoku University
A tetragonal rare-earth compound system
of RB4 has been attracting growing interest as a system where both the quadrupolar and magnetic degrees of freedom are
active in the geometrically frustrated lattice, which is equivalent to the ShastrySutherland model. We reported on the
short-ranged magnetic correlation in DyB4.
We observed a broadened peak proﬁle of
the resonant x-ray scattering in the intermediate phase where the quadrupolar moments are considered to be ﬂuctuating [1].
HoB4 exhibits similar phase transitons as in
DyB4 at TN1=7.5 K and at TN2=5.9 K. Results of ﬁrst neutron diffraction experimenthas already been reported by us that an incommensurate magnetic order takes place
at TN1 and a ﬁrst-order-like phase transition at TN2 into a commensurate structure
described by q=(100) [2]. Resonant x-ray
scattering shows that the low-temperaturephase below TN2 is similar to that of DyB4,
where both the magnetic and quadrupolar moments are fully ordered with monoclinic distortion. In the present experiment, we concentrated our attention to thebroad diffuse scattering in the intermediatephase TN2<T<TN1 and in the paramagnetic phase TN1<T.
We have performed inelastic neutron scattering experiments on a single crystalline
HoB4. The sample was grown by theﬂoating-zone method using 11-Boron isotope. The measurement was performed
on a triple-axis spectrometer TOPAN, installed at the 6G port of JRR-3 in JAEA. The
collimators of B-30’-30’-B was used with
PG ﬁlter at ﬁnal neutron energy of 13.5
meV. Scans over a wide reciprocal lattice
space were made on the (HOL) plane.
One of the surprising results is that a verybroad magnetic diffuse scattering occur
around (0 0 0.5) and (1 0 0) simultaneously.
These scatterings remain up to about 20 K.

Figure 1 shows the intensity map at T=9
K in the paramagnetic phase. In the region
TN2<T<TN1, which is deﬁned as phase II,
satellite reﬂections develop at (d d 0.5 ± d’)(d=± 0.022, d’=0.07) on the diffuse scattering around (0 0 0.5). It should be noticed
that another strong diffuse scattering exists
around (1 0 2), which is equivalent to (1 00), the order parameter in phase III below
TN2. This result indicates that two orderparameters are competing; one is antiferromagnetic order with q=(d d 0.5 ± d’), presumably due to RKKY interaction, and theother is antiferromagnetic and quadrupolar order with monoclinic distortion as in
DyB4 with q=(1 0 0). It is also noticed that
this behavior of phase transition is quite
similar to that of HoB2C2.
Measurements of excitation spectra exhibit
two clear peaks at 1 meV and 2 meV.
The intensity becomes strong expeciallyaround (1 0 0) and (0 0 0.5) and the peakenergy seems to go soft with decreasing
temperature to TN2, while the energy atother wavevectors do not change. The detail of this softening behavior will be studied next.
[1] D. Okuyama, T. Matsumura, H. Nakao
and Y. Murakami, J. Phys. Soc. Jpn., 74,2434, (2005).
[2] T. Matsumura et. al., Activity Report
2005; D. Okuyama et. al., to be publishedin J. Magn. Magn. Mater.

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JAEA-Review 2008-067

Fig. 1. Intensity map of HoB4 at 9K in the paramagnetic phase.

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1-2-36

Anomalous magnetic transitions of TbCu2Si2
T. Shigeoka (A), M. Tanaka (A), M. Nishi (B)Graduate school of Sci. and Engin. Yamaguchi Univ. (A), ISSP, Univ. Tokyo (B)Anomalous magnetic behaviors have beenreported on a TbCu2Ge2 single crystal [1];It has the tetragonal ThCr2Si2-type crystal structure (space group: I4/mmm), orders antiferromagnetically below TN=12.3
K and shows an additional magnetic transition at Tt=9.3 K. A one-step metamagnetic transition appears around 17 T along
the hard magnetization direction at low
temperatures and persists above TN up to
Tm=25 K where a broad peak appears intemperature dependence of magnetic susceptibility. Recently it has been reported
that the TbCu2Si2 single crystal compoundshows very similar magnetic behaviors to
those of TbCu2Ge2 [2]; it orders antiferromagnetically below TN=11.9 K and has
additional magnetic anomalies at Tt=9.1 K
and Tm=25 K. The origin of those anomalies has unknown yet.
In order to investigate those transitions,
neutron diffraction study has been performed on the TbCu2Si2 single crystal using the triple axis spectrometer HQR installed at JEARI, Tokai, Japan.
At low temperatures, antiferromagnetic reﬂections associated with the propagation
vector k=(1/2, 0, 1/2) have been observed.
This result is agreement with that reported
by Pinto et al. [3]. The antiferromagnetic
structure is characterized by the propagation vector k and has Tb moments parallel to the [110] directions in the basal plane.
Above Tt, no new magnetic reﬂection could
be detected. Temperature dependence of
the antiferromagnetic peak (1/2 0 1/2) intensity shows in Fig.1. The intensity decreases gradually with increasing temperature and disappears above TN=12 K. No
distinctive anomaly can be seen around Tt.
A reorientation of the Tb moments from[110] to [100] in the basal plane at Tt has
been proposed from the result of resonant
and non-resonant X-ray magnetic scatter-ing [4]. There is, however, no clear evidence
for the spin reorientation from this neutron measurement. With respect to the transit1on at Tm, no magnetic reﬂection could
be observed; existence of magnetic correlation could not be found. The origin of transition at Tt and Tm is now puzzling yet.
Further study is need.
References[1] T. Shigeoka et al., Physica B 346 (2004)
112.
[2] T. Shigeoka and N. Kimura, J. Magn.
Magn. Matter. in press.
[3] H. Pinto et al., Phys. Rev. B 31(1985) 508.
[4] C. Song et al., Phys. Rev. B 64 (2001)
224414.

Fig. 1. Temperature dependence of antiferromagnetic (1/2 0 1/2) peak intensity in TbCu2Si2

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JAEA-Review 2008-067

1-2-37

Magnetic Structure of CrB2 in Magnetic Field
S. Yano1, R. Suwa1, H. Ichikawa1, M. Nishi2, K. Hirota2 and J. Akimitsu1
1Department of Physics and Mathematics, Aoyama-Gakuin Univ., 5-10-1 Fuchinobe,
Sagamihara; 2 Institute for Solid State Physics, The Univ. of Tokyo 106-1 Shirakata, Tokai
319-1106
CrB2 is an itinerant anti-ferromagnet with
TN = 88 K, of which crystal structure is
AlB2-type (P6/mmm).
In the magnetically ordered state of CrB2,
a cycloidal magnetic structure, in which themagnetic moments of 0.5 μ B turn in thec*-[110] plane with the propagation vectorof 0.285[110], was proposed by Funahashi
et al[1]. However, NMR data is inconsistent with the cycloidal model, Spin echo
11B NMR spectra suggest commensurate
structure[2]. Why the inconsistent data are
obtained between NMR and neutron data?
NMR experiments were performed withmagnetic ﬁeld however, neutron diffraction experiments were performed withoutmagnetic ﬁeld.
Therefore, in order to obtain the consistent data of CrB2, we performed the neutron diffraction experiments with an applied magnetic ﬁeld at 3 circle diffractometer PONTA (5G), JRR-3M reactor in JAERI(Tokai).
The single crystals of CrB2, whose size arelength 22 × diameter 5 [mm3] and length
7 × diameter 5 [mm3] were grown by theconventional ﬂoating zone method with Ar
atmosphere, using enriched 11B to avoid
the large neutron absorption due to 10B.
The measurements were taken at 1.8
K and applied magnetic ﬁeld up to 5.9T.
We applied magnetic ﬁeld along the [001]and [1-10] axes, and observed (hh0). As
shown Fig1, the propagation vector andscattering intensity did not change along
the [001] axis by changing the magnetic
ﬁeld, and also along the [1-10] axis. We concluded that the magnetic structure did notchange against the magnetic ﬁelds up to
5.9T. The result shows commensurate 120°state might be stabilized with larger magnetic ﬁeld.

In conclusion, we have determined the cycloidal magnetic structure under magnetic
ﬁeld up to 5.9T.
References[1] S. Funahashi et al.: Solid State Commun.
23 859 (1977).
[2] To be published.

Fig. 1. Observed intensity at 1.8K,H//[001]

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JAEA-Review 2008-067

1-2-38Competition of magnetic correlations in the paramagnetic phase of HoB4
Takeshi Matsumura, Daisuke Okuyama, and Takuya Mouri
Department of Physics, Graduate School of Science, Tohoku University
A tetragonal rare-earth compound system
of RB4 has been attracting growing interest as a system where both the quadrupolar and magnetic degrees of freedom are
active in the geometrically frustrated lattice, which is equivalent to the ShastrySutherland model. We reported on the
short-ranged magnetic correlation in DyB4.
We observed a broadened peak proﬁle of
the resonant x-ray scattering in the intermediate phase where the quadrupolar moments are considered to be ﬂuctuating [1].
HoB4 exhibits similar phase transitons as in
DyB4 at TN1=7.5 K and at TN2=5.9 K. Results of ﬁrst neutron diffraction experimenthas already been reported by us that an incommensurate magnetic order takes place
at TN1 and a ﬁrst-order-like phase transition at TN2 into a commensurate structure
described by q=(100) [2]. Resonant x-ray
scattering shows that the low-temperaturephase below TN2 is similar to that of DyB4,
where both the magnetic and quadrupolar moments are fully ordered with monoclinic distortion. In the present experiment, we concentrated our attention to thebroad diffuse scattering in the intermediatephase TN2<T<TN1 and in the paramagnetic phase TN1<T.
We have performed inelastic neutron scattering experiments on a single crystalline
HoB4. The sample was grown by theﬂoating-zone method using 11-Boron isotope. The measurement was performed
on a triple-axis spectrometer TOPAN, installed at the 6G port of JRR-3 in JAEA. The
collimators of B-30’-30’-B was used with
PG ﬁlter at ﬁnal neutron energy of 13.5
meV. Scans over a wide reciprocal lattice
space were made on the (HOL) plane.
One of the surprising results is that a verybroad magnetic diffuse scattering occur
around (0 0 0.5) and (1 0 0) simultaneously.
These scatterings remain up to about 20 K.

Figure 1 shows the intensity map at T=9
K in the paramagnetic phase. In the region
TN2<T<TN1, which is deﬁned as phase II,
satellite reﬂections develop at (d d 0.5 ± d’)(d=± 0.022, d’=0.07) on the diffuse scattering around (0 0 0.5). It should be noticed
that another strong diffuse scattering exists
around (1 0 2), which is equivalent to (1 00), the order parameter in phase III below
TN2. This result indicates that two orderparameters are competing; one is antiferromagnetic order with q=(d d 0.5 ± d’), presumably due to RKKY interaction, and theother is antiferromagnetic and quadrupolar order with monoclinic distortion as in
DyB4 with q=(1 0 0). It is also noticed that
this behavior of phase transition is quite
similar to that of HoB2C2.
Measurements of excitation spectra exhibit
two clear peaks at 1 meV and 2 meV.
The intensity becomes strong expeciallyaround (1 0 0) and (0 0 0.5) and the peakenergy seems to go soft with decreasing
temperature to TN2, while the energy atother wavevectors do not change. The detail of this softening behavior will be studied next.
[1] D. Okuyama, T. Matsumura, H. Nakao
and Y. Murakami, J. Phys. Soc. Jpn., 74,2434, (2005).
[2] T. Matsumura et. al., Activity Report
2005; D. Okuyama et. al., to be publishedin J. Magn. Magn. Mater.

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JAEA-Review 2008-067

Fig. 1. Intensity map of the magnetic diffuse scattering of HoB4 at 9 K in the paramagnetic phase.

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1-2-39Magnetic structure analisys of incommensurate phase in multiferroic RMn2 O5
H. Kimura A , K. Nishihata A , Y. Noda A , and K. KohnB
A IMRAM, Tohoku University
B Waseda University(incommensurate phase). It is seen that the
distribution of amplitude for the structure
factor at incommensurate phase is similar
but is not completely same as that atcommensurate phase, indicating that themagnetic structure in the incommensurate
phase is different from that in the commensurate phase. Detailed structure analysis isin progress.

YMn2O5, (h 1 l) zone(a) T = 25 K

5l (r. l. u.)

4

3

2

1

0

(b) T = 7.5 K

54

l (r. l. u.)

RMn2 O5 shows a colossal magnetoelectirc effect in which magnetization is
induced by electric ﬁeld or inversely electric polarization is induced by magnetic
ﬁeld. The key ingredient in the CME effectis multiferroics in which (anti)ferromagnetic
and ferroelectric orders coexist and connect
with each other. It has been experimentallyshown that this system shows successive
magnetic transitions of incommensurate–commensurate–incommensurate phaseswith decreasing temperature, where thebulk electric polarization is induced only inthe commensurate phase. However, the relation between the microscopic magnetism(magnetic structure) and bulk dielectrics inthis system has been not fully understandyet. We thus performed magnetic structure
analyses using single crystals for the lowtemperature incommensurate phase tocompare the magnetic structure of theincommensurate phase with that of thecommensurate phase solved previously.
The measurements were performed
at four circle neutron diffractometer
FONDER installed at T2-2 beam port in
JRR-3M. In this report, we introduce theresults only for YMn2 O5 . Integrated intensities of magnetic reﬂections were collected
at T = 7.5 K. Total number of observed
magnetic reﬂections are more than 200
including zero intensity. Note that the
averaged crystal structure at T = 7.5 K was
also solved successfully to obtain the absolute quantities of magnetic structure factor.
Since the incommensurate magnetic peaks
are located at ±q M = (1/2 ± δx 0 1/4 − δz ),the reciprocal scan along Q x was carriedout, which can integrate a pair of magnetic
peak intensities accurately. Figure 1 showsobserved structure factors as absolute
quantity in (h 1 l ) zone taken at (a); 25 K
(commensurate phase) and (b); 7.5 K

3

2

1

0

0

1

2

3

4

5

6

7

h (r. l. u.)
Fig. 1. Observed magnetic structure factors in (h 1 l )zone at (a); 25 K (commensurate phase) and (b);7.5 K (incommensurate phase).

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JAEA-Review 2008-067

1-2-40Spin dymamics of multiferroic compound of HoMn2 O5
H. Kimura A , Y. Noda A , and K. KohnB
A IMRAM, Tohoku University
B Waseda University
RMn2 O5 shows a colossal magnetoelectirc effect in which magnetization is
induced by electric ﬁeld or inversely electric polarization is induced by magnetic
ﬁeld. The key ingredient in the CME effectis multiferroics in which (anti)ferromagnetic
and ferroelectric orders coexist and connect
with each other. It has been experimentallyshown that this system shows successive
magnetic transitions of incommensurate–commensurate–incommensurate phaseswith decreasing temperature, where thebulk electric polarization is induced only inthe commensurate phase. The microscopic
magnetism in the view point of magnetic
structure has been studied intensively toclarify the relation between the microscopic magnetism and bulk dielectrics
in this system. However, there is only
a few studies about the spin and latticedynamics, which might be correlated witheach other in this multiferroic system. In
the present study, we have tried to detect“electromagnons”, of which excitations can
combine with the dielectric order parameter, to clarify the microscopic origin of thecolossal magnetoelectric effect.
The experiments were performed using
a single crystal of HoMn2 O5 at TOPAN,
AKANE and HER spectrometers installed
at 6G, T1-3, and C1-1 beam ports in
JRR-3M, respectively. In this paper, we
introduce the summary of results taken
at TOPAN. The constant-Q scans werecarried out around magnetic zone centerQ ∼ (0.5 0 1.75) at T = 3 K (incommensurate phase), 25 K (commensurate
phase), and 50 K (paramagnetic phase).
Figure 1(a) shows the energy spectra at
Q = (0.7 0 1.75) taken at three temperatures. It is seen that there are temperaturedependent signals in the spectra aroundω = 3 ∼ 5 meV. In order to know thedetails about these spectra, we took thetemperature variation of the signals at
ω = 3, 4, 5 meV. As seen in Fig. 1(b), thesignals gradually change with changing
temperature. However, in the data ofω = 3 and 4 meV, the intensities starts todeviate from each other below ∼ 18 K,
where the magnetic order changes fromcommensurate to incommensurate. Thesesignals are almost Q-independent, indicating that the excitation is a crystal ﬁeld
excitation associated with 4 f -moment of
Ho3+ ion. These results suggest that thecorrelation between neighbored Ho3+
moments changes at the transition fromthe commensurate phase to the incommensurate phase.

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1-2-41

Field-induced ordered state in the rare-earth compound Pr0.97 La0.03 Pb3
T. Onimaru1,2,3 , N. Aso4 , T. Sakakibara3 , T.J. Sato4 , H. Yoshizawa4 and H.S. Suzuki5
1 Graduated School of Advanced Sciences and Matter, Hiroshima University,
Higashi-Hiroshima
2 SORST, Japan Science and Technology Agency, Kawaguchi
3 Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa
4 Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Tokai,
Ibaraki
5 National Institute for Materials Science, Tsukuba
Very recently, we have found that
quadrupoles are aligned with long periodic structures in quadrupole ordering states in the rare-earth compound
PrPb3 .[1] In our work, we performed neutron diffraction experiments on in magnetic ﬁelds along the [001] direction. We
revealed that ﬁeld-induced magnetic moments should be distributed with the propagation vectors of k1 =[1/2±δ, 1/2, 0]
and/or k2 =[1/2, 1/2±δ, 0] (δ∼1/8), indicating that quadrupoles are aligned with asinusoidal (incommensurate) structure below the quadrupolar ordering temperature
TQ . In the dilute system Pr1− x Lax Pb3 ,it has been reported that TQ would go
down below 0.1 K even at the composition x =0.02.[2] It was expected from theLa composition dependence of TQ that thequadrupolar ordered state would disappear at around the composition of x =0.025.
On the other hand, in speciﬁc heat measurements on Pr0.97 La0.03 Pb3 , an anomaly
would appear only in magnetic ﬁelds.[3]In the present work, in order to conﬁrm
the existence of the ﬁeld-induced orderedstate and reveal the order parameter, we
performed neutron diffraction experiments
in magnetic ﬁelds. We measured a single
crystalline sample with high quality which
was prepared by the Bridgman methodwith using a Molybdenum crucible. In theneutron diffraction experiments, the sample was cooled down with a 3 He-4 He dilution refrigerator, and the magnetic ﬁeld
was applied up to 5 T with a superconductor magnet.
We found superlattice reﬂections at

q1 =(1/2±δ 1/2 0) and/or q2 =(1/2 1/2±δ0) (δ∼1/8) only in the magnetic ﬁelds
above 1 T. Fig. 1 shows the ﬁeld dependence of the square root of the integrated
intensity at around Q=(1/2 3/8 0) and theﬁeld dependence of the peak position (k)at T =0.23 K. Apparently, the square rootof the intensity was induced linearly fromthe ﬁeld of ∼1 T, indicating the antifferomagnetic component should be induced
linearly by increasing the ﬁelds above 1
T. The peak position k changes continuously around k =0.38, which means that
quadrupoles are probably distributed with
the incommensurate structure. From theseresults, it should be noted that the ﬁeldindeucd ordered state in Pr0.97 La0.03 Pb3 isthe same as the one found in the orderedphase in PrPb3 .
References[1] T. Onimaru et al., Phys. Rev. Lett. 94, 197201(2005).
[2] T. Kawae et al., Phys. Rev. B 65, 012409(2001).
[3] T. Kawae, private communication.

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1-2-42Magnetic and Crystal Structures of Tm2CrS4
Keitaro Tezuka(A), Mitsuru Abe(A), Yoshiyuki Watanabe(A), Taro Nambo(A), Yue Jin
Shan(A), Hideo Imoto(A), and Kenji Ohoyama(B)(A) Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University,
Utsunomiya 321-8585; (B) Institute for Materials Research, Tohoku University, Sendai
980-8577
Y2CrS4 shows an antiferromagnetic transition at 65 K due to the ordering of Cr2+
ions. Its powder neutron diffraction patterns at both 90 K and 10 K could be reﬁned by using the orthorhombic Er2CrS4type structure (Pca21, No. 29) [1,2] while
the magnetic structure was determined byusing the pattern at 10 K. Recently we measured magnetic susceptibility of Tm2CrS4
and found magnetic anomalies at ca. 60 K
and lower temperatures.
In this study, neutron diffraction measurements of Tm2CrS4 were performed at 80 K,
50 K, 40 K, 15 K, 10 K, and 3 K, on the highefﬁciency and resolution powder diffractometer, HERMES, of Institute for Materials Research, Tohoku University, installedat the JRR-3M Reactor in JAEA (Tokai). The
wavelength of a neutron incident is 1.8265.
Any distinct crystallographic phase transition was not observed between 80 K and
3 K. At 80 K, lattice parameters were determined to be a = 12.4337(13) , b = 7.4470(8), and c = 12.4082(13) , and decreased
with decreasing temperature. Rietveld reﬁnements conﬁrmed that the crystal structure was isomorphous with Y2CrS4 at allmeasured temperatures.
Below 60 K, some magnetic peaks wereobserved and the peak intensities were
gradually increased with decreasing temperature. This suggests that paramagnetic
chromium and thulium ions were ordered
together. These magnetic peaks could beindexed on the same crystallographic unit
cell. In order to determine the magnetic
structure, the magnetic peaks have been
analyzed with the following assumptions.
(1) Magnitudes of magnetic moments ofchromium and thulium ions are the samefor respective kinds of ions. (2) Magnitudes
of magnetic moments for chromium were
ﬁxed to be 3.27 Bohr magneton obtained by
the reﬁnement of neutron diffraction patterns at 10 K for Y2CrS4 [1,2]. (3) The directions of all magnetic moments are collinear.
These assumptions have led to a magnetic
structure as shown in Fig. 1. In this structure, magnetic moments of chromium andthulium ions order antiferromagneticallyin each set of the 4a sites. The directions of
all magnetic moments are parallel to the caxis. The reﬁned magnetic moment of Tm
is 4.57(4) Bohr magneton, which is smaller
than 7 Bohr magneton expected as thetrivalent free ions.
References[1] K. Tezuka et al., QuBS 2006, August
2006, Ricotti (Tokai，Japan), P-28-39.
[2] K. Tezuka et al., Activity Report on Neutron Scattering Research: Experimental Reports, Vol. 13, nact06-33342.

Fig. 1. Magnetic structure of Tm2CrS4.

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JAEA-Review 2008-067

1-2-43

Neutron Diﬀraction Study of Magnetic Transitions in M2(OD)3X
X.G. Zheng, M. Hagihala, K. Ohoyama*
Faculty of Science and Engineering, Saga University, Saga 850-8502, Japan
Recently we found a new geometricfrustration system Cu2(OH)3Cl andCo2(OH)3Cl with a 3-dimensional network of corner-sharing tetrahedrons of the
Cu2+ and Co2+ spins, respectively 1-3.
We found coexisting antiferromagnetic
order and spin ﬂuctuation in Cu2(OH)3Cl
2, and a kagome-ice-like partial ferromagnetic order in Co2(OH)3Cl 3, whichraise great interest on this new material
system. Further, we proceeded to investigate the magnetic structures in othertransition metal hydroxyhalide compounds Ni2(OH)3Cl, Mn2(OH)3Cl, andMn2(OH)3Br.
Neutron diffraction experiment was carried out at T1-3 (Hermes) using powder
sample of Ni2(OD)3Cl, Mn2(OD)3Cl, andMn2(OD)3Br.
Strong magnetic reﬂections were observed for Ni2(OD)3Cl, Mn2(OD)3Cl,
and Mn2(OD)3Br, respectively, at low
temperatures. They agree well with antiferromagnetic transitions observed withmagnetic susceptibility measurements
at TN = 5 K, TN = 3.4 K and TN = 3.3 K,
respectively, for Ni2(OD)3Cl, Mn2(OD)3Cl,
and Mn2(OD)3Br. Determination of theirrespective magnetic structures are in
progress.
References
1. X.G. Zheng et al., Phys. Rev. B 71, 052409(2005).
2. X.G. Zheng et al., Phys. Rev. Lett. 95,
057201 (2005).
3. X.G. Zheng et al., Phys. Rev. Lett. 97,
247204 (2006).

Fig. 1. Neutron diffraction patterns for Ni2(OD)3Cl,
Mn2(OD)3Cl and Mn2(OD)3Br, respectively.

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JAEA-Review 2008-067

1-2-44Magnetic structure and crystalline-electric-ﬁeld splitting in the tetragonalrare-earth compound CeB2 C2
I. Nakanowatari, T. Onimaru A , K. OhoyamaB , H. OnoderaC , T. J. Sato
ISSP U. of Tokyo, Department of Quantum Matter Hiroshima U. A , IMR Tohoku U.B ,Department of Physics Tohoku U.C
The rare-earth borocarbide CeB2 C2 exhibits long-range magnetic order at TN =7.3 K where incommensurately modulated
structure with the modulation vector q M =(0.161, 0.161, 0.100) is stabilized [1]. Magnitude of the ordered moment was inferred
to be very small. With applied magnetic
ﬁeld of about 1 T in the basel plane, CeB2 C2
is known to exhibit metamagnetic behavior, recovering the magnetic moment of
more than 0.9 µ B [2]. In order to elucidate
the magnetic structure of the ordered incommensurate phase, and to gain insight
into the origin of metamagnetic transition,
we have performed both the neutron elastic and inelastic scattering experiments.
Single crystals of Ce11 B2 C2 were grownby the ﬂoating zone method. A single crystal was mounted in a liquid-He cryostat
with a superconducting magnet and cooled
down to T = 2.0 K (below TN ).
First, we observed ﬁeld dependenceof the Bragg intensities. The magnetic
ﬁeld was applied along the [11̄0] direction. Shown in Fig. 1(a) is the ﬁeld dependence of the integrated intensity observed at the incommensurate peak position Q = (δ, δ, 1 − δ� ) with δ = 0.166 andδ� = 0.110. Also shown as Fig. 1(b) is
the ﬁeld dependence at Q = (2, 2, 1). In
both the ﬁgures, an abrupt change was observed at H = 0.9 T. Since the incommensurate peak intensity decreases whereas
the intensity at the lattice peak position
Q = (2, 2, 1) increases, we may conclude
that the metamagnetic transition observedin the M − H curve is due to the abruptchange of the magnetic structure fromthe low-ﬁeld incommensurate phase to theﬁeld-induced ferromagnetic/ferrimagnetic
structure.
Detailed magnetic structure

analysis is now in progress.
[1] K. Ohoyama et al., J. Phys. Soc. Jpn. 72(2003) 3303.
[2] H. Onodera et al., J. Magn. Magn. Mater.
221 (2000) 293.

Fig. 1. Field dependence of the integrated intensity
measured at (a) Q = (δ,δ,1-δ’) and (b) Q = (2,2,1).

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-2-45Magnetic Structures of Square-Lattice Antiferromagnets (MX)LaNb2O7 (M=Cu,
Mn...; X=Cr, Br)
H. Kageyama(A), A. Kitada(A), T. Watanabe(A), Y. Baba(A), Y. Ajiro(A), K.
Yoshimura(A), M. NIshi(B), K. Hirota(B), N. Tsujii(C), Y. Matsushita(C)(A)Kyoto University, (B)ISSP-NSL Univ. Tokyo, (C)NIMS
In recent years, much attention has been
given to low-dimensional antiferromagnetic (AFM) quantum spin systems thathave a ground state with no long-range
magnetic order and an energy gap in
the magnetic excitation spectrum. Amongthem, the S = 1/2 frustrated square lattice AFM system (J1-J2 model) is of special importance in light of Anderson sresonating valence bond (RVB) concept
to explain high-Tc superconductivity in
doped layered cuprates. Low-temperature
topotactic strategies such as intercalation/deintercalation offer effective routes
for the design and construction of new twodimensional (2D) magnetic materials.
Topochemical ion exchange reaction
has been employed to obtain a doublelayered Dion-Jacobson phase such as(CuCl)LaNb2O7 starting from a nonmagnetic mother compound RbLaNb2O7 [1-4].
As shown in Fig. 1 (a), the structure consists of magnetic [CuCl] planes having an
S = 1/2 square lattice arrangement that are
widely separated by nonmagnetic double
perovskite slabs. Thus it can be a very
good candidate for the 2D quantum squarelattice system. In 2004, we performed
inelastic neutron scattering experiments on(CuCl)LaNb2O7 using the ISSP-PONTA
triple-axis spectrometer installed at a 5G
beam port of JRR-3M at the Japan Atomic
Energy Research Institute. It has been revealed that this system indeed provides a
new class of two-dimensional (2D) Heisenberg spin systems that has a spin-singlet
ground state with a ﬁnite energy gap of
2.3 meV [5, 6]. Quite recently, we preparedisostructural compound (CuBr)LaNb2O7
using a method similar to that to obtain(CuCl)LaNb2O7. In spite of the fact thatthe lattice parameters are almost the same,the magnetic properties of the copper
bromine system is completely different
from the spin-liquid state observed in
the copper chlorine system. In contrast
to the spin-gapped behavior in the Cl
sample, the magnetic susceptibility of theBr sample shows the gapless behavior withan antiferromagnetic ordering at 31 K. In
order to reveal the magnetic structure, we
demonstrate the powder neutron diffraction proﬁles measured at 3 K and 45 K.
We found two magnetic peaks centered at
2 θ = 15 ° and 20 ° that can be indexedas (1/2 0 1/2) and (1/2 0 3/2), respectively, indicating the so-called collinear
type (or stripe) ordering, where arraysof ferromagnetic chain along [100] alignin an antiferromagnetic manner in thesquare lattice (see Fig. 1(a)). The collinear
ordering is expected to occur when themagnitude of the next-nearest-neighborexchange interaction is greater than that of
the nearest-neighbor interaction. To date,
only three examples have been reported
to exhibit collinear ordering among S =1/2 square lattice systems. Therefore, itwould be interesting to examine the natureof the collinearly ordered state and tocompare with the spin liquid state in theisostructural (CuCl)LaNb2O7.
To further understand the nature of
the unusual ground states observed in(CuCl)LaNb2O7 and (CuBr)LaNb2O7, it
would be quite interesting to compare
these compounds with other related materials. Thus, in this study, we performed
powder neutron diffraction experimentson the isostructural (MCl)LaNb2O7(M=Co, Cr, Mn), using the IMR-HERMES
diffractometer (T1-3). Neutrons with awere obtained
wavelength of 1.81386(7)by the 331 reﬂection of the Ge monmochro-

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

mator, and the 12 -blank-sample-18
collimation was employed. A powder
sample of 4 g was put into a vanadium
cylinder. Figure 1(b) demonstrates the neutron diffraction proﬁles of (CoCl)LaNb2O7
obtained at 8 K and 100 K. The lower temperature data have additional magnetic
reﬂections characterized by the propagation vector (pi, 0, pi), indicating thecollinear type of magnetic ordering. The
magnetic ordering temperature is obtained
to be 55K by measuring the intensity of(1/2, 0, 1/2). The manganese analogue
also exhibits the collinear order but atslightly higher temperature, while the neutron diffraction proﬁle of the chromium
analogue may indicate incommensurate
magnetic structure at low temperatures.
This work has been supported by Grantsin-Aid for Young Scientists (A) (No.
17684018) and Science Research on Priority
Area (No. 16076210) from MEXT of Japan,
and by the 21st Century COE Program, Kyoto University Alliance for Chemistry.
[1] T. A. Kodenkandath et al., J. Am. Chem.
Soc. 121, 10743 (1999).
[2] L. Viciu et al., Inorg. Chem. 2002, 3385
(2002).
[2] H. Kageyama et al., J. Phys.: Condens.
Matter 16, S585 (2004).
[3] H. Kageayma et al., Prog. Theo. Phys.
Suppl. 159, 39 (2005).
[4] H. Kageyama et al., J. Phys. Soc. Jpn. 74,
1702 (2005).
[5] H. Kageyama et al., J. Phys. Soc. Jpn. 74,
3155 (2005).
[6] N. Oba et al., J. Phys. Soc. Jpn. 75, 113601(2006).

Fig. 1.
(a) Crystal and magnetic structure of(MCl)LaNb2O7. (b) Powder neutron diffraction
proﬂes of (CoCl)LaNb2O7 at 8 K and 100 K.

－ 158 －

JAEA-Review 2008-067

1-2-46

Magentic structures of R2Pd2X (X=In, Sn)
T. Hataya, R. Watanuki, K. Suzuki
Deparatment of Advanced Materials Chemistry, Yokohama National Univ.
We have performed neutron powder
diffraction measurements on R2Pd2Sn(R=Dy, Ho, Er) where the magnetic R
atoms form the Shastry-Sutherland lattice (SSL). All the compounds show twoor three successive magnetic transitions
at low temperatures. In the lowesttemperature magnetic phase, all thecompounds are found to have a doubled
c-axis magnetic lattice constant, different
result from a typical SSL compound DyB4.
In the intermediate magnetic phases, incommensurate magnetic Blagg peaks wereobserved; therefore the phase transition
from the intermediate to the lowest temperature phases is an incommensurate tocommensurate lock-in magnetic transition.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 245－ 159 －

JAEA-Review 2008-067

1-2-47
Polarized Neutron Inelastic Scattering Study of Spin Fluctuation inLa2−x (Sr,Ba)x CuO4
S. Wakimoto, K. Kakurai, M. Takeda, M. Matsuda, M. Fujita1 , K. Yamada1
and J.M. Tranquada2
1

Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577
2
Brookhaven National Laboratory, Upton, New York 11973, USA

The recent discovery of universal magnetic excitation in the high-Tc cuprates,
which shows a novel hour-glass shape dispersion, has provided an important insight into the magnetic origin of the superconductivity.
Among the several pictures proposed to explain the hour-glass dispersion, the stripe model is expected to
be an important candidate. We have performed inelastic polarized neutron scatteringon stripe-ordered La1.875 Ba0.125 CuO4 (LBCO
1/8) and compared the results with those of
La1.92 Sr0.08 CuO4 (LSCO 8 %) which has no
stripe order. The purpose of this experimentis to understand the effects of the stripe orderon the low energy magnetic excitations andhence have an insight into the origin of theuniversal magnetic excitation.

are confined in the CuO2 plane, that is, thea − b plane, in the stripe-ordered state.
These results demonstrate that the polarization of the low energy spin fluctuation isdifferent between the samples with and without the stripe order. A possible explanation isthat the in-plane gap of the excitation which
is observed in the non-doped La2 CuO4 is recovered in the stripe-ordered sample. Further polarized and unpolarized neutron experiments are in progress to confirm this.

The experiments have been performed at
the TAS-1 triple axis spectrometer operated
in a uniaxial polarization mode. Verticallyand horizontally focused Heusler monochromator and analyzer were used. Inelastic measurements were done with a fixed final neutron energy of 14.7 meV, and a spin-flipper
and a PG filter were placed after the sample.
Figure 1 shows profiles observed at the energy transfer 4 meV in the vertical-field (VF)spin-flip (SF) and the horizontal-field (HF)
SF channels along the A-C trajectories shownin the bottom figure. Remarkably, it is shownthat for LSCO 8 % the HF-SF signal is almost double of the VF-SF signal indicating
isotropic spin fluctuations, whereas for LBCO
1/8 both the channels show comparable crosssections indicating anisotropic spin fluctuations where those along the c-axis are suppressed. We have also confirmed by the polarized neutron diffraction that the Cu spins
原子炉：JRR-3

装置：TAS-1(2G)Figure 1: Polarized neutron scattering cross section
at the energy transfer of 4 meV observed in the VFSF and HF-SF channels. The data for LSCO 8 % aremeasured along the A (circles) and B (squares) trajectories, while those of LBCO 1/8 are measured along
the C trajectory. The bottom figures show the scan
trajectories in the momentum space and the definitionof the polarization axes.

分野：中性子散乱（超伝導）－ 160 －

JAEA-Review 2008-067

1-2-48Successive Phase Transitions of LuBaCo4 O7 with Kagome and Triangular
Lattices
M. Soda, T. Moyoshi, Y. Yasui, M. Sato and K. Kakurai1
Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Spin systems on the pyrochlore, triangularand kagome lattices are well-known examples
of geometrically frustrated systems and expected to exhibit various interesting properties induced by strong magnetic fluctuations.
RBaCo4 O7 (R = Ca, Y and rare-earth elements) is one of typical examples of such
systems, because it has both triangular andkagome lattices of Co spins.1–3)
Magnetic, thermal and neutron diffraction measurements have been carried out
on single-crystal samples of LuBaCo4 O7 .
Anomalies of the magnetic susceptibility havebeen found at temperatures Ta1 ∼ 70 K andTa2 ∼ 50 K. We have also found a secondorder structural transition at Tc1 ∼ 165 K anda first-order structural transition at Tc2 ∼ 105
K (Tc2 ’ ∼ 80 K) with increasing (decreasing)temperature.
We have observed reflections at Q-points(h’/20l) and (h’/2h’/2l) (h’ = odd; group A)
below Tc1 , and additionally at the Q-points(h”/3±δh”/3±δl) (h”/3 = noninteger number; group B) below Tc2 , in the reciprocal
space of the hexagonal unit cell (a = b ∼6.27 Å, c ∼ 10.24 Å). We have found thatat T < Tc2 , the line shapes of the reflections
at the Q-points of group A can be describedby Lorentzian-type ones, while at Tc2 < T <Tc1 , they have Gaussian-type ones. Fromthe |Q|-dependence of the integrated intensities, the Gaussian and Lorentzian components
can be regarded as nuclear and magnetic origins, respectively. The magnetic (Lorentzian)component is dominant below Tc2 and only
the nuclear (Gaussian) component exists at
T between Tc2 and Tc1 . For the reflections
at the Q-points of group B, the δ value is
T -dependent. These reflections have broad
Lorentzian profiles and can be considered tobe magnetic.
原子炉：JRR-3

装置：TAS-2(T2-4)

Below Tc2 , we can easily find that the intensities of the nuclear superlattice reflections
are almost zero and the intensities of the magnetic reflections increase gradually with decreasing T . The profile shape of the magnetic
peaks indicates that the magnetic correlation
is not long-ranged even at 10 K, and the magnetic correlation length is estimated to be ξ∼ 100 Å. From the magnetic structure analyses, the magnetic reflections at the Q-pointsof groups A and B can be considered to originate from the moments on the kagome andtriangular lattices, respectively.
For both YBaCo4 O7 and LuBaCo4 O7 systems, the Co moments of the kagome andtriangular lattices exhibit short-range orders
with different magnetic periods.2) However,
several differences have been found between
the behaviors of the magnetic reflections of
YBaCo4 O7 and LuBaCo4 O7 . In YBaCo4 O7 ,the growth of the magnetic correlation anda similar structural distortion were found to
appear simultaneously at its Tc1 (∼ 105 K)
with decreasing T , whereas in LuBaCo4 O7 ,the short-range magnetic correlation grows
only below Tc2 . The periods of the magnetic modulation of the triangular lattice arealso different between these two systems. At
low temperatures, the structural distortion of
LuBaCo4 O7 system is different from that of
YBaCo4 O7 , which induces the significant differences in the magnetic properties between
these two systems.
References
1) M. Valldor, et al., Solid State Sci., 4, 923 (2002).
2) M. Soda, et al., JPSJ., 75, 054707(2006).
3) M. Soda, et al., JPSJ., 76, 084701(2007).

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JAEA-Review 2008-067

1-2-49Direct Observation of the Pressure-Induced Ferromagnetic Order in
Valence Transition Material YbInCu4
T. Osakabe, K. Kojima1 and K. Hiraoka2
1

Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8571
2
Graduate School of Science and Enigineering, Ehime University, Matsuyama 790-8577

YbInCu4 crystallizes in the cubic AuBe5(C15b)-type structure. At ambient pressure
with decreasing temperature, the compound
undergoes the first-order isomorphic valencetransition at TV = 42 K with the increase of
the unit-cell volume of about 0.5 %. At TV ,the 4f states of Yb ions change from high temperature (HT) well-localized states of Yb3+
to low temperature (LT) mixed-valent statesof Yb2.9+ . Recent studies under high pressures have revealed that the nonmagnetic LT
phase is completely suppressed and the magnetic HT phase is stabilized in all temperature ranges above PC = 2.5 GPa. Furthermore, it is suggested that the long-range magnetic order appears below TC = 2.4 K at 2.5
GPa.1) On the other hand, this compoundshows the superconductivity above 0.7 GPa
below 1.4 K. This pressure-induced superconductivity survives up to 4 GPa.2) The purposeof our work is to elucidate directly and microscopically the pressure-induced magnetic
order. We performed high-pressure neutron
diffraction experiments using the triple-axis
spectrometer TAS-1. The high-pressure was
generated up to 6.2 GPa by a newly-developed
hybrid-anvil device.3) The pressure transmitted by the glycerin medium was hydrostaticeven at 7.0 GPa. The sample size was about
1.0 × 0.5 × 0.25 mm3 . The pressure was applied along the [011̄] direction of the sample
and the diffraction plane was the [100]-[011]one. We used a neutron focusing device in order to increase the effective neutron intensity
at the sample position.4)
We have successfully observed the distinct
increase of the intensities only at the ferromagnetic (1̄11) or (1̄1̄1̄) reciprocal lattice
points below about TC = 2.5 K at 4.0 GPa and
6.2 GPa. As an example, we show the temper原子炉：JRR-3

装置：TAS-1(2G)

ature dependence of the intensities at 6.2 GPain Fig. 1. This result indicates that the ferromagnetic order appears at least above 4.0
GPa and TC is hardly affected by the pressure. On the other hand, the estimated magnetic moment in the ferromagnetic order isabout 0.68 µB and 0.76 µB per Yb ion at 4.0
and 6.2 GPa, respectively. These values arequite large compared to the Y-diluted system
Yb0.8 Y0.2 InCu4 , which shows the weak ferromagnetic order of 0.05 µB per Yb ion below
TC = 1.7 K and above 0.8 GPa.5)

Figure 1: Temperature dependence of the intensities
at the (1̄1̄1̄) ferromagnetic point and at the (2̄1̄1̄) antiferromagnetic point for P = 6.2 GPa.

References
1) T. Mito, et al., Phys. Rev. B, 67, 224409(2003).
2) M. Hedo, et al., Acta Phys. Polonica B, 34, 1193(2003).
3) T. Osakabe, et al., J. Magn. Magn. Mat., 310,
2725(2007).
4) T. Osakabe, et al., Rev. Sci. Instrum., 76, 073102(2005).
5) A. Mitsuda, et al., Phys. Rev. Lett., 88, 137204(2002).

分野：中性子散乱（磁性）－ 162 －

JAEA-Review 2008-067

1-2-50Magnetic Structure of TbRhIn5
T. Sugai1,2 , F. Mizuno1,2 , N. Metoki1,2 , Y. Haga1,2 , N. V. Hieu3 , T.Takeuchi3 ,K. Sugiyama3 , R.Settai3 and Y. Onuki1,3
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
2
Department of Physics, Tohoku University, Sendai 980-8587
3
Graduate School of Science, Osaka University, Toyonaka 560-0043
1

netic moment µ = 7.7 µB /Tb is consistent
with gJ = 9 µB /Tb. Relatively large error ismost likely due to the strong absorption of Inwith a large sample size with 4 mm length.

Intensity (counts/sec)

Intermetallic compounds ATX5 (A: Lanthanoid or Actinide, T: Transition metal,
X: In or Ga) with the tetragonal HoCoGa5 type (P4/mmm) crystal structure, so called“115”, attract strong interest because of theheavy fermion superconductivity in Ce-115
and Pu-115 or various magnetic structuresin U-115 and Np-115. On the other hand,
RRhIn5 (R: Nd, Tb, Dy, Ho)1) are local antiferromagnets. The magnetic susceptibility
shows Curie-Weiss behaviour, where the Néeltemperatures are in good agreement with deGennes factor. A similar two-step metamagnetic transition is observed in RRhIn5 (R: Nd,
Tb, Dy, Ho), when the magnetic field is applied along the c-axis (easy axis). We performed neutron scattering experiment in order to determine the magnetic structure of
TbRhIn5 . We used triple-axis spectrometers
LTAS and MUSASI (low angle beam port) installed in JRR-3 guide hall.

2θ(deg.)Figure 1: The (1/2 0 1/2) antiferromagnetic reflection. Inset is the temperature dependence of the peakintensity.

Figure.1 shows the longitudinal scan profileof the (1/2 0 1/2) antiferromagnetic reflection
at 2.8 K, which disappeared at 50 K above
Neel temperature. Inset shows the temperature dependence of (1/2 0 1/2) peak intensity.
We estimated the Neel temperature TN to beapproximately 47.3 K. This value is consistent
with the susceptibility measurement.
Figure.2 shows the magnetic structure for
TbRhIn5 , determined from the comparison of
the integrated intensity of the antiferromagnetic reflections on the (h 0 l ) plane withmodel calculations. Tb magnetic moments
are parallel to the c-axis and order with apropagating vector Q = (1/2 0 1/2). The moment direction is consistent with the susceptibility study, when the c-axis is the easy axis.
We also confirmed the magnetic structure for
RRhIn5 (R: Nd, Dy, Ho). The obtained mag原子炉：JRR-3

Figure 2: The magnetic structure of TbRhIn5 .

References
1) H. V.Hieu, et al., J. Phys. Soc. Jpn., 75, 074708(2006).

装置：LTAS(C2-1)・MUSASI(T2-3)－ 163 －

分野：中性子散乱（磁性）JAEA-Review 2008-067

1-2-51
Magnetic Structure of TbMnO3 Studied with Spherical Neutron Polarimetry
R. Kajimoto, M. Matsuda, M. Takeda, K. Kakurai, Y. Mitsui1 , H. Yoshizawa1 , T. Kimura2
and Y. Tokura3
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Neutron Science Laboratory, ISSP, University of Tokyo, Tokai, Ibaraki 319-1106
2
Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974, USA
3
Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656
1

In the present study, we conducted a detailed study on the change in the spin structure in TbMnO3 using the spherical neutron
polarimetry technique, which should shedlight on the origin of the ferroelectricity.
Polarized neutron diffraction measurements
were carried out using CRYOPAD installedon TAS-1 spectrometer with the incident neutron energies 14.7 meV and 34 meV.
Polarization of the scattered neutron
beam was determined as Pif = (I+i,+f −I+i,−f )/(I+i,+f +I+i,−f ), where Ii,f represents
the scattering intensity with initial and final
polarizations i and f , respectively. Figure 1
shows temperature (T ) dependences of Pyx ,2 + P 2 ) 12 , and (P 2 + P 2 ) 12 at a magPzx , (Pyyyzzyzz
netic Bragg point (4, q, 1). In the present measurement condition, Pyx and Pzx reflect thechirality of the spiral spin structure. Because
they are nearly equal to zero even at T < TC ,two chirality domains with clockwise and anticlockwise chiralities are distributed equallyin the spiral phase.

(4,0.27,1)
1.0

Neutron Polarization

TbMnO3 shows a collinear sinusoidal spinordering below TN = 42 K, where the spins
point to the b axis and modulate along theb axis with a wave number q ∼ 0.28b∗ . The
spin structure is transformed into a cycloidal
spiral structure below TC = 28 K, where thespins rotate within the bc plane. The component along the c axis of the spiral structure is shorter than that along the b axis,
which results in an elliptically distorted spiral structure1) . Recently, it has been foundthat TbMnO3 as well as some other isostructural manganites shows a ferroelectric transition at TC , and that its dielectric properties
are strongly coupled with its magnetism2) .

Pyx
Pzx

0.8

√(Pyy2+Pyz2)

0.6√(Pzy2+Pzz2)

0.4

TC

0.2
0
0

10

装置：TAS-1(2G)

20

T (K)

30

40

Figure 1: Temperature dependences of neutron polarizations measured at a magnetic Bragg point (4, q, 1).

will become unity for a collinear spin structure, while it will become zero for an ideal
spiral structure. In Fig. 1, they are nearly
equal to unity at TC < T < TN . They gradually decrease below TC as a function of T , butthey saturate around 15 K and do not seem toreach zero at T = 0 K. These results indicatethat the collinear spin structure in TbMnO3 istransformed into a spiral structure below TC
by gradually swelling the c component withdecreasing T . The transformation into thespiral structure is incomplete at the lowest
temperature, resulting in the elliptical spiral
2 + P2structure. The T dependences of Pyy
yz
22
and Pzy + Pzz bear a strong resemblance tothat of the spontaneous electric polarization
Pe , which develops below TC 2) , suggesting astrong coupling between Pe and the spiral spinordering.
References
1) M. Kenzelmann, et al., Phys. Rev. Lett., 95, 087206(2005).
2) T. Kimura, et al., Nature(London), 426, 55(2003).

2 + P 2 and P 2 + P 2
On the other hand, Pyy
yz
zy
zz

原子炉：JRR-3

TN

分野：中性子散乱（磁性）－ 164 －

JAEA-Review 2008-067

1-2-52
Unusual Magnetic Structure and the Successive Transition in NpFeGa5
N. Metoki1,2 , F. Honda1 , S. Jonen1 , K. Kaneko1 , T. Sugai1,2 , F. Mizuno1,2 , G. H. Lander3 ,D. Aoki4 , Y. Homma4 and Y. Shiokawa4
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
2
Department of Physics, Tohoku University, Sendai 980-8578
3
EC-JRC, Institute for Transuranium Elements, Postfach 2340, D-76125 Karlsruhe, Germany
4
Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313
1

Figure 1 shows the result of the temperature dependence for the spin-flip (SF) andnon-spin-flip (NSF) scattering cross-section ofthe (1/2 1/2 0) reflection with the c-axis of thesample and the guide field for the neutron
spin state being perpendicular to the scattering plane. The magnetic moment perpendicular to the c-axis and the scattering vector
Q = [1/2 1/2 0] provides the SF cross-section,
whereas the NSF scattering cross-section represents the squared moment parallel to thec-axis. The SF scattering cross-section wasobserved at all temperatures below TN1 witha weak anomaly at TN2 . On the other hand,a clear NSF signal was observed only below
TN2 . These experimental results indicate unambiguously that the magnetic moment is in
the basal plane for TN2 < T < TN1 , while themoment is inclined for T < TN2 .
Figure 2 shows the magnetic structure of
NpFeGa5 both for high and low temperaturephases. Our analysis revealed that NpFeGa5
keeps a collinear structure with a moment
原子炉：JRR-3

装置：TAS-1(2G)(1/2 1/2 0)
NSF
SF

8

2

I (10 cts / 1800 s)

NpFeGa5 exhibits a successive magnetictransition at TN1 = 118 K and TN2 = 75 K.1)
Our recent study revealed the c-type antiferromagnetic order with q = (1/2 1/2 0) below TN1 . The strong and weak intensities of(1/2 1/2 l) with l odd or even, respectively,
indicate the Fe sublattice ordering with thesame structure as in the Np sublattice, but
the opposite moment direction in a chemical
unit cell. We observed an anomaly in the temperature dependence of the antiferromagnetic
intensity around TN2 . Spin polarization analysis has been carried out in order to clarify
the double transition in NpFeGa5 , which is
an iso-structural compound of heavy fermion
superconductors Ce115 and Pu115.

6
4

TN2

TN1

NpFeGa52-80’-80’filter: PG + Saphire

0
0

50

100
T (K)

Figure 1: Temperature dependence of the spin-flip(SF) and non-spin-flip (NSF) scattering cross-sectionof the (1/2 1/2 l) reflection in NpFeGa5 .

Figure 2: Magnetic structures of NpFeGa5 .

inclination angle about 25 degrees from thebasal plane. The result of the scattering intensity of the unpolarized diffraction experiment is well reproduced from the model calculation based on the magnetic structures in
Fig.2. The magnetic moment at the base temperature would be 0.8 Bohr magneton per Np
and 0.3 Bohr magneton per Fe atom, respectively.
References
1) D. Aoki, et al., J. Phys. Soc. Jpn., 74, 2323(2005).

分野：中性子散乱（磁性）－ 165 －

JAEA-Review 2008-067

1-2-53
Coulomb Interaction in NpCoGa5 Probing through Phonon Spectroscopy
K. Kaneko1 , N. Metoki1,2 , S. Raymond3 , J.-P. Sanchez3 , P. Piekarz4 , K. Parlinski4 ,A. M. Oleś4,5 , D. Aoki6 , Y. Homma6 , Y. Shiokawa1,6 , S. Ikeda1 , T. D. Matsuda1 , Y. Haga1,2 ,Y. Ōnuki1,7 and G. H. Lander1,8Advanced Science Research Center, JAEA, Tokai, Naka, Ibraki 319-1195
2
Department of Physics, Tohoku University, Sendai 980-8578
3
DRFMC-CEA, 38054 Grenoble, France
4
Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
5
Max-Planck-Institut für Festkörperforschung, Heisenbergerstrasse 1, D-70569 Stuttgart, Germany
6
Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313
7
Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043
8
EC-JRC, Institute for Transuranium Elements, Postfach 2340, D-76125 Karlsruhe, Germany
1

Figure 1 shows the representative results of
the neutron inelastic scattering spectra alongthe Γ-Z line at room temperature. Clear
peaks corresponding to transverse acoustic(TA) and transverse optic (TO) phonons wereobserved as shown in Fig. 1(a). The obtained phonon dispersion relation along theΓ-Z line of NpCoGa5 together with thoseof UCoGa5 , PuCoGa5 and theoretical calculations at room temperature are summarized in Fig. 1(b). Note that the TO modeof NpCoGa5 () shows a lower energy thanthat of UCoGa5 (•)7) , and higher than that of
原子炉：JRR-3

装置：TAS-1(2G)

NpCoGa5(0 0 q)RT

q = 0.8400
q = 0.7

q = 0.5

E ( meV )10
q = 0.6
Intensity

The discovery of superconductivity in the
PuT Ga5 system attracts an considerable interest with its relatively high Tsc 1, 2) . The
overall features including the NMR studies
support the idea of magnetically mediated superconductivity in PuT Ga5 3, 4) . However, theimportance of phonons on the pairing cannot be ruled out at present as in the caseof high-Tc cuprate. Furthermore, the phonon
spectroscopy with the ab initio lattice dynamics calculation offers an ability to probe electronic properties5, 6) . So far, we studied thephonons in an itinerant paramagnet UCoGa5
as well as PuCoGa5 , and revealed that the results are compatible with the presence of a local Coulomb repulsion U between f electronsin PuCoGa5 whereas a purely itinerant approach with U =0 agrees well in UCoGa5 6, 7) .
In order to obtain the deeper understandingon the f -electron state in A-115, we measured
phonons in the isostructural itinerant antiferromagnet NpCoGa5 .

NpCoGa5(0 0 q)q = 0.4

200

q = 0.3

5

q = 0.2(a)q = 0.1
0

5

TATO
UCoGa5( U= 0 )PuCoGa5( U=3 eV)

10
E ( meV )

(b)
0

0.2

0.4

(0 0 q) (r. l .u.)

Figure 1: (a) Neutron inelastic scattering spectraof NpCoGa5 at room temperature. (b) The obtained phonon dispersions of NpCoGa5 , UCoGa5 7)
and PuCoGa5 6) along Γ-Z at room temperature. Thelines show the result of calculation with U =0 and 3 eV
for UCoGa5 and PuCoGa5 , respectively.6, 7)

PuCoGa5 ()6) . This tendency qualitatively
agrees with the itinerancy of 5f -electrons in
an A-115 system: the strong itinerant character of U-115 and rather magnetic in Np-115.
Theoretical calculation on NpCoGa5 are now
in progress.
References
1) J.L. Sarrao, et al., Nature (London), 420, 297(2002).
2) F. Wastin, et al., J. Phys. Condens. Matter., 15,
S2279(2003).
3) N.J. Curro, et al., Nature (London), 434, 622(2005).
4) H. Sakai, et al., J. Phys. Soc. Jpn., 74, 1710(2005).
5) P. Piekarz, et al., Phys. Rev. B, 72, 014521(2005).
6) S. Raymond, et al., Phys. Rev. Lett., 96, 237003(2006).
7) N. Metoki, et al., Physica B, 378-380B, 1003(2006).

分野：中性子散乱（磁性）－ 166 －

JAEA-Review 2008-067

1-2-54
Polarized Neutron Inelastic Scattering Study of Central Mode in TlCoCl3
A. Oosawa, K. Kakurai1 , Y. Nishiwaki2 and T. Kato3
Department of Physics, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
2
Department of Physics, Tokyo Women’s Medical University, Shinjuku-ku, Tokyo 162-8666
3
Faculty of Education, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 273-8522

In this study, we carried out the polarized
neutron inelastic scattering experiments forthe central mode using the same procedureas that in the previous experiments for the
spin-wave excitation continuum performed in
the previous year1, 2) in TlCoCl3 . In contrast
to the spin-wave excitation continuum, theintensity of the central mode increases withincreasing temperature because the origin of
the mode is thermally excited domain walls3) .
Q enFigure 1 shows the profile of constant-Q
ergy scans of TlCoCl3 for non-spin-flip (NSF)
scattering in the vertical field (VF) and horizontal field (HF) configurations at Q = (1.45,
1.45, 0.6) for T = 10 and 61 K. As shownin Fig. 1, we can clearly see that the intensity of the central mode in the vicinity of
E = 3 meV increases with increasing temperature. Each polarized neutron inelastic scattering intensity in the NSF channel in the
VF and HF configurations for the scattering (h, h, l)-plane is expressed as the following
equations, respectively4) ,Q, ω) + Inonmag , (1)INSF,VF = C · Sxx (QINSF,HF = Inonmag .

(2)Q, ω) and Inonmag are the transwhere Sxx (Qverse magnetic fluctuation and the nonmagnetic fluctuation, respectively. HenceQ, ω) can be extracted from the differSxx (Qence between INSF,VF and INSF,HF . As shownin Fig. 1, no remarkable difference between
INSF,VF and INSF,HF at T = 61 K can be seen,Q, ω) is hardly included inindicating that Sxx (Qthe central mode of TlCoCl3 . While, significant difference between INSF,VF at T = 10
K and that at T = 61 K is seen. This result indicates that the non-magnetic fluctuations including the phonons are enhancedwith increasing temperature. In the previ原子炉：JRR-3

装置：TAS-1(2G)

6
4

TlCoCl3
Q=(1.45,1.45,0.6)
NSF

2

Neutron Counts (/ ~50min.)

1

10

4
8
6
4

T=61K, VF
T=61K, HF
T=10K, VF

2

10

3
8
6
4
2

10

2

-1

0

1

2

3

4

5

6

7

E (meV)Q energy scans of
Figure 1: Profiles of constant-Q
TlCoCl3 for NSF scattering in the VF and HF configurations at Q = (1.45,1.45,0.6) for T = 10 K and
61 K.

ous unpolarized neutron inelastic scatteringexperiments of CsCoCl3 3) , finite intensity ofQ, ω) in the central mode has been conSxx (Qcluded from the difference between the intensity at low temperature and that at hightemperature. However, the present resultin TlCoCl3 indicates that the difference observed in the previous unpolarized experiments of CsCoCl3 is not due to the existenceQ, ω) in the central mode, but theof Sxx (Qnon-magnetic fluctuations such as phonons.
While, for the longitudinal magnetic fluctuaQ, ω), a finite intensity was observedtion Szz (Qin the central mode of TlCoCl3 , the same as
CsCoCl3 (not shown).
References
1) A. Oosawa, et al., JAEA-Review, 4, 61(2007).
2) A. Oosawa, et al., J. Phys. Soc. Jpn., 75, 074719(2006).
3) H. Yoshizawa, et al., Phys. Rev. B, 23, 2298(1981).
4) R. M. Moon, et al., Phys. Rev., 181, 920(1969).

分野：中性子散乱（磁性）－ 167 －

JAEA-Review 2008-067

1-2-55Magnetic Structures in Mn3 Cu1−x Gex N: Evidence for the Close Relationshipwith Magneto-volume Effect
S. Iikubo1 , K. Kodama1 , K. Takenaka2,3 , H. Takagi2,3 and S. Shamoto1
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
2
RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198, Japan
3
CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan

Recently, Takenaka and Takagi reported
that the Magneto-Volume Effect (MVE) is
broadened against T in Mn3 Cu1−x Gex N leading to a giant negative thermal expansion(NTE) coefficient1) . NTE materials have already been used in a wide area of technicalapplications. While the volume change is negligibly small at ferromagnetic transition TC =143 K in Mn3 CuN, a large first order phasetransition MVE appears at TC ∼ 100 K at
x = 0.15. With increasing x, the magnetictransition temperature increases and the increase in the volume is broadened in T. At
x ∼ 0.5, the large negative thermal expansion coefficient is about α ∼ −2 × 10−5 /K
in the temperature range of 270 ≤ T ≤ 350
K, whose amplitude is one of the largest onesin all NTE materials. Basically, the volume
can be expanded according to the change in
the amplitude of magnetic moment. Although
Fruchart and Bertaut classified the magnetic
properties of Mn3 AN system by the numberof valence electrons on A ion2) , there is no
simple relationship between the magnitude of
MVE and the valence electron number. In order to study the microscopic magnetic properties and MVE, neutron diffraction studies
have been carried out.
Polycrystalline samples of Mn3 Cu1−x Gex N
were prepared by a solid state reaction1) .
The experiments were performed on thehigh-resolution powder diffractometer HRPD
(λ=1.8233 Å) and the triple axis spectorometer TAS-2 (λ=2.3590 Å) installed at JRR-3 of
JAEA. Their collimations were open (effective
value of 35’)-20’-6’ and 14’-40’-40’-80’, respectively. Powder samples of Mn3 Cu1−x Gex N
weighing ∼7 g were set in vanadium holders, which were enclosed in Al cans filled with
He gas. They were mounted in a closed-cycle
原子炉：JRR-3

refrigerator below room temperature and ina furnace above room temperature. The obtained results are summarized as a T-x phase
diagram of crystal and magnetic structures asshown in Fig. 1. Magnetic transition temperatures determined by neutron diffraction
studies and magnetization measurements areplotted by closed circles and open circles, respectively. The present neutron study revealed that cubic crystal structure and Γ5g
anti-ferromagnetic spin structure are key ingredients for the large magneto-volume effectin this itinerant electron system, while it isnegligibly small in a tetragonal and ferromagnetic phase. This experimental result proposes the necessity of new theoretical framework on MVE, which takes account of the ordered magnetic structure3) .
400
TC, TN (neutron)
TC, TN (magnetization)
300

T (K)

1

Cubic, Paramagnetic
200

100
Tetragonal
Ferromagnetism

0
0.0

0.1

Cubic, Γ5gAnti-ferromagnetic structure
0.2

0.3

0.4

0.5

x

Figure 1: T-x phase diagram of crystal and magnetic
structures on Mn3 Cu1−x Gex N.

References
1) K. Takenaka and H. Takagi, Appl. Phys. Lett.,
87, 261902(2005).
2) D. Fruchart and E. F. Bertaut, J. Phys. Soc. Jpn.,
44, 781(1978) .
3) S. Iikubo, K. Kodama, K. Takenaka, H. Takagi
and S. Shamoto, in preparation.

装置：HRPD(1G), TAS-2(T2-4)－ 168 －

分野：中性子散乱（磁性）JAEA-Review 2008-067

1-2-56
Evaluation of Magnetization on Fe16 N2 Nanoparticles
by Polarized Neutrons Diffraction
Y. Ishii1,2 , M. Takeda1 , K. Kakurai1 , T. Kikuchi1,2 , T. Shinohara1 , T. Oku1 , J. Suzuki1 ,Y. Sasaki3 , M. Kishimoto3 , M. Yokoyama2 and Y. Nishihara2
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Department of Science, Ibaraki University, Mito, Ibaraki 310-8512
3
Hitachi Maxell, Ltd., Koizumi, Oyamazaki-Cho, Otokuni-Gun, Kyoto 618-8525, Japan1

2

Figure 1 shows the ∆I of the sample witha diameter of 19 nm. This measurement was
performed with 80 meV neutrons. The simulation in Fig.1 drawn by a solid line, it isassumed that the magnetic form factor of Fe
in Fe16 N2 is the same as that in α-Fe. The
experimental data are well reproduced by thesimulated curve. Thus, it is concluded that
原子炉：JRR-3

装置：TAS-1(2G)

3000

Fe16N219 nm
λ = 0.98 Å

2500

counts / 80 sec

The averaged diameters of samples used inthese experiments are approximately 19 and17 nm. The triple-axis neutron spectrometer,
TAS-1, installed at JRR-3 was used in thisexperiment. The neutron energy was fixed at
14.7 and 80 meV. A magnetic field of 10 kOe
was applied to the samples during measurements to saturate the magnetization. The direction of neutron spin was turned for a parallel or anti-parallel state to the saturated magnetization vector by a spin flipper, and thenumber of neutrons were recorded in each case
(I+ and I− ). The magnitude of ferromagnetic
moments appear as a difference ∆I = I+ −I− .
The magnetic form factor was determined using known crystal structure factors and ∆I.
The magnitude of magnetic moments was determined from the magnetic form factor andflipping ratios, f r = I+ /I−

the magnetic form factor is very similar to αFe.
Figure 2 shows I+ and I− in the vicinityof (202) and (220) Bragg peaks of the sample
with the diameter of 19 nm. This diffraction
pattern was obtained using 14.7 meV neutrons. The flipping ratios were calculated using the height of each Bragg peak. The magnitude of magnetic moments of Fe16 N2 can be
deduced without any information on the laminated layer from the results of Fig1 and 2.
The same measurements were performed forthe sample with a diameter of 17 nm. The
magnetization measurements using the magnetometer had given different values of saturation magnetization for these two samples.
The polarized neutron diffraction measurements, however, revealed that both Fe16 N2
nanoparticles have the same magnitude of themagnetic moments of 2.0 µB .

2000

(flipper ON) - (flipper OFF)simulation

1500
1000
500
0
2

3

4

5

6

Q (1/Å)7

8

9

Figure 1: Difference ∆I = I+ − I− and simulation.
λ = 2.359 Å 2000
19 nm
parallelanti-parallel 1500
Fe16N2

4000

counts / 100 sec.

Needle-shaped ferromagnetic metals are often used for magnetic recording tapes. It is,however necessary to make small and spherical shape to increase the recording capacityand density. Recently, Fe16 N2 round nanoparticles with a diameter of 20 nm were produced by Hitachi Maxell, Ltd.. But it is difficult to obtain exact magnitude by a conventional magnetometer due to the laminatedlayer around Fe16 N2 . We performed polarized neutron diffraction measurements to determine net magnetization.

3500
3000
2500

1000

2000
1500

202
2.8

2.9

220

3.0

3.1

500

103
3.2

3.3

Q (1/Å)Figure 2: Experiment by polarized neutrons difraction
at λ = 2.37Å.

分野：中性子散乱（磁性）－ 169 －

JAEA-Review 2008-067

1-2-57
Magnetic Structure of Fe-N Nanoparticles for Magnetic Recording Tape Studied
by Small-angle Polarized Neutron Scattering
T. Kikuchi1,2 , T. Oku1 , T. Shinohara1 , J. Suzuki1 , Y. Ishii1,2 , M. Takeda1 , K. Kakurai1 ,Y. Sasaki3 , M. Kishimoto3 , M. Yokoyama2 and Y. Nishihara2
Quantum Beam Science Directorate, JAEA, Tokai Ibaraki 319-1195
Department of Science, Ibaraki University, Mito Ibaraki 310-8512
3
Hitachi Maxell, Ltd., Koizumi, Oyamazaki-Cho, Otokuni-Gun Kyoto 618-8525, Japan
1

2

Fe16 N2 -based spherical Fe-N nanoparticle
has attracted considerable attention as new
material for magnetic recording tapes owing
to its large magnetic anisotropy and the possibility of the emergence of large magnetic
moment. However, evaluation of the local
magnetic moment is difficult by magnetization measurement, because the surface of the
Fe-N nanoparticle is covered with structurally
unknown non-magnetic laminate layer for theoxidation prevention. In order to evaluate
the inner magnetic structure of the nanoparticle precisely, we have performed small-angle
polarized neutron scattering experiments using the SANS-J-II instrument of JRR-3. We
applied a magnetic field of 1 T to samples
and measured SANS intensities of I + and I −in the cases that the spin polarity of incident neutrons is positive and negative, respectively. Fig.1 shows scattering profiles+−
I⊥
and I⊥
along the direction perpendicular to the applied magnetic field, respectively
We analyzed these scattering profiles using amodel of spherical nanoparticles with a coreshell structure under the assumption of themagnetic moment of 2.1 µB /Fe atom. We
evaluated the mean radius r̄, non-magnetic
layer’s thickness ∆r, and magnetization of thenanoparticles m and compared them with theresults obtained by TEM and magnetization
measurements as shown in Fig.2. These characteristic parameters were analyzed as a function of the effective polarization degree of theincident neutrons Pef f with the accuracy χ2of the profile fitting, because there was thepossibility that the spin of the incident neutrons was depolarized by the local magnetic
field produced in the sample. χ2 was minimized at Pef f of 50 %, and evaluated r̄ and m
原子炉：JRR-3

装置：SANS-J(C3-2)

are consistent with the results of macroscopic
measurements. Analytical accuracy of the internal magnetic structure of the nanoparticles
will improve by determining the depolarization correctly in the future.

Figure 1: Sans intensities vs. q.

Figure 2: Evaluated r̄, ∆r, and m as a function ofPef f .

分野：中性子散乱（磁性）－ 170 －

JAEA-Review 2008-067

1-2-58Successive Phase Transitions of LuBaCo4 O7 with Kagome and Triangular
Lattices
M. Soda, T. Moyoshi, Y. Yasui, M. Sato and K. Kakurai1
Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Spin systems on the pyrochlore, triangularand kagome lattices are well-known examples
of geometrically frustrated systems and expected to exhibit various interesting properties induced by strong magnetic fluctuations.
RBaCo4 O7 (R = Ca, Y and rare-earth elements) is one of typical examples of such
systems, because it has both triangular andkagome lattices of Co spins.1–3)
Magnetic, thermal and neutron diffraction measurements have been carried out
on single-crystal samples of LuBaCo4 O7 .
Anomalies of the magnetic susceptibility havebeen found at temperatures Ta1 ∼ 70 K andTa2 ∼ 50 K. We have also found a secondorder structural transition at Tc1 ∼ 165 K anda first-order structural transition at Tc2 ∼ 105
K (Tc2 ’ ∼ 80 K) with increasing (decreasing)temperature.
We have observed reflections at Q-points(h’/20l) and (h’/2h’/2l) (h’ = odd; group A)
below Tc1 , and additionally at the Q-points(h”/3±δh”/3±δl) (h”/3 = noninteger number; group B) below Tc2 , in the reciprocal
space of the hexagonal unit cell (a = b ∼6.27 Å, c ∼ 10.24 Å). We have found thatat T < Tc2 , the line shapes of the reflections
at the Q-points of group A can be describedby Lorentzian-type ones, while at Tc2 < T <Tc1 , they have Gaussian-type ones. Fromthe |Q|-dependence of the integrated intensities, the Gaussian and Lorentzian components
can be regarded as nuclear and magnetic origins, respectively. The magnetic (Lorentzian)component is dominant below Tc2 and only
the nuclear (Gaussian) component exists at
T between Tc2 and Tc1 . For the reflections
at the Q-points of group B, the δ value is
T -dependent. These reflections have broad
Lorentzian profiles and can be considered tobe magnetic.
原子炉：JRR-3

装置：TAS-2(T2-4)

Below Tc2 , we can easily find that the intensities of the nuclear superlattice reflections
are almost zero and the intensities of the magnetic reflections increase gradually with decreasing T . The profile shape of the magnetic
peaks indicates that the magnetic correlation
is not long-ranged even at 10 K, and the magnetic correlation length is estimated to be ξ∼ 100 Å. From the magnetic structure analyses, the magnetic reflections at the Q-pointsof groups A and B can be considered to originate from the moments on the kagome andtriangular lattices, respectively.
For both YBaCo4 O7 and LuBaCo4 O7 systems, the Co moments of the kagome andtriangular lattices exhibit short-range orders
with different magnetic periods.2) However,
several differences have been found between
the behaviors of the magnetic reflections of
YBaCo4 O7 and LuBaCo4 O7 . In YBaCo4 O7 ,the growth of the magnetic correlation anda similar structural distortion were found to
appear simultaneously at its Tc1 (∼ 105 K)
with decreasing T , whereas in LuBaCo4 O7 ,the short-range magnetic correlation grows
only below Tc2 . The periods of the magnetic modulation of the triangular lattice arealso different between these two systems. At
low temperatures, the structural distortion of
LuBaCo4 O7 system is different from that of
YBaCo4 O7 , which induces the significant differences in the magnetic properties between
these two systems.
References
1) M. Valldor, et al., Solid State Sci., 4, 923 (2002).
2) M. Soda, et al., JPSJ., 75, 054707(2006).
3) M. Soda, et al., JPSJ., 76, 084701(2007).

分野：中性子散乱（磁性）－ 171 －

JAEA-Review 2008-067

1-2-59Magnetic Excitations in Lightly-Doped La2−x Srx CuO4
M. Matsuda, S. Wakimoto, M. Fujita1 , K. Yamada1 and J. M. Tranquada2
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
1
Institute for Materials Research, Tohoku University, Sendai 980-8577
2
Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA.

Recently, detailed inelastic neutron scattering studies have been performed up
to high energies in various systems suchas YBa2 Cu3 O6.6 ,1) La1.875 Ba0.125 CuO4 2)
and La1.84 Sr0.16 CuO4 .3) All of them show
hourglass-shaped magnetic excitations withthe parallel incommensurate correlations at
low energies. On the other hand, there arefew studies of magnetic excitations in the
diagonal incommensurate phase in lightlydoped La2−x Srx CuO4 , although conventional
spin wave excitations were reported in the
diagonal stripe phase of La2−x Srx NiO4 .4)
We previously tried to measure magnetic
excitations in the diagonal incommensurate phase using a twinned crystal of
La1.976 Sr0.024 CuO4 .5) The results suggestthat the magnetic correlations change frombeing incommensurate to commensurate at ∼7 meV and ∼ 70 K. However, since some theassumptions are needed to analyze the datain twinned crystal, information was limited.
It is important to compare the magnetic
excitatons in both the parallel and diagonal
incommensurate phases in detail to clarify
what is the intrinsic magnetic properties inthe superconducting phase.
We performed inelastic neutron scattering
measurements on TAS-2 and LTAS using analmost untwinned crystal of La2−x Srx CuO4
(x ∼ 0.04), in which elastic magnetic peaks
are observed at (1, ±δ, 0)ortho or (0, 1±δ,0)ortho , to observe magnetic excitations in
the diagonal incommensurate phase. We observed energy and temperature dependencesof magnetic excitations in the range of 0 ≤ω ≤ 12 meV and 4 ≤ T ≤ 290 K. The results show that the incommensurability (δ)
decreases gradually with increasing energy up
to 12 meV, as shown in Fig. 1. This is qualitatively consistent with the behavior in the
原子炉：JRR-3

parallel incommensurate phase. The temperature dependence of the magnetic excitations
shows that the incommensurability gradually
decreases with increasing temperature andbecomes almost commensurate below 12 meVat room temperature.

Figure 1: Typical consant-energy spectra at T = 4
K in La2−x Srx CuO4 (x ∼ 0.04). The diagonal incommensurate peaks are observed at (1, ±δ, 0) or (0, 1±δ,0).

References
1) S. M. Hayden, et al., Nature, 429, 531(2004).
2) J. M. Tranquada, et al., Nature, 429, 534(2004).
3) S. M. Hayden, et al., Nature Phys., 3, 163(2007).
4) P. Bourges, et al., Phys. Rev. Lett., 90, 147202(2003).
5) M. Matsuda, et al., Phys. Rev. B, 62, 9148(2000).

装置：TAS-2(T2-4), LTAS(C2-1)－ 172 －

分野：中性子散乱（超伝導）JAEA-Review 2008-067

1-2-60
New-Type Phase Transition of Honeycomb Lattice System Li2 RuO3
Y. Miura, Y. Yasui, M. Sato, N. Igawa1 and K. Kakurai1
Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Li2 RuO3 has layers of the honeycomb lattice of edge-sharing RuO6 octahedra witha LiO6 octahedron at the corner of eachhexagon of RuO6 . The Ru valence is +4
and the four electrons exist in the 4d t2g orbits. Li atom layers are between the honeycomb layers. For this system, we have founda phase transition at temperature T = Tc ∼540 K.1) With decreasing T , the electrical resistivity exhibits an anomalous increase at Tc ,suggesting the “metal-to-insulator”-like transition, and the magnetic susceptibility also
shows a sharp decrease.
To clarify the mechanism of the transition, powder neutron diffraction measurements were carried out at room temperature(RT) and 600 K using a high resolution powder diffractometer (HRPD) installed at JRR3 of JAEA in Tokai, and Rietveld analyses
were carried out using RIETAN-2000. Although the space group at RT was previously reported to be C2/c2, 3) , several superlattice peaks which cannot be explained by
C2/c were observed. To reproduce these reflections, we adopt the space group P 21 /m.
The result of the Rietveld fitting with P 21 /m
is rather well. As the possible space groupat 600 K, we have adopted C2/m, the minimal non-isomorphic supergroup of P 21 /m,
because this space group allows the secondorder transition at Tc . (From the experimental data, it is not easy to definitely distinguish
if it is the second-order one or the first-orderone.)
At 600 K, Ru atoms form an almost ideal
honeycomb structure. At RT, a significant
reduction (by ∼ 13 %) of the bond lengths
was found between two of the six Ru-Ru pairsof the hexagon (figure (right panel)). To answer why such drastic changes take place, we
consider the coupling of the lattice distortion
with the formation of the molecular orbits of
原子炉：JRR-3

装置：HRPD(1G)











Figure 1: The distortion pattern of Ru-honeycombskeleton at RT (left) and the energy levels of themolecular orbits of Ru4+ -Ru4+ pairs (right) below Tc .
The electrons in these levels are shown by the arrows
presenting the spin directions.

the t2g electrons of Ru4+ -Ru4+ of edge sharing RuO6 octahedra. The energy levels of thebonding and corresponding antibonding orbits are shown in the Figure 1(right), where
we can see that the nonmagnetic electron configuration is realized below Tc .
Although transitions accompanied with thesignificant anomalies of the electrical resistivity and the magnetic susceptibility similar to those of the present system have beenreported for La4 Ru2 O10 with corner-sharing
RuO6 octahedra and for Tl2 Ru2 O7 with a pyrochlore structure, their microscopic mechanisms are different from that presently proposed. Li2 RuO3 with edge-sharing RuO6 octahedra is considered to present, as far as weknow, a new type of phase transitions associated with the structural distortion inducedby the molecular-orbit formation of the d electron states.
References
1) Y. Miura, et al., J. Phys. Soc. Jpn., 76, 033705(2007).
2) J. F. Durac, C. R. Acad. Sc. Paris Ser. B, 270,
223(1970).
3) A. C. W. P. James and J. B. Goodenough, J. Solid
State Chem., 74, 287(1988).

分野：中性子散乱（構造）－ 173 －

JAEA-Review 2008-067

1-2-61
Direct Observation of the Pressure-Induced Ferromagnetic Order in
Valence Transition Material YbInCu4
T. Osakabe, K. Kojima1 and K. Hiraoka2
1

Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8571
2
Graduate School of Science and Enigineering, Ehime University, Matsuyama 790-8577

YbInCu4 crystallizes in the cubic AuBe5(C15b)-type structure. At ambient pressure
with decreasing temperature, the compound
undergoes the first-order isomorphic valencetransition at TV = 42 K with the increase of
the unit-cell volume of about 0.5 %. At TV ,the 4f states of Yb ions change from high temperature (HT) well-localized states of Yb3+
to low temperature (LT) mixed-valent statesof Yb2.9+ . Recent studies under high pressures have revealed that the nonmagnetic LT
phase is completely suppressed and the magnetic HT phase is stabilized in all temperature ranges above PC = 2.5 GPa. Furthermore, it is suggested that the long-range magnetic order appears below TC = 2.4 K at 2.5
GPa.1) On the other hand, this compoundshows the superconductivity above 0.7 GPa
below 1.4 K. This pressure-induced superconductivity survives up to 4 GPa.2) The purposeof our work is to elucidate directly and microscopically the pressure-induced magnetic
order. We performed high-pressure neutron
diffraction experiments using the triple-axis
spectrometer TAS-1. The high-pressure was
generated up to 6.2 GPa by a newly-developed
hybrid-anvil device.3) The pressure transmitted by the glycerin medium was hydrostaticeven at 7.0 GPa. The sample size was about
1.0 × 0.5 × 0.25 mm3 . The pressure was applied along the [011̄] direction of the sample
and the diffraction plane was the [100]-[011]one. We used a neutron focusing device in order to increase the effective neutron intensity
at the sample position.4)
We have successfully observed the distinct
increase of the intensities only at the ferromagnetic (1̄11) or (1̄1̄1̄) reciprocal lattice
points below about TC = 2.5 K at 4.0 GPa and
6.2 GPa. As an example, we show the temper原子炉：JRR-3

装置：TAS-1(2G)

ature dependence of the intensities at 6.2 GPain Fig. 1. This result indicates that the ferromagnetic order appears at least above 4.0
GPa and TC is hardly affected by the pressure. On the other hand, the estimated magnetic moment in the ferromagnetic order isabout 0.68 µB and 0.76 µB per Yb ion at 4.0
and 6.2 GPa, respectively. These values arequite large compared to the Y-diluted system
Yb0.8 Y0.2 InCu4 , which shows the weak ferromagnetic order of 0.05 µB per Yb ion below
TC = 1.7 K and above 0.8 GPa.5)

Figure 1: Temperature dependence of the intensities
at the (1̄1̄1̄) ferromagnetic point and at the (2̄1̄1̄) antiferromagnetic point for P = 6.2 GPa.

References
1) T. Mito, et al., Phys. Rev. B, 67, 224409(2003).
2) M. Hedo, et al., Acta Phys. Polonica B, 34, 1193(2003).
3) T. Osakabe, et al., J. Magn. Magn. Mat., 310,
2725(2007).
4) T. Osakabe, et al., Rev. Sci. Instrum., 76, 073102(2005).
5) A. Mitsuda, et al., Phys. Rev. Lett., 88, 137204(2002).

分野：中性子散乱（磁性）－ 174 －

JAEA-Review 2008-067

1-2-62Magnetic Structure of TbRhIn5
T. Sugai1,2 , F. Mizuno1,2 , N. Metoki1,2 , Y. Haga1,2 , N. V. Hieu3 , T.Takeuchi3 ,K. Sugiyama3 , R.Settai3 and Y. Onuki1,3
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
2
Department of Physics, Tohoku University, Sendai 980-8587
3
Graduate School of Science, Osaka University, Toyonaka 560-0043
1

netic moment µ = 7.7 µB /Tb is consistent
with gJ = 9 µB /Tb. Relatively large error ismost likely due to the strong absorption of Inwith a large sample size with 4 mm length.

Intensity (counts/sec)

Intermetallic compounds ATX5 (A: Lanthanoid or Actinide, T: Transition metal,
X: In or Ga) with the tetragonal HoCoGa5 type (P4/mmm) crystal structure, so called“115”, attract strong interest because of theheavy fermion superconductivity in Ce-115
and Pu-115 or various magnetic structuresin U-115 and Np-115. On the other hand,
RRhIn5 (R: Nd, Tb, Dy, Ho)1) are local antiferromagnets. The magnetic susceptibility
shows Curie-Weiss behaviour, where the Néeltemperatures are in good agreement with deGennes factor. A similar two-step metamagnetic transition is observed in RRhIn5 (R: Nd,
Tb, Dy, Ho), when the magnetic field is applied along the c-axis (easy axis). We performed neutron scattering experiment in order to determine the magnetic structure of
TbRhIn5 . We used triple-axis spectrometers
LTAS and MUSASI (low angle beam port) installed in JRR-3 guide hall.

2θ(deg.)Figure 1: The (1/2 0 1/2) antiferromagnetic reflection. Inset is the temperature dependence of the peakintensity.

Figure.1 shows the longitudinal scan profileof the (1/2 0 1/2) antiferromagnetic reflection
at 2.8 K, which disappeared at 50 K above
Neel temperature. Inset shows the temperature dependence of (1/2 0 1/2) peak intensity.
We estimated the Neel temperature TN to beapproximately 47.3 K. This value is consistent
with the susceptibility measurement.
Figure.2 shows the magnetic structure for
TbRhIn5 , determined from the comparison of
the integrated intensity of the antiferromagnetic reflections on the (h 0 l ) plane withmodel calculations. Tb magnetic moments
are parallel to the c-axis and order with apropagating vector Q = (1/2 0 1/2). The moment direction is consistent with the susceptibility study, when the c-axis is the easy axis.
We also confirmed the magnetic structure for
RRhIn5 (R: Nd, Dy, Ho). The obtained mag原子炉：JRR-3

Figure 2: The magnetic structure of TbRhIn5 .

References
1) H. V.Hieu, et al., J. Phys. Soc. Jpn., 75, 074708(2006).

装置：LTAS(C2-1)・MUSASI(T2-3)－ 175 －

分野：中性子散乱（磁性）JAEA-Review 2008-067

1-2-63Magnetic Structure of TbMnO3 Studied with Spherical Neutron Polarimetry
R. Kajimoto, M. Matsuda, M. Takeda, K. Kakurai, Y. Mitsui1 , H. Yoshizawa1 , T. Kimura2
and Y. Tokura3
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Neutron Science Laboratory, ISSP, University of Tokyo, Tokai, Ibaraki 319-1106
2
Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974, USA
3
Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656
1

In the present study, we conducted a detailed study on the change in the spin structure in TbMnO3 using the spherical neutron
polarimetry technique, which should shedlight on the origin of the ferroelectricity.
Polarized neutron diffraction measurements
were carried out using CRYOPAD installedon TAS-1 spectrometer with the incident neutron energies 14.7 meV and 34 meV.
Polarization of the scattered neutron
beam was determined as Pif = (I+i,+f −I+i,−f )/(I+i,+f +I+i,−f ), where Ii,f represents
the scattering intensity with initial and final
polarizations i and f , respectively. Figure 1
shows temperature (T ) dependences of Pyx ,2 + P 2 ) 12 , and (P 2 + P 2 ) 12 at a magPzx , (Pyyyzzyzz
netic Bragg point (4, q, 1). In the present measurement condition, Pyx and Pzx reflect thechirality of the spiral spin structure. Because
they are nearly equal to zero even at T < TC ,two chirality domains with clockwise and anticlockwise chiralities are distributed equallyin the spiral phase.

(4,0.27,1)
1.0

Neutron Polarization

TbMnO3 shows a collinear sinusoidal spinordering below TN = 42 K, where the spins
point to the b axis and modulate along theb axis with a wave number q ∼ 0.28b∗ . The
spin structure is transformed into a cycloidal
spiral structure below TC = 28 K, where thespins rotate within the bc plane. The component along the c axis of the spiral structure is shorter than that along the b axis,
which results in an elliptically distorted spiral structure1) . Recently, it has been foundthat TbMnO3 as well as some other isostructural manganites shows a ferroelectric transition at TC , and that its dielectric properties
are strongly coupled with its magnetism2) .

Pyx
Pzx

0.8

√(Pyy2+Pyz2)

0.6√(Pzy2+Pzz2)

0.4

TC

0.2
0
0

10

装置：TAS-1(2G)

20

T (K)

30

40

Figure 1: Temperature dependences of neutron polarizations measured at a magnetic Bragg point (4, q, 1).

will become unity for a collinear spin structure, while it will become zero for an ideal
spiral structure. In Fig. 1, they are nearly
equal to unity at TC < T < TN . They gradually decrease below TC as a function of T , butthey saturate around 15 K and do not seem toreach zero at T = 0 K. These results indicatethat the collinear spin structure in TbMnO3 istransformed into a spiral structure below TC
by gradually swelling the c component withdecreasing T . The transformation into thespiral structure is incomplete at the lowest
temperature, resulting in the elliptical spiral
2 + P2structure. The T dependences of Pyy
yz
22
and Pzy + Pzz bear a strong resemblance tothat of the spontaneous electric polarization
Pe , which develops below TC 2) , suggesting astrong coupling between Pe and the spiral spinordering.
References
1) M. Kenzelmann, et al., Phys. Rev. Lett., 95, 087206(2005).
2) T. Kimura, et al., Nature(London), 426, 55(2003).

2 + P 2 and P 2 + P 2
On the other hand, Pyy
yz
zy
zz

原子炉：JRR-3

TN

分野：中性子散乱（磁性）－ 176 －

JAEA-Review 2008-067

1-2-64
Unusual Magnetic Structure and the Successive Transition in NpFeGa5
N. Metoki1,2 , F. Honda1 , S. Jonen1 , K. Kaneko1 , T. Sugai1,2 , F. Mizuno1,2 , G. H. Lander3 ,D. Aoki4 , Y. Homma4 and Y. Shiokawa4
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
2
Department of Physics, Tohoku University, Sendai 980-8578
3
EC-JRC, Institute for Transuranium Elements, Postfach 2340, D-76125 Karlsruhe, Germany
4
Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313
1

Figure 1 shows the result of the temperature dependence for the spin-flip (SF) andnon-spin-flip (NSF) scattering cross-section ofthe (1/2 1/2 0) reflection with the c-axis of thesample and the guide field for the neutron
spin state being perpendicular to the scattering plane. The magnetic moment perpendicular to the c-axis and the scattering vector
Q = [1/2 1/2 0] provides the SF cross-section,
whereas the NSF scattering cross-section represents the squared moment parallel to thec-axis. The SF scattering cross-section wasobserved at all temperatures below TN1 witha weak anomaly at TN2 . On the other hand,a clear NSF signal was observed only below
TN2 . These experimental results indicate unambiguously that the magnetic moment is in
the basal plane for TN2 < T < TN1 , while themoment is inclined for T < TN2 .
Figure 2 shows the magnetic structure of
NpFeGa5 both for high and low temperaturephases. Our analysis revealed that NpFeGa5
keeps a collinear structure with a moment
原子炉：JRR-3

装置：TAS-1(2G)(1/2 1/2 0)
NSF
SF

8

2

I (10 cts / 1800 s)

NpFeGa5 exhibits a successive magnetictransition at TN1 = 118 K and TN2 = 75 K.1)
Our recent study revealed the c-type antiferromagnetic order with q = (1/2 1/2 0) below TN1 . The strong and weak intensities of(1/2 1/2 l) with l odd or even, respectively,
indicate the Fe sublattice ordering with thesame structure as in the Np sublattice, but
the opposite moment direction in a chemical
unit cell. We observed an anomaly in the temperature dependence of the antiferromagnetic
intensity around TN2 . Spin polarization analysis has been carried out in order to clarify
the double transition in NpFeGa5 , which is
an iso-structural compound of heavy fermion
superconductors Ce115 and Pu115.

6
TN2

4

TN1

NpFeGa52-80’-80’filter: PG + Saphire

0
0

50

100
T (K)

Figure 1: Temperature dependence of the spin-flip(SF) and non-spin-flip (NSF) scattering cross-sectionof the (1/2 1/2 l) reflection in NpFeGa5 .

Figure 2: Magnetic structures of NpFeGa5 .

inclination angle about 25 degrees from thebasal plane. The result of the scattering intensity of the unpolarized diffraction experiment is well reproduced from the model calculation based on the magnetic structures in
Fig.2. The magnetic moment at the base temperature would be 0.8 Bohr magneton per Np
and 0.3 Bohr magneton per Fe atom, respectively.
References
1) D. Aoki, et al., J. Phys. Soc. Jpn., 74, 2323(2005).

分野：中性子散乱（磁性）－ 177 －

JAEA-Review 2008-067

1-2-65
Coulomb Interaction in NpCoGa5 Probing through Phonon Spectroscopy
K. Kaneko1 , N. Metoki1,2 , S. Raymond3 , J.-P. Sanchez3 , P. Piekarz4 , K. Parlinski4 ,A. M. Oleś4,5 , D. Aoki6 , Y. Homma6 , Y. Shiokawa1,6 , S. Ikeda1 , T. D. Matsuda1 , Y. Haga1,2 ,Y. Ōnuki1,7 and G. H. Lander1,8Advanced Science Research Center, JAEA, Tokai, Naka, Ibraki 319-1195
2
Department of Physics, Tohoku University, Sendai 980-8578
3
DRFMC-CEA, 38054 Grenoble, France
4
Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
5
Max-Planck-Institut für Festkörperforschung, Heisenbergerstrasse 1, D-70569 Stuttgart, Germany
6
Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313
7
Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043
8
EC-JRC, Institute for Transuranium Elements, Postfach 2340, D-76125 Karlsruhe, Germany
1

Figure 1 shows the representative results of
the neutron inelastic scattering spectra alongthe Γ-Z line at room temperature. Clear
peaks corresponding to transverse acoustic(TA) and transverse optic (TO) phonons wereobserved as shown in Fig. 1(a). The obtained phonon dispersion relation along theΓ-Z line of NpCoGa5 together with thoseof UCoGa5 , PuCoGa5 and theoretical calculations at room temperature are summarized in Fig. 1(b). Note that the TO modeof NpCoGa5 () shows a lower energy thanthat of UCoGa5 (•)7) , and higher than that of
原子炉：JRR-3

装置：TAS-1(2G)

NpCoGa5(0 0 q)RT

q = 0.8400
q = 0.7

q = 0.5

E ( meV )10
q = 0.6
Intensity

The discovery of superconductivity in the
PuT Ga5 system attracts an considerable interest with its relatively high Tsc 1, 2) . The
overall features including the NMR studies
support the idea of magnetically mediated superconductivity in PuT Ga5 3, 4) . However, theimportance of phonons on the pairing cannot be ruled out at present as in the caseof high-Tc cuprate. Furthermore, the phonon
spectroscopy with the ab initio lattice dynamics calculation offers an ability to probe electronic properties5, 6) . So far, we studied thephonons in an itinerant paramagnet UCoGa5
as well as PuCoGa5 , and revealed that the results are compatible with the presence of a local Coulomb repulsion U between f electronsin PuCoGa5 whereas a purely itinerant approach with U =0 agrees well in UCoGa5 6, 7) .
In order to obtain the deeper understandingon the f -electron state in A-115, we measured
phonons in the isostructural itinerant antiferromagnet NpCoGa5 .

NpCoGa5(0 0 q)q = 0.4

200

q = 0.3

5

q = 0.2(a)q = 0.1
0

5

TATO
UCoGa5( U= 0 )PuCoGa5( U=3 eV)

10
E ( meV )

(b)
0

0.2

0.4

(0 0 q) (r. l .u.)

Figure 1: (a) Neutron inelastic scattering spectraof NpCoGa5 at room temperature. (b) The obtained phonon dispersions of NpCoGa5 , UCoGa5 7)
and PuCoGa5 6) along Γ-Z at room temperature. Thelines show the result of calculation with U =0 and 3 eV
for UCoGa5 and PuCoGa5 , respectively.6, 7)

PuCoGa5 ()6) . This tendency qualitatively
agrees with the itinerancy of 5f -electrons in
an A-115 system: the strong itinerant character of U-115 and rather magnetic in Np-115.
Theoretical calculation on NpCoGa5 are now
in progress.
References
1) J.L. Sarrao, et al., Nature (London), 420, 297(2002).
2) F. Wastin, et al., J. Phys. Condens. Matter., 15,
S2279(2003).
3) N.J. Curro, et al., Nature (London), 434, 622(2005).
4) H. Sakai, et al., J. Phys. Soc. Jpn., 74, 1710(2005).
5) P. Piekarz, et al., Phys. Rev. B, 72, 014521(2005).
6) S. Raymond, et al., Phys. Rev. Lett., 96, 237003(2006).
7) N. Metoki, et al., Physica B, 378-380B, 1003(2006).

分野：中性子散乱（磁性）－ 178 －

JAEA-Review 2008-067

1-2-66
Softening of Magnetic Excitations Leading to Pressure-Induced Quantum Phase
Transition in Gapped Spin System KCuCl3
K. Goto1,4 , T. Osakabe1 , K. Kakurai1 , Y. Uwatoko2 , A. Oosawa3 and H. Tanaka4
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
Institute for Solid State Physics, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581
3
Department of Physics, Sophia University, Kioi-cho, Chiyoda-ku, Tokyo 102-8554
4
Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo 152-8551
1

2

The experiments were performed using
TAS-1 and LTAS spectrometers installed at
JRR-3 in JAEA, Tokai. In general, it is difficult to carry out neutron inelastic scattering under high pressure because of the small
sample space and the attenuation of the neutron beam due to the thick pressure cell. In
the present study, we used a newly designed
cylindrical high-pressure clamp cell made of
mesoalite. The inner diameter of the sample
capsule was 8.0 mm and the working height is
22 mm. A KCuCl3 single crystal was shaped
into a column of 7.8 mm in diameter and 14
mm in length with the central axis parallelto the crystallographic b-axis. A mixture of
Fluorinert FC70 and FC77 was used as thepressure-transmitting medium. A hydrostaticpressure of P = 4.7 kbar was applied at helium temperatures. The pressure was determined from the lattice constants of a NaCl
crystal placed in the sample space. A welldefined single excitation mode was observed.
The dispersion relations in the a∗ −c∗ plane
were obtained, as shown in Fig. 1. Softeningof the triplet mode due to the applied pressure
is clearly observed at all Q values. The exci原子炉：JRR-3

tation gap for P = 4.7 kbar corresponding to
the lowest excitation energy was evaluated as∆ = 1.52 meV. Using the random phase approximation, we have analyzed the dispersion
relations and obtained the intradimer and effective interdimer interactions. It was foundthat the intradimer interaction decreases under hydrostatic pressure and the effective interactions between the nearest dimers along
the a-direction and in the (1, 0, 2̄) plane increase. These pressure dependences of the exchange interactions give rise to the observedpressure-induced QPT from a gapped groundstate to an AF state in KCuCl3 . The present
result has been published elsewhere3) .
5
4
E (meV)

KCuCl3 is an interacting spin dimer system, which has a singlet ground state withan excitation gap of ∆ = 2.67 meV1) .
KCuCl3 undergoes a pressure-induced quantum phase transition (QPT) to an antiferromagnetic (AF) state. The critical pressure obtained through magnetization measurements
is Pc = 8.2 kbar2) . To investigate the pressure dependence of individual exchange interactions and the change of dispersion relations
under pressure, we have performed neutron
inelastic scattering experiments on KCuCl3
under high hydrostatic pressure.

3
Q = (h, 0, 1)

2
1
0
0.5

Q = (0, 0, 2h + 1)

KCuCl3
T = 1.4 K
0.25

0.0
h (r.l.u)

0.25

0.5

Figure 1: Dispersion relations ω(Q) in KCuCl3 measured at P = 4.7 kbar for Q along (h, 0, 1) and(0, 0, 2h + 1). Dashed line is the dispersion curve at
ambient pressure.

References
1) T. Kato, et al., J. Phys. Soc. Jpn., 67, 752(1998).
2) K. Goto, et al., J. Phys. Soc. Jpn., 75, 064703(2006).
3) K. Goto, et al., J. Phys. Soc. Jpn., 76, 053704(2007).

装置：TAS-1(2G), LTAS(C2-1)－ 179 －

分野：中性子散乱（磁性）JAEA-Review 2008-067

1-2-67
Neutron Elastic Scattering in Quantum Spin System NH4 CuCl3
T. Ono1 , K. Goto1,4 , Y. Kubota1 , H. Tanaka1 , N. Metoki2 , F. Honda2 and K. Kakurai2
1

Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo 152-8551
2
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195

NH4 CuCl3 is a weakly coupled spin dimer
system, which has the same crystal structure
as KCuCl3 at room temperature1) . With decreasing temperature, NH4 CuCl3 undergoes
structural phase transitions at Tt1 = 156 K
and Tt2 = 70 K2) . The magnetic groundstate of NH4 CuCl3 is gapless in contrast to
KCuCl3 3) . NH4 CuCl3 undergoes 3D magnetic ordering at TN = 1.3 K3) . Remarkable feature of NH4 CuCl3 is that the magnetization curve has two plateaus at onequarter and three-quarters of the saturation
magnetization4) . Although various models forthe formation of the magnetization plateaus
have been proposed5) , the mechanism leading
to the magnetization plateaus has not beenclarified. Recently, magnetic Bragg reflection
was observed at Q = (0, 0, 1)2) , and its intensity decreases with increasing external field.
To investigate the magnetic structure in theordered phase, we have performed a neutron
elastic scattering experiment on NH4 CuCl3 atzero magnetic field.
The experiment was performed using theTAS-2 spectrometer installed at JRR-3 in
JAEA, Tokai. The incident neutron energy
was fixed at Ei = 14.7 meV, and the horizontal collimation sequence was chosen as guide80’-80’-open. A single crystal of ∼ 0.25 cm3
was used. The sample was mounted in thecryostat with its (010) plane parallel to thescattering plane, so that the reflections in thea∗ − c∗ plane were investigated. The sample
was cooled to 50 mK using a dilution refrigerator.
Magnetic Bragg peaks were observed below TN = 1.3 K at Q = (h, 0, l) with the
integer h and odd l. These reciprocal lattice points are equivalent to those for themagnetic-field and pressure induced orderedphases in TlCuCl3 6, 7) . No Bragg peak indicating superlattice structure along the a-axis
原子炉：JRR-3

装置：TAS-2(T2-4)

was observed. Table 1 summarizes the integrated intensities of magnetic Bragg reflections normalized to the (001) reflection. It isnoted that Bragg intensities for Q = (0, 0, 5),(1, 0, 1) and (1, 0, −1) are strong. These intensities for the magnetic-field and pressure
induced ordered phases in TlCuCl3 are lessthan 0.1. From the magnetization and excitation data2, 4) , we can deduce that one-quarterof the spins are ordered below TN and the restof spins are in the singlet state at zero magnetic field. At present, the magnetic structureof NH4 CuCl3 cannot be determined uniquely.
Neutron elastic scattering experiments taking
other scattering plane are needed.
Table 1: Integrated magnetic Bragg peak intensities
observed at 50 mK. The intensities are normalized tothe (001)M reflection.

(001)M
1.000(101)M
0.385(103̄)M
0.485(003)M
0.000(101̄)M
0.302(201)M
0.000(005)M
0.425(103)M
0.109(201̄)M
0.000

References
1) R. D. Willett, et al., J. Chem. Phys., 38, 2429(1963).
2) Ch. Rüegg, et al., Phys. Rev. Lett., 93, 037207(2004).
3) B. Kurniawan, et al., J. Phys.: Condens. Matter,
11, 9073(1999).
4) W. Shiramura, et al., J. Phys. Soc. Jpn., 67, 1548(1998).
5) M. Matsumoto, Phys. Rev. B, 68, 180403(R)(2003),
and references therein.
6) H. Tanaka, et al., J. Phys. Soc. Jpn., 70, 939(2001).
7) A. Oosawa, et al., J. Phys. Soc. Jpn., 72, 1026(2003).

分野：中性子散乱（磁性）－ 180 －

JAEA-Review 2008-067

1-2-68Magnetic Structure of Co2 TeO3 Cl2
T. Kashi, Y. Yasui, T. Moyoshi, M. Sato, N. Igawa1 and K. Kakurai1
Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Co2 TeO3 Cl2 has so-called delta or sawtooth
chains consisting of corner-sharing triangles ofCo spins,1) and two crystallographically distinct Co2+ sites exist in this system. If the exchange interaction between the nearest neighbor Co spins is antiferromagnetic, a rather
strong magnetic fluctuation is expected.
Measurements of the magnetic susceptibility χ and specific heat C of Co2 TeO3 Cl2 haverevealed that two transitions take place attemperatures T = 73 K (TN1 ) and 15 K (TN2 ).
At TN1 , a small anomaly has been observed inthe χ − T curve. A weak ferromagnetic moment shows up at TN2 with decreasing T . In
the C/T − T curve, anomalies characteristicof second-order phase transitions are observed
at both transition temperatures.
For this system, we have carried out
the powder neutron diffraction measurements
down to 2.8 K at the high resolution powder
diffractometer (HRPD) of JRR-3 of JAEA in
Tokai, and carried out Rietveld analyses using RIETAN-2000 at two temperatures TN2 <T < TN2 and T < TN2 .
Neutron powder patterns were taken at 85
K (> TN1 ), 25 K (between TN2 and TN1 ) and
2.8 K (< TN2 ). At 25 K, superlattice reflections (h/2 k/2 l/2) (h, k, l = odd) were
found and at 2.5 K, superlattice reflections (hk l/2) (h, k, l = odd) were also found. The
integrated intensities and 2θ positions of thepeaks appearing at 25 K have been found not
to change with T from 25 to 2.8 K. By using
the obtained intensities of the magnetic reflections, we have determined the magnetic structures of the ordered phases. At 25 K, only
the Co(2) moments order antiferromagnetically with their spins along the b-axis, where
the ordered moment is 3.6 (±0.2) µB .
At 2.8 K, the Co(1) moments not only
order nearly parallel to the a-axis but
alse cant towards the b-axis by 13.3◦ due
原子炉：JRR-3

装置：HRPD(1G)

Figure 1: Magnetic structure of Co2 TeO3 Cl2 at 2.8
K. The open and closed circles indicate the Co(1) andCo(2) sites, respectively. The arrows indicate the directions of magnetic moments. The Co(1) spins cantfrom the a-axis toward the b-axis by ∼13.3◦ .

to Dzyaloshinski-Moriya interaction, whichcauses the weak ferromagnetism observed below TN2 . The ordered moment is 3.3 (±0.2)µB . The magnetic structure of Co(2) spins
and their ordered moment are unchanged
when T is changed through TN2 . For the noncollinear magnetic structure and the nearly
individual orderings of the sublattices of theCo(1) and Co(2) sites, the structural characteristics of the present system with isosceles
triangles seems to be important.
References
1) R. Becker, et al., J. Solid. State. Chem., 179,
836(2006).

分野：中性子散乱（磁性）－ 181 －

JAEA-Review 2008-067

1-2-69Spherical Polarization Analysis of Artificially Confined Spin-Density Waves in
Cr/Sn Multilayers
M. Takeda, M. Nakamura, K. Kakurai, K. Mibu1 and E. Lelièvre-Berna2Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho,Showa-ku, Nagoya, Aichi 466-8555
2
Institut Laue-Langevin, 6 rue Jules Horowitz BP 156 - 38042 Grenoble Cedex 9, France
1

In Cr/Sn(001) multilayers in whichmonatomic Sn nonmagnetic layers are periodically embedded, spin-density waves(SDWs) are formed below the Néel temperature like that in bulk Cr. They are,however, quite different to the SDW in bulk
Cr. For instance the wavelength of the SDW
is defined not simply by the nesting vectorof Cr but also by the artificial periodicity introduced by the Sn layers1, 2) . We performed
the spherical neutron-polarization analysisof these anomalous SDW structures byusing CRYOPAD(CRYOgenic Polarization
Analysis Device)3, 4) on TAS-1 to get detailed
magnetic structural information which could
not be obtained with unpolarized neutron
experiments5) .
The samples were [Cr(10.0 nm)/Sn(0.2nm)] × 24 grown on MgO(001) substrates.
The incident neutrons were polarized andmonochromatized with a Cu2 MnAl polarizing
monochromator. The energy of the neutrons
was fixed at 14.7 meV. The scans were done
through the (001) and (010) reciprocal points,
where the nuclear peaks were forbidden, along
the [001] (out-of-plane) and [010] (in-plane)
directions.
The film had a commensurate antiferromagnetic (CAF) structure at 290 K andchanged into the incommensurate SDW(ISDW) state with decreasing temperature.
Several satellite peaks corresponding to the
ISDW structures appeared in the scan profiles. The position of each peak can be written as (01 ± N ∆) or (00 1 ± N ∆) where∆ = a001 /Λ, and Λ is the distance of artificial
boundary ( tCr + tSn = 10.2 nm).
The polarization matrix, Pij , was measured
at 270 K and 4.3 K6) . The matrix elements
原子炉：JRR-3

装置：TAS-1(2G)

are given in Ref. 5. At (010) peak the outof-plane and in-plane component of magnetic
interaction vectors, M (Q), are detected whileat (001) only two in-plane components reflect
in Pij . The observed Pyy is equal to -Pzz for(001) at 270 K. On the other hand, |Pyy | islarger than |Pzz | for (010). This indicates thatthe sample has a multi-domain CAF structurewith M (Q) mostly normal to the plane andthat the distribution of the domain is isotropic
in the (001) plane at 270 K.
In the ISDW phase at 4.3 K, M (Q)seems to incline towards the in-plane because|Pzz | > |Pyy | for the first satellite peak of (01∆). Significant depolarization is observed in
Pxx for (00 1+∆). This would imply that thispeak has both nuclear and magnetic origins.
Further investigation is, however, necessary toderive a firm conclusion.
The neutron polarimetry experiments gave
us much more detailed magnetic structural information on the ISDW, which could not havebeen obtained by the conventional unpolarized and polarized neutron diffraction measurements. Measurements of Pij for the otherreflections and temperature dependence of Pij
are expected to give a better insight into themagnetic nature of this multilayer.
References
1) K. Mibu, M. Takeda, J. Suzuki, A. Nakanishi,
T. Kobayashi , Y. Endoh and T. Shinjo, Phys.
Rev. Lett., 89, 287202(2002).
2) M. Takeda, K. Mibu, T. Shinjo, Y. Endoh and
J. Suzuki, Phys. Rev. B, 70, 104408(2004).
3) F. Tasset, Physica B, 156-157, 627(1989).
4) M. Takeda, M. Nakamura, K. Kakurai, E. LelièvreBerna, F. Tasset and L. -P. Regnault, Physica B,
356, 136(2005).
5) P. J. Brown, Physica B, 297, 198(2001).
6) M. Takeda, M. Nakamura, K. Kakurai, K. Mibu
and E. Lelièvre-Berna, Physica B, 397, 56(2007).

分野：中性子散乱（磁性）－ 182 －

JAEA-Review 2008-067

1-2-70
Neutron Scattering Study of Metamagnetic Phase Transition in HoRhIn5
Compounds
N.V. Hieu1 , S. Jonen2 , T. Takeuchi3 , K. Sugiyama1 , R. Settai1 , Y. Ōnuki1,2 , T.D. Matsuda2 ,Y. Haga2 and N. Metoki2
Graduate School, Osaka University, Toyonaka, Osaka 560-0043
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
3
Low Temperature Center, Osaka University, Toyonaka, Osaka 560-0043
1

2

The metamagnetic transition of a single
crystal of HoRhIn5 was studied by neutron
diffraction. This compound exhibits an antiferromagnetic structure with q = (1/2,0,1/2)
below TN = 15.8 K. The magnetization curvefor H||[001]exhibits a characteristic two-step
metamagnetic transition at Hm1 = 3.4 T
and Hm2 = 5.4 T at T = 2 K1) . Neutron diffraction experiments have been carriedout using the TAS-2 and MUSASI spectrometers installed at the research reactor JRR-3
in JAEA. Experiments under high magnetic
fields were carried out at (hk0) and (h0l) scat
tering plane with H||[001]by using a verticalor horizontal superconducting magnet.
Figure 1 shows the field dependence of the(3/2 0 5/2) antiferromagnetic peak intensityof HoRhIn5 . The AF1 represents the antiferromagnetic phase for H < Hm1 , and AF2 forHm1 < H < Hm2 is the intermediate phasewith the intensity roughly 25% of that forAF1. It means that the antiferromagnetic
modulation in AF2 would be half that of AF1.
On the other hand, the ferromagnetic momentin AF2 is a half of the saturation value, as ashown in Fig. 2. These results indicate flipping of the Ho moment. The temperature dependence of Hm1 and Hm2 obtained in thepresent work is in good agreement with thephase diagram extracted from the magnetization measurements. The magnetic structure
at the intermediated phase AF2 could notbeen determined yet. Further experiments
will be required to clarify the magnetic structure in magnetic fields.
References

Figure 2: Magnetic field dependence of ferromagnetic
moment measured at (110) reflection for HoRhIn5 .

1) N.V. Hieu, et al., J. Phys. Soc. Jpn., 75,
074708(2006).

原子炉：JRR-3

Figure 1: Field dependence of the intensity of (3/2 0
5/2) antiferromagnetic reflection for HoRhIn5 .

装置：MUSASI(T2-3)

分野：中性子散乱（磁性）－ 183 －

JAEA-Review 2008-067

1-2-71
Measurements of the Magnetic form Fators of α-Fe and CoFe Powder
by Polarized Neutron Deffractometry
S. Oitani1,2 , Y. Ishii1,3 , M. Takeda1 , K. Kakurai1 ,Y. Sasaki4 , M. Kishimoto4 and Y. Nishihara3
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Department of Physics, Ehime University, Matsuyama, Ehime 790-8577
3
Department of Physics, Ibaraki University, Mito, Ibaraki 560-1234
4
Development and Technology Division, Hitachi Maxell,Ltd, Ooyamazaki ,Kyoto 618-8525
1

2

Ferromagnetic nanoparticles are attracting
attention from the viewpoint of applications
to magnetic recording materials. Polarized
neutron diffraction measurements at ambient
temperature using 80 meV neutrons were performed to estimate the value of magnetizationof the nanoparticles.
The triple-axis neutron spectrometer, TAS1, installed at JRR-3 was used to obtain themagnetic form factor. A magnetic field of 10
kOe was applied perpendicular to the scattering vector to saturate the magnetization.
In the polarized neutron diffraction measurements, Bragg peak intensities from thesamples with net magnetizations depend on
the neutron spin direction with respect to themagnetization direction.
The intensities are written as follows.
dσ)+dΩ= {FN (Q) + F̄M (Q)}2 exp(−2W )

(1)

dσ
)−
dΩ
= {FN (Q) − F̄M (Q)}2 exp(−2W )(2)

I+ = (

I− = (

FN (Q) + F̄M (Q)F R = dσ=FN (Q) − F̄M (Q)( dΩ )−
2
1 + γ(Q)=1 − γ(Q)
原子炉：JRR-3

2

装置：TAS-1(2G)FM (Q)FN (Q)(4)

The magnetic moment was determined byfitting using the well-known magnetic form
factor of α-Fe taking the depolarization effectinto consideration. The scaled magnetic form
factor using the magnitude of magnetic moments determined by the fitting procedure isshown in Fig. 1.

Figure 1: Scaled magnetic form factor of α-Fe

where FN (Q) and FM (Q) are nuclear andmagnetic structure factors, respectively, andexp(−2W ) is the Debye-Waller factor. WhenFN (Q) is known, FM (Q) can be determinedfrom the flipping ratio (FR) as follows.
dσ
( dΩ
)+

γ=

The measured magnetic moment per atomof each sample is shown in Table 1. These results show that the polarized neutron powder
diffraction method is a powerful and accurate
tool to microscopically determine the magnetization of ferromagnetic nanoparticles.
sampleα-Fe (19 nm)
CoFe (35 nm)
CoFe (45 nm)(3)reference
2.2 µB
2.47 µB
2.47 µB

Table 1: Measured magnetic moments

分野：中性子散乱（磁性）－ 184 －

result2.14 ± 0.32 µB
2.42 ± 0.17 µB
2.44 ± 0.33 µB

JAEA-Review 2008-067

1-2-72Magnetic-field Induced Magnetic Phase Transitions in Multiferroic Compound of
ErMn2 O5
H. Kimura, S. Wakimoto1 , Y. Noda, K. Kaneko1 , N. Metoki1 , K. Kakurai1 and K. Kohn2
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577
1
JAEA, Tokai, Ibaraki 319-1195
2
Department of Physics, Waseda University, Tokyo 169-8555

The recent discovery of a colossal magnetoelectric (CME) effect in manganese oxides
of RMnO3 and RMn2 O5 (R = rare earth
elements)1, 2) opens possibilities of new candidates for multifunctional devices such as amagnetically controlled ferroelectric memory.
These systems show a multiferroic behavior
where an antiferromagnetic order and a ferroelectric order coexist, which is thought tobe ingredient essential for realizing the CME
effect. However, microscopic mechanisms of
the CME effect is not fully understood yet.
We have conducted neutron diffraction measurements under high magnetic fields in themultiferroic ErMn2 O5 and found unambiguous relation between the microscopic magnetism and the field-induced ferroelectricity.
Neutron diffraction measurements were
performed using the thermal neutron tripleaxis spectrometer TAS-2. A single crystal of
ErMn2 O5 was mounted on the (h 0 l) scattering plane with a horizontal-field superconducting magnet, which results in applying afield up to 5 T along the a- and c-axis. The
incident and final energies of neutrons were
fixed at 14.3 meV.
Figure 1 summarizes the magnetic field (H)– temperature (T ) phase diagrams for magnetic phases, showing that there exists no fielddependence when the magnetic field was applied along the a-axis while incommensurate– commensurate – incommensurate magnetic
phase transitions are induced by applying thefield along the c-axis. In this figure, the H– T phase diagram for dielectric property reported in Ref. 3 is superposed, showing thatthe well-defined ferroelectric state is induced
only in the CM phase. This one-to-one correspondence between the magnetic phase diagram and the dielectric phase diagram under
原子炉：JRR-3

装置：TAS-2(T2-4)

ErMn2O5(a) H // a50

TN

HT-ICM (PE)

40
30

TC

CM (FE)

Temperature (K)20
10LT-1DICM (X’)0(b) H // c50

TN

HT-ICM (PE)

40
30

TC

CM (FE)

20
10
LT-1DICM
(X’)

0
0

1

LT-2DICM (X)
2

3

4

5

6

Magnetic field (T)Figure 1: H −T magnetic phase diagram in ErMn2 O5 ,where magnetic field was applied along (a) a-axis
and (b) c-axis. The dielectric phase diagram taken
by Higashiyama et al.3) is superposed in this figure.
Abbreviations: HT-ICM; High-temperature incommensurate magnetic, CM; Commensurate magnetic,
LT-1DICM; Low-temperature one dimensionally modulated incommensurate magnetic, LT-2DICM; Lowtemperature two dimensionally modulated incommensurate magnetic, PE; Paraelectric, FE; Ferroelectric,
X and X’; unidentified.

a magnetic field clearly indicates that the electric polarization is magnetically induced andthe commensurate magnetic structure is indispensable to the ferroelectricity in the multiferroic RMn2 O5 system.
References
1) T. Kimura, et al., Nature (London), 426, 55 (2003).
2) N. Hur, et al., Nature (London), 429, 392 (2004).
3) D. Higashiyama, et al., Phys. Rev. B, 72, 064421(2005).

分野：中性子散乱（磁性）－ 185 －

JAEA-Review 2008-067

1-2-73Temperature and Electric Field Dependences of Spin Chirality in Multiferroic
Compound of HoMn2 O5
H. Kimura, S. Wakimoto1 , K. Nishihata, Y. Noda, M. Takeda1 , K. Kakurai1 and K. Kohn2
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577
1
JAEA, Tokai, Ibaraki 319-1195
2
Department of Physics, Waseda University, Tokyo 169-8555

Polarized neutron diffraction measurements
were performed using the triple-axis spectrometer TAS-1 installed at JRR-3. An incident beam was unpolarized by a PG(002)monochromator while a scattered beam waspolarized by a Heusler(111) monochromator.
A single crystal of HoMn2 O5 was mounted onthe (h 0 l) scattering plane. The incident
and final energies of neutrons were fixed at
14.7 meV.
Figure 1 shows the temperature dependences of magnetic Bragg reflections with achiral component (filled symbols) and without a chiral component (open symbols) un原子炉：JRR-3

装置：TAS-1(2G)

Non chiral3

Integrated intensity (arb. unit)

It is well known that the multiferroic compounds of HoMn2 O5 show a colossal magnetoelectric (ME) effect. This material has successive magnetic transition below 45 K from ahigh-temperature incommensurate magnetic(HT-ICM) phase to a commensurate magnetic (CM) phase, and finally to a lowtemperature incommensurate magnetic (LTICM) phase as the temperature decreases. A
recent neutron diffraction study1) as well as
dielectric measurements2) under a magnetic
field have established that a well-defined ferroelectricity is induced only in the CM phase.
Our magnetic structure analysis also revealed
that there exists spiral spin structure in the
CM phase3) , which can produce a spontaneous electric polarization by an inverse effect of Dzyaloshinski–Moriya interaction with
Si × Sj products. Thus, we have thus performed polarized neutron diffraction measurements under an electric field to clarify the relation between the rotation direction of the
spiral component (spin chrality) and the direction of spontaneous electric polarization,
which can confirm whether the transverse spiral structure yields an electric polarization.

(0.5 0 -1.75), Epol = +5 kV/mm

Chiral

2
1
0
-1
-2
-3
0

LT-ICM (X)10

CM (FE)
2030

Temperature (K)HT-ICM(PE)

40

Figure 1: Temperature dependences of magnetic
Bragg reflection with chiral component (filled symbols) and without chiral component (open symbols).
Electric-field-cooling was performed below 50 K with+ 5 kV/mm. The dielectric phase is paraelectric (PE),ferroelectric (FE), and unidentified (X) phases in HTICM, CM, and LT-ICM phases, respectively.

der an electric-field cooling with + 5 kV/mm.
This result shows that there is no chiral component in the HT-ICM phase (paraelectricphase) while the chiral component arises in
the CM phase (ferroelectric phase). Furthermore, in the CM phase, there is one-to-one
correspondence between the electric field dependence of the amplitude of the chiral component and that of the amplitude of electric
polarization, suggesting that the spin chirality yields the electric polarization. However,
the relevance between the chirality component and the dielectric property in the LTICM phase is not clarified yet.
References
1) H. Kimura, et al., J. Phys. Soc. Jpn., 75, 113701(2006).
2) D. Higashiyama, et al., Phys. Rev. B, 72, 064421(2005).
3) H. Kimura, et al., J. Phys. Soc. Jpn., 76, 074706(2007).

分野：中性子散乱（磁性）－ 186 －

JAEA-Review 2008-067

1-2-74Magnetic Structure and Phase Diagram of NpIn3 Studied by Neutron Scattering
under Magnetic Field
F. Mizuno1,2 , T. Sugai1,2 , N. Metoki1,2 , Y. Haga1,2 , D. Aoki3 , Y. Homma3 and Y. Siokawa3
Actinide compound magnetism and superconductivity research group, JAEA,Tokai,Ibaraki 319-1195
2
Department of Physics, Tohoku University, Sendai, Miyagi 980-8578
3International Research Center for Nuclear Material Science, Tohoku University, Oarai, Ibaraki
311-1313

装置：TAS-2(T2-4)

Intensity(counts10 /60s)

NpIn3 H=02

30

(3/8 3/8 5/8)
( 0 0 1 ) 25

7
6

20
5
15

4

10

3

2

原子炉：JRR-3

8

Intensity(counts10 /600s)

5

2

0
5

10

15

Temperature(K)Figure 1: Temperature dependence of the (3/8 3/8
5/8) and (0 0 1) reflections intensity.

2

NpIn3 is a cubic compound with
AuCu3 -type structure. The ferromagnetic
order was reported in a narrow temperature
region for 10 K < TC < 14 K, while an antiferromagnetic ground state is stable below
TN = 10 K. A previous neutron diffraction
study1) reported a longitudinal modulated
magnetic order with q=(3/8 3/8 3/8) in the
ground state. Two metamagnetic transitions
have been reported for three principal directions, H  <100>, <110> and <111> fromthe antiferromagnetic (AF) ground state to
the AF+FM phase, which is followed by the
FM phase at high fields. Here the orderparameter of the intermediate AF+FM phase
is unknown yet.
In order to clarify the order parameter andmagnetic structure, we studied NpIn3 by neutron scattering under a magnetic field with atriple-axis spectrometer TAS-2 in JRR-3.
The intensity of the (0 0 1) reflection increases below 14 K then decreases rapidly
at 10 K down to the background. We observes magnetic reflections, for example (3/8
3/8 5/8) (Fig.1). These results are consistent
with a previous study1) . The intensity of the(3/8 3/8 5/8) reflection decreases rapidly under the magnetic fields above 3 T. We found
the reflections (0 1/2 1/2) and (1 1/2 1/2)
in the AF+FM phase. A field dependence ofthe (1 1/2 1/2) peak intensity for various temperature is observed(Fig.2). These data indicate that the (1 1/2 1/2) peak appears in the
AF+FM phase. The critical field between the
AF and the AF+FM phases is in good agreement with a magnet susceptibility2) .

Intensity(10 counts / 900s)

1

14
13
NpIn3
(1 1/2 1/2)

12
11

4K
4.4K
4.8K
5.3K

10
9
0

2

4

6

8

10

Field(T)
Figure 2: Field dependence of the (1 1/2 1/2 ) reflection intensity for various temperature.

References
1) E. Colineau, et al., Physica B, 206-207, 528(1995).
2) D. Aoki, et al., J. Phys. Soc. Jpn., 75, 084710(2006).

分野：中性子散乱（磁性）－ 187 －

JAEA-Review 2008-067

1-2-75Magnetic Ordering Process in the Layered Triangular Lattice System
LuFe2 O4 in Applied Field
K. Kakurai, M. Matsuda, K. Yoshii1 , N. Ikeda2 , Y. Ishii, H. Kito3 and Y. Yamada4
Neutron Materials Research Center, QuBS, JAEA, Tokai, Ibaraki 319-1195
1
Synchrotron Radiation Research Center, QuBS, JAEA, Hyogo 679-5148
2
Department of Physics, Okayama Univ., Okayama 700-8530
3
National Insitute of Advanced Industrial Science and Technology, Tsukuba 305-8561
4
ARCSE, Waseda University, Tokyo 169-0072

In LuFe2 O4 , the Fe ions are arranged toform the hexagonal double layers and stackin the sequence of (AB), (CA), (BC),... along
the rhombohedral unique axis. The averagevalence of the Fe ions is expected to be Fe+2.5
in these materials. More recently the evidence
for ferroelectricity arising from electron correlations is found by means of resonant Xray scattering experiment directly determining the ordering of the Fe+2 and Fe+3 ions1) .
Furthermore, the temperature dependence ofthe electric polarization indicates an intimate
relation between the coherence length of thecharge-ordered region and the magnetic correlations. We have been studying the magnetic ordering process in zero applied field of
LuFe2 O4 , which clearly shows charge ordering
at RT. A clear sign of 3-D ferrimagnetic ordering at TN = 242 K has been observed. But
at around Tf = 177 K there is yet anothercharacteristic temperature, where the intensity distribution among the magnetic Bragg
peaks changes and the correlation along c∗
direction decreases drastically2) . Thus theground state in zero applied field seems to bea some type of spin frozen state. To shed somelight on this anomalous spin freezing process
we performed both magnetization measurements and neutron scattering experiments under an applied magnetic field along the c-axis.
Figure 1 (a) depicts the temperature dependence of the Q = (1/3,1/3,0) magnetic peak in
H = 1 T and 3 T applied field vertical to thescattering plane. Under the applied field of 1
T, TN is slightly increased and Tf is decreased
to about 150 K. Under the applied field of 3T, TN increases even more (almost to 260 K)
and Tf is now completely suppressed. Figure
原子炉：JRR-3

装置：TAS-2(T2-4)

1 (b) shows the magnetization measurementsin the corresponding magnetic field, and theferromagnetic component shows exactly thesame behaviour as the antiferromagnetic component observed by neutron scattering. These
results indicate that the spin frozen groundstate in zero field is suppressed by the applied field along the c-axis. A neutron scattering experiment using a horizontal field magnet
will clarify the low temperature behaviour ofthe correlation in c∗ direction in applied fields,
and is planned for near future.

Figure 1: (a) Temperature dependence of Q =(1/3,1/3,0) magnetic peak intensity in H = 1 and 3 T
applied field. (b) Temperature dependence of magnetization in H = 1 and 3 T applied field.

References
1) N. Ikeda, et al., Nature, 436, 1136(2005).
2) S. Nagai, et al., JAEA-Review, 2005-089, 82(2005).

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JAEA-Review 2008-067－ 189 －

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JAEA-Review 2008-067

1-3-1

Incommensurate Magnetic Order in the Pressure-Induced Superconductor CeRhSi3
N. Aso, H. Miyano, H. Yoshizawa, N. KimuraA , T. KomatsubaraA , H. AokiA
NSL-ISSP Univ. of Tokyo, Graduate School Sci. Tohoku Univ.A
Coexistence between magnetism and superconductivity is the central issue in condensed matter physics. Recently noncentrosymmetric heavy-fermion superconductor CePt3 Si [1] and UIr [2] were reported. From the fundamental point ofview of symmetry, the discovery of thesematerials are very surprising because there
are two basic symmetries which are considered indispensable to form Cooper pair:time reversal symmetry and parity. The
former is important for Cooper pairingin any case while the latter is mandatory for pairing in the triplet channel.
Thus there is no right picture for the
non-centrosymmetric superconductivity atpresent.
Kimura et al. [3] discovered another noncentrosymmetric superconductor CeRhSi3 .
Its crystal structure is the BaNiSn3 -type belonging to space group I4mm (No. 107)
without an inversion center. [4] CeRhSi3
exhibits the antiferromagnetic (AFM) ordering below TN = 1.6 K at ambient pressure. By increasing the pressure, TN showsa maximum around 0.7 GPa, then gradually decreases. Superconductivity appears
in a wide pressure range from 1.2 to 2.3 GPa(and more). Very recently, CeIrSi3 , withthe same crystal structure, was reported
to be categorized in the pressure-induced
superconductor. [5] It shows AFM ordering below TN = 5.0 K at ambient pressure,then TN decreases monotonically with increasing pressure. Superconductivity appears in a wide pressure region from 1.8
to 3.5 GPa. Concerning the magnetic structure, there is only one neutron diffraction
work on polycrystalline samples for bothmaterials, [6] which exhibits no magnetic
reﬂections with possible maximum magnetic moment of 0.25 µB /Ce. To determine
the magnetic structure which is closely
connected with the superconductivity in

CeRhSi3 , therefore, we performed the neutron diffraction measurements using single
crystals CeRhSi3 .
Single crystals were grown by Czochralsky pulling method in a tetra-arc furnace.
Neutron diffraction experiments have been
performed on ISSP triple-axis spectrometers GPTAS (4G) and PONTA (5G) installedat the research reactor JRR-3M of Japan
Atomic Energy Agency, with the incident
energy of ki ∼ 2.67 Å−1 and the conﬁguration of 2-axis mode. Pyrolytic graphite ﬁlters were used for both incident and scattered neutron to reduce the higher-ordercontamination. The crystals were cooled
down to 0.75 K.
We have searched magnetic reﬂectionsin the major symmetry axes of three scattering planes of (H0L), (HHL) and (HK0).
Only in the (H0L)-zone, the magnetic reﬂections can be observed. Figure 1 (a)and (b) show typical scan proﬁles through(H, 0, 1.5). One can clearly recognize theBragg reﬂections at incommensurate reciprocal points Q = (0.215, 0, 1.5) and Q =(0.785, 0, 1.5), respectively, at 0.75 and 1.5
K (below TN ), which disappeared at 2.0 K(above TN ). These observation indicate thatthe above Bragg reﬂections are of magnetic
origin. The magnetic intensity of the former is larger than that of the latter, whichroughly indicates that the magnetic moment lies in the a − b plane. This fact is inexcellent agreement with an anisotropy ofthe susceptibility measurement. [7]Temperature dependence of the peak intensities at Q = (0.215, 0, 1.5) and (0.785,
0, 0.5)are not shown in this report. At Q
= (0.215, 0, 1.5), the intensities of ∼ 800
counts well below TN gradually decreases
with temperature and suddenly drops to ∼180 counts of background intensity aroundTN ∼ 1.6 K. The temperature dependence
at Q = (0.785, 0, 0.5) also shows the sim-

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 18－ 191 －

JAEA-Review 2008-067[5] I. Sugitani, Y. Okuda, H. Shishido, T. Yamada, A. Thamizhavel, E. Yamamoto, T.
D. Matsuda, Y. Haga, T. Takeuchi, R, Settai
and Y. Onuki, J. Phys. Soc, Jpn. 75 (2006), p.
043703.
[6] A. Krimmel, M. Reehuis and A. Loidl,
Appl. Phys. A 74 Suppl. (2002) p. S695.
[7] N. Kimura, Y. Umeda, T. Asai, T.
Terashima and H. Aoki Physica B 294-295(2001) p. 280.
1000

Counts/M2400k(~5min)ilar behavior. It should be noted that theobtained Néel temperature of 1.6 K corresponds to the anomaly in both the susceptibility and electrical resistivity measurements using single crystals. [7]To determine the incommensurate magnetic structure, we have performed radialscans at 17 inequivalent Bragg points. After calculating the integrated intensities ofvarious models, we propose that the longitudinal spin-density wave (LSDW) state isrealized below TN in CeRhSi3 . This magnetis structure is in excellent agreementwith the dHvA experiments [7], in which
dHvA signals in both CeRhSi3 and LaRhSi3
are observed and the different Fermi surfaces lead to that the 4f electrons of CeRhSi3
are itinerant. The samll size of the magnetic moment is 0.16(10) m B /f.u., which indicates that this material is located in thevicinity of quantum critial point (QCP).
Another interesting feature of the magnetic structure is the propagating along caxis of up-up-down-down spin arrangement because Q = (0, 0, 1) is not allowed
for the BaNiSn3 -type crystal structure. Thisis possibly due to the lack of the inversion
center along c-axis and the legand electronsof Rh and/or Si atoms might play an important role in the magnetic structure.
The neutron experiments were supported by ISSP, University of Tokyo (PACS
No. 6418). A part of this work was supported by the Grant-in-Aid for the Ministryof Education, Culture, Sports, and Scienceof Japan.

JRR-3M/GPTAS
ki=2.67A-1

800

40'-80'-40' (2PG)
0.75 K
1.5 K
2.0 K

600

400

200

(a)
0

0.20

(b)
0.22

0.24 0.74 0.76 0.78 0.80 0.82

(H,0,1.5) (r.l.u.)

Fig. 1. Peak proﬁles through (a) Q = (0.215, 0, 1.5)
(left) and (b) Q = (0.785, 0, 1.5) (right), which has
asymmetric shape due to the sample mosaicity.

References[1] E. Bauer, G. Hilscher, H. Michor, Ch. Paul,
E. W. Scheidt, A. Gribanov, Yu. Seropegin,
H. Noel, M. Sigrist and P. Rogl, Phys. Rev.
Lett 92 (2004), p. 027003.
[2] T. Akazawa, H. Hidaka, H. Kotegawa, T.
C. Kobayashi, T. Fujiwara, E. Yamamoto,Y. Haga, R. Settai and Y. Onuki, J. Phys.
Soc. Jpn. 73 (2004), p. 3129.
[3] N. Kimura, K. Ito, K. Saitoh, Y. Umeda, H.
Aoki and T. Terashima, Phys. Rev. Lett. 95(2005), p. 247004.
[4] Y. Muro, N. Takeda and M. Ishikawa, J.
Phys. Soc, Jpn. 67 (1998), p. 3601.

－ 192 －

JAEA-Review 2008-067

1-3-2

Evolution of commensurate magnetic state in the heavy-fermion superconductor
CeRh0.6 Co0.4 In5
M. Yokoyama1 , N. Oyama1 , S. Oinuma2 , I. Kawasaki2 , K. Tenya2 ,H. Amitsuka2 , T.J. Sato3 , M. Matsuura3 and K. Hirota3
1 Faculty of Science, Ibaraki University, Mito 310-8512
2 Graduate School of Science, Hokkaido University, Sapporo 060-0810
3 Institute for Solid State Physics, The University of Tokyo, Tokai, 319-1106
In recent years, there has been growinginterest in the physical property near thequantum critical point (QCP) in the heavyfermion systems. The heavy-fermion compound CeRhIn5 orders in an incommensurate antiferromagnetic (AF) phase withthe modulation of qh = (1/2, 1/2, 0.297)[1]. It is revealed in the Co-doped alloys
CeRh1− x Cox In5 [2] that the AF phase issuppressed with increasing x, and then disappears at xc ∼ 0.7. At the same time, thesuperconducting phase appears between
x = 0.4 and x = 1. The evolution ofsuperconducting state around xc implies
that these two states are strongly coupledwith each other. To investigate the relation
between these two phases, we have performed the elastic neutron scattering experiments for CeRh0.6 Co0.4 In5 [3].
Single crystals of CeRh0.6 Co0.4 In5 weregrown by the In-ﬂux method. The samples were shaped into bar (typical size: ∼3 mm2 × 20 mm) in order to minimize theeffects of the neutron absorption caused by
the Rh and In ions contained in the samples. The unpolarized and polarized elastic
neutron scattering experiments were performed using triple-axis spectrometers GPTAS and PONTA located at the JRR-3M research reactor of JAEA, respectively. The
measurements were performed in the (hhl)scattering plane for both the experiments.
Figure 1 shows the neutron scattering
pattern obtained by the (1/2, 1/2, 1 + ζ)
(0 ≤ ζ ≤ 1) scan at 1.4 K, using unpolarized neutron beam. We have found thatthree nonequivalent Bragg peaks, otherthan nuclear ones expected from the tetragonal structure, develop at low temperatures. The wave vector characterizingthese peaks are estimated to be qh =(1/2, 1/2, 0.306), q1 = (1/2, 1/2, 0.402),
and qc = (1/2, 1/2, 1/2). The polarized neutron scattering experiments indicate that all these peaks originate fromthe magnetic scatterings. The appearanceof the Bragg peaks for qh is attributed tothe incommensurate AF order, since pure
CeRhIn5 also shows this type of order. On
the other hand, the development of the
Bragg peaks relevant to the modulation ofqc and q1 indicates that new AF orders
evolve with intermediate Co concentration.
We are now planning to perform further
neutron scattering experiments for entire x
range to elucidate the nature of these AF
phases.
References[1] W. Bao et al., Phys. Rev. B 62 (2000) R14621;
Phys. Rev. B 67 (2003) 099903(E).
[2] V.S. Zapf et al., Phys. Rev. B 65 (2001)
014508.
[3] M. Yokoyama et al., J. Phys. Soc. Jpn. 75(2006) 103703.
400
CeRh0.6Co0.4In5
Q = (1/2,1/2,1+ξ)300

T = 1.4 K
δ = 0.306
δ' = 0.402

200
100
0
0

0.2

0.4
0.6
ξ (r.l.u)

0.8

1Fig. 1. The antiferromagnetic Bragg-peak proﬁles at
1.4 K.

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JAEA-Review 2008-067

1-3-3

Ferromagnetic and antiferromagnetic orders in CaRu1−x Mnx O3
M. Yokoyama1 , H. Miyagawa1 , A. Noguchi1 , N. Oyama1 , Y. Nishihara1 and H.
Kawanaka2
1 Faculty of Science, Ibaraki University, Mito 310-8512
2 National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568
structure becomes stable in the Mn-richconcentration range.
Furthermore, theintensities of some Bragg-peaks, suchas the (101) and (020) peaks, are foundto show notable temperature variations.
They are roughly in proportional to M2 ( T ),suggesting that the ferromagnetic orderdevelops in the intermediate x range.
These features are roughly consistent withthe previous report on the Mn-rich region[5]. The precise analysis on the present
neutron diffraction data is now in progress.
References[1] I. Felner et al.: PRB 66 (2002) 054418.
[2] V. Hardy et al.: PRB 73 (2006) 094418.
[3] V. Durairaj et al.: PRB 73 (2006) 214414.
[4] A. Maignan et al.: PRB 73 (2006) 024410.
[5] A.I. Shames et al.: PRB 70 (2004) 134433.

CaRu1-xMn xO3
T = 15 K
x = 0.4

Intensity (arb. units)

The nature of metal-insulator transitionin the transition-metal oxides is one of
the intriguing issues in the condensedmatter physics. The distorted perovskite
compound CaRuO3 (the GdFeO3 -type orthorhombic structure; space group Pnma)
is considered to be paramagnetic metal,
and located in the vicinity of the metalinsulator transition. Recently, it is revealed
that the ionic substitutions for the Ru site
dramatically enhance the magnetic correlation [1, 2, 3, 4]. In particular, we foundthat the substitution of Mn for Ru induces
both the ferromagnetic and antiferromagnetic (AF) components in magnetizationM, accompanying the variation of the electrical resistivity from metallic to insulating
behavior. These features are expected to be
attributed to the variations of the d electronic state, and it is therefore interesting
to investigate the microscopic properties ofthe d electrons in the intermediate Mn concentration range. In the present study, we
have performed powder neutron diffraction experiments for CaRu1− x Mnx O3 .
The
polycrystalline
samplesof
CaRu1− x Mnx O3 with x = 0.4 0.6 and0.7 were prepared by the solid-statemethod. The neutron diffraction measurements for powdered samples were
performed in the temperature ranges between 15 K and 290 K, using the HERMES
spectrometer installed at the research
reactor JRR-3M of JAEA. The wavelengthof the incident neutron was selected tobe 1.8264 Å. Figure 1 shows the neutron
powder diffraction proﬁles at 15 K for
x = 0.4, 0.6 and 0.7. We have observed
the development of Bragg peaks ascribedto the AF order with the G-type structure.
These AF Bragg-peak intensities increase
with increasing x, indicating that the AF

x = 0.6

x = 0.7

20

30

40
50
2θ (deg)60

70Fig. 1. Neutron powder diffraction proﬁles of
CaRu1− x Mnx O3 with x = 0.4, 0.6 and 0.7 at 15 K.
The open and closed arrows indicate the antiferromagnetic and ferromagnetic Bragg peaks positions,
respectively.

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JAEA-Review 2008-067

1-3-4

Magnetic excitations of high TQ compound YbAl3C3
M. Kosaka(A), Y. Kato(A), H. Nowatari(A) and K. Ohoyama(B)(A)Department of Physics, Saitama Univ., (B)IMR, Tohoku Univ.
YbAl3C3 shows a second-order transition
at 80 K on the result of speciﬁc heat measurement. We think that this transition indicates an antiferroquadrupolar ordering(AFQ) and we interested in the reason of
extremely high transition temperature. It
is important to determine crystalline electric ﬁelds (CEF) parameters to discuss detail of the AFQ. Therefore, we carried out
inelastic neutron scattering experiments of
YbAl3C3.
Fig.1(a) shows inelastic neutron spectra of
YbAl3C3 and LuAl3C3 at 8 K and 100 K.
The well-deﬁned excitations are observed
around 14, 20, 33 and 43 meV. The spectra of LuAl3C3 shows phonon contributions around 14 and 43 meV. However, theintensity of the peak around 43 meV of
YbAl3C3 decreases obviously with increasing temperature. Therefore, this excitation
is attributed to magnetic one. As a result, itis thought that the split of the CEF are 20,
33 and 43 meV.
On the other hand, unexpected magnetic
excitations were observed around 1.5 and2.9 meV in Fig.1(b). It seems that these excitations appear below 80 K. A decrease intemperature splits the excitations into two
peaks and the intensities develop dramatically. At this stage, we do not have an
understanding of the mechanism that allows such a giant magnetic excitations toform. However, a valence of Yb ion is estimated to be a trivalent state with large
antiferromagnetic interaction between Yb
ions by magnetic measurements (effective
Bohr magneton 4.57, Weiss temperature -94
K). Furthermore, Yb ions form a triangularlattice and no magnetic transition was observed down to 20 mK. We think that suchthe behavior of low energy excitations suggests a sign of a frustration or a ﬂuctuation
between Yb magnetic moments.

Fig. 1. Inelastic neutron spectra of YbAl3C3 andLuAl3C3.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-3-5

Antiferromagnetic Phase Transition in the Kondo Semiconductor CeOs4 Sb12
K. Iwasa1 , S. Itobe1 , M. Kohgi2 , C. P. Yang1 , K. Kuwahara2 , H. Sugawara3 , H. Sato2 ,N. Aso4
1
Tohoku Univ. , Tokyo Metropolitan Univ.2 , The Univ. of Tokushima3 , Univ. of Tokyo4
CeOs4 Sb12 has a band gap of around
10 K estimated from the temperature dependence of electrical resistivity, while itshows the large T-linear coefﬁcient of speciﬁc heat γ = 200mJ/K2 /mol (E. Baueret al., J. Phys.: Condens. Matter 13 (2001)
4495, H. Sugawara et al., Phys. Rev. B
71 (2005) 125127). Our previous inelastic
neutron scattering experiment revealed noclear crystal-ﬁled excitation, in contrast to
the Curie-Weiss behavior of magnetic susceptibility in higher temperature region (C.
P. Yang et al., J. Phys. Soc. Jpn. 74 (2005)2862). These facts indicate that CeOs4 Sb12
is a so-called Kondo semiconductor due tothe strong c- f hybridization. It is notablethat this material shows a phase transition
at 0.9 K under zero magnetic ﬁeld and theordering temperature is enhanced by applied magnetic ﬁelds. SDW or CDW transitions are suggested from the Sb-NQR resultin the ordered phase (M. Yogi et al., J. Phys.
Soc. Jpn. 74 (2005) 1950).
In order to identify the nature of ordering in CeOs4 Sb12 , we performed neutron diffraction experiment at the tripleaxis spectrometer TOPAN (6G) and HER(C1-1). We adopted the dilution refrigerator of ISSP, Univ. of Tokyo. A single crystal
sample synthesized by the Sb-ﬂux method
was cooled down to 0.1 K.
We succeeded in observing weak antiferromagnetic reﬂections characterized bya wave vector q = (1 0 0) below the ordering temperature, as shown in the ﬁgure.
Assuming the magnetic ordering at the Ceion sites forming the bcc lattice, we evaluated the ordered moment value of around
0.05µB /Ce. Such a tiny ordered magnetic
moment as well as the unusual phase diagram are consistent with the SDW-like antiferromagnetic instability due to the c- f
hybridization as proposed in the theoret-

ical works on Kondo semiconductors (T.
Ohashi et al., Phys. Rev. B 70 (2004)
245104, Y. Imai et al., J. Phys. Soc. Jpn.
75 (2006) 033706). On the other hand, theantiferromagnetic peak disappears above
1 T in contrast to the reported phase diagram. The antiferromagnetic region coincides with that of large magnitude of electrical resistivity. Thus, we expect that theelectronic state change from the gappedstate in the low ﬁeld region to the metallic
one above 1 T correlates with the magnetic
state.

Fig. 1. Scan proﬁles through Q = (1 0 0) of
CeOs4 Sb12 .

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JAEA-Review 2008-067

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Magnetic Excitation in the Antiferro-Type Multipolar Ordering Phase of PrFe4 P12
K. Iwasa1 , L. Hao1 , K. Kuwahara2 , M. Kohgi2 , H. Sugawara3 , Y. Aoki2 , H. Sato2 , andT. D. Matsuda4
1
Tohoku Univ. , Tokyo Metropolitan Univ.2 , The Univ. of Tokushima3 , JAEA4
trast to the quasielastic response above TA ,although it is not shown here. We have already conﬁrmed that these excitations areless dispersive, so that they are originatedfrom the excitations in low-lying crystalﬁeld levels. These peaks are considered
to be elementary excitations in the higher
multipolar ordering phase. When the magnetic ﬁeld was applied to 2.75 T corresponding to the intermediate region of theordered phase, the 1.4 meV peak seems
to split in two or three peaks. This phenomenon can be naively understood as alifting of the crystal-ﬁeld-level degeneracy.
As discussed recently, the Γ1 -type or scalartype order conserves the local symmetry
and the crystal-ﬁeld level splitting thorough the transition temperature, although
the two Pr ions in the bcc unit cell become
inequivalent. This scenario is consistent
with the observed splitting of the excitation
peak.

300

2006.10.5 C1-1 PrFe4P12 Magnet
kf = 1.555, G-B-filter-Radial3coll-HFA-20mmSlit-D
Q = (0, 1.9, 0)
T ~ 1.6 K , B = 2.75 T
T ~ 1.6 K , B = 0

250

Counts / 4000 kMN

PrFe4 P12 has recently attracted much attentions because of the heavy electron behavior that is novel for Pr-based compounds (H. Sugawara et al.: Phys. Rev. B
66 (2002) 134411, H. Sato et al.: Phys. Rev. B
62 (2000) 15125). It undergoes a nonmagnetic phase transition at TA = 6.5 K (Y.
Aoki et al.: Phys. Rev. B 65 (2002) 064446, L.
Keller et al.: J. Alloys and Compounds 323324 (2001) 516). X-ray superlattice reﬂections characterized by the wave vector q =(1 0 0) were observed below TA (K. Iwasa etal.: Physica B 312-313 (2002) 834). Our neutron diffraction study revealed antiferromagnetic reﬂections induced by magnetic
ﬁelds below TA . These phenomena indicate antiferro-type ordering of the 4 f electrons of Pr ions (L. Hao et al.: Acta Physica
Polonica B 34 (2003) 1113). Recently, thisantiferro-type ordered phase has been interpreted as the Γ1 -type or scalar-type order of higher-rank multipole that does notbreak the local symmetry (A. Kiss and Y.
Kuramoto: J. Phys. Soc. Jpn. 75 (2006)
103704). In the heavy electron phase, magnetic excitation spectra from the polycrystalline sample are heavily overdamped andquasielastic (K. Iwasa et al.: Acta Physica
Polonica B 34 (2003) 1117). This fact indicates that the 4 f 2 electrons of Pr3+ ion
hybridize strongly with carriers. Since elementary excitation in the multipolar ordering phase is an interesting subject, we performed inelastic neutron scattering measurements for single crystal samples.
Inelastic neutron scattering experiments
were carried out on the cold- and thermalneutron spectrometers HER (C1-1) and
TOPAN (6G), respectively.
Figure 1 shows energy spectra at Q =(0 1.9 0) obtained in the HER experiment.
At zero magnetic ﬁeld at 1.6 K, two sharp
peaks appear at 1.5 and 3.2 meV, in con-

200

150

100

50

0
-2

-1

0

1

2

3

4

Energy [meV]Fig. 1. Inelastic magnetic neutron scattering proﬁles
at Q = (0 1.9 0) in the ordered phase of PrFe4 P12 .

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JAEA-Review 2008-067

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Inelastic Neutron Scattering from the Heavy-Electron System NdFe4 P12
K. Iwasa1 , L. Hao1 , H. Sugawara3 H. Sato2
Tohoku Univ.1 , Tokyo Metropolitan Univ.2 , The Univ. of Tokushima3
intensity decreases with decrease of temperature, these intensities are considered tobe come from structural ﬂuctuation. In the
typical heavy-electron systems, magnetic
quasielastic intensities have been generally
observed, due to interaction between thelocalized 4 f electrons and conduction electrons. In this case, the intensity of broad
response increases with decrease of temperature, as the Pauli paramagnetic susceptibility. The observed result of NdFe4 P12
is completely opposed. As written in theother report of this volume, we observed
similar phonon spectra in PrRu4 Sb12 andPrOs4 Sb12 , in which the ﬁlled Pr ions vibrate with large amplitude within the surrounding large cage of Sb. The relaxation
mode may be given by the strong interaction between the Pr-ion motion and theelectronic state. If the observed quasielastic
response in NdFe4 P12 was also come fromsuch electron-phonon coupling, the heavy
electron behavior would relate with the observed structural ﬂuctuation spectra. We
have to continue the study to clarify themechanism of appearance of the quasielastic intensity.
350

150000
NdFe4P12 CTI
kf = 2.5525
B-60-60-60
PGF-after

Counts / 1000 kMN (~100 sec)

300
250

100000Q = (4, 0, 0)
10 K
100 K
200 K
300 K

200
150

50000
100
50
0

-2

0

2

4

6

8

Counts at center / 100 kMN (~10 sec)Rare-earth ﬁlled skutterudite compounds have been extensively studiedin terms of strongly correlated electron
phenomena. One of the topics is heavy
electron state appearing in the system with
two or more 4 f electrons per rare-earth
ion. PrFe4 P12 with 4 f 2 conﬁguration of
Pr3+ is a typical example, which shows
the Sommerfeld coefﬁcient for electronic
speciﬁc heat γ = 1.4J/mol/K2 and theclear −logT behavior of electrical resistivity (Y. Aoki et al., Phys. Rev. B 65
(2002) 064446, H. Sugawara et al., Phys.
Rev. B 65 (2002) 134411). Our inelastic
neutron scattering experiment revealed thequasielastic magnetic response indicating
the strongly hybridized state (K. Iwasa etal., Acta Physica Polonica B 34 (2003) 1117).
A similar −logT behavior is also foundin NdFe4 P12 with 4 f 3 conﬁguration of
Nd3+ (H. Sato et al., Phys. Rev. B 62 (2000)
15125). However, it undergoes a ferromagnetic phase transition at TC = 1.9 K andthe magnitude of ordered magnetic moment was evaluated as 1.6µB /Nd (L. Keller
et al., J. Alloys and Compounds 323-324(2001) 516), which is much larger than the
typical heavy electron materials and seems
not to be consistent with the singlet formation due to Kondo effect. Thus, the heavy
electron behavior in electrical resistivity of
NdFe4 P12 with well-localized 4 f electrons
is a mysterious property. In order to investigate the 4 f electron state of this material,
we performed inelastic neutron scatteringexperiments.
The triple-axis spectrometer TOPAN(6G) and HER (C1-1) were adopted tomeasure energy spectra from a singlecrystalline sample.
Figure 1 shows energy spectra at Q =(4 0 0) of NdFe4 P12 as a function of temperature. Quasielastic intensities extending
beyond 5 meV were detected. Because the0Energy [meV]Fig. 1. Energy spectra at Q = (4 0 0) of NdFe4 P12 asa function of temperature.

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Thermoelectric properties and crystal structures of chemically-modiﬁed layered
thermoelectric materials
Hiroshi Nakatsugawa, Hyeon Mook Jeong, Rak Hee Kim and Natsuko Gomi
Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 Japan
Since the discovery of large thermoelectric
power in the layered compounds, misﬁtlayered cobalt oxides particularly have attracted much interest as candidates forthermoelectric (TE) materials. We have employed a high-resolution neutron powder diffraction technique to investigate
the modulated crystal structure of [(Ca1-x
Pbx)2CoO3]0.62CoO2 polycrystalline samples. The solubility limit of Pb was determined on the basis of powder X-ray
diffraction (XRD) intensities at room temperature using a JEOL JDX-3530 diffractomater (CuK α). Neutron powder diffraction (ND) data were collected at room temperature using the Kinken powder diffractometer for high efﬁciency and high resolution measurements (HERMES) of Institute for Materials Research (IMR), Tohoku
University, installed at the JRR-3M reactor in Japan Atomic Energy Research Institute (JAERI), Tokai. Neutrons with a wavelength of 0.18265 nm were obtained by
the 331 reﬂection of the Ge monochromator. The ND data were collected on thoroughly ground powders by a multiscanning mode in the 2 θ range from 3.0 °to
153.9 °with a step width of 0.1 °and wereanalyzed using a Rietveld reﬁnement program, PREMOS 91, adopting a superspacegroup of C2/m(1p0)s0, where the CdI2type [CoO2] subsystem has C2/m symmetry while the RS-type BL [Ca2CoO3] subsystem has C21/m symmetry. The crystal
structures and interatomic distance plots
were obtained with the use of PRJMS and
MODPLT routines, respectively; both were
implemented in the PREMOS 91 package. Figure 1 shows Co1-O (upper panels) distances in the [CoO2] subsystem andCo2-O (lower panels) distances in the RStype subsystem of (a) x=0 (left) and (b)x=0.02 (right) plotted against t. Amongthese bonds, two apical Co2-O3 bonds are
fairly shorter than the other four equatorial Co2-O2 bonds, ranging from 0.17 to
0.195 nm for x = 0 and from 0.165 to 0.19
nm for x=0.02. The mean distance of Co2O3 bonds for x=0 does not change verymuch as that of Co2-O3 bonds for x=0.02,
i.e., both distances are 0.18 nm. This factindicates that the Co ions in the RS-type
subsystem are not replaced by tetravalentlead ions in the x range from 0 to 0.02. On
the other hand, the four equatorial Co2O2 bonds for x=0 (lower left panel) show
small modulation amplitudes from 0.205
and 0.275 nm, relative to the x=0.02 (lower
right panel) of 0.18 and 0.3 nm. However,
the mean distances of the Co2-O2 bonds ofthe two phases are almost equal, i.e., 0.24
nm. In contrast to the Co2-O bonds, the six
Co1-O1 bonds illustrated in the upper panels remain stable with increasing x, where
the mean distance of the Co1-O1 bonds is
0.19 nm.

Fig. 1. Fig.1 Co1-O distances in the [CoO2] subsystem and Co2-O distances in the RS-type subsystem.

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JAEA-Review 2008-067

1-3-9

Spin Dynamics of Rare Earth Antiferroquadrupolar Ordering Compound HoB2C2
K. Ohoyama(A), H. Onodera(B), E. Matsuoka(B)(A)Institute for Materials Research, Tohoku Univ., (B) Faculty of Science, Tohoku Univ.
The RB2C2 (R=rare earth) compounds,
which have the tetragonal LaB2C2 typestructure with P4/mbm symmetry show
diversiﬁed magnetic properties caused bycoexistence of antiferroquadrupolar (AFQ)
and antiferromagnetic (AFM) interactions.
In particular, DyB2C2 is the ﬁrst tetragonal rare earth compound in which an
AFQ ordering is realised. Since the exact
ground state by crystalline electric ﬁeld under tetragonal symmetry has no degree of
freedom on electric quadrupolar moments,
it was thought that no AFQ ordering canbe realised in the tetragonal rare earth compounds.
On the contrary, we have proved thatsome of RB2C2 are AFQ ordering compounds with higher TQ than other typical AFQ compounds. Thus, to understand necessary conditions of AFQ orderings in rare earth compounds, it is indispensable to clarify characters of the AFQ
ordering in RB2C2. Of the RB2C2 system,
HoB2C2 is particularly unique because of
the following points: (i) the AFQ ordering in HoB2C2 is realised at TQ=4.5K below the magnetic ordering temperature,
TN=5.9K[2], (ii) anomalous magnetic diffuse scattering is observed above TQ up to
2TQ[4].
We expect that the AFQ orderings in
RB2C2 probably yield anomalies of dynamic properties because the lattice andspin systems in RB2C2 must be coupledby the AFQ orderings through the strong
LS coupling. In particular, in HoB2C2,
characteristic diffuse scattering is observed
around the transition temperatures, implying some kind of spin ﬂuctuation. Therefore, to observe magnetic excitations in
HoB2C2, we performed inelastic scatteringexperiments on a single crystalline sampleof HoB2C2 on the triple axis spectrometer HER at the C1-1 beam hole of JRR3-

M of JAERI(Tokai). The collimation condition was g-open-PG ﬁlter-S- Radial -B,
kf=1.550AA-1 with the horizontal focusing
analyzer condition
In the experiments on C1-1, we observed
obvious magnetic excitations at T=1.4K below TQ and TN around the (1,0,0) position
which is the magnetic zone center. Figure shows the energy spectrum at (1,0,0)
in HoB2C2 at T=1.42K . As shown in theﬁgure, an obvious magnetic excitation wasobserved around 1meV, which shows theenergy gap at the zone center. Moreover,in this experiments, we newly found higher
magnetic excitation around 3meV. On theother hands, we observed no quasi-elastic
scattering within the resolution limit evenin the temperature region where the characteristic magnetic diffuse scattering is observed[4]. This indicates that the characteristic magnetic diffuse scattering in HoB2C2
is mainly due to elastic scattering not tosome spin ﬂuctuations.
References[1] H. Yamauchi et al.: J. Phys. Soc. Jpn. 68(1999) 2057.
[2] H. Onodera et al.: J. Phys. Soc. Jpn. 68(1999) 2526.
[3] K. Kaneko et al.: Phys. Rev. B. 68 (2003)
012401.
[4] A. Tobo et al.: Physica B 312-313 (2002)
853-854.

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JAEA-Review 2008-067

1-3-10Magnetic structure study of the multi-step metamagnet CeIr3Si2
Y. Muro(A), K. Motoya(A), K. Shigeto(B), T. Takabatake(B)(A)Department of Physics, Faculty of Science and Technology, Tokyo University of
Science,(B)ADSM, Hiroshima University
CeIr3Si2 crystallizes in the orthorhombic
ErRh3Si2-type structure (Imma, No. 74).
The lattice parameters are a=7.1765 A,
b=9.7274 A and c=5.5971 A. The resultsof electrical resistivity, speciﬁc heat andmagnetic susceptibility measurements reveal that CeIr3Si2 is a Kondo-lattice compound showing two successive magnetictransitions at 4.1 K and 3.3 K. Below 3.3
K, the isothermal magnetization of polycrystalline sample displays four-step metamagnetic transitions at 0.6 T, 0.9 T, 1.2 T
and 1.43 T. It should be needed to obtainthe magnetic structures between each transition ﬁeld in order to study the origin of
multi-step metamagnetism of CeIr3Si2. We
have been performing the elastic neutron
scattering of powder sample and singlecrystal one.
At ﬁrst, we measured the powder neutron diffraction at 300 K, 10 K, 3.7 K and
1.5 K under 0 T. The powder pattern at 300
K agrees with the orthorhombic ErRh3Si2type structure as shown in Fig.1(a). At 1.5
K, we observed a possible magnetic Bragg
peak at 2theta=25.8 degree as shown in
Fig.1(b).
We also made a measurement using asingle crystal sample. No magnetic reﬂections have been observed on the principal
indices at 0.7 K. Therefore, we will perform futher measurements including noninteger indices.

Fig. 1. Powder neutron diffraction patterns of
CeIr3Si2.

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JAEA-Review 2008-067

1-3-11

Investigation of the magnetic excitations in high-TC cuprates Bi2.1 Sr1.9 CaCu2 O8+δM. Matsuura1 , K. Hirota1 , H. Eisaki2 , N. Kaneko2 , Y. Yoshida2 , A. Iyo2 and C.-H. Lee2
1 Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106
2 AIST, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568(3π,3π) (open circles). If the peak at E =36 meV and (π,π) is magnetic in origin,
the peak intensity should follow the squareof magnetic form factor of Cu2+ which decreases from 0.43 at (π,π) to 0.19 at (3π,3π).
Further investigation of the magnetic excitations in Bi2212 will be required by using
polarized neutrons.
References[1] S. M. Hayden et al., Nature 429, 531 (2004).
[2] J. M. Tranquada et al., Nature 429, 534(2004).
[3] H. F. Fong et al., Nature (London) 398, 588(1999).



1000

500




0

-500

-1000

Open-80'(28mm)-S-PG-80'-Open, ki=3.86
20

30

40

50


8000

The interplay between antiferromagnetic(AF) spin ﬂuctuations and superconductivity is the central issue in the physics ofhigh-transition temperature (high-Tc ) superconductivity because of the persistent
AF ﬂuctuations in the superconducting
phase. Recently, similar magnetic spectra have been reported from two families of high-Tc materials, La2− x Bax CuO4
and YBa2 Cu3 O6+ x [1, 2], which includes
a characteristic hourglass magnetic excitation. If spin ﬂuctuations are important
for the mechanism of high-Tc superconductivity, they should be universal for all
copper-oxide systems. Although two families of high-Tc materials show the similarmagnetic excitation spectrum, it is still not
clear whether they are the universal feature of all cuprates. One way to resolve
this issue is to investigate another high-Tc
system Bi2.1 Sr1.9 CaCu2 O8+δ (Bi2212). We
explored the magnetic spectrum in optimally doped Bi2212.
Single crystalsof Bi2212 were grown using travellingsolvent-ﬂoatingzone method.
Neutronscattering experiments were performed on
the triple-axis spectrometer PONTA installed at the JRR-3 Reactor of the JAEA.
We have aligned 19 single crystals on Al
plates. The total mass of aligned crystals
is 16.5g (2.5cc), which is 40 times as large as
the crystal used in the previous report[3].
Our experiment shows a clear enhancement of the scattering at (π,π) around36 meV below Tc , however, we could not
conﬁrm the Q dependence expected from amagnetic peak. Figure 1(a) shows the difference spectrum at T = 1.2 K (T < Tc )and 100 K (T > Tc ) at Q =(1/2 1/2 -14) asa function of energy. Although the difference spectrum have a peak around 36 meV,the peak at (π,π) in the Q-scan (shownby closed circles in Fig.1(b)) disappears at
(h h -14)(h-1 h-1 -14)

7000

6000

5000

4000

0.2

0.3

0.4

0.5

0.6

0.7

0.8



Fig. 1. a) Difference spectrum of constant-Q scan at(1/2 1/2 -14) at T = 1.2 K (T < Tc ) and 100 K (T >Tc ). b) constant-Energy spectra at h̄ω = 36 meVwith (hh-14) and (h − 1 h − 1 -14).

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JAEA-Review 2008-067

1-3-12Evolution of spin gap structure in underdoped LSCO
M. Kofu1 , M. Fujita2 , and K. Yamada2
1 Univ. of Virginia, 2 IMR Tohoku Univ.
Neutron scattering studies for highTc cuprates have revealed that a welldeﬁned gap opens at low temperaturein the energy spectra, which is called“spin gap”, in LSCO (La2− x Srx CuO4 ) andYBCO (YBa2 Cu3 O6+y ). As for LSCO, thespin gap is observed only around the optimum doping concentration 0.15 ≤ x ≤0.18 [1]. On the other hand, the spin gap
of YBCO appears in the wide underdoped
region 0.5 ≤ y ≤ 0.95 [2]. The invisibility of spin gap in underdoped LSCO is alongstanding issue. To solve the issue, wehave carried out a systematic series of inelastic neutron scattering experiments on
single crystals of LSCO with x lower than
optimal doping.
Single crystals of LSCO with x = 0.125,
0.13, 0.135, 0.14, 0.15 were grown by atraveling solvent ﬂoating zone method.
For these crystals, we estimated the superconducting transition temperature Tc
by the shielding signals and the Sr concentration x by the inductively coupledplasma (ICP) analysis. The values of x and
Tc are summarized in Table. 1 and are almost consistent with the previous results.
Neutron scattering experiments were performed with the triple-axis spectrometer
TOPAN installed at JRR-3M. We selected
the ﬁnal energy of 13.5 meV with the horizontal collimator sequence of 40� -30� -30� 80� . In order to gain sufﬁcient intensity, we
mounted single crystals with total weightof more than 2.5 cc (=17 g) for each concen-

tration.
In the low energy region (ω ≤ 10 meV),the spin excitation appears at incommensurate (IC) positions Q = ( 12 ± δ 12 0), ( 121
2 ± δ 0) in the high-temperature tetragonal(HTT) notation. Figure 1 shows the energy
spectra of the dynamical magnetic susceptibility χ�� ( Qδ , ω ) at the IC peak position
Q = Qδ below 10 K. As for x ≥ 0.135,
the clear spin gap were observed and its
structure is almost unchanged. While, forx = 0.125 and 0.13, the spectrum shows an
upturn behavior around 3 meV. This sudden change of the spectrum around x =0.13 indicates that the low-energy additive
state appears with keeping the gap structure in x ≤ 0.13. In addition, we foundweak elastic magnetic peaks for x = 0.13,
and the peaks becomes sharp and strong
for x = 0.125, which is coincident with theappearance of the additional state. Therefore, the spin gap appears robust in 0.125 ≤x ≤ 0.15 and the low-energy additional
state emerges near x ∼ 1/8.
References[1] C. H. Lee et al.: J. Phys. Soc. Jpn. 69, 1170
(2000).
[2] Pengcheng Dai et al.: Phys. Rev. B 63,
054525 (2001).

Table 1. x and Tc in La2− x Srx CuO4

samplex = 0.15
x = 0.14
x = 0.135
x = 0.13
x = 0.125

Sr x
Tc
0.142(8) 37.6 K
0.130(5) 36.3 K
0.125(5) 33.7 K
0.120(6) 30.9 K
0.115(6) 25.8 K

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Report Number: 116－ 203 －

JAEA-Review 2008-067

1-3-13

Concurrent Measurements of Neutron Diﬀraction and AC Susceptibility in thePressure-Induced Superconducting Ferromagnet UGe2
N. Aso, S, BanA , Yoshiya Uwatoko, Y. HommaB , Y. ShiokawaB , N. K. SatoA
ISSP Univ. of Tokyo, Dept. Phys. Nagoya U.A , IMR Tohoku Univ.B
Saxena et al.
discovered the ferromagnetic (FM) superconductor UGe2 inwhich superconductivity (SC) occurs at
high pressure range between ∼1.0 and ∼1.5 GPa. [1]. In the FM phase, there
seems to be another phase transition or
crossover at Tx (� 32 K at ambient pressure). This characteristic temperature Tx
also decreases with increasing P and becomes suppressed to zero at a critical pressure Px (� 1.2 GPa) where a maximum
SC transition temperature (TSC ∼ 0.7 K)
appears. In our previous work [2], we
presented the temperature dependence ofmagnetic Bragg peak intensities under P by
the neutron diffraction (ND) technique toreveal the nature of the transition at Px . We
have found that the low-T behavior of theuniform magnetization can be explainedby a conventional Stoner model, indicatingthat the FM state below Px can be understood as the perfectly polarized state.
Very recently, Ban et al. reinvestigateda SC phase diagram of UGe2 by AC magnetic susceptibility measurements. [3] They
found that the TSC and volume fraction
show a “M-shaped” structure as a functionof P and suggested that both of two criticalpoints play an important role in the occurrence of SC. These observations are possibly ascribed to the improved homogeneityof the P transmitting medium. To examine the correlation between SC and FM in
UGe2 , we have to performe ND measurements by simultaneously detecting the superconductivity in UGe2 .
A single crystal was grown by Czochralsky pulling method with a tetra-arc furnace. The P was generated by a berylliumcopper pressure cell [4] using Daphne oil
7373 as a P transmitting medium, insteadof Fluorinert FC-75 used in the previous
measurements. [2, 4] Coils of ac susceptibil-

ity measurements are wound in the outsideof the cylinder. The P was estimated by determining the TSC of Sn. Elastic ND experiments has been performed on the tripleaxis spectrometer PONTA (5G) at temperature down to 0.1 K using a dilution refrigerator.
In this study, the pressure was tuned
just above Px , where no FM Bragg peakjump was observe corresponding to Tx .
AC susceptibility measurements successfully show the 80 % volume fraction of SC
at 0.2 K with TSC of 0.58 K in UGe2 . As
shown in ﬁg. 1, there seems little change
in the FM bragg peak proﬁles between at
0.2 K (below TSC ) and 1 K (above TSC ).
References[1] S.S. Saxena et al., it Nature (London) 406(2000) 587.
[2] N. Aso et al., Phys. Rev. B 73 (2006) 054512.
[3] S. Ban et al., to be published in JMMM
(2007) (Proc. of ICM 2006).
[4] N. Aso et al., AIP Conf. Proc. 850 (2006) 705.

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JAEA-Review 2008-067

1-3-14Magnetic order and magnetic excitations in the Kondo-semiconductor CeOs4 Sb12
M. Kohgi1 , K. Iwasa2 , K. Kuwahara1 , N. Aso3
1 Dept. Physics Tokyo Metropolitan Univ., 2 Dept. Physics Tohoku Univ., 3 ISSP-NSL Univ. ofTokyo

scaled by the 3/2 power of the temperature. The experimental result shows thatthe temperature dependence of the magnetic moment associated with the antiferromagnetic order obeys well the 3/4 powerlaw. It was also observed that the intensity of the (1,0,0) magnetic peak decreases
linearly with increasing magnetic ﬁeld anddisappears at about 1 T.
These results suggest that the low temperature ordered phase of CeOs4 Sb12 observed below about 1 K is categorized asthat of the weak antiferromagnetism in theitinerant electron system that is describedby the spin-ﬂuctuation theory by T. Moriya
group. However, the fact of the disappearance of the antiferromagnetic Bragg peakat about 1T is puzzling since the reported
upper critical magnetic ﬁeld of the orderedphase determined by the speciﬁc heat andresistivity measurements is more than 10 T
at low temperatures. Further experimentis necessary to establish overall featuresof the unusual electronic state of the compound.
8000

CeOs4Sb12
Q=(1,0,0)Counts / MN12000 (~8min)

CeOs4 Sb12 is a candidate of a Kondosemiconductor realized in the group of theskutterudite compounds which show various strongly correlated electron phenomena in the same crystal structure. In ourprevious experiments we found that thecompound shows an antiferomagnetic ordering with a tiny magnetic moment of
about 0.05 µB /Ce at the temperatures below about 1 K. We also observed some indication of magnetic excitations with an energy scale of 10 K around the magnetic
zone center in our inelastic neutron scattering measurement down to 0.7 K. The purpose of the present work is to get more detailed information on the nature of the unusual magnetic order and magnetic excitations in the compound. We carried out
an experiment at the cold neutron triple
axis spectrometer C1-1:HER equipped witha large horizontally focused analyzer. The
single crystal sample of 13 g was cooled
down to 80 mK using the dilution refrigerator. Final neutron energy of 5 meV(kf =1.553 Å−1 ) was employed.
In the inelastic scattering measurements,
we observed similar inelastic response withthe energy transfer below about 1 meVaround Q=(1,0,0) reciprocal lattice point at
80 mK as those observed in the previous
experiment. However, the signal intensities were very weak and it was difﬁcult
to well characterize them except the features described above from the data obtained within the allocated beam time.
We also measured temperature and magnetic ﬁeld dependencies of the intensityof the (1,0,0) magnetic Bragg peak in order to get useful information about the ordered state below 1 K. Fig. 1 depicts theobserved temperature dependences of thepeak intensities at magnetic ﬁelds of zeroand 0.5 T. Note that the horizontal axis is

7500

0T
0.5 T

7000

6500

6000

0

1

2
T3/2 (K3/2)

3

4

Fig. 1. Temperature dependence of the (1,0,0) peakof CeOs4 Sb12

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-3-15Spin correlations in electron-doped antiferromagnetic ordered phase of
Pr1-xLaCexCeO4
M. Fujita1, M. Nakagawa2, and K. Yamada1
1 Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
2 Department of Physics, Tohoku University, Aramaki, Sendai 980-8578, Japan
High-transition temperature (Tc ) superconductivity mediated by spin ﬂuctuations
is one of central issues in the strongly correlated electron systems. Extensive neutron
scattering measurements on hole-doped
La2− x Srx CuO4 have revealed an evolutionof spin correlation by doping and its intimate relationship with the superconductivity [1, 2]. To understand a novel magnetism in carrier-doped Mott insulatorsand the role in the high-Tc SC mechanism, comparative studies betweeen holedoped and electron-doped systems are indispensable. However, due to the difﬁculty
in preparing superconducting single crystalline samples, experimental studies forelectron-doped system have been far behind compared to those for hole-doped system.
Recent neutron-scattering study revealed the existence of the commensurate
low-energy spin ﬂuctuations in optimally electron-doped Nd1.85 Ce0.15 CuO4
(NCCO)[3] and Pr0.89 LaCe0.11 CuO4 [4].
These observations indicate that the collective spin ﬂuctuations commonly exist
in the SC phase irrespective of carrier
type. However, to investigate the universal nature in the electron-doped systemfurther systematical study is important.
We therefore performed systematic neutron scattering measurements on the
Pr1− x LaCex CeO4 system.
Figure 1 shows the peak proﬁles with ω=3, 5, and 8 meV for
the non-superdonducting sample of
Pr0.93 LaCe0.07 CuO4 (TN ∼100K). Clear commensurate low-energy spin ﬂuctuations
are observed at the antiferromagnetic zone
center as is the case of non-doped mothercompound.
However, the peak-widthis slightly broader than the resolution

limited value. This result suggests thatthe doped electron can affect the spin
ﬂuctuations and reduces the spatial coherence length. Further upon doping, thepaek-width drastically broadens when
the system becomes superconductor andthe broadening of the width continuously
progresses in the superconducting phase,indicating a close relation between the spincorrelations and the superconductivity inthe electron-doped system.
References[1] K. Yamada et al.: Phys. Rev. B 57 (1998)6165.
[2] M. Fujita et al.:Phys. Rev. B 65
(2002)064505.
[3] K. Yamada et al.: Phys. Rev. Lett 90(2003)137004.
[4] M. Fujita et al.: Physica C 392-396 (2003)130.

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JAEA-Review 2008-067

1-3-16

Spin ﬂuctuations in high-temperature-tetragonal phase of
La1.70Sr0.24Ce0.06CuO4
M. Fujita1, M. Enoki2, and K. Yamada1
1 Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
2 Department of Physics, Tohoku University, Aramaki, Sendai 980-8578, Japan
It is known that incommensurate (IC)spin ﬂuctuations in the underdoped
La2− x Srx CuO4 shows a close relation withthe superconductivity[1]. On the other
hand, our neutron-scattering measurement on La1.875 Ba0.125 CuO4 revealed anenhancement of the low-energy spin correlations in the low-temperature-tetragonalphases, in which the superconductivity
is strongly suppressed[2]. Therefore, thesuperconductivity, the spin ﬂuctuations
and the crystal structure are intimately
correlated.
In order to clarify the inherent relation between the spin ﬂuctuations
and the superconductivity without
the effect of lattice distortion, we performed neutron-scattering experiment on
In this system,
La1.70 Sr0.24 Ce0.06 CuO4 .
the bulk structure remains the hightemperature-tetragonal phase with ﬂat
CuO2 planes down to 8K. Since the Ce
ion is introduce as Ce4+ , replacementof La4+ by Ce4+ results into the reduction of one hole Thus, the effective holeconcentration in La1.70 Sr0.24 Ce0.06 CuO4
considered to be 0.18, corresponding toslightly over-doping.
Figure 2 shows constant-energy (ω) spectra for ω=(a) 2 meV, (b) 5 meV and (c)8 meV measured below Tc (=22 K). At 5
meV and 8 meV, well-deﬁned IC peaks
are observed, while no clear magnetic signal was observed at 2meV, indicating an
opening of spin gap in the magnetic excitation spectrum. This observation is consistent with that in the optimally-doped
and slightly overdoped region of LSCO
with 0.14≤ x ≤0.20[3] and quite different
from the spin excitations in the overdoped
LSCO with x=0.25[4] which shows low energy spin excitations at least down to 2

meV. Thus the observed spin excitation in
the La1.70 Sr0.24 Ce0.06 CuO4 is rather close tothat in the optimally-dope sample. Thissimilarity suggests that the doped Ce indeed reduces the hole concentration andthe small lattice distortion in the overdoped LSCO does not affect the spin correlations. Thus, the spin correlations at the
speciﬁc hole concentration of 1/8, whichis strongly inﬂuenced by the lattice distortion, can be investigated in the 6% Cedoped La1.82 Sr0.18 CuO4 without the significant structural effect for the next step.
References[1] K. Yamada et al.: Phys. Rev B 57 (1998)6165.
[2] M. Fujita et al.:Phys. Rev. B 70
(2004)104517.
[3] T. E. Mason et al.: Phys. Rev. Lett. 71(1993)919: C.H. Lee et al.: J. Phys. Soc. Jpn.
69 (2000)1170.
[4] S. Wakimoto et al.: Phys. Rev. Lett. 92(2004)217004.

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JAEA-Review 2008-067

1-3-17Spin correlations in electron-doped antiferromagnetic ordered phase of
Pr1-xLaCexCeO4
M. Fujita1, M. Nakagawa2, and K. Yamada1
1 Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
2 Department of Physics, Tohoku University, Aramaki, Sendai 980-8578, Japan
High-transition temperature (Tc ) superconductivity mediated by spin ﬂuctuations
is one of central issues in the strongly correlated electron systems. Extensive neutron
scattering measurements on hole-doped
La2− x Srx CuO4 have revealed an evolutionof spin correlation by doping and its intimate relationship with the superconductivity [1, 2]. To understand a novel magnetism in carrier-doped Mott insulatorsand the role in the high-Tc SC mechanism, comparative studies betweeen holedoped and electron-doped systems are indispensable. However, due to the difﬁculty
in preparing superconducting single crystalline samples, experimental studies forelectron-doped system have been far behind compared to those for hole-doped system.
Recent neutron-scattering study revealed the existence of the commensurate
low-energy spin ﬂuctuations in optimally electron-doped Nd1.85 Ce0.15 CuO4
(NCCO)[3] and Pr0.89 LaCe0.11 CuO4 [4].
These observations indicate that the collective spin ﬂuctuations commonly exist
in the SC phase irrespective of carrier
type. However, to investigate the universal nature in the electron-doped systemfurther systematical study is important.
We therefore performed systematic neutron scattering measurements on the
Pr1− x LaCex CeO4 system.
Figure 1 shows the peak proﬁles with ω=3, 5, and 8 meV for
the non-superdonducting sample of
Pr0.93 LaCe0.07 CuO4 (TN ∼100K). Clear commensurate low-energy spin ﬂuctuations
are observed at the antiferromagnetic zone
center as is the case of non-doped mothercompound.
However, the peak-widthis slightly broader than the resolution

limited value. This result suggests thatthe doped electron can affect the spin
ﬂuctuations and reduces the spatial coherence length. Further upon doping, thepaek-width drastically broadens when
the system becomes superconductor andthe broadening of the width continuously
progresses in the superconducting phase,indicating a close relation between the spincorrelations and the superconductivity inthe electron-doped system.
References[1] K. Yamada et al.: Phys. Rev. B 57 (1998)6165.
[2] M. Fujita et al.:Phys. Rev. B 65
(2002)064505.
[3] K. Yamada et al.: Phys. Rev. Lett 90(2003)137004.
[4] M. Fujita et al.: Physica C 392-396 (2003)130.

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JAEA-Review 2008-067

1-3-18A phase transition between the itinerant and the localized f-electron states in theheavy fermion antiferromagnet Ce(Ru0.9Rh0.1)2(Si1-yGey)2
Yoshikazu Tabata, Rtota. Yamaki, Chikahide. Kanadani, Shiho Ohya, Shuzo Kawarazaki
Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043
In the heavy fermion systems, f-electrons
are hybridized with conduction electrons(cf-hybridization), and hence, localized
spins and heavy quasi-particles coexist[1].
This duality of f-electrons can lead an alternation between an itinerant and a localized magnetic orders by changing thestrength of the cf-hybridization in theheavy fermion systems[2,3]. The former
is a spontaneous magnetic polarizationof the heavy quasi-particle band (quasiparticle band regime), whereas the latter isformed by the localized spin via the RKKYinteraction (RKKY-regime).
In the course of searching for such an alternation of schemes of the magnetic order, we have studied the magnetic properties of the pseudo-binary alloy system Ce(Ru0.9Rh0.1)2(Si1-yGey)2. The basematerial Ce(Ru0.9Rh0.1)2Si2 is known as
an archetypal heavy fermion compound
which shows a spin density wave (SDW)transition[4]. By substituting Ge for Si, we
effectively apply negative pressure to the
SDW phase through the lattice expansion, and the magnetic order can be shiftedto the antiferromagnetic order formed by
the localized f-spins(LAF)[3,5]. Recently,
we found a 1st order phase transition between the SDW and the LAF phases in theCe(Ru0.9Rh0.1)2(Si1-yGey)2 system by thesubstitution of Ge for Si[6].
In 2006, we have performed neutron scattering experiments under hydrostatic pressure for Ce(Ru0.9Rh0.1)2(Si1-yGey)2 with
y = 0.30, showing the LAF transition atambient pressure, using the 4G spectrometer installed at the JRR-3M. Figure 1 shows
temperature dependences of integrated intensities of magnetic reﬂections with (a)q1 = (0.344,0,0) and (b) q3 = (0,0,0.358).

The former and the latter reﬂections, theq1- and the q3-reﬂections, correspond to
the LAF and the SDW phases respectively. The ﬁgure shows that only the q1reﬂection is found at ambient pressure.
On the other hand, the q1-reﬂection disappears and the q3-reﬂection appears at highpressure region, P > 0.5GPa. In the intermediate pressure region, 0.30GPa < P <0.5GPa, both the magnetic reﬂections arefound, which indicates the coexistence of
the SDW and the LAF phases. This experimental results under hydrostatic pressure
strongly suggest the pressure induced 1storder phase transition between the SDW
and the LAF phases, reproducing very
nicely the chemical pressure effects for theCe(Ru0.9Rh0.1)2(Si1-yGey)2 system.
[1] K. Miyake and Y. Kuramoto, Physica B
171 (1991) 20.
[2] S. Quezel, P. Burlet, J. L. Jacoud, L.
P. Regnault, J. Rossat-Mignod, P. Lejay,
J. Flouquet, J. Magn. Magn. Mater. 76-77(1988) 403.
[3] K. Watanabe, Y. Uwatoko, Y. Tabata,H. Kadowaki, C. Kanadani, T. Taniguchi,
S. Kawarazaki, J. Phys. Soc. Jpn. 72 (2003)
1751.
[4] S. Kawarazaki, M. Sato, H. Kadowaki, Y.
Yamamoto, Y. Miyako, J. Phys. Soc. Jpn. 66(1997) 2473.
[5] Y. Tabata, K. Watanabe, T. Taniguchi, C.
Kanadani, S. Kawarazaki, Physica B 329333 (2003) 508.
[6] Y. Tabata et al., to be published.

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JAEA-Review 2008-067

Integrated Intensity (arb. units)

4.0
3.5

(a) q1-reflection

P=0.00GPa
0.30GPa
0.45GPa
0.80GPa(b) q3-reflection

P=0.00GPa
0.30GPa
0.50GPa
0.80GPa

3.0
2.5
2.0
1.5
1.0
0.5
0.0

Integrated Intensity (arb. units)

4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0

2

4

6

8

10

Temperature (K)Fig. 1. Temperature dependences of the integrated
intensities of magnetic reﬂections with (a) q1 =(0.344,0,0) and (b) q3 = (0,0,0.358) under hydrostaticpressure.

－ 210 －

JAEA-Review 2008-067

1-3-19Charge and magnetic order in La2-xSrxCoO4
K. Horigane, T. Uchida, H. Hiraka*, K. Yamada* and J. Akimitsu
Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara229-8558; *Institute for Materials Research, Tohoku University, Sendai 980-8577
Layered cobaltate La2-xSrxCoO4 (LSCO)
has been studied for the spin state transition from high-spin (HS) to intermediate
spin (IS). Moritomo et al. observed significant reduction of resistivity with increasing x beyond 〜0.7, and reduction of theeffective moment from 4.0 μ B to 2.6 μ
B [1]. They ascribed these changes to atransition of the spin state of the Co3+
ions from the HS (x ≦ 0.6) to the IS (x≧ 0.8), because the double-exchange interaction between HS state Co2+ and IS
state Co3+ ions is expected to stabilize
the IS Co3+ state. On the other hand, Zaliznyak et al. claimed that charge ordering is important to realize the IS state [2].
In the recent neutron experiments, theyreported that the breathing-type modulation is realized in La1.5Sr0.5CoO4. As a result, an eg doublet of dx2-y2 and d3z2r2 orbitals are split. They concluded that
Co3+ ions in La1.5Sr0.5CoO4 are in the
IS state at low temperature, which favors
the Jahn-Teller (JT) distorted charge-order(CO) phase. Our purpose of this study is toclarify the relationship between IS and COphase.
Single crystal of La2-xSrxCoO4 (0.4 ≦ x≦ 0.6) was grown by the TSFZ method, of
which volume was about 1.0 cc each. It was
mounted in a cryostat with the b-axis vertical, allowing to observe the (h0l) reciprocallattice plane. We took a unit cell (√ 2atet ×√ 2atet × c) as twice as the primitive cell
(atet × atet × c). The neutron scattering experiments were carried out on the 3-axis
spectrometer AKANE (T1-2).
The elastic neutron scattering at Q=(1,0,l) is
shown in Fig.1. In the all Sr concentration x,
the structural peaks of checkerboard typecharge order were observed. Comparing
with the recent neutron experiment of La2xCaxCoO4 (LCCO), the peaks were diffu-

sive and not commensurate to the lattice.
The broad peak intensities become large
with increasing l, indicating that out-ofplane strain of oxygen is larger than inplane strain. From l dependence of chargeorder peaks, LSCO is expected to modulate
a apical oxygen, as a result an eg doublet
splitting that generate IS state is realized.
It is expected that oxygen displacement εof LCCO is larger than that of LSCO because of the strong CO peaks of Ca system. Moreover, the CO correlation length of
LCCO is about ﬁve times larger than that of
LSCO system and CO state is realized in awide Ca concentration range. From above
discussion, it is expected that IS state of Ca
system is more stable than that of LSCO
system. In our magnetic susceptibility measurement on LCCO (0.5<x<0.8), intermediate spin state transition was observed atlower concentration comparing with the Sr
system. These neutron and susceptibility
results suggest that charge ordered phase
plays an important role to stabilize the intermediate spin state of Co3+ ions.
Reference[1]Y. Moritomo et al., Phys. Rev. B 55 (1997)
14725[2]I. A. Zaliznyak et al., Phys. Rev. B 64
(2001) 195117

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JAEA-Review 2008-067

1-3-20Rattling in ﬁlled-skutterudite compounds
Koji KANEKO1 , Naoto METOKI1,2 , Hiroyuki KIMURA3 , Yukio NODA3 ,Tatsuma D. MATSUDA1 , Masafumi KOHGI4
1 Advanced Science Research Center, Japan Atomic Energy Agency
2 Department of Physics, Tohoku University
3 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
4 Department of Physics, Tokyo Metropolitan University
in the real space, which reaches roughly
0.5 Å in the full width at half maximum(FWHM). The Pr nuclear density distribution at 8 K becomes sharp, almost isotropic
and gaussian-form, although the width distribution at 8 K of 0.15 Å in FWHM isroughly twice broader than those for Os
and Sb. Note that the highest density of
Pr distribution at 8 K founds at the centerof the cage within an experimental accuracy. These features are far from the simple harmonic model, in other words, thepresent result suggests the strong anharmonicity for the Pr potential in the Sb cage.
[1] M. B. Maple et al.: J. Phys. Soc. Jpn. 71(2002) Suppl. pp. 23.
[2] F. Izumi and R. A. Dilanian, ”Recent Research Developments in Physics,” Vol. 3, Part
II.
40

PrOs4Sb12

x10

d 8 K ( 103 fm / Å3 )

3

2

2

8K
R. T.

1

30

0
-0.5

0

0.5

20

1

d RT ( fm / Å3 )In clathrate compounds, structure anddynamics of a guest ion inside a large hostcage play an important role for those physical properties. Filled-skutterudite compounds are supposed to belong to suchfamily, where a rare-earth ion locates ina relatively large pnictogen icosahedral
cage. Recently one of the skutterudite
compound PrOs4 Sb12 was reported to bea heavy fermion superconductor[1]. The
non-magnetic singlet ground state and theexistence of the ﬁeld-induced antiferroquadrupolar order suggest a novel mechanism for the formation of heavy quasiparticles and unconventional superconductivity in PrOs4 Sb12 . In order to clarify thedetailed structure without a model, single crystal neutron diffraction experiments
were carried out and obtained data wereanalyzed by using the maximum entropy
method (MEM).
Single crystal neutron diffraction experiments have been carried out on the fourcircle diffractometer FONDER, installed at
the T2-2 beam port in the guide hall of theresearch reactor JRR-3. The data were taken
at 8 K and room temperature by using thesingle crystal of PrOs4 Sb12 with ∼40 mm3 .
The obtained Bragg reﬂection intensity was
analyzed by maximum entropy method(MEM) with a software PRIMA[2].
A space- and time-averaged nuclear density distribution including a thermal vibration can be obtained by the MEM analysis. Figure 1 shows a cross-sectional drawing of Pr distribution along the [1 0 0] direction for 8 K and room temperature. The
results unveil a widely spread Pr distribution in the Sb cage at room temperature.
The Pr density distribution is almost ﬂat

10

0

0
-0.5

0
(x 0 0)0.5(Å)

Fig. 1. Cross-sectional drawing of Pr distribution in
PrOs4 Sb12 along the [1 0 0] direction.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-3-21

Magnetic structures of PrA2Mn2O7 (A=Ca, Sr)
Y. Tokunaga(A), M. Uchida(A), T.J. Sato(B), T. Arima(A, C), and Y. Tokura(A, D)(A)ERATO-SSS, JST, (B)ISSP, Univ. of Tokyo, (C)IMRAM, Tohoku Univ, (D)Dept. Appl.
Phys, Univ. of Tokyo(1996).
[3] Y. Moritomo et al., J. Phys. Soc. Jpn. 68,
631 (1999).
4

Intensity (counts/40 sec.)

1.4x10-2

3.0x10(a)

PrCa2Mn2O7(1/4 1/4 3)t

1.2

0.8

0.4

1.5

0.2

TN

TCO2 TCO1

0.0
100

200

300

1.0
400

Temperature (K)

5

6x10

2.0

H=5 kOe
H||ab

0.6

0

(b)
PrSr2Mn2O7

5

-2

8x10

A-type
(003)

4

6
3
H=5 kOe
H||ab

2

1

(201)
(x20)

4

Magnetization (PB/Mn)

Intensity (counts/20 sec.)

2.5

CE-type1.0

Magnetization (PB/Mn)

Although the competition between
the A- and the CE-type antiferromagphase is reported for
netic (AFM)
LaSr2Mn2O7[1], purely CE-type AFM
phase is not reported so far in the halfdoped bilayer manganites system. We
have investigated magnetic structuresof PrCa2Mn2O7 and PrSr2Mn2O7. Single crystals of PrCa2Mn2O7 (with twin
structures because of the orthorhombic
distortion) and PrSr2Mn2O7 were prepared by a ﬂoating-zone method. Neutron
scattering measurements were carriedout on the triple axis spectrometer GPTAS in the JRR-3M. We measured on thepseudo-tetragonal (hhl) reciprocal zone for
PrCa2Mn2O7 and the (h0l) reciprocal zone
for PrSr2Mn2O7.
Figure 1(a) shows the temperature dependence of the bulk magnetization measured
by a SQUID magnetometer and the peakintensity at Q=(1/4, 1/4, 3), which is corresponding to a measure of the order parameter of CE-type AFM. With decreasing the temperature, the peak intensity at
Q=(1/4, 1/4, 3) increases monotonicallybelow T N=143 K, while that at the Q=(0,0, 3) (characteristic of the A-type AFM) is
negligibly small (not shown). On the other
hand, the monotonic increase of the peakintensity at the Q=(0, 0, 3) with decreasing
temperature is observed for PrSr2Mn2O7(See Fig. 1(b)).
These results indicate that the magnetic structure of PrCa2Mn2O7 is the CEtype AFM down to the lowest temperature, while that of PrSr2Mn2O7 is theA-type AFM, similarly to the case of
NdSr2Mn2O7[2][3].

2

TN

0
0

100

200

300

400

Temperature (K)Fig. 1. Temperature dependence of in-plane components of the bulk magnetization and peak intensities at selected positions for (a)PrCa2Mn2O7 and(b)PrSr2Mn2O7.

[1] M. Kubota et al., J. Phys. Soc. Jpn. 68,
2202 (1999).
[2] P.D. Battle et al., Phys. Rev. B 54, 15967
Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-3-22Crystalline Electric Field Excitations in Pr3Pd20Ge6
H. Amitsuka(A), T. Wakabayashi(A), I. Kawasaki(A), M. Yokoyama(B), and N. Aso(C)(A)Graduate School of Science, Hokkaido Univ., (B)Faculty of Science, Ibaraki Univ.,(C)ISSP-NSL, the Univ. of Toky
Pr3Pd20Ge6 crystallizes in the cubic
Cr23C6-type structure (Fm3m) with two
inequivalent Pr sites of 4a (Oh) and 8c(Td). The previous experiments of inelastic neutron scattering (INS) [1] andhigh-ﬁeld magnetization [2] suggested
that the crystalline-electric-ﬁeld (CEF)
lowest level of the Pr 4f electrons is thequadrupole doublet Gamma3 for both the
4a and 8c sites. On the other hand, theelastic constant c44 was found to show
a 1/T behavior at low temperatures [3],which cannot be account for sorely by
the Gamma3 ground state. We also foundthat the magnetic susceptibility of thiscompound shows no tendency of saturation down to 0.1 K, indicating that the 4f
electrons should have a magnetic groundstate in at least one of the Pr sites [4]. From
the detailed CEF analyses on the M(B, T)
and C(B, T) results, we proposed that themagnetic Gamma5 triplet sits at the lowest
level in the 4a site while the G3 doublet is in
the 8c site [4]. This ”two-site” CEF schemesemi-quantitatively well reproduces the
B and T variations of magnetization andspeciﬁc heat, particularly the step-like ﬁne
structures observed in the low-temperature
M(B) curves and a ﬁeld-induced ﬁrst orderphase transition. The energy separations
between the lowlying two levels are estimated as Gamma5(0)-Gamma3(˜0.5 meV)and Gamma3(0)-Gamma5(˜0.3 meV) for 4aand 8c sites, respectively. These excitations,however, are difﬁcult to be distinguishedfrom each other by the energy resolution
in the previous INS measurements. In thepresent project, we reperformed the INS
experiments for a powdered Pr3Pd20Ge6
sample on the triple axis spectrometers
PONTA at 5G beam hole and HER at C1-1of the JRR-3M reactor in JAEA, extending
the energy window up to 15 meV andimproving the energy resolution downto ˜ 0.1 meV, respectively. We have observed signiﬁcant ﬁne structures in the INS
spectra. Their intensities and temperaturedependencies are quantitatively well reproduced by the numerical calculations
based on the two-site CEF model. The CEF
parameters determined here, however, areslightly larger than those obtained fromthe magnetization data, but they give morereasonable ﬁts for C(T). The reanalyses on
the M(B, T) curves are now in progress.
[1] L. Keller et al., Physica B 259-261 (1999)
336.
[2] M. Nakayama et al., Physica B 281&282(2000) 152.
[3] T. Horino et al., Physica B 281&282(2000) 576.
[4] H. Amitsuka et al., J. Phys. Soc. Jpn. 71(2002) suppl. 124.

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JAEA-Review 2008-067

1-3-23High-Pressure Eﬀects in Strongly Correlated 5f Electron Systems
H. Amitsuka(A), K. Matsuda(A), I. Kawasaki(A), K. Tenya(A), M. Yokoyama(B), N.
Tateiwa(C) T.C. Kobayashi(D), S. Kawarazaki(E) and H. Yoshizawa(F)(A)Graduate School of Science, Hokkaido Univ., (B)Faculty of Science, Ibaraki Univ. (C)ASRC,
JAEA, (D)Graduate School of Science, Okayama Univ. (E)Graduate School of Science, Osaka
Univ. (F)ISSP-NSL, The Univ. of Tokyo
ity will be able to be clariﬁed in near future.
Further experimental studies are planningin our group.
[1] H. Amitsuka et al., Phys. Rev. Lett. 83(1999) 5114; J. Phys. Soc. Jpn. 69 (2000)(Suppl. A), p. 5.

URu2Si2Q = (1,0,0)

Intensity (PB2)

In order to obtain a reliable pressuretemperature phase diagram of the heavyelectron (HE) superconductor URu2Si2, wereperformed the ac-susceptibility and elastic neutron-scattering (NS) measurements
by using a small single-crystalline rod (2mm in diameter, 6 mm in length) and a CuBe clamp-type high-pressure cell (P < 1.1
GPa).
We found that at ambient pressure thissample shows the weakest antiferromagnetic (AF) Bragg reﬂections reported sofar, corresponding to the volume-averaged
staggered moment of m ord ˜ 0.011 mB/U.
This implies that the AF signal at the lowP range is irrelevant to HO, and that HO
breaks different symmetries from those forthe high-P AF order. The so-called ”smallmoment antiferromagnetic phase” will be
unlikely to be present as the uniform order.
Under applied pressure, the AF scattering
intensity exhibits a sharp increase at P ˜ 0.7
GPa at low temperatures. The saturation
value of the AF scattering intensity above
0.7 GPa corresponds to m ord ˜ 0.41 mB/U,
which is in good agreement with that (˜ 0.39mB/U) observed above 1.5 GPa in our previous high-P NS measurements [1]. The superconductivity is dramatically suppressedby the evolution of AF phase, indicatingthat the superconducting state does not coexist with the antiferromagnetism, unlike
many other HE superconductors. In otherwords, the intrisic interaction that can mediate the Cooper pairing in this system exists only in the HO state. Since the present
investigations clearly demonstrated that a
volume fraction of the low temperature AF
long range order phase below 0.7 GPa canbe minimized, the intrinsic properties ofthe HO phase, such as the superconductiv-

0.2
0.1
0
0

1.5
10

1.0
20

0.5
30 0

Fig. 1. Overall view of the pressure-temperaturedependence of the integrated magnetic Braggscattering intensity at Q = (1,0,0) in URu2Si2 obtained by using GPTAS at 4G in JAEA. The lines are
guides to the eye.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 185－ 215 －

JAEA-Review 2008-067

1-3-24

Neutron scattering study of Pr0.5Sr0.5CoO3
Y. Oohara(A), M. Kubota(B), and J. Takeuchi(C)(A)NSL-ISSP Univ. Tokyo, (B)IMSS-PF KEK, (C)Fac. Sci. Eng. Shimane Univ.

Pr0.5Sr0.5CoO3

3000

Intensity (arb. units)

(220)

11 K
300 K

5000
4000
3000
2000

(110)

6000
(200)
(220) 5500

Pr0.5Sr0.5CoO3

6000

Intensity (arb. units)

Pr0.5 Sr0.5 CoO3 exhibits metal-insulatortransition at 230 K. Ferromagnetism is also
induced below 230 K. Recently, Mahendiran and Schiffer suggests the existence of
antiferromagnetic order below 100K frommagnetization measurements.
We have perfomed neutron difﬁraction
measurements to explore the magnetic order.
We have performed neutron diffraction
measurements with the ISSP triple-axis
spectrometer HQR installed at the T11
experimental port of JRR-3M in JAEAI(Tokai). We prepare the 0.5 cc crtstal sample and cooled with a 4 He gas closed-cycle
cryostat.
Figure 1 shows powder diffraction patters of 11 K and 300 K. It indicates that theferromagnetic order exists in the low temperature. It also indicates that the structural phase transition exists.
Figure 2 shows temperature dependenceof ferromgnetic Bragg peak and nuclear
peak. It indicates that the ferromagnetic order temperture is 230K nad the phase transition temperature, 120 K.
No antiferromagnetic magnetic peak isobserved. Nevertheless, the ferromgnetic
moments becomes depressed at 120 K. The
structural phase transition may affect magnetic order.
Reference
1) R. Mahendrian et. al: Phys. Rev. B 68
(2003) 024427.

(200)

1000

2500
5000
2000

4500
4000

1500

Tp

3500

0

40

50

60
70
ο
2θ (� )

80

90

Tc
1000

0

50

100

150

200

3000
250

Temperature (K)Fig. 1. Diffraction pattern (Fig.1) and temperaturedependence of Bragg intensity (Fig.2)

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-3-25

Role of the electronic spins in a novel superconductor CeCoIn5
H. Kawano-Furukawa A , S. Ohira-KawamuraB , A. Yoshida A , and H. ShishidoC
A Department of Physics, Ochanomizu University
B Academic and Information Board, Ochanomizu University,
C Department of Physics, Kyoto University
state below 2.8 K. Fig. 1 shows the elastic
neutron scans at q = (1/2, 1/2, l ) for thex = 0.6 system, with l ranging from 0.25 to
0.55. For 0.45 ≤ l ≤ 0.55, the scan at q =(1/2, 1/2, 1 + l ) is shown instead of q =(1/2, 1/2, l ) to exclude Bragg peaks frommosaic. The open and closed circles indicate the results obtained at 5 K and 1.5 K,
respectively. A Bragg peak is observed at
qc = (1/2, 1/2, 1/2), indicative of the appearance of a commensurate AFM phase.
The helical SDW phase, which is observedin the pure CeRhIn5 , with a propagation
vector qh = (1/2, 1/2, 0.297) is alreadyvanished here. Thus, the SC phase coexists
with the commensurate AFM phase. The
present study suggests the signiﬁcant relationship between these two phases.
References

1.5

qc=(1/2, 1/2, 1/2)

[1] H. Hegger et al.: Phys. Rev. Lett. 84 (2000)
4986.
[2] W. Bao et al.: Phys. Rev. B 62 (2000) 14621;
Phys. Rev. B 67 (2003) 099903(E).
[3] W. Bao et al.: Phys. Rev. B 65 (2002)
100505(R).

Intensity (counts/sec)

A series of CeMIn5 (M = Rh, Co andIr) has the highest superconducting (SC)transition temperature Tc = 2.3 K forheavy fermion materials. Such a highSC transition temperature can be realized
by strong antiferromagnetic (AFM) ﬂuctuations. Pure CeRhIn5 exhibits an incommensurate AFM phase below TN = 3.8 K, withthe modulation of qh = (1/2, 1/2, 0.297).[1,2, 3] In this phase, a helical spin density
wave (SDW) state is suggested to appear.
It is expected that a quantum critical point(QCP) exists at x ∼ 0.75 with strong magnetic ﬂuctuations, and the AFM phase vanishes here. On the other hand, the superconductivity appears in x ≥ 0.4. Therefore, the SC phase in this family lies near
the QCP, and coexists with the AFM phasein the intermediate x region. In order tounderstand the role of the magnetic spins
for the superconductivity in these systems,
we performed neutron scattering measurements on CeRh1− x Cox In5 .
Single crystals of CeRh1− x Cox In5 withx = 0.3, 0.4, 0.6, 0.7 and 0.75 were prepared. Elastic and quasi-elastic neutron
scattering experiments were carried out at
4G (GPTAS). (hhl) was selected as the scattering plane. The x = 0.3, 0.4 and 0.6
samples were cooled down to 1.5 K by using a 4 He cryostat, and the x = 0.7 and0.75 ones were cooled down to 0.7 K witha 1K cryostat. The neutron momenta ofk = 3.814 Å−1 and 2.67 Å−1 were selected
for the measurements on the x = 0.3, 0.4
and 0.7 samples and the x = 0.6 and 0.75
samples, respectively.
In the x = 0.7 and 0.75 systems, which
are near the QCP, neither magnetically ordered phase nor the magnetic ﬂuctuation
is observed. On the other hand, the x =0.6 system exhibits a magnetically ordered

1.5 K
5K

1.0

0.5

0.0
0.3

0.4

0.5

l

Fig. 1. Elastic neutron scans for CeRh0.4 Co0.6 In5 .
Open and closed circles indicate the results at 5 K
and 1.5 K, respectively.

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1-3-26Flux Line Lattice in CeCoIn5
H. Kawano-Furukawa A , A. Yoshida A , S. Ohira-KawamuraB , H. ShishidoC , K.
Shirahata A , and S. Konno1
A Department of Physics, Ochanomizu University
B Academic and Information Board, Ochanomizu University
C Department of Physics, Kyoto University
CeCoIn5 is a new heavy fermion superconductor with quasi two-dimensional
electronic structure and the supercon=
ducting transition temperature Tc
2.3 K. Recently the speciﬁc heat[1], ultrasound velocity[2] and NMR[3] measurements pointed out a possibility ofan occurrence of a Fulde-Ferrell-LarkinOvchinnikov (FFLO) phase. In the FFLO
phase, modulation of the magnetic ﬁeld in
the ﬂux line appears along the vortex direction. It is necessary to know the ﬂux line
lattice (FLL) structure before observation of
the FFLO state.
We performed a SANS experiment on
CeCoIn5 at the C1-2 spectrometer (SANSU). The single crystal samples (the average size is 3 × 3 × 0.5 mm3 ) were alignedon the sample holder so that the c-axis isparallel to the neutron beam. A 4 He (orange) cryostat with a 3 T magnet was used,and cool the sample down to 1.6 K. The
magnetic ﬁeld was applied parallel to thec-axis and the neutron beam to make thevortices along this direction. The neutron
wave length of 7.08 Åwas selected, and the
PSD was set to 8 m and 16 m positions.
From a recent report[4], a phase transition from a triangular FLL to a square oneat ∼0.55 T is suggested. However, it is noteasy to observe the FLL in this system, because the absorption factors of Co and In
are so high. Totally 12 scattering spots are
expected to be observed at the nearest position from the origin in the triangular FLL,
because of nonequivalent two directions of
the FLL. On the other hand, only 4 spots
should be observed in the square FLL, presumably with higher intensity. We tried observation of the square one. Fig. 1 shows aneutron scattering intensity as a function of

the radius from the origin on the detector,r, (in pixel) at 1.6 K under 1.5 T. The background has already been subtracted. A
small peak is observed at around 29 pixel.
In this study, we succeeded in the observation of the FLL in CeCoIn5 even undera magnetic ﬁeld of 1.5 T.
References[1] A. Bianchi et al.: Phys. Rev. Lett. 91 (2003)
187004.
[2] T. Watanabe et al.: Phys. Rev. B 70 (2004)
020506.
[3] K. Kakuyanagi et al.: Phys. Rev. Lett. 94(2005) 047602.
[4] L. DeBeer-Schmitt et al.: Phys. Rev. Lett. 97(2006) 127001.

Fig. 1. Neutron scattering intensity at 1.6 K as afunction of the radius from the origin of the detector.
Uniform background has already been subtracted.

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1-3-27Flux Line Lattice Symmetry in MgB2 -type Superconductor CaAlSi probed by
Small Angle Nuetron Scattering
S. Kuroiwa1 , Y. Sugiyama1 , T. Muranaka1 , H. Kawano-Furukawa2 and J. Akimitsu1
1 Department of Physics and Mathematics, Aoyama-Gakuin Univ., Kanagawa 229-8558
2 Department of Physics, Ochanomizu Univ., Tokyo, 112-8610
Since the ﬂux line lattice (FLL) conﬁguration can be dominated by the Fermi surface
property and underlying crystal symmetry,investigations of FLL state play an important role to understand the superconducting mechanism. In this work, we have focused on the superconductivity in a MgB2 type superconductor CaAlSi (CAS).
According to the recent report [1], theCAS possesses two types of multi-stacked
crystal structures, in which a clear ﬁvelayered (5H-CAS) or six-layered (6H-CAS)
superlattice along the c-axis was observed.
On the other hand, we ﬁrst fabricated a nosuperstructured CAS (1H-CAS) with AlB2 like structure [2]. In order to clarify the
relationship between the crystal symmetry,structure of superconducting order parameter and vortex lattice symmetry in threephases of CAS, we have performed the ﬁrst
small angle nuetron scattering (SANS) experiments.
The SANS experiment was conductedby using SANS-U spectrometer installedin JRR-3 at Japan Atomic Energy Agency(JAEA), and single crystal of respecetive
phase with the dimension 7 × 7 × 2 mm3
was used. The mean wavelength of incident neutron beam monochromatized by amechanical velocity selector was set to λn∼ 6.7 Å with resolution ∆λn /λn = 10 %.
Figure 1 shows the representative SANS
diffraction patterns in 6H-CAS (not shown
the data of 1H- and 5H-CAS) at 2 K applied ﬁelds parallel to the crystalline (a) cand (b) a-axes. We found that the hexagonal FLL structure under H �c over the entire temperature/ﬁeld range was observedin the respective phases in CAS, but thatthey exhibit a no sign of reorientation withincreasing temperature/ﬁeld as in multi-

gaped superconductor MgB2 [3]. Meanwhile, only 6H-CAS shows a distortion
with Bragg peaks lying on an ellipse underH � a due to the magnetic penetration depth
anisotropy.
Consequently, we obtained an usual FLL
phase diagram in 6H-CAS expected for theuniaxial conventional superconductor described by London theory. The further
SANS experiments are also needed to determine the comprehensive FLL phase diagram in 5H- and 1H-CAS.
References[1] H. Sagayama, et al.: J. Phys. Soc. Jpn. 75(2006) 043713.
[2] S. Kuroiwa, et al.: Phys. Rev. B 74 (2006)
014517.
[3] R. Cubitt, et al.: Phys. Rev. Lett. 91 (2003)
047002.

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1-3-28Order Parameter of Phase IV in (Ce,La)B6
K. Kuwahara(1), K. Iwasa(2), N. Aso(3), M. Sera(4), F. Iga(4)(1) Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, (2) Department of
Physics, Tohoku University, Sendai 980-8578, (3) Institute for Solid State Physics, Universityof Tokyo, Chiba 277-8581, (4) Department of Quantum Matter, ADSM, Hiroshima University,
Higashi-Hiroshima 739-8530
Cerium hexaboride CeB6 undergoes successive phase transitions from paramagnetic phase (Phase I) to antiferroquadrupolar ordering with a wave vector k =[1/2,1/2,1/2] at TQ = 3.3 K (Phase II)
and to antiferromagnetic ordering with 4k magnetic structure at TN = 2.3 K (Phase
III). This complex magnetic phase diagram
comes from the multipolar degrees of freedom in a Gamma8 quartet ground state of
Ce3+ ion. By substituting La for Ce in thismaterial, one can change the strength of themultipolar interactions. In the La diluted
compound CexLa1-xB6, with decreasing x,
TQ rapidly decreases, while TN slightly decreases. Then, a new ordered state called”Phase IV” appears at x < ˜ 0.8. In Phase
IV, various unusual properties such as thelarge softening of the c44 mode in the ultrasonic measurement, the isotropic cusp in
the bulk magnetic susceptibility, the trigonal lattice distortion along the [111] direction, have been reported. Recently the resonant X-ray scattering experiment (Mannix
et al, Phys.Rev.Lett. 95(2005)117206) andthe theoretical analysis (Kusunose and Kuramoto, J.Phys.Soc.Jpn. 74(2005)3139) havereported that the octupolar ordering with awave vector [1/2,1/2,1/2] occours in Phase
IV. In this case, the superlattice reﬂectionsat (h/2,k/2,l/2) with high Q-vectors are
expected to be detected by neutron scattering because the magnetic form factor ofmagnetic octopole moment exhibits a maximum at a high Q-vector. Therefore wehave performed the neutron diffraction experiment on (Ce,La)B6 in Phase IV.
The large single crystal of B11 99.52%
enriched Ce0.7La0.3B6 was grown by theﬂoating zone method. In this sample of Ce
70%, Phase IV is below ˜ 1.5K. The sam-ple was mounted in a 3He-4He dilution refrigerator with (hkk) as horizontal scattering plane. The neutron diffraction experiment was performed on the thermal neutron triple axis spectrometer TOPAN (6G)
with the incident energy Ei = 41 meV.
We scanned in reciprocal space along themain symmetry directions at lowest temperature of 0.2 K and found the superlattice
reﬂections at (h/2,h/2,k/2). Furthermore
the intensity of the superlattice reﬂections
have a tendency to increase as increasing
Q-vectors. This result is consistent with theoctupolar ordering.

Fig. 1. Proﬁle of Ce0.7La0.3B6 at (3/2,3/2,3/2) at
0.2 K and 2 K

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1-3-29Neutron diﬀraction study of PrFe4P2 under high pressure
K. Kuwahara(1), T. Osakabe(2), D. Kawana(1), K. Iwasa(3), M, Kohgi(1), D. Kikuchi(1),H. Sugawara(4), Y. Aoki(1), H. Sato(1)(1) Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, (2) Neutron
Materials Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195, (3) Department of
Physics, Tohoku University, Sendai 980-8578, (4) Faculty of Integrated Arts and Sciences,
Tokushima University, Tokushima 770-8592
PrFe4P12 undergoes the non-magnetic
phase transition at TA = 6.5 K underambient pressure. By applying pressure,the non-magnetic ordered phase disappears and the insulating phase appears
around Pc = ˜ 2.4 GPa (Hidaka et al.:Phys.Rev.B 71(2005)073102, J.Phys.Soc.Jpn.
75(2006)094709). In order to get the microscopic information about the order parameter in this pressure-induced insulating phase, we have performed highpressure neutron diffraction measurements
on PrFe4P12 single crystals up to 3.8 GPa
at low temperatures under magnetic ﬁelds
using the triple-axis spectrometer TOPAN
at JRR-3M in JAEA and a new hybrid-type
pressure cell which is composed of a large
sapphire anvil and a tungsten carbide anvil(Osakabe et al., International Conference
on Magnetism, Kyoto, Japan, 2006 [PHYSICA B, in press]). The pressure cell was set
inside a superconducting magnet with the[0,0,1]-axis vertical to the (h,k,0) scattering
plane.
We have observed the distinct magnetic
Bragg peak with a wave vector q =(1,0,0)
in the insulating phase above Pc. Figure 1(a) shows the proﬁle of the theta-two thetascan around (1,0,0) under 3.8 GPa. The superlattice peak at lowest temperature 1.6 K
corresponds to an antiferromagnetic longrange order characterized by q = (1,0,0)
with the large magnetic moments of about
2 mB/Pr along the [0,0,1] direction. The result indicates that the 4f electronic statesof Pr ions under the cubic crystal ﬁeld aremagnetically degenerate in low energy region. By measurements of the temperatureand magnetic ﬁeld dependences of the antiferromagnetic peak, as shown in Fig. 1 (b),furthermore, we found slight but distinct
anomalies below about 4 K in the insulating phase, suggesting some change of themagnetic structure around 5 K.

Fig. 1. (a) antiferromagnetic Bragg reﬂection at(1,0,0) under 3.8 GPa and (b) the temperature dependence of the (1,0,0) antiferromagnetic peaks
in several magnetic ﬁelds under 3.8 GPa in thepressure-induced insulating phase of PrFe4P12.

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1-3-30Magnetic and electronic nature of shandite-type type metallic ferromagnet
Sn2 Co3 S2 and its related compounds with Kagome lattices
Masanori Matoba, Atsushi Umetani, Eiji Nagoshi and Takashi Kubodera
Center for Applied Physics and Physico-Informatics, Keio University
Pyrite- and shandite-type transition
metal disulﬁdes are both minerals that canbe artiﬁcially synthesized. While Pyritetypes of MS2 (M=Fe, Co, Ni,etc.) havebeen the subject of the intense researchdue to their variety of interesting physicalproperties [1, 2], few studies have been
made of shandite-type M3 A2 S2 (A=Sn, Pb,
In, and Tl; M=Co, Ni, Rh and Pd) [3, 4]
with two-dimensional Kagome lattices.
Earlier studies report that shandite-type
Co3 Sn2 S2 is a metallic ferromagnet with
TC (=177K), and that Ni3 Sn2 S2 is a paramagnetic metal [3, 4]. In a solid solution of ferromagnetic metal CoS2 (TC=120K) and an antiferromagnetic MottHubbard insulator NiS2 , ferromagnetism
is gradually suppressed with Ni substitution [2]. However, the detailed Ni substitution effect in (Co1− x Nix )3 Sn2 S2 with 2D Kagome latticesnot has been examined
and the electronic nature is not clear. In
this report, we discuss the hitherto unknown electrical and magnetic propertiesfor (Co1− x Nix )3 Sn2 S2 [5] in comparison
with Co1− x Nix S2 .
Polycrystalline (Co1− x Nix )3 Sn2 S2 samples were carefully prepared by a solidstate reaction method in a evacuated quartz
tube and characterized by powder x-ray
diffraction (XRD), Rietveld reﬁnement using the Rietan 2000 [6], and x-ray photoemission spectroscopy (XPS). Electricalresistivity was measured at 10-300 K by
the conventional dc four-probe technique.
DC magnetization was measured by a superconducting quantum interface device(Quantum Design, MPMS) at 10-300K.
Neutron powder diffraction (NPD) patterns were obtained with Kinken powder
diffractometer [7] for high efﬁciency andhigh resolution measurements (HERMES)
installed at the T1-3 beam hole of the guidehall at the Japan Research Reactor 3M (JRR3M) in Japan Atomic Energy Research Institute (JAERI).
Figure 1(a) shows the temperature dependence of magnetic susceptibility (χ)
for (Co1− x Nix )3 Sn2 S2 in ﬁeld cooled (FC)conditions. Co3 Sn2 S2 shows the ferromagnetic transition at 178K, which almost
agrees with previous work [4]. With increasing Ni concentration (x), the magnitude of χ and TC are gradually decreased
as Co1− x Nix S2 [2], and ferromagnetism issuppressed above x = 0.2. However,unlike in the case of Co1− x Nix S2 , there isno antiferromagnetic phase throughout thefull range of composition. This Ni substitution effect indicates that the ferromagnetism on Kagome lattices originates froman exchange split of the Co 3d orbital, so
substitution of Ni, which has one more
electrons than Co, increases the number ofelectrons in the 3d orbital and suppresses
the ferromagnetism on Kagome lattices.
As shown in the inset in Fig.1(a), themagnetization does not saturate up to 5.5T
at 10K, unlike CoS2 . From the M-H curve
we can roughly estimate a small saturation moment (ps ) of 0.2µB per Co atom
(which is slightly smaller than previous
data (0.29µB ) [4]), while in CoS2 ps is
0.85µB .
(Co1− x Nix )3 Sn2 S2 are metallic withroom temperature resistivities (ρ) of
10−3 ∼10−4 Ωcm and show a kink in resistivity at TC , as shown in Fig.1(b). While,a hump at TC appears in CoS2 , which has
certain degree of localized moment.
The unsaturated magnetization, a small
saturation moment, and the absence of ahump in resistivity indicate that Co3 Sn2 S2
is an itinerant weak ferromagnet. Thesephenomena are different from those ofCo1− x Nix S2 , in which ferromagnetism is

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JAEA-Review 2008-067

also gradually suppressed with Ni substitution that develops antiferromagnetism,
and the end member compound NiS2 is a
Mott-Hubbard antiferrmagnetic insulator.
While, the inverse susceptibility of
Co3 Sn2 S2 can be ﬁtted to the Curie-Weisslaw above TC ; from this ﬁt, we obtain peff
= 0.96 per Co. Figure 1(c) shows RhodesWolfarthplots that plot TC and pc /ps (pc =√2
1 + pe f f − 1) for metallic ferromagnets[7] K. Ohoyama et al., Jpn. J. Appl. Phys. 37,
3319 (1998).
[8] P. Rhodes and E. P Wohlfarth, Proc. Roy.
Soc. A273, 247 (1963).
[9] K. Shimizu, et al, J. Phys. Soc. Jpn. 59, 305(1990).
[10] A. Mielke, J. Phys. A24, 3311 (1991); ibid.
A25, 4335 (1992); Phys. Lett. A174, 443(1993).

following Curie-Weiss law. The value of
pc /ps is 1.9 for Co3 Sn2 S2 and 1.8 for CoS2
(pc /ps ∼= 1 for localized moment system).
According to the Rhodes-Wolfarth scheme,
Co3 Sn2 S2 has the same degree of localized
moment as CoS2 . However, from our results, we cannot determine the magnetismof this compound, especially whether it has
a localized moment or not.
Finally we would like to comment the
NPD data at 10 K, 200 K (T < TC )and 300 K (T > TC ) for Co3 Sn2 S2 asshown in Fig.1(d). Indeed, magnetic peaks
originated from magnetic long-range order shows the simple ferromagnetism on 2D Kagome lattices, indicating the Mielke’s
prediction [10] that the ground states of
Kagome lattices based on the Hubbard
model is only one and exhibits the simple ferromagnetism in a ﬁnite range of theelectron ﬁlling factor. The next step will
be to reveal differences between the electronic structures of (Co1− x Nix )3 Sn2 S2 andCo1− x Nix S2 and to reveal the electron ﬁlling effect on ferromagnetism on the 2-D
Kagome lattices.
References[1] J. A. Wilson and A. D. Yoffe, Adv. Phys.
18, 193 (1969).
[2] S. Ogawa, J. Appl. Phys. 50, 2308 (1979).
[3] S. Natarajan et al, J. Less. Common. Metals
138, 215 (1988).
[4] H. Rosner, R. Weihrich, and W. Schnelle,
abstract of 2005 APS March Meeting(March 21-25, 2005, Los Angeles).
[5] T. Kubodera, H. Okabe, Y. Kamihara, and
M. Matoba, Physica B378-380, 1142 (2006).
[6] F. Izumi and T. Ikeda, Mater. Sci. Forum,
321-324, 198 (2000).

Fig. 1. (a) Magnetic susceptibility and (b) normalized electrical resistivity for (Co1− x Nix )3 Sn2 S2 . (c)Rhodes-Wohlfarth plot [8, 9]. (d) Neutron powder
diffraction data for Co3 Sn2 S2 .

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1-3-31

Mn-substitution eﬀect on spin correlations in La1.90 Sr0.10 CuO4
M. Fujita(1), M. Enoki(2), and K. Yamada(1)(1) Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan(2) Department of Physics, Tohoku University, Aramaki, Sendai 980-8578, Japan
shape excitations observed in the LBCO
and YBCO systems. The substitution of
Mn ions with large magnetic moment may
strongly affect the spin correlations and reduce the energy scale of the excitations.
References[1] J.M. Tranquada et al.: Nature 375 (1995)561.
[2] S. M. Hayden et al.: Nature (London) 375(1995)534.
[3] G. S. Uhrig, et al.: Phys. Rev. Lett. 93(2004)267003, and references therein.
[4] H. Yamase and H. Kohno: J. Phys. Soc. Jpn.
70 (2001)2733, and references therein.
[5] M. Fujita: unpublished data.

Counts/330sec

Counts/320sec

Counts/620sec

La1.90Sr0.10Cu0.99Mn0.01O4,T=40K

Counts/360sec

A recent ﬁnding that magnetic
ﬂuctuations both in an insulating
La1.875 Ba0.125 CuO4 (LBCO)[1] and in asuperconducting YBa2 Cu3 O6.6 (YBCO)[2]have a similar fascinating hour-glass-shapedispersion has attracted much attention
in regard to the nature of magnetic ﬂuctuations in high-Tc superconductors: withincreasing energy ω, two incommensurate
branches disperse inwardly toward (π, π)
and ﬁnally merge at (π, π) at a so-called
resonance energy ω r =40-50 meV. Upon
further increasing energy, the excitations
exhibit an outward dispersion, which
results in an hourglass-shape excitation.
It seems that understanding the origin of
the novel spin excitations holds the key
to understanding the role of the spin correlations in the high-Tc superconducting
mechanism[3, 4].
Quite recently, we have studied
the low-energy spin ﬂuctuations in
La1.90 Sr0.10 CuO4 with and without Mn
doping into Cu sites[5]. We found thatthe incommensurate spin ﬂuctuations
observed in La1.90 Sr0.10 CuO4 become commensurate when 3% Mn ions are doped.
This results suggests that the dispersion
changes into conventional spin-wave likeone and a reduction of ω r by Mn-doping.
To gain further insight into this problem,
we performed neutron-scattering measurements on the intermediate Mn doping sample La1.90 Sr0.10 Cu0.99 Mn0.01 O4 . Figure 1
shows observed constant-energy spectrafor ω=(a) 2 meV, (b) 3 meV, (c) 4 meV and(d) 6 meV at 40 K. The excitations are incommensurate at low energies. However,they emerge into the commensurate (π, π)point as the energy is increases to 3 meV.
At energies higher than 3 meV, the excitations again become incommensurate. Thisfeature strikingly resembles the hourglass-200

ω=6meV(0.5 k 0)

100

0
150

ω=4meV

100
50
0
200

ω=3meV100

0200

ω=2meV
100

0
0.1

0.3

0.5

0.7

0.9

k (r.l.u.)
Fig. 1. Low-energy spin ﬂuctuations for the 1% Mndoped La1.90 Sr0.10 CuO4 .

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1-3-32Magnetism and Superconductivity in RE Ni2 B2 C
H. Kawano-Furukawa A , N. Adachi A , S. Ohira-KawamuraB , H. YoshizawaC ,N. H. AndersenD , and H. TakeyaE
A Department of Physics, Ochanomizu University
B Academic and Information Board, Ochanomizu University
C ISSP-NSL, University of Tokyo
D Materials Research Department, Risoe National Laboratory
E National Institute for Materials Science (NIMS)
RENi2 B2 C (RE is a rare earth or Y) exhibits various physical properties such as
superconductivity (SC) or magnetic order,
by substitution of the rare earth site. In particular, one of them, ErNi2 B2 C, is known
to show the microscopic coexistence of the
SC and weak ferromagnetism (WFM). Another system, TbNi2 B2 C, does not show theSC, while it has a quite similar crystal structure and magnetic property to ErNi2 B2 C.
We have studied the magnetism of this system to understand the coexistence of the
SC and WFM by comparison. The systemshows a spin density wave (SDW) phase
below TN = 15 K and the coexistence of
this phase and a weak ferromagnetic phase
below TWFM = 8 K in the absence of the external magnetic ﬁeld. We have found thatmany magnetic ordered phases appear in
the external ﬁeld from the magnetization
measurement. In the present study, we investigate the magnetic structures for thesephases by the neutron scattering measurement, to complete the phase diagram ofthis system in the magnetic ﬁeld.
The experiment was carried out at the
4G spectrometer (GPTAS). A set of a
4 He cryostat and a transverse ﬁeld magnet was used. The single crystal sample ofTbNi2 B2 C was cooled down to 1.6 K. The
magnetic ﬁeld was applied parallel to the aaxis, which corresponds to the easy-axis of
the system. (h0l) was selected as the scattering plane. Representative ﬁelds where
each phase appears, H = 0.9 T, 1.5 T, 2.1 T
and 2.8 T were chosen.
The neutron magnetic scattering proﬁlesin the (h01) direction in various magnetic
ﬁelds at 1.6 K are shown in Fig. 1. The

magnetic Bragg peaks corresponding to the
SDW phase are observed at q (=11/20a∗ ),3q, 5q and 7q. Their positions are notshifted, as the ﬁeld increases. On the other
hand, the magnetization increases step-bystep, suggesting changes in the spin conﬁguration. This fact implies that the spin
is ﬂipped as the magnetic ﬁeld increases,
without changing the modulation of themagnetic structure. It is expected that nesting of a Fermi surface is not so sensitive tothe magnetic ﬁeld.

Fig. 1. Neutron magnetic scattering proﬁles in the(h01) direction in the magnetic ﬁelds of 0 T, 0.9 T,
2.1 T and 2.8 T at 1.6 K.

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1-3-33Low-energy magnetic excations in a heavy fermion superconducting
antiferromagnet CeRhIn5
N. Aso, H. Miyano, H. Yoshizawa, G. F. ChenA , N. K. SatoA
ISSP Univ. of Tokyo, Dept. Phys. Nagoya U.A
we prepared a lot of large single crystals of CeRhIn5 and succeeded in detecting the dynamical spin susceptibility at the
ISSP/HER spectrometer in the reserach reactor JRR-3/JAEA. Figure 1 shows inelastic neutron scatteirng spectrum at the antiferromagnetic ordering wave vector Q =(0.5,0.5,2.7) at temperatures of T = 1.4 K(below TN ), 10 K and 40 K (above TN ).
Accurate temperature-dependence of the
dynamical susceptibility have shown that,surprisingly, the low-energy magnetic excitations gradually start developing below
40 K (10 times larger than TN ). We are
now continuing to study the overview ofthe low-energy part of its dynamical susceptibility of both CeRhIn5 .
References[1] H. Heeger et al., Phys. Rev. Lett. 84 (2000)
4986; S. Kawasaki et al., Phys. Rev. B 65
(2002) 20504; T. Muramatsu et al., J. Phys.
Soc. Jpn. 70 (2001) 3362.
[2] T. Park et al., Nature 440 (2006) 65.
[3] G. F. Chen et al., Phys. Rev. Lett. 97 (2006)
17005.
250

CNTS/M1420k(~10min)

The interplay between magnetism andsuperconductivity is the interesting andimportant issue on condensed matterphysics. Although it has been considered
to be exlusive over quantum critical point,
it is now widely accepted that both superconductivity (SC) and antiferromagnetism(AFM) coexist in the vicinity of quantum
critical point in the systems of the pressureinduced superconductor CePd2 Si2 , CeIn3 ,and CeRhIn5 [1, 2] and so on after a lotof energetic investigations. Since it, however, is very difﬁcult to establish the coexistence of both two phases under pressure
because of the inhomogeneity of the pressure, there is open to argument if the coexistance is intrinsic. Very recently G.G.
Chen et al. from Nagoya Univ. [3] reported
that high-quality single crystalline CeRhIn5
display the SC at TSC ∼ 90 mK evenunder ambient pressure and its pressuretemperature phase diagram is drasticallyrenewed. These ﬁndings indubitably indicate that the identical f electron plays bothroles of SC and AFM. Therefore CeRhIn5
is a very importance material for the investigations on the coexistance of SC and
AFM. To elucidate the coexistance mechanism of both SC and AFM, it is very useful to perform inelastic neutron scattering
which is a very powerful tool to directly observe the dynamical spin susceptibility ofthe system. The main goal of our study is
to determine the wave vector dependence
and its enegy scale of the dynamical susceptibility CeRhIn5 , and to ﬁnd out the connection between SC and the dynamical susceptibility.
On the other hand, since the Rh andIn nuclei are strong neutron absorbers,
there has been little information on lowenergy magnetic excitations by inelastic
neutron scattering studies. In this work,

Q=(0.5 0.5 2.7)
T=1.4K
T=10K
T=40K

200

150

100

50

0
-2

-1

0

1

2

3

Energy (meV)Fig. 1. Inelastic neutron scatteirng spectrum at
the antiferromagnetic ordering wave vector Q =(0.5,0.5,2.7) as a function of temperature.

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JAEA-Review 2008-067

1-3-34

Crystal structure in a non-centrosymmetric pressure-induced superconductor
CeRhSi3
N. Aso, H. Miyano, H. Yoshizawa, N. KimuraA , T. KomatsubaraA , H. AokiA
NSL-ISSP Univ. of Tokyo, Graduate School Sci. Tohoku Univ.A
Coexistence between magnetism and superconductivity is the central issue in condensed matter physics. Recently noncentrosymmetric heavy-fermion superconductor CePt3 Si [1] and UIr [2] were reported. From the fundamental point ofview of symmetry, the discovery of thesematerials are very surprising because there
are two basic symmetries which are considered indispensable to form Cooper pair:time reversal symmetry and parity. The
former is important for Cooper pairingin any case while the latter is mandatory for pairing in the triplet channel.
Thus there is no right picture for the
non-centrosymmetric superconductivity atpresent.
Kimura et al. [3] discovered another noncentrosymmetric superconductor CeRhSi3 .
Its crystal structure is the BaNiSn3 -type belonging to space group I4mm (No. 107)
without an inversion center. [4] CeRhSi3
exhibits the antiferromagnetic (AFM) ordering below TN = 1.6 K at ambient pressure. By increasing the pressure, TN showsa maximum around 0.7 GPa, then gradually decreases. Superconductivity appears
in a wide pressure range from 1.2 to 2.3
GPa (and more). To determine the magnetic structure of the AFM state, we performed the neutron diffraction measurements using single crystals CeRhSi3 , proving that the longitudinal spin-density wave
state with the incommensurate wave vector Q ∼ (0.215, 0, 0.5) is realized below TN
with a small magnetic moment of 0.16(10)m B /f.u., which indicates that this material
is located in the vicinity of quantum critialpoint (QCP). [5] On the other hand, as far
as we know, there is no information on thelattice parameters and atomic position at
low temperature in this material. Therefore
there is no band structure calculations sug-gesting the nesting vector which directly
connects with the SDW structure.
To determine the crystal structure in
CeRhSi3 at low temperature, we performed
the powder neutron diffraction measurements at the HERMES in JRR-3/JAEA. Figure 1 shows the typical power pattern in
CeRhSi3 at 1.1 K (below TN ). The red solidlines are the obtained data and the blue
broken lines are the calculations. Since themagnetic moment is small, no incommensurate magnetic peak is observed. Futhermore we, unexpectedly, found the unknown second phase in the powder. Thesefeatures are seen in the previous neutron
powder diffraction measurments. [6] Then
unfortunately we can not determine thecrystal structure in CeRhSi3 at low temperature.
References[1] E. Bauer et al., Phys. Rev. Lett 92 (2004), p.
027003.
[2] T. Akazawa et al., J. Phys. Soc. Jpn. 73(2004), p. 3129.
[3] N. Kimura et al., Phys. Rev. Lett. 95 (2005),
p. 247004.
[4] Y. Muro et al., J. Phys. Soc, Jpn. 67 (1998), p.
3601.
[5] N. Aso, H. Miyano, H. Yoshizawa, H.
Kimura, T. Komatsubara, H. Aoki, to be
published in JMMM (2007), Proc. ICM
2006.
[6] A. Krimmel, M. Reehuis and A. Loidl,
Appl. Phys. A 74 Suppl. (2002) p. S695.

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JAEA-Review 2008-067

1-3-35

Neutron scattering study of Nd0.25 Sr1.75 MnO4
Y. Oohara(A), M. Kubota(B), and H. Kuwahara(C)ISSP Univ Tokyo(A), IMS KEK(B), and Sci & Tech Sophia Univ(C)Nd1− x Sr1+ x MnO4 exhibits complicatedmagnetic phases due to orbital order. At
x=0.75, charge order exists below 250 K,
and magnetic order of the antiferromagnetic colinear structure below 150 K.1
We have performed neutron scattering
measurements with the ISSP triple-axis
spectrometer GPTAS installed at the 4G
experimental port and HQR installed at
the T11 experimental port of JRR-3M in
JAEA(Tokai).
We prepared the 0.5 cc crystal sample
and cooled with a 4 He gas closed-cycle
cryostat.
Figure (a) shows temperature dependence of magnetic Bragg intensity. It indicates that magnetic order appears below
150 K, TN1 . There is a hysteresys between
150 K and 75 K, TN2 .
Figure (b) shows that temperature dependence of the magnetic ﬂuctuation. It
has a peak at 75 K. No hysteresys was observed.
Temperature dependence of the magnetcic ﬂuctuation can be attributed to critical slowing down phenomena. It indicatesthat T N2 is the phase transition temperature. Orbital order may set in.
Reference
1) Kimura et. al: Phys. Rev. B 65 (2001)
020407.

5000
dec
inc

Intensity (arb. units)

4000
TN2

3000

2000
TN1
1000

0

0

50

100
150
200
Temperature (K)

250

500
dec
inc

Intensity (arb. units)

400

300
TN2

200

TN1
100

0

0

50

100
150
200
Temperature (K)250

Fig. 1. Temperature dependence of the magnetic
Bragg intensity (Fig.(a)) and magnetic ﬂuctuation(Fig. (b)).

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JAEA-Review 2008-067－ 229 －

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1-4-1

Neutron Diﬀraction Study on the Local Structure around Chloride Ions in Anion
Exchange Resins
Y. Kameda, K. Yamanaka*, Y. Amo, and T. Usuki
Department of Material and Biological Chemistry, Faculty of Science, Yamagata University,
Ymagata 990-8560, *R & D Center, Organo Corporation, Kanagawa 229-0012
Ion exchange resins have wide application in extensive ﬁelds of fundamental
sciences and industries. In order to obtain structural information on the correlation between the cation and the ion exchanging group [1], and on the hydrogenbonded network among water molecules
within the resins [2], neutron diffraction
with isotopic substitution method has frequently been adopted.
In the present report, we describe theresults of neutron diffraction on hydrated
anion exchange resins (AER) containing
35Cl/37Cl isotopically substituted chloride
ions to investigate the environmental structure around the chloride ion which is interacting with the anion exchange group,(CH3)3N-.
Anion exchange resins (Amberlite
IRA402BL, Cl- form) with different
35Cl/37Cl ratios (equilibrated with D2O), I(AER-35Cl)0.0679(D2O)0.9321, 99.0% 35Cl,
and II (AER-natCl)0.0679(D2O)0.9321,
75.8% 35Cl (natural abundance), wereprepared by repeated soaking of the OHform resins by aqueous Na*Cl solutions.
Light water molecules within the resins
were exchanged to D2O in order to obtain
good statistical accuracy of the observed
difference function. The resin beads weresealed in a cylindrical quartz cell (12.0 mm
in inner diameter and 1.1 mm in thickness).
Neutron diffraction measurements werecarried out at 298 K using the ISSP diffractometer 4G (GPTAS) installed at the JRR3M research reactor with an incident neutron wavelength of 1.092(3) A. Beam collimations used were 40’-80’-80’ in goingfrom the reactor to the detector. Scatteredneutrons were collected over the angularrange of 3 < 2 theta < 118 deg. which corresponds to 0.30 < Q < 9.86 1/A. The pre-set time was set to 410s. The total number of observed counts was at least 1100000
counts, and regarded as high as 1800000
counts. Measurements were made in advance for an empty cell, a vanadium rodof 10 mm in diameter, and an instrumental
background. After corrections for the background, absorption and multiple scatterng,
the observed count rates were converted to
the normalized scattering cross section byuse of corrected scattering intensities fromthe vanadium rod.
The ﬁrst-order difference function [3],delta Cl(Q), which involves information on
the local structure around the chloride ion,
was obtained from the numerical difference between scattering cross sections observed for the samples I and II. In theprersent experimental conditions, the observed delta Cl(Q) involves Cl-...D2O andCl-...(CH3)3N- contributions. The distribution function, GCl(r), (Fig. 1) derived
from the Fourier transform of the observeddelta Cl(Q) is characterized by a well resolved ﬁrst peak at around r = 2 A, followed by the second peak appearing at 3 <r < 4 A. These peaks should involve contributions from Cl-...the nearest neighbor
D2O molecules as well as Cl-...(CH3)3Ninteractions. The ﬁrst peak may containboth contributions from Cl-...D(D2O) andCl-...H(CH3) interactions. The former contributes as a positive peak in the distribution function, while the latter should appear as a negative peak. Structural parameters for the Cl-...D2O and Cl-...(CH3)3Ninteractions were determined by the leastsquares ﬁtting analysis of the observeddelta Cl(Q) function. It has been revealed
that the chloride ion is neughboring ona (CH3)3N- group of the ion exchange
resin with the nearest neighbor Cl-...N dis-

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

tance of 3.10(3) A. The average number of
D2O molecules within the ﬁrst hydration
shell of the chloride ion was determined
to be 2.4(1) with the nearest neighbor Cl...D(D2O) distance of 2.25(2) A.
References[1] R. H. Tromp and G. W. Neilson, J. Phys.
Chem., 100 (1996) 7380.
[2] Y. Kameda, K. Yamanaka, M. Sasaki, Y.
Amo, and T. Usuki, Bull. Chem. Soc. Jpn.,
79 (2006) 1032.
[3] J. E. Enderby and G. W. Neilson, ”Water, A Comprehensive Treatiese”, Plenum
Press, New York, (1979), Vol. 6, p. 1.

Fig. 1. Observed distribution function around thechloride ion in the anion exchange resin (solid line).
The Fourier transform of the best-ﬁt of the calculated delta Cl(Q) function (thick broken line).

－ 232 －

JAEA-Review 2008-067

1-4-2

Dynamics of Meso-scale ﬂuctuations in liquid chalcogens near the metal-nonmetaltransition
Y.Ohmasa, K.Fujii, T.Hoshino and M.Yao
Department of Physics, Graduate School of Science, Kyoto University

I ( Q, t)/I ( Q, 0) = Afast exp(−t/τfast )+ Aslow exp(−t/τslow ).

Here Afast and Aslow represent the fraction of the fast and slow components, satisfying Afast + Aslow = 1, and τfast and τslow
are the relaxation times of the fast and slow
dynamics, respectively. From a curve ﬁtting analysis, the relaxation times are estimated as τfast ∼ 0.1nsec and τslow ≥10nsec. The slow component becomesdominant in the low-Q region, and thisprocess may lead to the anomalous soundattenuation.

References[1] M. Yao and H. Endo, J. Non-Cryst.
Solids 205-207 (1996) 85, and references
therein.
[2] M. Yao, N. Itokawa, H. Kohno, Y. Kajihara and Y. Hiejima, J. Phys.: Condens.
Matter 12 (2000) 7323
1
Q=
−1
0.04A
−1

I(Q,t)/I(Q,0)

Liquid Te-Se mixtures exhibit a metalnonmetal (M-NM) transition in a relatively
narrow temperature range [1]. This transition is accompanied by anomalies in thermodynamic properties such as the thermal expansion coefﬁcient and compressibility. Recently, sound attenuation measurements for liquid Te-Se mixtures revealed that there occur dynamic anomalies
in the M-NM transition region [2]. From
the frequency dependence of the soundattenuation coefﬁcient α, their relaxation
time is estimated to be of the order ofnano-seconds. These anomalies may be related to the relaxation between the metallic and non-metallic states in the liquid,
and it is interesting to study the spaceand time-structure of the mesoscale ﬂuctuations. Neutron spin-echo (NSE) is a powerful technique which gives information on
the intermediate scattering function I ( Q, t).
However, to our knowledge, there is no
NSE measurement under such high temperature conditions.
In the present work, we developed a newelectric furnace which can be used for NSE
measurements up to ∼ 600o C. In order not
to disturb the magnetic ﬁeld around thesample, we used non-inductive resistanceheaters. By using this furnace, we measured NSE signals for liquid Te7 Se3 mixture.
Figure 1 shows the intermediate scattering function I ( Q, t)/I ( Q, 0) observed at
490o C. It is noticed that I ( Q, t)/I ( Q, 0) increases with decreasing the wave vector Q.
These data can be expressed by a superposition of two exponential relaxation processes as follows:

0.055A

−1

0.07A

0.5

o

Te7Se3 490 C

0
0

1

2

time [nsec]
Fig. 1. Intermediate scattering function I(Q,t)/I(Q,0)
for liquid Te7Se3 at 490C. The solid lines indicate theﬁtting curves expressed as a superposition of two
exponential relaxation functions.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-4-3

QENS Studies of Fast Molecular Reorientations in Isotropic, Cholesteric, Glassand Crystalline Phases of 5*CB
H. Suzuki(A), N. Sakisato(A), J. Krawczyk(A), A. Inaba(A), T. Kikuchi(B), O.
Yamamuro(B)(A)Osaka Univ., (B)ISSP-NSL, Univ. Tokyo
Chain branching and chirality ofmolecules affect various physical properties substantially, such as the phasebehavior. We have been interested in phaserelation and dynamics of some chiralmolecules that form a liquid crystalline
phase. Here, we report the results obtained
from neutron scattering experiments for
isopentyl cyanobiphenyl (5*CB).
5*CB has a cholesteric phase, whereas
5CB, which is an enantiomer of 5*CB, has anematic phase. The calorimetric measurements as well as the dielectric relaxation
measurements have already been made [1][4]. The isotropic liquid is easily undercooled to form a cholesteric phase, whichis metastable and forms a glass on further
cooling below 210 K. There exist two crystalline phases (metastable and stable). The
dielectric relaxation measurements showedthat the molecular reorientational motion
along the short axis becomes quite slow
near the glass transition temperature of 210
K. The purpose of this experiment was
to investigate the molecular reorientationalmotion along the long axis and the internal
molecular motions.
We performed neutron scattering experiments on 5*CB using the AGNES spectrometer at JRR-3M. The measurements weremade at 350 K, 325 K, 300K, 275 K, and 250
K for the isotropic liquid and at 225 K forthe cholesteric phase with a low-resolution
mode (delta E = 120 micro-eV), and also at
350 K and 300 K with a high-resolution
mode (delta E = 49 micro-eV). As a reference sample, 5CB was also investigated at
350 K and 325 K for the isotropic-liquid andat 300 K for the nematic phase with a lowresolution mode.
First, we assumed that the spectra obtained were convoluted with a delta func-tion (an elastic component) and a Lorentz
function (a quasielastic component). However, the ﬁtting was not quite. Next, we
tried to ﬁt the data with two Lorentz functions, which was actually better. So, we
might have observed the diffusional motion as well as the reorientational motion. The high-resolution spectra were also
ﬁtted well with two Lorentz functions,and the HWHM was similar to that obtained from the low-resolution spectra. The
narrower component can be assigned tothe translational diffusion of the moleculeand the wider component to the reorientational motion, presumably the reorientational motion around its long axis. The
HWHM of the narrow component is plotted against the momentum transfer (Q) to
determine the diffusion constant at eachtemperature. An Arrhenius plot for the diffusion constants gives an activation energyof 15.1 kJ/mol (Fig. 1), indicating that the
diffusion constant does not affected by theisotropic-cholesteric phase transition. For
the wide component, there still remains thepossibility that there is complicated reorientational motions.
The 5CB spectra could also be ﬁtted
by two Lorentz functions. The HWHM of
the narrow component was signiﬁcantly
broader than that for 5C*B, indicating thatthe diffusive motion of 5*CB is slower
than that of 5CB. The activation energies
obtained are very similar for both compounds.
It is also interesting to know the difference in the vibrational DOS among
three phases of 5*CB, the glassy cholestericphase, metastable crystal and the stable
crystal. The heat capacity of the metastable
crystal at low temperature (below 70 K)
was signiﬁcantly smaller than that of the

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

stable crystal, while the metastable crystal
has glass transition at 100 K. The inelastic
incoherent neutron scattering revealed thatthe stable crystal had larger DOS than themetastable crystal at low energies around
1.5 meV, which is consistent to the result
obtained by calorimetry [4].
[1] J. Mayer, J. Krawczyk, M. MassalskaArodz, I. Natkaniec, J. A. Janik, O.
Steinsvoll, Physica B, 371 249-256 (2006)[2] W. Witko, J. Sciesinski, E. Sciesinska, M.
Massalska-Arodz, J. Mayer, R.Dabrowski,
Mol. Cryst. Liq. Cryst. 330, 391 (1999).
[3] J. Mayer, M. Massalska-Arodz, J.
Krawczyk, Mol. Cryst. Liq. Cryst. 366, 211220 (2001).
[4] A. Inaba et al, in preperation.

Fig. 1. An Arrhenius plot of the diffusion constantobtained for 5*CB and 5CB－ 235 －

JAEA-Review 2008-067

1-4-4

Visualization of Density Fluctuation of Supercritical Carbon Dioxide Using Reverse
Monte Carlo Simulation
Takashi Sato, Masaaki Sugiyama1 , Masakatsu Misawa2 , Kei Hamada, Keiji Itoh1 ,Kazuhiro Mori1 , and Toshiharu Fukunaga1
Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
1 Research Reactor Institute, Kyoto University, Osaka 590-0494, Japan
2 Department of Chemistry, Faculty of Science, Niigata University, Niigata 950-2181, Japan
ated until the calculated intensity reproduces the experimental one.
Figure 1 (a) shows a SANS proﬁle ofthe supercritical CO2 at a state of 38 ◦ C,
8.64 MPa, 0.49 g/cm3 . A correlation length
which can characterize the size of cluster inthis state is 16.4 Å. A solid line in the Fig. 1(a) is the calculated scattering intensity obtained by applying the RMC simulation tothe observed one. It can be conﬁrmed thatthe experimental result is well reproducedby the RMC simulation. The real-space image derived from the RMC result is shownin Fig. 1(b). The structure of the density
ﬂuctuation of CO2 molecules can be well
expressed.
(a)(b)
Experiment
RMC

3

250

2

200

10

y/A

I(Q)

It is well known that carbon dioxide(CO2 ) molecules aggregate themselves andmake clusters around a critical point (31.0◦ C, 7.38 MPa, 0.468 g/cm3 ). The aggregate
property is considered to be an important
key for understanding many characteristicfeatures of supercritical CO2 as a solvent.
Therefore, clariﬁcation of the cluster structure in detail is absolutely necessary. Generally, small-angle neutron or X-ray scattering (SANS or SAXS) methods are used forobserving the density ﬂuctuation structureof supercritical CO2 . Although, real-space
information of the cluster is very important
to investigate the structural property of thecluster, it had been difﬁcult or almost impossible to visualize the structure by previous analyzing methods. And so, to accomplish the visualization of the density ﬂuctuation, we have tried to apply a Reverse
Monte Carlo (RMC) simulation to a SANS
data observing the supercritical CO2 .
The SANS experiment was performed
using SANS-U of the Institute for Solid
State Physics, the University of Tokyo. For
measurement, the supercritical ﬂuid (SCF)
system installed at KUR-SANS is used with
modiﬁcation for applying to the SANS-U.
In the RMC simulation, the system consistsof 50 × 50 × 50 cells which are simple cubic of 5.533 Å3 . Up to four CO2 molecules
can be entered in each cell. Initially, themolecules are randomly put into the cells
and then a scattering intensity is calculated.
Next, one of the molecules randomly chosen is moved to another cell and the scattering intensity is also calculated. Whenthe calculated intensity after moving comescloser to the experimental one, this movement is accepted. This procedure is iter-

6
5
4

150
100

3

50
2
2

3

4

5

6 7 8 9

-1

Q/A

0.1

2

50

100

150

x/A

200

250

Fig. 1. (a) Open circles and a solid line indicate
the experimental SANS intensity and the calculated
one by the RMC simulation, respectively. (b) Realspace image of the supercritical CO2 derived fromthe RMC simulation.

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1-4-5

Concentration ﬂuctuations of DMSO-water mixtures
Kanako UEKI, Takeharu FUJINAGA, Satosi NAKAMURA, Koji YOSHIDA, and Toshio
YAMAGUCHI
Fukuoka University
Amyloid ﬁbril formation is now recognized as a phenomenon common to many
proteins and peptides. Amyloid ﬁbrils
are associated with fatal diseases such as
Alzheimer’s, which is caused by misfolding of proteins. Thus, it is important toinvestigate the underlying mechanism of
Amyloid formation for understanding theproperties of Amyloid ﬁbrils and preventing the formation of the ﬁbrils. It was reported that ﬂuoroalcohols and dimethylsulfoxide (DMSO) completely dissolved β
2 -microglobulin amyloid ﬁbrils althougha high concentration [i.e., 80%(v/v)] was
required for DMSO [1]. The dissolution
mechanism is not known, however. It isvery likely that the dissolution of amyloid ﬁbril is related to solvent environment
in these mixtures. The small-angle neutron scattering (SANS) in dimethylsulfoxide (DMSO)-D2 O mixtures of DMSO mole
fractions (0.3, 0.4, 0.5, 0.6, 0.8) was measured at 298 K. A sample was kept in aquartz cell of 1-mm or 2-mm path length.
The distance between the sample and detector was 2 m, corresponding to Q of
0.02 - 0.14 Å−1 . Measurements were also
made for background, an empty cell, andlupolen used for intensity normalization.
For the SANS data, the Ornstein-Zernikeplots were made according to I (Q)−1 = I(0)−1 (1+ξ 2 Q2 ) where ξ is the OrnsteinZernike (OZ) correlation length, and I(0) is
the intensity at Q = 0 Å−1 . The maximum inthe correlation length ξ obtained from theanalysis of SANS data was found at x DMSO
� 0.5. As the correlation length ξ is a measure of concentration ﬂuctuation, the SANS
data also indicate the structural transitionof solvent cluster at this solvent composition. These results are in good agreementwith those obtained from X-ray diffraction[2].

[1] N.Hirota-Nakaoka, et al., J. Biochem.,
134,159 (2003). [2] K. Ueki, ”Structure of
DMSO-Water Mixtures and Synthesis of
Amyloid-like Fibrogenic Peptide” Diploma
thesis of Fukuoka University, March, 2006.

Fig. 1. The OZ correlation length as a function of
DMSO mole fraction for DMSO-D2O mixtures at
298 K.

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JAEA-Review 2008-067

1-4-6

Temperature Dependence of water dynamics in nano-porous material FSM
S. Takata, T. Otomo, S. Setoyama, Y. Fukushima, Y. Inamura, O. Yamamuro
Japan Atomic Energy Agency (JAEA), High Energy Accelerator Research Organization (KEK),
Toyota Central R&D Labs., Inc., The University of Tokyo
In absorption water in the pore ofmesoporous silica such as FSM-16 (Folded
Sheets Mesoporous Materials), brieﬂy, it
can be considered that two kinds of waterfrom which mobility is different exist. One
is the absorbed water beside the pore wall
(mono-layer water) and another is otherabsorbed water in the pore. Especially, themobility of mono-layer water is strictly restricted by the hydrogen bonding to thesurface hydroxyl group. The dynamics ofmono-layer water would be different fromthat of other water.
In order to obtain the activation energy of
the absorption water in FSM16 pore, wehave investigated the dynamics of monolayer water and full-layer water by using
AGNES in the temperature range 150K318K. On the basis of the result of adsorption isotherm of FSM, the absorption
amount of water in the sample was adjusted by steam pressure. The observed
spectra of mono-layer sample were analyzed with the model function, given by the
convolution of a Gaussian and a Lorentzianfunction (L1). For the full-layer sample, thespectra were expressed by the convolutionfunction using double Lorentzian function(L1, L2). Here, L1 and L2 are contributions
from mono-layer and the other water, respectively. To extract HWHM of L2, twoof ﬁtting parameters were ﬁxed. HWHM
values of L1 were ﬁxed to values obtained
from mono-layer measurements. The ratioof the intensity for L1 and L2 was also ﬁxed
in that of the amount of absorption water.
As the resolution function, the spectrum ofsame sample at 150K was used. Fig.1 shows
the temperature dependence of HWHM of
L2 as a function of the squared scatteringvector. This result is well represented byrandom diffusion model shown as solidlines. Fig.2 shows Arrhenius plot of the

diffusion coefﬁcient of the mono-layer andfull-layer sample. Consequently, the values of activation energy of the mono-layer
and full-layer sample were 2.5 and 4.7
kcal/mol, respectively. It is interesting tonote that the tendency of the temperaturedependence of the diffusion coefﬁcient offull-layer water is in good agreement withthat of bulk-water [1].
Reference[1] T.Takamuku et. al. J.Phys. Chem. B 1997
101 5730-5739

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1-4-7

Quesielastic and Inelastic Neutron Scattering Study of Ionic Liquid bmimI
Y. Inamura A , O. YamamuroB , S. HayashiC and H. HamaguchiC
A Quantum Beam Science Directorate,Japan Atomic Energy Agency
B , Institute for Solid State Physics, University of Tokyo
C Graduate School of Science, University of Tokyobe calculated from the temperature dependences of self-diffusion constants from theanalysis of QENS data. The activationenergy of bmimI (16.8 ± 1.2 kJ/mol) is
close to that of bmimCl (15.6 ± 0.7 kJ/mol)and nbmimFeCl4 (16.4 ± 0.9 kJ/mol) at observed time scale. On the other hand, theactivation energy of bmimFeCl4 (12.8 ±0.6kJ/mol) has obviously lower value thanthe others. These results show that theactivation energy is essentially decreased
with an increase of the anion size. We
consider that the high activation energy ofnbmimFeCl4 is due to the dipole interaction between nbmim ion with strong polargroups (-CN).
30x10-3

bmimI (100K)
bmimCl (100K)

25

S(Q,E) [arb.unit]

Room temperature ionic liquids (RTILs)
are interesting materials as green solvents owing to their non-volatility, noncombustibility and so on. In previous
works, we have carried out neutron scattering measurements on bmimCl (proto-typeRTIL) , bmimFeCl4 and nbmimFeCl4 (single component magnetic liquids) to investigate the dynamics related to the originof the low melting temperature. In thisstudy, we have measured quiasielastic andinelastic neutron scattering from 1-butyl-3methyl-imidazolium iodide (bmimI), witch
has an bigger anion than one of bmimCland is suitable to watch the size effect on
dynamics directly. These measurements
were performed on the AGNES spectrometer installed at the cold neutron guide (C31-1) of JRR-3M in JAEA (Tokai).
Figure 1 shows the boson peak of bmimIand bmimCl in glass state at 100K. The
peak position of bmimI appears obviously at lower energy region than that of
bmimCl. This result suggests that the sizeof anion affects the interaction between
molecules in RTILs at glassy state to change
the vibrational mode contributing the boson peak. We carried out the temperaturescan for the elastic neutron scattering intensity of glassy bmimI. This intensity reﬂects the mean-square displacement of thevibrational or diffusional motion of bmim.
The intensity curve has a bent near a glasstransition temperature reﬂecting the onsetof some relaxation phenomenon, e.g. a fastbeta relaxation. This behavior is similar tothat of bmimCl, bmimFeCl4 , nbmimFeCl4
and that of molecular and polymer glasses.
The quasielastic neutron scattering data for
RTILs of bmim group we measured shows
the tendency according to the jump diffusion model. The activation energy can

20

15

10

5

0
0

2

4

6

8

10

Energy Transfer [meV]Fig. 1. Comparison of Boson Peaks of bmimCl andbmimI

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JAEA-Review 2008-067

1-4-8

Quasi-elastic neutron scattering study on diﬀusion dynamics of water molecules intert-butyl alcohol-water mixture
M. Misawa and M. Nakada
Institute of Science and Technology, Niigata University, Niigata 950-2181, Japan
In a previous paper [1], we reported thatthe characteristic behavior of the excess
partial molar volume Ve of 1-propanolwater mixture was interpreted satisfactorily in terms of the hydrophobic hydration of the fractal surface of alcohol clusters. The fraction of the hydrated watermolecules on the fractal surface was determined by means of quasi-elastic neutron
scattering. Tert-butyl alcohol (TBA)-water
mixture is characterized also by the polydisperse mass fractals [2]. Furthermore, thesolution shows the same characteristic behavior of Ve as that of the 1-propanol-water
mixture. The purpose of this study is tomeasure the dynamics of water moleculesof the TBA-water mixture and examine
whether or not the same interpretation of
Ve as applied to the 1-propanol-water mixture is valid for the TBA-water mixture.
Diffusion dynamics of water moleculesin the TBA-water mixture has been measured at 25, 47 and 70 °C by using AGNES(C3-1-1) spectrometer, JRR3M at JAEA. In
order to observe the dynamics of watermolecules, the TBA molecules substituted
partially by deuteron (CD3)3COH and thelight water molecules H2O were used. The
mixtures of TBA content x of 0.0, 0.01,
0.02, 0.04, 0.06, 0.08, 0.10, 0.14 and 0.17 inmole fraction were examined. The dynamical structure factors S(Q,E) in the region ofquasi-elastic scattering have been obtainedin the range of Qe from 0.376 to 2.504 Aˆ-1.
Detailed analysis on the visualized
mesoscale structure of the current solution
suggested that the water molecules in thesolution were classiﬁed into two types atleast: one was the bulk-like state and another was the surface-state restricted to thefractal surface of alcohol clusters. Therefore, the S(Q,E)’s from x=0.01 to 0.10 havebeen analyzed by a linear combination of

the S(Q,E)’s for these two states. The fraction α of water molecules located at thefractal surface and the average number
Nws of water molecules in the surface-state
per TBA molecule (Fig. 1) have been obtained as a function of x. By extrapolating
Nws to x=0, we get the value of 19˜21 forNws. This means that about 19˜21 watermolecules are located on the surface of an
isolated TBA molecule in water. It is conﬁrmed that the anomalous excess partial
molar volume of the TBA-water mixture is
explained reasonably well in terms of α inthe same way as that for 1-propanol-water
mixture [3].
References[1] M. Misawa, Y. Inamura, D. Hosaka andO. Yamamuro, J. Chem. Phys., 125 (2006)
074502.
[2] M. Misawa, T. Sato, A. Onozuka, K.
Maruyama, K. Mori, S. Suzuki and T.
Otomo, to be published in J. Appl. Cryst.
[3] M. Nakada, O. Yamamuro, K.
Maruyama and M. Misawa, submitted
to J. Phys. Soc. Jpn.

Fig. 1. Composition dependence of Nws for TBAwater mixture at 25 °C.

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JAEA-Review 2008-067

1-4-9

Dynamics of Water and Methanol Molecules in Binary Liquid Mixture Conﬁned in
Mesopores of MCM-41.
Shuichi Takahara and Shigeharu Kittaka
Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho,
Okayama 700-0005, Japan
We had investigated dynamics ofwater and methanol molecules in pureliquid conﬁned in mesopores of MCM41 by using quasi-elastic neutron scattering (QENS), and found that both of rotational and translational motions of thesemolecules in MCM-41 become slower compared with those in bulk liquid aroundroom temperature. In the present study, dynamics of water and methanol moleculesin binary liquid mixture conﬁned in MCM41 was investigated. MCM-41 is one of themost suitable sample to study conﬁned liquids, since it has highly controlled cylindrical nano-space with very narrow pore size
distribution.
MCM-41 sample, whose pore diameters were 3.74 nm, were prepared by themethod of Beck et al. To observe dynamics of water and methanol molecules separately, we prepared two kinds of partiallydeuterated binary liquid mixture of waterand methanol (molar ratio 1:1), i.e., H2OCD3OH and D2O-CH3OD. The former
gives QENS spectra mainly due to watermolecules and the latter those mainly due
to methanol ones, especially methyl groupin it. For the QENS measurements, we prepared ﬁve MCM-41 samples whose pores
were ﬁlled with different adsorbate: H2OCD3OH and D2O-CH3OD, H2O, CD3OH,
CH3OD. The QENS measurements of theseﬁve pore-ﬁlled MCM-41 samples, corresponding ﬁve bulk-liquid samples, a dried
MCM-41 sample and an empty cell werecarried out by using time-of-ﬂight typespectrometer AGNES installed at the JRR3M reactor of Japan Atomic Energy Research Institute. The wavelength of neutron
beam was 0.422 nm, the momentum transfer (Q) range 6.4-25.0 nm-1, and the temperature range 200-300 K.

QENS spectra of H2O-CD3OH and D2OCH3OD conﬁned in MCM-41 as well as
corresponding bulk-liquid samples at Q =18.0 nm-1 and T = 300 K are shown in Figure 1. Here, the displayed spectra are thedifference between raw spectra and spectraof the dried sample, and thus contain thecontributions only from the conﬁned liquid. All the spectra are normalized ones, inwhich peak maxima have been coincidedwith each other to emphasize the change
in quasi-elastic wings of the spectra. By
comparing line widths of the spectra, it isfound that motions of methanol molecules
is faster than those of water molecules forboth bulk and conﬁned liquid. It is also
found that molecular motions in conﬁned
liquid are slower than those in bulk liquid
for both water and methanol molecules.
Detailed analysis is now in progress.

Fig. 1. QENS spectra of conﬁned samples of H2OCD3OH (bold line) and D2O-CH3OD (open circles)
and bulk samples of H2O-CD3OH (ﬁne line) andD2O-CH3OD (closed circles) at Q = 18.0 nm-1 and T= 300 K.

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JAEA-Review 2008-067

1-4-10Wide-q Observation of the Self-Assembled Fractal Porous Silica by
Ultra-small-angle Neutron Scattering
D. Yamaguchi, H. Mayama1 , S. Koizumi, K. Tsujii1,2 and T. Hashimoto
Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195
1
Nanotechnology Research Center, RIES, Hokkaido University, Sapporo 001-0021
2
CREST, JST, Kawaguchi, Saitama 338-8570

The concept of fractal has been well established by the precedent studies and now
we recognize that fractal structures are to be
included in various natural objects, such asbroccolis, branching trees, and so on. Furthermore, sometimes a fractal structure is
deeply related with a specific property of thematerial. A super water-repellent surface
made of an alkylketene dimer (AKD), which isa kind of wax, is a typically good example 1) .
When AKD forms a rough surface having a
specific surface fractal dimension of Ds = 2.3,
it shows an extremely large contact angle of174◦ for water droplets as compared with theflat surface. Moreover, it is elucidated thatthe water-repellency largely depends on thesurface dimension of Ds . Thus, to control
the fractal dimension is of importance to draw
favourable properties of the material.
Later on, Mayama et al. have successfully applied the self-assembled AKD particle to the synthesis of porous silica materials, which have well-controlled fractal dimensions 2) . They utilized flaky AKD particles
as a mould and formed a silica matrix by socalled sol-gel method. After the solidificationof the silica matrix, the original AKD mould
was completely burnt away at a high temperature (650 ◦ C) and became pores having
a particular fractal dimension. The fractal
dimension of the porous silica turned out tobe controlled by the compression of the AKD
mould at different ratios and that fact was
confirmed by the real-space observation withscanning electron microscopy.
In this study, we further investigate thisporous silica material by the scattering
method, which brings us the following advantages: (i) to facilitate the evaluation of thefractal dimension of the materials, and (ii) to
原子炉：JRR-3

装置：PNO(3G)

elucidate the hierarchical structure.
Two fractal porous silica specimens, whichwere prepared by the above sol-gel method
and under different compression conditions,were employed for ultra-small-angle neutron
scattering(USANS). The measurements were
performed on the Bonse-Hart type double
crystal diffractometer (at 3G beamport) as
well as on the pinhole and focusing SANS
spectrometer SANS-J-II at the research reactor JRR-3. From the resultant scatteringprofiles shown in Fig.1, we can discern thatthe different mass fractal dimensions were observed in the q-range of q ≤ 1 × 10−2 nm−1
between the two specimens whose compression conditions are different.

Figure 1: Wide-q scattering profiles for fractal porous
silica materials.

References
1) S. Shibuichi, et al., J. Phys. Chem., 100, 19512(1996).
2) H. Mayama and K. Tsujii, J. Chem. Phys., 125,
124706(2006).

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1-5-1

Evaluation of Membrane Lipid Dynamics by Time-Resolved Small-Angle Neutron
Scattering
M. Nakano(A), M. Fukuda(A), T. Kudo(A), H. Endo(B)(A)Graduate School of Pharmaceutical Sciences, Kyoto Univ., (B)ISSP-NSL, Univ. of Tokyo
In biological plasma membranes interbilayer transport and transbilayer movement of phospholipids are controlled byphospholipid transfer proteins and translocase enzymes [1]. Evaluation of these lipid
dynamics is, however, limited due to lackof its methodology.
Richter and co-workers [2] have reported that the unimer exchange of polymer micelles in dimethylformamide can bedetected by small-angle neutron scattering (SANS) technique using hydrogenatedand deuterated polymers. This technique
can be applied to phospholipids since
the transfer of the lipids is known to
be a slow process with a half-life ofhours, i.e., detectable timescale by SANS.
In this study, large unilamellar vesicles(LUVs) of dimyristoylphosphatidylcholine(DMPC) were prepared and used for timeresolved SANS (TR-SANS) measurements
to evaluate the rate of interbilayer andtransbilayer transfers of the lipid.
DMPC and d54-DMPC were obtained
from Avanti Polar Lipids Inc. (Alabaster,
AL). LUVs consisting of d54-DMPC (DLUV) or DMPC (H-LUV) with a diameterof ca. 100 nm were prepared by extrusion
method using Tris-buffered saline containing equivalent volume of D2O and H2O.
LUVs consisting of 1:1 mixture of both
lipids (D/H-LUV) were also prepared bymixing these lipids before hydration. Phospholipid concentration of each LUV preparation was set to 20 mM. SANS measurements were performed using SANS-U with
7 of incident neutron beam. Sample-todetector distance was set to 4 m.
D-LUV and H-LUV showed almost identical scattering proﬁle, while D/H-LUV exhibited little scattering, suggesting that the
scattering length density of D/H-LUV accords with that of solvent, i.e., contrast

matching condition.
When equimolar amounts of D-LUVand H-LUV are mixed, scattering intensity should be equal to the average of each
LUV preparation if there is no intervesicular lipid exchange. On the other hand, thelipid exchange between D- and H-LUV reduces the difference in the scattering lengthdensity of LUVs from solvent (i.e., contrast)with time. In this case, decay of the contrast depends on both the lipid exchange
and ﬂip-ﬂop, and can be described bya double-exponential decay function with
rate constants of the exchange and ﬂip-ﬂop.
TR-SANS experiments were carried out atfour different temperatures. Each measurement was started immediately after mixing
equivalent volume of D-LUV and H-LUV.
The data were collected every 3 min. Timecourse of the normalized contrast was calculated from the scattering intensity. The
contrast decayed more steeply with an increase in temperature. In addition, the normalized contrasts reached below 0.5, suggesting an involvement of ﬂip-ﬂop. The
obtained contrast decays were well reproduced by the double-exponential function,
which are represented by solid curves in
Figure 1. Arrhenius plots of the obtained
parameters exhibited good linear relationship, suggesting high accuracy of the data.
The half-lives of the lipid exchange andﬂip-ﬂop at 37 °C were estimated at about
150 and 510 min, respectively. The results presented here demonstrate that TRSANS is a powerful method to determine
the membrane lipid dynamics.
References[1] J. C. M. Holthuis and T. P. Levine, Nat.
Rev. Mol. Cell Biol. 6 (2005) 209.
[2] L. Willner et al., Europhys. Let. 55 (2001)
667.

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JAEA-Review 2008-067

Fig. 1. Contrast decays of LUVs after mixing Dand H-LUV at four different temperatures. Solid
curves are ﬁtting curves according to the doubleexponential function.

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1-5-2

Surface and Interface Structure of (Deuterated Polystyrene with Silsesquioxane
End Group/Polystyrene) Blend Thin Films
Kyota Miyamoto, Nao Hosaka, Motoyasu Kobayashi, Atsushi Takahara
Institute for Materials Chemistry and Engineering, Kyushu University
Polymer thin ﬁlms have numerous technological applications which require thepresence of a homogeneous ﬁlm. However, producing stable ﬁlms is problematicsince the polymer thin ﬁlms tend to dewet
from the substrate. Previous study revealed
that the addition of polyhedral oligomericsilsesquioxanes (POSS) to the polystyrene(PS) thin ﬁlms led to an inhibition of dewetting in the ﬁlms [1]. This inhibition effectcan be attributed to the changes of the energetics of the surface and interface of the
ﬁlm by the segregation of POSS. Furthermore, the enhancement of the PS thin ﬁlms
by the addition of POSS-terminated PS (PSPOSS), prepared to improve the afﬁnity of
POSS with PS, was also demonstrated [2].
In this study, neutron reﬂectivity (NR) technique is used to characterize the surface
and interfacial structures of the deuterated
PS-POSS (dPS-POSS)/PS blend thin ﬁlm.
dPS-POSS2.9k (Mn = 2900, Mw/Mn =1.09)/PS44k (Mn = 44000, Mw/Mn = 1.04)(32/68 w/w) blend thin ﬁlm was spincoated from the toluene solution onto acidcleaned Si wafer. The ﬁlm was annealed
under vacuum at 393 K for 3 hours. NR
measurement was carried out using MINE
at JRR-3M with 0.88nm of incident neutron beam. Figure 1 shows the NR proﬁleof the dPS-POSS2.9k/PS44k (32/68 w/w)
blend thin ﬁlm. The solid line denotes theﬁtting curve based on the model scattering
length density (b/V) proﬁle, as shown in
the inset of Figure 1. Increase in the b/Vvalues was observed at the both of surface
and interface of the ﬁlm, which suggested
that dPS-POSS was enriched at the interface as well as the surface. Similar results
were also observed in the different deuteration contrast ﬁlm (PS-POSS2.5k (Mn = 2500,
Mw/Mn = 1.11)/deuterated PS38.5k (Mn =38500, Mw/Mn = 1.07) blend)reported in

our previous study. From these results,
it can be concluded that the segregation of
POSS moiety was not due to the deuteration effect. The segregation of PS-POSS,
which changes the surface and interfacial
free energy of the ﬁlm, can be an importantfactor in the dewetting inhibition effect.
References[1] N. Hosaka, N. Torikai, H. Otsuka, A.
Takahara, Langmuir, in press.
[2] K. Miyamoto, N. Hosaka, H. Otsuka, A.
Takahara, Chem. Lett., 36, 1098-1099 (2006).

Fig. 1.
Neutron reﬂectivity proﬁle of dPSPOSS2.9k/PS44k (32/68 w/w) blend thin ﬁlm. The
inset shows the scattering length density proﬁle ofthe ﬁlm.

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JAEA-Review 2008-067

1-5-3

Structure Analyses of Ultra-Hydrophilic Zwitter-ionic Polymer Brush at Water
Interface by Neutron Reﬂectivity
M. Kobayashi, K. Miyamoto, N. Hosaka, A. Takahara
Institute for Materials Chemistry and Engineering, Kyushu University
Poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) is a highly hydrophilicpolyelectrolyte specially designed for biocompatible medical devices[1]. Neutron
reﬂectivity (NR) of surface-grafted PMPCin an aqueous solution have been studied to analyze the interface structure ofswollen polymer brushes, which are fairly
extended in a good solvent due to thehigh osmotic pressure[2]. In this study, theauthors investigated the salt effect on theswollen PMPC brush structure by NR.
High-density PMPC brush was preparedby surface-initiated atom transfer polymerization from the quartz immobilized withsurface initiator. NR measurements werecarried out with the multilayer interferometer for neutrons (MINE), using wavelength of 0.88nm. Neutron beam irradiatedfrom quartz to the interface between heavy
water and PMPC brush on quartz glass.
A critical angle was clearly observed at
q = 0.11 nm-1 in Figure 1 owing to thedifference in scattering length density between quartz and heavy water. Scattering
length density proﬁles of PMPC brush inheavy water calculated from the reﬂectivity curves in Figure 1(b) and (c) indicatedthat the PMPC chains were stretched up to
50 nm in heavy water forming concentration gradient of heavy water. Interestingly,
quite similar reﬂective curve was observed
from the interface of PMPC brush at 0.1 M
of NaCl deuterium oxide solution. Generally, isolated polyelectrolyte would shrink
in salt solution because the electrostatic repulsion between polymer chains decrease.
However, salt ion cannot be diffused intoa high-density polymer brush layer due
to the high osmotic pressure and high local charge density. Similar results have already been reported by Matsuoka[3], andKurihara[4]. In addition, the authors havefound that the dimension of free PMPC inwater is independent on the ionic strengthof salt solution[5]. Therefore, the thickness
of PMPC brush in solution was supposed
to be hardly changed even in a salt solution.
References[1] K. Ishihara, T. Ueda, N. Nakabayashi,
Polym. J. 22, 355 (1990).
[2] M. Kobayashi, N. Hosaka, M. Kaido, A.
Suzuki, N. Yamada, N. Torikai, K. Ishihara,
A. Takahara, Soft Matt. submitted.
[3] P. Kaewsaiha, K. Matsumoto, H. Matsuoka, Langmuir, 20, 6754 (2004).
[4] S. Hayashi, T. Abe, N. Higashi, M. Niwa,
K. Kurihara, Langmuir 18, 3932 (2002).
[5] Y. Matsuda, M. Kobayashi, M. Annaka,
K. Ishihara, A. Takahara, Chem. Lett. 35,
1310 (2006).

Fig. 1. Experimental NR proﬁles of bare quartz (a),PMPC brush (b) in heavy water, in 0.1 M NaCl solution (c), and corresponding ﬁts. Assumed scattering
length density proﬁle for (b) and (c) is shown above.

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1-5-4

Structural Formation Process of Polymers under Shear Flow
Go Matsuba, Koji Nishida, Takahiko Kawai, Toshiji Kanaya
Institute for Chemical Research, Kyoto University
Crystallization of polymers under shear
ﬂow have been extensively investigatedbecause polymers are exposed to various ﬂows such as elongational, shear andmixed ﬂows during industrial processing.
These processes can signiﬁcantly affect the
crystallization kinetics and ﬁnal morphology. For example, when polymer crystallizes under ﬂows, the so-called shishkebab structure could be observed. The
shish-kebab structure consists of long central ﬁber core (shish) and lamellar crystals (kebab) periodically attached along
the shish structure and surrounded by theshish structure. We showed that the small
angle neutron scattering (SANS) with deuterium labeling method was very powerfulto study the crystallization kinetics of polymers under shear ﬂow.
In the present experiment, we performed
the time-resolved SANS measurements
on crystallization processes of blendsof deuterated low molecular weightand protonated ultra-high molecularweight polyethylene (PE) with the handmade shear cell specialized for observation of polymer crystallization process
with/without shear ﬂow [1]. The blend
samples were molten at 190 C and thencooled down to a crystallization temperature of 124.5 C at a rate of about 40
C/min. The sample was subjected to pulse
shear just after reaching the crystallization
temperature. The shear rate and strain
are 90 (1/s) and 1000 %, respectively.
The molecular weight of low molecularweight deuterated and protonated ultrahigh molecular weight PE (d-PE/h-PE)
is 56,500 and 2,000,000, respectively. The
time-resolved SANS measurements werecarried out on SANS-U spectrometer on
JRR-3, JAEA, Tokai, Japan.
Figure 1 shows that the time evolution of
2D SANS proﬁles for a blend d-PE/h-PE =3/97 under shear ﬂow. Just after inducing
shear ﬂow (0.5 min), the streak-like scattering normal to the shear direction could
be observed, and then the strong scattering
proﬁles parallel to the shear direction appeared and became stronger after 2.5 min.
The normal streak-like scattering and parallel scattering were assigned to shish andkebab structures, respectively. These results suggest that the shish structure grows
before kebab structural formation. Furthermore, the observed shish-structure is in micron ordered and very similar to the shishlike structure observed with time-resolved
light scattering measurements. As h-PE
concentration decreases the scattering proﬁle became isotropic. This result suggeststhat the structural formation process depend on the existence of entanglements ofhigh molecular weight components.
Reference:[1] K. Nishida et al, Activity Reports on
Neutron Scattering Research, ISSP, U ofTokyo, 13, 2006.

Fig. 1. Figure 1. Time evolution of 2D SANS proﬁles for deuterated and hydrogenated polyethylene
blend.

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JAEA-Review 2008-067

1-5-5

Structural Formation of Uni-Lamellar Vesicles
in a Mixture System of Long- and Short-Chain Lipids
N. L. Yamada A , N. Torikai A , S. OkabeB , N. OsakaB , and M. ShibayamaB
A KENS, IMSS, High Energy Accelerator Research Organization,B NSL, ISSP, The University of Tokyo
It has been well known that natural
swelling of a dry phospholipid ﬁlm usually produces large multi-lamellar vesicles[1]. These mimic biomembranes produced
from synthetic phospholipid molecules
have been extensively studied to understand the actual behavior of real biomembranes. Living cells and their organelle,
however, exist as uni-lamellar vesicles(ULVs). Therefore, effective methods tocreate the ULVs have been studied so far[2].
For a phospholipid mixture system consisting of long- and short-chain lipids, it
was reported that bilayered micelles with
10-100 Å diameter, so-called bicelle, arespontaneously formed at low temperature,and they fuse into vesicles at high temperature. Especially, ULVs with 100-1000 Å
diameter are formed only when the bilayers are charged [3]. This suggests that theelectrostatic interaction is important for the
ULV formation in the lipid-mixture system. The mechanism of the ULV formation, however, has not been studied well.
Therefore, we have performed small-angle
neutron scattering (SANS) experiments on
the lipid-mixture system to investigate theeffect of the electrostatic interaction on the
ULV formation.
In this study, we have performed SANS
experiments on a typical lipid mixture
system, dimyristoylphosphatidylcholine(DMPC) and dihexanoylphosphatidylcholine (DHPC) mixture system, at
SANS-U, JRR-3M, JAEA, Tokai, Japan [4].
Since multivalent cations adhere onto thehydrophilic part of lipid molecules, thelipid mixture was dissolved in CaCl2 aqueous solution of 3 mM to obtain charged
bilayers. The experiments were performed

for the lipid mixtures with different NaCl
concentration, that is, the shielding lengthof the electrostatic interaction. The obtained results are shown in Fig. 1. The
SANS proﬁles for 0 and 50 mM NaCl arevery similar, irrespective of the existenceof the salt. It is found from the form factor
of a ULV, i.e. the proﬁles in the low-q
region, that its diameter for 50 mM (about1200 Å) is almost the same as that for
0 mM. On the other hand, the low-q proﬁlewas drastically changed and a new Bragg
peak corresponding to a multi-lamellar
structure with repeat distance of about
75 Å was observed for 100 mM NaCl.
From these results, we concluded that theelectrostatic interaction has a little effect on
the shape of the ULV, but contributes muchto its stability.
References[1] Reeves J. P. and Dowben R. M., J. Cell. Physiol. 73 (1969) 49.
[2] N. L. Yamada et al., submitted to Europhys.
Lett. (arXiv:cond-mat/0607672).
[3] M.-P. Nieh et al., Biophys. J. 82 (2002) 2487.
[4] S. Okabe et al., J. Appl. Cryst., 38 (2005) 1035.

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1-5-6

Surface Segregation in Miscible Polymer Mixtures of Block Copolymer /Homopolymers
Daisuke Kawaguchi, Naoya Torikai1 , Masahiro Hino2 , Atsushi Takano, Yushu
Matsushita
Department of Applied Chemistry, Nagoya University, 1 KEK-KENS, 2 KURRI
In a miscible blend of two polymers
with equivalent degree of polymerization,
the lower surface energy component is enriched at the surface to minimize the total free energy of the system. However, it
is impossible to strictly control a chain arrangement along the direction normal to
the surface. In this study, we evaluated surface segregation phenomena in mixturesof poly(4-trimethylsilylstyrene)(T), polyisoprene(I), and their block copolymer (TI),
whose blends are miscible at room temperature, 1 and compare to what extent of segregation of T homopolymer and that of T
block of TI in T/TI/I blend ﬁlms.
NormalT(hT),
its
partially
deuterated one (dT), normal I(hI),poly(4-trimethylsilylstyrene-blockisoprene) (hTI) and poly(deuterated
4-trimethylsilylstyrene-block-isoprene)(dTI) were used in this study. Weightaverage molecular weights, Mw, for hT, dT,
hI, hTI and dTI are 34k, 43k, 24k, 85k and
65k, respectively. Surface free energy of T,
being evaluated to be 31.9 mJ/m2 basedon contact angle measurements, is lower
than that of I of 37.4 mJ/m2 . dT/hTI/hI
and hT/dTI/hI blend ﬁlms were preparedby spin-coating method from toluene
solutions onto silicon wafers. Since thevolume fractions of T, TI and I were 1:1:1,
the ratio of T to I in the whole ﬁlm is 1:1.
Neutron reﬂectivity (NR) measurements
were carried out using MINE-2 reﬂectometer. Incident neutrons have the wavelengthof 0.88 nm and the resolution of 5.1 %. The
reﬂectivity was calculated on the basis of
the scattering length density proﬁle along
the depth direction by using Parratt 32.
Fig.1(a) shows neutron reﬂectivity proﬁles for dT/hTI/hI and hT/dTI/hI blend
ﬁlms. Experimental data sets were repre-

sented by circles and squares. Solid lines
denote the calculated neutron reﬂectivities based on the scattering length density,(b/V), proﬁles shown in the parts (b) and(c) of Fig. 1. The (b/V) values for dT, hT
and hI were taken to be 3.63 x 10−4 , 0.57
x 10−4 and 0.27 x 10−4 nm−2 , respectively,
using the scattering lengths per monomericunits and the bulk densities of these polymers. Since the calculated curves werein good agreement with the experimental
data, it can be conceived that the model(b/V) proﬁles well represent the composition proﬁles in the blend ﬁlms normal to
the surface. For the dT/hTI/hI blend ﬁlm,the (b/V) value at the surface is higher
than that of the internal bulk region, as
shown in Fig.1(b). This means that dT homopolymer is enriched at the surface. On
the other hand, for the hT/dTI/hI blend
ﬁlm, dTI was not segregated at the surface.
These results indicate that surface segregation power of T component of TI is much
lower than that of T homopolymer.
Reference [1] M. Harada, T. Suzuki,
M. Ohya, D. Kawaguchi, A. Takano, Y.
Matsushita, Macromolecules, 38, 1868-1873(2005).

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JAEA-Review 2008-067

Fig. 1.
(a) Neutron reﬂectivity proﬁles for
dT/hTI/hI and hT/dTI/hI blend ﬁlms. Solid lines
denote the calculated reﬂectivities based on scattering length density, (b/V) proﬁles for (b) dT/hTI/hI
and (c) hT/dTI/hI blend ﬁlms.

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1-5-7

Dynamic anisotropy of polymer thin ﬁlms
R. Inoue1 , T. Kanaya1 , K. Nishida1 and I. Tsukushi2

1 Institute for Chemical Research, Kyoto University, 2 Chiba Institute of Technology

Polymer thin ﬁlms are very much utilized in industry because their propertiesare related to many phenomena such as
adhesion, wetting, lubricant and so on.
Therefore polymer thin ﬁlms are focused
not only from scientiﬁc point of views
but also from industrial point of view.
We have so far studied the dynamics ofpolymer thin ﬁlms with inelastic neutron
scattering method [1] and found that thedecrease of mobility (mean square displacement < u2 >) was observed withﬁlm thickness for macroscopically isotropic
samples. However, polymer chains are
spatially conﬁned in the thickness direction. In that sense, polymer thin ﬁlm isa 2D-conﬁned system. Therefore, we expected that the motional anisotropy would
be observed with decreasing ﬁlm thickness. No other researches concerning the
dynamic anisotropy of polymer thin ﬁlms
have not been done yet as far as we know.
In the present experiment we studied the
dynamics of polymer thin ﬁlms in parallel and perpendicular directions to polymer surface using triple axis spectrometer(TAS), mainly focusing on the glassy state.
The sample used in this experiment washydrogenated PS with molecular weight
290K and we prepared thin ﬁlms 1000Åand
400Åin thickness, which were supportedon Al foil and bulk sample as a reference. The measurements were performed
on 4G spectrometer and incident energy
was 30meV. Fig. 1(a) indicates the Q2 dependence of elastic intensity for 400Åthinﬁlms at 230K for parallel and perpendicular geometries to surface of polymer thinﬁlms and the solid lines are results ofﬁt considering the contribution from nonGaussian parameter [2]. From ﬁt, we canevaluate < u2 > for both geometries andfound that < u2 > decreased with decreasing ﬁlm thickness for both geometries as in-dicated in Fig. 1(b). However, the evaluated < u2 > s for both geometries almost
identical within experimental error, implying that the notable dynamic anisotropy
was not observed even for the thinnest ﬁlm(= 400Å). It can be said that the dynamics
for both geometries are correlated. The detailed analysis is now under progress in order to understand this result.
Reference[1] R. Inoue et al., Phys. Rev. E. 74,
021801 (2006).
[2] T. Kanaya et al., Phys. Rev. B. 61,
R6451 (2000).

Fig. 1. (a) Q2 dependence of elastic intensity of
400Åthin ﬁlms. (b) Thickness dependence of <u2 > for parallel and perpendicular geometries at
230K.

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1-5-8

Dynamics of diblock polymer in the form of lamellar structure
R. Inoue1 , T. Kanaya1 , H. Ogawa1 , K. Nishida1 , I. Tsukushi2 and O. Yamamuro3
1 Institute for Chemical Research, Kyoto University, 2 Chiba Institute of Technology, 3 ISSP,

University of Tokyo

Recently, the physical properties ofspatially conﬁned glass-forming materials
were studied very much and they werefocused not only from scientiﬁc point ofview but also from industrial point of view
because their properties were strongly related to nanotechnology. There are so many
ways for the spatial conﬁnement of glassforming materials like porous glass, thinﬁlm, molecular sieve and so on. One of thebiggest objectives in the researches for conﬁned systems is estimation of the characteristic length scale that is responsible forglass transition. However, surface or interface effects could not be ignored withdecreasing the size or scale, therefore thecharacteristic length scale for glass transition could not be evaluated from simple
size effect only. Estimation the contribution
from surface or interface effect is needed
for the full understating of above problem.
We have so far studied the dynamics ofpolymer thin ﬁlms using inelastic neutron
scattering method and found the decreaseof mobility with ﬁlm thickness. We assumed that this result was caused by theexistence of low mobility layer that exist
between thin ﬁlm and substrate. It was
expected that the interface affected the dynamics very much. In this experiment, westudied the dynamics of diblock copolymer in the form of lamella structure andfocused on the motion of polymer chainsthat were conﬁned in the form of lamellar structure. Compared to polymer thinﬁlms, this system is as it were, chemical conﬁnement. We used the deuterated
polystyrene (d-PS)/hydrogenated polybutadiene (h-PB) diblock copolymer (SB) with
Mw =64k/43K in the former of lamellar andhomo h-PB with Mw =43K as a reference
sample. We studied the incoherent scattering from h-PB owing to the large scatter-ing cross section from hydrogen comparedto other atoms (C, D). The measurements
were done with AGNES and the incident
energy was set to 4.40 meV. First we focused on the boson peak and Fig.1(a) indicates the dynamic scattering law S(Q, ω)
at 80K. The boson peak was observed ataround 2meV for both polymers. Seemingly the intensity and peak position were
the same and it was considered that boson peak was not affected by conﬁnement.
Next we evaluated mean square displacement < u2 > for both polymers. In the lowtemperature region (below the Tg ∼170K
of PB), the difference was too small to observe. However, above the Tg of PB thedifference was observed. The up-turn of< u2 > was observed for homo h-PB, indicating the onset of relaxation process, on
the other hand it was not so clear for SB
diblock copolymer. This indicates that therelaxation process was affected by conﬁnement.

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1-5-9

Investigation on nanostructure in a block copolymer ﬁlm having sulfonic acidgroupsKozo Matsumoto, Shuji Kage, and Hideki Matsuoka
Department of Polymer Chemsitry, Kyoto University
Nanostructure in a block copolymer ﬁlm
having sulfonic acid groups, which can beapplicable for a proton conducting polymer electrolyte membrane for a fuel cell,
was investigated by small angle neutron
scattering (SANS).
A
cross-linkable
block
copolymer,
poly(styrene-co-4-(1methylsilacyclobutyl)styrene)-bpoly(neopentyl styrenesulfonate) (poly(Stco-SBS)-b-polySSPen),was
preciselysynthesized by a nitroxy-mediated living
radical polymerization. The degrees ofpolymerization for poly(St-co-SBS) andpolySSPen were estimated to be 136 and61, respectively. The molar ratio of St/SBS
was determined to be 0.9/0.1. A crosslinked ﬁlm with free sulfonic acid groups,
poly(St-co-SBS)-b-polySSH, was obtainedby casting a toluene solution of the block
copolymer with a platinum catalyst andheating it at 230 degree C.
Neutron scattering experiments on the dry
polymer ﬁlm and wet polymer ﬁlm in deuterium oxide were performed by SANSU. Strong neutron scattering was observedin the small angle region in both samples,indicating that some kinds of nanostructure were formed in the block copolymer
ﬁlms. The SANS proﬁle for the dry sample
was reproduced well by applying a hard
sphere model (Figure A), which suggested
that spherical domains (12.5 nm in radius)
were randomly distributed in the ﬁlm. On
the other hand, the proﬁle for the wet sample was reproduced by adapting Fournet
model (Figure B), which suggested that interaction between neighboring two spherical domains existed. The domain radius
and the mean distance between the neighboring domains were evaluated as 14nm
and 18nm, respectively. We can reasonably
understand these results if we consider thatthe spherical polySSH domains existed ina matrix composed of poly(St-co-SBS) andthat the polySSH domain was swollen by
deuterium oxide in the wet sample.
The proton conductivity of the block
copolymer ﬁlm has been already examined
and it was found that the ﬁlm possesses
high conductivity that is comparable to awell-known sulfonic acid containing membrane Naﬁon produced by Dupont.

Fig. 1. Figure (A) SANS experimental and ﬁtting
proﬁles for dry block copolymer ﬁlm; Figure (B)SANS experimental and ﬁtting proﬁles for the wet
block copolymer ﬁlm in deuterium oxide.

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JAEA-Review 2008-067

1-5-10

Structural analysis of a dilatancy solution
Takuji Kume(1), Hiromitsu Kawada(1), Takuro Matsunaga(2), Sho Miyazaki(2), Noboru
Osaka(2), Satoshi Okabe(2), Mitsuhiro Shibayama(2)(1) Skin Care Research Labs. Kao Corporation. (2) Neutron Science Laboratory, Institute for
Solid State Physics, The University of Tokyo.
We have found that nanometer-size
emulsion and polymer (HEC; Hydroxyethylcellulose) system have shear thickening behaviors, i.e., dilatancy behaviors.
Nanometer-size emulsion were made byhigh pressure emulsiﬁcation, and their diameter was ca. 30nm [1]. The weight average molecular weight of HEC was ca.
1,300,000 and its concentration was 0.4
wt%.
It is predicted that there are some interactions between emulsion and polymer
in this system. In order to analyze suchinteractions more precisely than in previous experiments, we carried out simultaneous measurements of small-angle neutron
scattering (SANS) coupled with rheology,
Rheo-SANS. A Rheo-SANS system was installed at SANS-U (C1-2), JRR3M in JAEA
(Tokai). Rheological measurements can be
carried out on a Physica MCR-501 (Anton
Paar) equipped with a double cylinder typeshear cell. (Fig. 1)
Simultaneous measurements of rheology
and SANS were carried out at several
steady shear rates (the range of the shear
rate being 0.1 - 100 [1/s]). Typical results ofthe measurements are shown in Fig. 2 and3. Fig. 2 shows clear dilatancy (viscosity
thickening) at the shear rate of ca. 4 [1/s].
Fig. 3 shows the corresponding SANS proﬁles observed at the shear rates of 0.1 to100 [1/s]. At the shear rate above the dilatant point, a steep increase of the scattering intensity was observed in the low-Q region. This result indicates that some semimicrometer-size structure was formed under shear ﬂow at the shear rate above thedilatant point.

visional Meeting on Colloid and Interface
Chemistry, Chem. Soc. Japan (2004) p97.

Reference[1] T. Kume et al., Preprint of the 57th DiActivity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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1-5-11

Small-Angle Neutron Scattering Study on Strain-Induced Crystallization andNonuniformity of Natural Rubber
M. Shibayama(A,B), T. Karino(A,B), Y. Yasuda(C), Y. Ikeda(C), S. Kohjiya(D)(A)ISSP-NSL Univ. Tokyo, (B)CREST, Lpn, Sci. Tech. Agency, (C)Kyoto Inst. Tech., (D)Inst.
Chem. Res., Kyoto Univ.
It is well known that natural rubber (NR)contains non-rubber components such asproteins, phospholipids and fatty acids,
carbohydrates and inorganic substances.
However, no reports on the direct morphological evidence of non-rubber components in solid have been published as far
as we know. Thus, the microscopic structure of NR was investigated by SANS in
this study. It was compared with thoseof deproteinized NR (DPNR) and isoprenerubber (IR). The results of small-angle Xray scattering (SAXS) and atomic force microscopy (AFM) were also discussed in order to elucidate the structural characteristics of NR. Peroxide-cross-linked NR andIR samples were prepared by milling andheat-pressing. SANS experiments werecarried out at SANS-U (C1-2), JRR-3M in
JAEA (Tokai). The wavelength was 7.0 Å.
The sample-to-detector distances were chosen to be 2.00 and 8.00 m. The scattered intensity were collected with an area detector and then circularly averaged. Dry andswollen samples with deuterated toluene
were subjected to SANS.
The following conclusions were obtained. (i) Both SANS and SAXS intensities, ISANS (q) and ISAXS (q), of NR havea strong q-dependence as shown in Figure 1, indicating presence of large scale
inhomogeneities. Here, q is the magnitude of the scattering vector. This strong
q-dependence disappears by deprotenization (DNPR). The inhomogeneities were assigned to protein aggregates, which was
supported by AFM. These aggregates were
found to be larger in size as well as in volume fraction than those of cross-link inhomogeneities introduced by cross-linking
since cross-liking did not produce any signiﬁcant increase in scattering. (ii) IR does

not show such inhomogeneities. (iii) The
microscopic structures of swollen crosslinked NR by deuterated toluene are successfully reproduced by SANS intensity
functions consisting of squared-Lorentz
and Lorentz functions. The size of protein aggregates was evaluated to be of theorder of 200 Å or larger. (iv) Swelling ofboth cross-linked NR and cross-linked IR
introduces gel-like concentration ﬂuctuations whose mesh size is of the order of 20
Å. These results indicate that NR possesses
inherent inhomogeneities in bulk and additional thermal concentration ﬂuctuationsin swollen state, respectively.[1, 2]
References[1] M. Shibayama: Macromol. Sci. Phys. 199(1998)1.
[2] T. Karino et al.: Biomacromolecules, inpress.

Fig. 1. SANS (symbols) and SAXS curves (thin lines)of NR rubbers (a) before (NR) and (b) after milling(NR0) without cross-linker. The thick dotted anddashed lines denote the ﬁt with SL-function.

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JAEA-Review 2008-067

1-5-12

Small-Angle Neutron Scattering Study on the Miscibility and Concentration
Fluctuation of Hydrogen Bonding Polymer Blends
Osamu Urakawa, Hiroyoshi Ikuta, Toshiyuki Shikata
Dept Macromolecular Sci. Osaka Univ.
The effects of hydrogen bonding (Hbonding) on the composition ﬂuctuationin miscible polymer blends were examinedby utilizing small-angle neutron scattering (SANS) method. Speciﬁcally, we used
the blends composed of poly(vinyl acetateco-vinyl alcohol) (P(VA-VOH)) with various VOH content (fOH) and deuteratedpoly(ethylene oxide) (dPEO), since the formation of the H-bond between the hydroxyl group of P(VA-VOH) and the ether
oxygen of dPEO is expected. Furthermore, the advantageous point of this system is that the degree of H-bonding can
be changed by the variation of fOH. In
this study, we prepared P(VA-VOH) samples having different fOH (molar fraction)(= 0, 0.10, 0.18, 0.28, 0.35) by the saponiﬁcation reaction of PVA. The blend composition of P(VA-VOH):dPEO = 80:20 was
mainly examined for the SANS measurements.
For all the blends, the SANS intensities increased with increasing temperature
T implying the existence of lower critical solution temperature. For the P(VAVOH)/dPEO (80/20) blends with fOH<0.28, the scattering proﬁles S(q) could bewell represented by the random phase approximation (RPA) theory. Based on thistheory, the interaction parameter X was determined as a function of T. Figure 1 shows
the fOH dependence of X at T=343K. As
seen in this ﬁgure, the X shows a minimum at around fOH=0.15, meaning thatthe blend at this particular fOH is the mostmiscible. Furthermore, we found that the
random copolymer theory (solid curve inthe ﬁgure) could quantitatively explain thefOH dependence of X.
For the blend of fOH=0.35, on theother hand, the RPA theory did not ﬁt
the S(q) well, especially at the small q re-gion. The experimental data at the small q
were found to be more suppressed than thetheoretical prediction. This behavior suggests that the formation of larger number of
H-bonds might suppress the composition
ﬂuctuation.

Fig. 1. fOH dependence of the interaction parameter
X for P(VA-VOH)/dPEO (80/20) blends at T=343K.
Solid curve represents the ﬁtted result with the random copolymer theory.

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JAEA-Review 2008-067

1-5-13

Micellization behavior of non-surface active amphiphilic block copolymer
containing ﬂuorine in aqueous solutions
Hideki Matsuoka, Shuji Kage, Ploysai Kaewsaiha, Yoshiko Suetomi, Shota Hara, Hao
Chen, Kozo Matsumoto
Department of Polymer Chemistry, Kyoto University
Introduction
Ionic amphiphilic diblock copolymer
consisting of polyelectrolyte and hydrophobic chains shows ”non-surface
activity” when some physico-chemical
and molecular structural parameters
are satisﬁed. Although they are nonsurface active, surprisingly they form
micelles in aqueous solutions, which was
conﬁrmed by static and dynamic lightscattering and other experimental techniques. In this study, the nanostructureof micelles of non-surface active polymer,
poly(pentaﬂuorostyrene)-b-poly(styrene
sulfonate) ((PFS)m-b-(SSNa)n) was investigated by SANS.

The micelles of polymers with m:n=41:66
and 30:105 were spherical with and without added salt. The size of core and the aggregation number evaluated by SANS werelarger for m:n=41:66 than for m:n=30:66. In
addition, the shell thickness for m:n=41:105
was larger than that for m:n=41:66 although their core size are comparable.
These tendencies can be understood by
the concept of ”Packing Parameter” concept, although they were non-surface active, which is anomalous character for amphiphilic molecules.

Experimental
Polymers with m:n=30:66, 41:66, and 41:105
were synthesized by living radical polymerization and their heavy water solutions
with concentration of 0.1 wt% were measured by SANS-U. The dependencies on
m:n and added salt concentration of micelle nanostructure was investigated. The
results were summarized in Table 1.
Results and Discussion
Added Salt Concentration Dependence
Spherical micelles were observed for polymer with m:n=30:66 under no salt condition. However, at [NaCl]=0.1M NaCl,both of spherical and cylindrical micelles
were observed. At higher salt concentration, only rod-like micelles were observed.
This behavior can be explained by thechange of ”effective” area of head group(i.e. ionic hydrophilic block) by the shielding effect of added salt ions for the electrostatic interaction in ionic corona region.

Fig. 1. Micelle nanostructure by SANS

Effect of Hydrophilic Chain Length
Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-5-14Microstructure Analysis of Weakly-charged Gels Having Diﬀerent Spatial
Distribution of Charged Groups 〜pH Dependence〜
T. Suzuki A , T. Karino A , F. IkkaiB , M. Shibayama A
A The Institute for Solid State Physics, The Univ. of Tokyo, B Nihon L’OR ÉAL K.K.
Gel microstructure formation according
to spatial conﬁguration of charged groups
in gel network has been investigated using a two-dimensional SANS spectrometer (SANS-U) of Institute for Solid State
Physics, Univ. of Tokyo, located at JRR3M
in Japan Atomic Energy Agency (JAEA),
Tokai, Japan. Three types of gel consisting of hydrophobic N-isopropylacrylamide(NIPAm) and weakly-charged acrylic acid(AAc) copolymers were prepared with different distributions of AAc monomer units
in the network. The ﬁrst type is NIPAm/AAc copolymer gel in which NIPAm and AAc are randomly copolymerized in monomer unit by redox polymerization (code;redox-mono-AAc). The second type is a UV-crosslinked NIPAm/AAc
gel in which AAc is copolymerized inunits of polymers (code;UV-poly-AAc).[1]The third type is a NIPAm/poly-AAc polymer gel prepared using redox method
in which poly-AAc was not cross-linked
but physically entrapped in the NIPAm
polymer network (code;redox-poly-AAc).
These three types of gel contain the sameamount of charged groups (NIPAm/AAc= 668mM/32mM) but different spatial conﬁgurations of charged groups.
Fig.1. shows the T dependence of SANS
proﬁles, I (q) of each NIPA/AAc copolymer gel at pD=6 or 11. Here, the solid
denote theoretical ﬁtting curves. With increasing temperatures, a broad peak appears in I (q)s for redox-mono-AAc and
UV-poly-AAc. For a theoretical ﬁttingwith this broad peak, we employed RabinPanyukov (RP) theory.[2] RP ﬁttings werequite successful for each experimental result. These results show that UV-poly-AAc
undergoes microphase separation with along-period larger than that of redox-

mono-AAc. Note that these long-period
lengths depend on pD for both UV-polyand Redox-mono. The latter results in ahigher effective degree of ionization than
UV-poly-AAc due to the ion condensation
along the poly-AAc chains. On the other
hand, in redox-poly-AAc, no pD dependence was observed. In the case of redoxpoly-AAc, non-crosslinked poly-AAc does
not affect the gel structure at the microscopic levels. These ﬁndings demonstratethat the charge conﬁguration in a weaklycharged polymer gel can be tuned andit plays a signiﬁcant role in microscopic
structures.
References[1] Ikkai, F.; Adachi, E. Macromol. Rapid.
Commun. 2004, 25, 1514.
[2] Rabin, Y.; Panyukov, S. Macromolecules
1997, 30, 301.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-5-15

Analysis of Aggregation States in Ultrathin Polymer Blend Films Conﬁned
Between Solid Substrates
Yoshihisa Fujii(1), Keiji Tanaka(1), Toshihiko Nagamura(1), Masaya Hino(2)
1. Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
2.
Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan
Surface structure in polymer materials has been widely studied, experimentally and theoretically, due to a wide variety of technological applications as well
as scientiﬁc interests. So far, we have examined surface segregation phenomenon
in the miscible blends of polystyrene (PS)and poly (vinyl methyl ether) (PVME).[1]In the case of symmetric blends in terms ofdegree of polymerization (N), PVME andPS were preferentially segregated at theﬁlm surface and the interface with a siliconwafer, respectively, to minimize the free energy of the system. However, there are
few reports dealing with segregation phenomenon in ultrathin blend ﬁlms conﬁned
between solid substrates.
A blend ﬁlm of PVME and perdeuterated
PS (dPS) was spin-coated from a toluene
solution onto a silicon wafer with a native oxide layer, and then, a silicon layer
was evaporated on it. The mixing ratio of
the blend was ﬁxed to be 50 wt %. The
thickness of the blend ﬁlm evaluated byellipsometry was approximately 110 nm.
The ﬁlm was annealed for 150 h at 333 K
in vacuo, which was well above the bulk
glass transition temperature and below thelower critical solution temperature. The
composition proﬁle of the (dPS/PVME)
blend ﬁlm along the direction normal to thesurface was studied by the multilayer interferometer for neutrons (C3-1-2-2, MINE)
at ISSP, the University of Tokyo. Incident
neutrons with the wavelength of 0.88 nm
and the resolution of 5.1 % were guided
into the specimen, which was vertically set
onto a goniometer, from the surface silicon
deposition layer. The reﬂectivity was calculated on the basis of the scattering lengthdensity proﬁle using Parratt32, which is afreeware from the Hahn-Meitner Institute(HMI).
Fig. 1 shows the scattering vector,
q, dependence of neutron reﬂectivity forthe (dPS/PVME) blend ﬁlm conﬁned silicon oxide layers. Although the data ﬁtting analysis has not been perfectly completed yet, we tentatively reach a conclusion that the dPS fraction increased withgetting closer to both blend/silicon oxideinterfaces. This result would be explainedin terms of minimization of the free energy at the substrate interfaces. That is,
the higher surface energy component energetically prefers to contact with the hydrophilic silicon oxide. More conclusive
study, which discusses interfacial decay
length, excess amount and its molecularweight dependence, will be reported in thenear future.
Reference[1] D. Kawaguchi, K. Tanaka, T. Kajiyama,
A. Takahara, S. Tasaki. Macromolecules 36,(2003) 6824.

Fig. 1. Neutron reﬂectivity for the (dPS/PVME)
blend ﬁlm conﬁned silicon oxide layers.

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1-5-16

Concentration ﬂuctuation for polymer blend thin ﬁlm close to critical
Hiroki Ogawa, Rintaro Inoue, Toshiji Kanaya, Koji Nishida
Institute for chemical research, Kyoto university
and we found that the interface roughness
between surface PVME and PS/PVME (orsurface roughness) increases with annealing time. The fringed pattern in the proﬁle disappeared once due to dewetting.
However, further annealing of 360 minutes
show that fringes appear again. It suggeststhat PVME thin layer segregate on the Si
substrate.
104

(a)

103
102

Reflectivity

101
100

360min10-1
10-2

120min

10-3

3min

10-4

1min

10-5

one phase

10-6
0.02

0.04

0.06

0.08

0.10

Q(Å-1)
-200

(b)

0
200

Depth / ÅMany interesting phenomena are reported on thin ﬁlms of polymer blends. We
also found in optical microscope and lightscattering measurements that spinodal decomposition type dewetting preferentiallyoccurs in the PS and PVME blend thinﬁlms for the in-plane structure in a thickness region less than 100 nm in the twophase region. In this study we investigated the density proﬁle perpendicular tothe ﬁlm surface, using neutron reﬂectivity (NR) before dewetting. We found fromthe NR results that concentration ﬂuctuations occur normal to the surface before
dewetting, which may induce the dewetting. NR measurement was carried out
using the MINE neutron reﬂectometer installed at the cold neutron guide C3-1-22 in JRR-3M reactor. We used deutareted
PS (dPS, Mw=288,000) and hydrogenated
PVME (Mw=90,000) in this study. The
fraction of PS dps in the blend was 0.3,
which corresponds to the critical composition in the bulk. The polymer blends wereprepared by spin-coating onto a siliconwafer. Thicknesses of the polymer blend
ﬁlms were 98nm. All the ﬁlms were preannealed at 90 °C in the one phase region
for 30 min and then temperature-jumped
into the two phase region for phase separation, and annealed for a given duration.
The ﬁlms were rapidly quenched to room
temperature for the measurements. Figures
1 show the time evolution of neutron reﬂectivity proﬁles (a) and density proﬁles (b).
A typical example of time evolution of NR
proﬁles at 0, 1, 3, 120, 360 min after T-jumpfrom one phase region to two phase region
are shown in Figure 1(a). Time evolution of
the composition ﬂuctuations along z-axis
evaluated from NR proﬁles is shown in Figure 1(b). In one phase region (t = 0 min)the NR proﬁle is well described by threelayer model (PVME/(PVME/PS)/PVME),

one phase
1min
3min
6hours

400
600
800
1000
1200
0.0

0.5

1.0

1.5

2.0

2.5

3.0x10-6

Scattering length density/Å-2Fig. 1. Time evolution of neutron reﬂectivity in
two phase region (a)and Time evolution of composition ﬂuctuations in depth direction in two phaseregion(b).

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-5-17

Eﬀects of Temperature on the Shear-Induced Structural Transition in the Lamellar
Phase of Nonionic Surfactants
Yuriko Koasaka, Makiko Ito, Youhei Kawabata, and Tadashi Kato
Department of Chemistry, Tokyo Metropolitan University
In the past 10 years, much attention
has been paid to the effects of shear ﬂow
on the structure of a lamellar phase owing to the development of the apparatus
which enables us to determine their structures directly under shear ﬂow. In the previous studies, we have measured smallangle neutron scattering (SANS) on thelamellar phases of a nonionic surfactant
C16H33(OC2H4)7OH (C16E7) in D2O at
70C under shear ﬂow with shear rate of
0.01 - 10 s-1 which is much lower than thosefor other studies reported so far. We havefound anomalous decrease in the lamellar
spacing for the shear rate of 0.1-1 s-1 suggesting local phase separation into concentrated lamellar and water-rich regions [1,2].
In the present study, we have investigatedeffects of temperature on these structuraltransition.
Measurements of SANS were carried out
at the instrument SANS-U of Institute for
Solid State Physics of University of Tokyo
in JRR-3M at Tokai with a Couette shear cell
[3].
Figure 1 shows temperature dependenceof the repeat distance at 0, 1, and 3 s-1 forthe velocity-gradient direction for the sample containing 48 wt% of C16E7. The repeat distance at 1 s-1 decreases discontinuously at about 68C. At 3 s-1, on the other
hand, the repeat distance takes smaller values than at rest but suddenly increases atabout 70C. In our previous SAXS study on
the same system at rest, it has been foundthat the lamellae have water-ﬁlled defects
in the lower temperature range and that thefraction of these defects decreases with increasing temperature and disappear above
about 68C. So the present results suggestthat the discontinuous decrease in the re-peat distance by shear ﬂow is strongly correlated with the existence of the waterﬁlled defects.
References[1] T. Kato et al. Langmuir 20 (2004) 3504.
[2] T. Kato et al., J. Phys. Cond. Matt. 17(2005) S2923.
[3] Y. Takahashi et al., J. Soc. Rheol. Jpn. 28(2000) 187.
[4] K. Minewaki et al. Langmuir 17, 1864
(2001).

Fig. 1. Figure 1. Temperature dependece of therepeat distance at 0, 1, and 3 s-1 for the velocitygradient direction for the sample containing 48 wt%
of C16E7.

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1-5-18Pressure-Induced Phase Separation of Block Copolymers in Aqueous Solution
N. Osaka A , T. Karino A , S. Okabe A , M. Nagao A , M. Shibayama A , A. SasaiB , S. AoshimaB
A ISSP-NSL Univ. Tokyo, B Osaka Univ.
Recently, pressure effects on polymer
aqueous solutions have attracted attention
in the ﬁelds of industrial applications. On
the other hand, little work was done in basic polymer science, though pressure is an
important variable as one of the thermodynamic parameters. Therefore, we focus on
the phase behaviors and structural changeof polymers in D2 O by varying pressure
and temperature.
Block-copolymers, we used, are thermosensitive polymers, showing LCST
(Lower Critical Solution Temperature) at
about 40◦ C in D2 O. In the former study[1],phase behaviors at various pressures andtemperatures were intensively studied
with a concentrated polymer solution(15wt%). However, in that case, complex
interactions between micelles prevented
detailed and microscopic analyses ofthe polymers and the hydrated water.
Therefore, to understand the pressure
effect more quantitatively, dilute polymer
solutions (0.5wt%) where the micellarinteraction can be ignored was used in thisstudy.
Pressure dependent SANS experiments
were conducted with a pressure chamber,
PCI-400-SANS, Teramex, Co. Ltd. Kyoto,
Japan. The applied pressure was transmitted via a rubber diaphragm connectedto the inner cell made of aluminum withquartz and sapphire windows. The outerchamber was ﬁlled with D2 O and the pressure was controlled by pressurizing D2 O
by a double-cylinder hand pump. The
SANS measurements were done at T: 28,
40, 50◦ C and P: 0.1-400MPa. The SANS experiments were done according to the P-T
phase diagram obtained by dynamic lightscattering (DLS) experiments.
Micellization temperatures (MT) weredetected by DLS by increasing temperature
at ﬁxed pressures. By increasing tempera-ture, a new peak was observed, which is ascribed to the micellar diffusive mode. Obtained P-T phase diagram was a upwardconvex curve, which behavior is very similar with the former concentrated solution[1].
SANS experiments were done by pressurizing at ﬁxed temperatures. At 28◦ C
below MT, the block copolymers underwent micellization at high pressure. At
40 and 50◦ C, which were close to andabove MT, respectively, the micelles wereformed at ambient pressure. By pressurzing, the micelles were destroyed at near
100MPa and the block copolymers weredispersed. However, further pressurizing induced reentrant micellization at near
200MPa. Fig. 1 shows the schematic pictures of the same core-size-micelles at 50◦ C
at low pressure (left) and high pressure(right) obtained by ﬁtting the scattering
curves with the use of Pedersen’s micellar
model[2]. The water volume fraction in the
micellar core was larger at the high pressure than at the low pressure. This result
indicates that hydrophobic interacion important to form micelles was weak at highpressures and another competing interaction might be dominant at high pressures.
References[1] N. Osaka, M. Shibayama, Phy. Rev.
Lett. 2006, 96, 048303.
[2] J. S. Pedersen, M. C. Gerstenberg,
Macromolecules, 1996, 29, 1363.

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1-5-19Rheo-SANS behavior of Entangled Polymer Chains with Local Label Under Fast
Shear Flow
Hiroshi Watanabe (a), Toshiji Kanaya (a), and Yoshiaki Takahashi (b)Institute for Chemical Research, Kyoto University (a) and Institute for Material Chemistry andEngineering, Kyushu University (b)The shear-thinning of entangled polymer chains has been attributed to signiﬁcant orientation of the entanglement segments under the shear ﬂow. However, thechain conformation itself has been hardly
examined under the shear ﬂow, and no information is available for the orientation
distribution along the chain backbone.
For this problem, we have examined
the rheo-SANS behavior for polybutadiene (PB) samples dissolved in a deuterated oligomeric butadiene (oB) at the volume fraction of 0.28. The measurement was
conducted with the SANS-U spectrometerat the Neutron Scattering Laboratory, Institute for Solid State Physics, University ofTokyo. The incident beam diameter was
0.3 cm, and the sample-to-detector distance
was set at 4.0 m.
The PB samples were composed of
deuterated and protonated blocks (dPB
and hPB) and had almost identical molecular weights of the whole chain (M ˜ 120K)
and the hPB block (minor block; M[hPB]
˜ 20K). The location of the hPB block
was different for the samples. The PB1 and
PB2 samples had the hPB block at the end
and middle of the chain, respectively. The
hPB blocks were dilute and not overlapping with each other in the PB/oB systems.
The SANS data detected the conformationof these hPB blocks that corresponded totwo entanglement segments in the system(M[hPB]/Me˜ 2).
The SANS proﬁle was azimuthally symmetric at equilibrium but became a little
anisotropic under fast shear ﬂow in the
non-Newtonian regime. As an example ofsuch anisotropic proﬁles, Figure 1 shows
double-logarithmic plots of the scattering
intensity I(q) for the PB1/oB and PB2/oB
systems normalized by the volume fraction

and molar volume of the hPB block against
the scattering vector q normalized by theradius of gyration Rg of this block at equilibrium. The ﬁlled and unﬁlled circles indicate the intensity sector-averaged over 15
deg in the vorticity and velocity directions,
respectively. The solid curves indicate theDebye function that well described the dataat equilibrium. For clarity of the ﬁgure, theplots and Debye function for the PB2/oB
system are shifted downward.
For the data shown in Figure 1, the shear
rate normalized by the linear viscoelastic
relaxation time was kr = 24 (for PB1/oB)
and 29 (for PB2/oB). At these shear rates,
the viscosity of the systems was signiﬁcantly smaller than the zero-shear viscosity (by a factor of ˜ 40). Despite this nonlinearity, the I(q) data just moderately deviate from the Debye function (describing
the data at equilibrium); cf. Figure 1. The
anisotropy is larger for the PB2 chain having the hPB block at the middle than the
PB1 chain having the hPB block at the end,
but this difference due to the location of thehPB block is not very prominent.
These SANS data allow us to examine
the current molecular picture for the entangled chains under fast shear ﬂow. This
picture assumes that successive entanglement segments are not orientationally correlated and behave as independent stresssustaining units even under fast ﬂow. Under this assumption, a ratio of the hPB
block size in the velocity direction to that in
the vorticity direction was estimated fromthe nonlinear viscoelastic data. This ratio,
˜ 1.4, was too large compared to the ratio
estimated from the SANS data in Figure
1. Thus, the above assumption fails for theentangled chains under fast ﬂow. The successive entanglement segments appear to

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have the orientational correlation possibly
due to the dynamic tube dilation mechanism.

Fig. 1. Normalized I(q) data of the PB1/oB and
PB2/oB systems at 25C in the vorticity and velocity
directions (ﬁlled and unﬁlled symbols). The solid
curves indicate the Debye function describing thedata at equilibrium.

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1-5-20

Dynamics of aromatic molecules entrapped in the clathrate phase of syndiotactic
polystyrene
Fumitoshi Kaneko(A), Tatsuya Kawaguchi(A), Koichi Ute(B)Graduate School of Science, Osaka Univ.(A), Graduate School of Engineering Science, Osaka
Univ.(B)
Syndiotactic polystyrene (sPS) is a relatively new commodity polymer. It exhibits
a variety of crystalline states depending on
crystallization conditions, alpha and beta
of TT conformation and gamma, delta andempty-delta of TTGG conformation. The
appearance of the delta form is one of
the important characteristics of sPS. It isa clathrate crystalline phase with small
molecules, such as chloroform, benzene,
toluene, xylene and so forth. The guest
molecules are included in the cavities between polymer sheets of TTGG helical conformation. In this study we have investigated the dynamical properties of two
kinds of stored aromatic compounds, benzene and p-xylene.
In order to reduce the contribution ofsPS matrix to quasielastic neutron spectra(QNS), hydrogenated guest molecule wereincorporated into the cavities of sPS matrices prepared from fully deuterated styrene.
All QNS spectra were measured with
AGNES spectrometer of JRR3M (Tokai).
Figure 1 shows QNS spectra of thetwo sPS clathrates. As for the sPS(benzene)clathrate, the Q dependence of EISF suggests the rotational diffusion of benzene byjump motions among six sites around a circle with a radius of about 2.5A, i.e., thejump motion around the six-fold rotation
axis. p-Xylene shows a signiﬁcant Q dependence of EISF together with a widely
spread QNS components in the whole temperature region between 300 and 40 K.
The Q dependence of p-xylene is muchlarger than that of benzene even at 100K,
which cannot be attributed only to the rotational diffusion of methyl hydrogen atomby the three-site jump motion, although themethyl hydrogen atoms are the major scattering source in p-xylene. These character-istics of the QNS spectra indicates the existence of fast and large motion of p-xylene
molecules as a whole, probably a large librational motion of p-xylene.

Fig. 1. Figure 1. QNS spectra of syndiotactic
polystyrene clathrate phase containing benzene at
200K (a) p-xylene at 200K and 100K (b) and (c).

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1-5-21

Mobility of Polymer Chain in Clathrate Phase of Syndiotactic Polystyrene
T. Kawaguchi, F. Kaneko
Graguate School of Science, Osaka Univ.
Syndiotactic polystyrene (sPS) is widely
known to show interesting crystalline
phases. One of them is characterized by
the clathrate formation with various organic molecules, so called delta-form crystal. Recently, we reported that a wide rangeof compounds can be inserted as a guest
molecules by guest exchange phenomenon.
It became apparant that relatively large
molecules can be easily incoporated into
the cavity espesilly with a solution mixed
with penetrable solvents. We thought thatthe plasticizing effects the acceleration of
guest exchange. We aimed to produce a
new kind of polymer based functional materials and thought it is worth investigating
the chain dynamics in amorphous region ofsPS delta-phase.
We performed quasielastic scattering measurements on the inelastic neutron spectrometer, AGNES, installed at the JRR3M reactor. The sPS sample was supplied
by Idemitsu Petrochemical Co., Ltd. The
delta-phase samples of sPS were obtainedby exposing amorphous sPS ﬁlms, whichwere previously prepared by quenching
the melt in ice-water, to fully deuterated
toluene vapor at 300K for 3days. After exposure process, the sPS delta-phase samples were dried in a vacuum for 8h to eliminate excess toluene from amorphous region. The delta-phase samples were processed by treatment with boiling acetone
for 8h followed by washing with methanol
to prepare the delta empty-phase sample.
The delta-phase samples were inserted
into cells in two ways. First, the cell was
ﬁlled with delta-phase sample and a little amount of dueterated toluene providing saturated toluene vapor as a plasticizer,
denoted ”wet”. Second, the cell was ﬁlledwith delta-phase ﬁlms only, denoted ”dry”.
We calculate the mean square displace-ment <U2> from the momentum transfer Q dependence of the elastic scattering for each measurement. The <U2>s of”wet” is larger than others especially above
room temperature. The quasielastic scattering components of ”wet” are also larger
than others especially above room temperature. On the other hand, at a very low temperature, there are few differnces between<U2>s and/or S(Q,E) spectra of each samples.
We have been trying to analyse the data toobtain details.

Fig. 1. Figure 1. Temperature dependence of S(Q,w)
of ”wet” sPS delta-phase.

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1-5-22

Sol-gel transition of methylated polyrotaxane
T. Karino, Y. Okumura, M. Shibayama, and K. Ito
Institute for Solid State Physics, University of Tokyo, Graduate school of Frontier Sciences,
University of Tokyo, CREST, JST
Recently, we prepared successfully a new
type of polyrotaxane having hydrophobically modiﬁed α-cyclodextrin (CD). Methylated polyrotaxanes, which are substituted
the hydroxyl groups on CD with methylgroups, showed thermosensitive sol-gel
transition. In this experiment, we carriedout small-angle neutron scattering (SANS)
measurement in order to investigate thestructure change as a function of temperature.
Polyrotaxane was prepared frompoly(ethylene glycol) (PEG) and CD. The
molecular weight of PEG was 3.5×104 . The
ﬁlling ratio of CD was 27%. The hydroxyl
groups on CD molecules were substitutedby methyl groups using sodium hydrate
and methyl iodide. The degree of methylation was 60% (M60). SANS experiments
were carried out at the SANS-U spectrometer. The sample-to-detector distance was 2
and 8m. The temperature was varied from
20 to 80◦ C. The methylated polyrotaxane
was dissolved in D2 O.
Fig. 1 shows temperature dependenceof SANS intensity function, I(q), for M60.
I(q)s increase with increasing temperature. In particular, I(q) drastically upturns at 60◦ C, which agreed well with themacroscopic observation of sol-gel transition. The variation of these scattering proﬁles is similar to a sol-gel transition ofblock copolymer solution by temperatureinduced microphase separation.
In low temperatures, I(q)s decrease
monotonically as a function of q. Thismeans that the polymer solution was homogeneous. We estimated the correlation
length, ξ, by using the Ornstein-Zernikefunction for semi-dilute polymer solutions.
The obtained ξ was about 17Å. Above thegelation temperatures, Tgel , I(q) shows not
only a rapid increase of intensity but alsoa characteristic shoulder about 0.015Å−1 .
The inset in Fig.1 shows the so-called
Kratky plot ( i.e., q2 I (q) vs q) for T > Tgel .
In the gel state, the Kratky plots show a single peak. In order to elucidate the gel structure, we evaluated the characteristic size of
inhomogeneities in the gel sate using thefollowing equation,
I (q) = I (0) exp(− R2G q2 )(1)

where RG is the radius of gyration, I (0)is zero-scattering intensity. In this case,
RG means the size of the hydrophobic domains. The obtained RG was about 160Å.
The following facts were disclosed. CD
molecules on PEG are dispersed homogeneously below Tgel . On the other hand,with increasing temperature, CD molecules
are aggregated each other due to hydrophobic interaction of methyl groups on
CD. These aggregations play as a role ofphysical cross-linking points[1, 2].
References[1] T. Karino et al.:Macromolecules 39(2006)9435.
[2] T. Karino et al.: Macromolecules 40 (2007)
in press.

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1-5-23

Neutron spin echo studies on bending modulus of bilayer membrane in
DGI/SDS/D2O system
H. Mayama, X. -J. Chen, M. Nagao, H. Seto and K. Tsujii
Hokkaido Univ., Univ. of Tokyo, Kyoto Univ.
Dynamics and bending modulus of ndodecylglyceryl itaconate (DGI) bilayer
membrane in a DGI/SDS/D2 O systemwere studied. The DGI membrane shows
iridescent color from blue to red becauseof Bragg diffraction when the distance between the DGI membrane reach the order of 200 nanometer by the change in theconcentrations of DGI and SDS. However,
the reason why the distance is extended
so large is still unclear. In order to makeclear this, we investigated dynamics andbending modulus of DGI membrane using
a neutron spin echo spectrometer and analyzed them along the Zilman and Granek
model (Phys. Rev. Lett. 77, 4788 (1996)).
In our experiment, DGI concentration
was ﬁxed at 1.6 wt % (44 mmol l−1 ) andSDS concentration was changed and temperature was ﬁxed at 56 - 58 ◦ C. At lower
concentration of SDS the color is red, however, the color shifts to blue with an increase of SDS concentration. We adopted
red sample (No. 1, [SDS] = 4 ×10−4 wt %SDS, 1.1 ×10−2 mmol l −1 ) and green one(No. 9, [SDS] = 2.7 ×10−3 wt %, 7.43 ×10−2
mmol l−1 ), where the interplanar distanced was determined to be 240 nm and 220 nm
for No. 1 and 9 samples, respectively.
Figs.
1 and 2 show dependence
of intermediate correlation function
I ( Q, t)/I ( Q, 0) on Fourier time t forNo.
1 and 9 samples, respectively.
The dotted lines are ﬁtting lines by
I ( Q, t)/I ( Q, 0) ∝ exp[−(ΓQ t)2/3 ], which is
obtained from Zilman and Granek model,
where Γ is coefﬁcient containing some parameters. It is expected that data scatteringof No. 9 samples is arising from the beamline condition, not originated from sample.
Figs. 3 and 4 indicate the dependenceof ΓQ on wave number Q. According

to the model, ΓQ ∝ AQ3 , where AQ =0.0025γkB T 3/2 κ −1/2 η −1 , γ is almost constant (∼ 1), κ is the bending modulus, η isthe viscosity of ﬂuid. The solid lines are ﬁtting results on the basis of the model andthe obtained indexes are 3.19 and 2.97 forNo. 1 and 9 samples, respectively. The
values are good agreement with that of themodel. Next, from the obtained A, γ = 1,and η = viscosity of bulk water at the absolute temperature T, we obtained κ =6.7kB T and 34.3kB T for No.1 and 9 samples.
The experimental results can be thus described by the model. Let’s discuss the reason why the addition of SDS reduce d. The
obtained κ rapidly increases from 6.7kB T
and 34.3kB T. This may be explained byfollowing scenario. In the solution, dissociated SDS molecules are adsorbed on thesurface of bilayer membrane because of hydrophilic interaction and then the charge
density on the surface is increased. At
lower SDS concentration, the membrane is
ﬂexible and can ﬂuctuate. However, withthe addition of SDS the membrane becomes
stiff and the amplitude of ﬂuctuation becomes small. Thus, the interplanar distanceis decreased. In order to understand full
scenario, further experiment is required.

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Fig. 1.

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1-5-24Structural study for Thermoplastic Elastomer Consist of Carboxyl-terminatedTelechelic Poly(ethylene-butylene) and Stearylamine
Yoshiaki Takahashi and Akihiko Takada
Institute for Materials Chemistry & Engineering, Kyushu University
1. Introduction
Carboxyl-terminatedtelechelicpoly(ethyrene-butylene) (CTPEB) andstearylamine (Octadecylamine; ODA) mixtures show a very interesting rheologicalproperties which is quite similar to thermoplastic elastomers as mentioned below.
To understand the origin of the rheologicalproperties, it is essential to analyze thestructure. Since the main repeating unitsof CTPEB and ODA are CH2, such study
can be performed only by means of SANS
measurements using deuterium-labeled
samples. Unfortunately, we could not havebeam time for this study but preliminary
measurements are carried out during IRT
work. Here we brieﬂy report the resultswith rheological properties and othercharacteristics of the system.
2. Preparation, characterization and rheological properties of the sample
The number averaged molecular weight of
CTPEB was 1400. CTPEB and ODA are dissolved in toluene and they are mixed at acondition the moles of carboxyl and amine
residues become the same, then the solvent was removed in a vacuum oven. The
sample thus prepared had a thermal transition peak in DSC thermogram at around
310 k. IR spectroscopy and WAXD analysis did not show any evidence of formation of large ionic complex but existence ofsmall amount of crystalline of stearylamine
at low temperature and its disappearance
at elevated temperature.
Dynamic viscoelastic measurements werecarried out in a temperature range of 283 ?
343 k. At low temperatures, elastomeric behavior was observed in full range of tested
frequency (0.1 ? 100 rad/sec). That is, storage moduli G were always higher thanloss moduli G and G was almost constantat the order of 0.5 MPa. On the other hand,liquid like behavior similar to the behaviorof pure telechelic polymer was observed atelevated temperature. Stress-strain curves
obtained at 298 k with different shear rates
showed that non-linear behavior starts ataround 1 % strain and the maximum ofstress is observed at around 100 % strain.
Thus, dynamic viscoelastic properties ofthis system in linear region are similar tothermoplastic elastomers; that is, elastic at
low temperature and liquid like at elevatedtemperature. However, it is a very fragile
elastomer.
3. SANS measurements
Deutrated CTAB was prepared by adition reaction of deuterium gas to carboxylterminated polybutadiene. The SANS measurements are performed by SANS-U spectrometer at the Neutron Scattering Laboratory of the ISSP, The University of Tokyo,
established at C1-2 beam line of JRR3M in
JAERI (Tokai), Ibaraki, Japan. The wavelength and beam size of incident neutrons
was 0.7 nm and 3 mm?, respectively. The
temperature were 298 (elastic state) and to
338 k (liquid-like state).
The data at high q are almost the same irrespective of temperature. The data at low
q become higher at the lower temperature,
while it dropped to background level at
the higher. At the lower temperature, there
existed a small shoulder at around q =1.2 (1/nm), which is close to the peak position for aluminum tri-stealyrate/decalin
system studied previously. Note that aluminum tri-stealyrate/decalin system show
gel-like behaviors and the peak positionis very close to that of crystalline ofstealyrate derivatives. Thus we speculatethat stealyrate residues in CTPRB/ODA
still have ordered structure inside the networked structure, though the regularity ismuch lower than that in the crystals. To

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clarify the structure, further works are definitely needed.

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1-5-25

Thermal transition of viscoelasticity and association structure of small molecule
gelator with metal ions
Akihiko Takada and Yoshiaki Takahashi
Institute for Material Chemistry and Engineering, Kyushu University
1. Introduction
It is known that some groups of small
molecules associate with each other to forma large size of aggregate in solution state.
Such solutions show some speciﬁc viscoelasticities such as gelation and large viscosity. Among such small molecules, small
molecule galator containing metal ions is
one of major interesting groups. We investigated such small molecule gelator andfound that some of them showed thermaltransition on viscoelstic properties, suchas complexes of alkyl triazine and platinum or copper and so on. We preliminary
found some of the small molecule gelators with metals showed a heat-set type ofthermal gel-transition. In this study, we investigated thermal transition of viscoelsticity and association structure of such small
molecule gelators containing metal ions.
2. Rheological properties of the samples
We prepared complexes of alkyl triazine
and metals such as platinum and copperwith the molar ratio of 3:1 in tetrachlorocarbon, chloroform and dichloromethane.
These complexes showed highly viscous
property at room temperature. When thesolution of platinum complex was heated
to 50oC, the viscous solutions changed intogels even when their concentration was below 1wt%. Dynamic viscoelstic measurements on these solutions showed that, at
higher temperature, the storage modulus
G was almost independent of angular frequency and almost one order higher thanloss moduls G , which conﬁrmed that the
sample was gel in this state. On the other
hand, at lower temperature regions, G became higher than G for low angular frequency regions. Creep and creep recovery
measurement conﬁrmed ﬂow property ofthe samples. The thermal transition was
found to occur between 30oC and 50oC.

Furthermore, the transition was found to
be reversible.
3. SANS meaturements
SANS measurements were carried out by
SANS-U spectrometer at the Neutron Scattering Laboratory of the ISSP, The University of Tokyo, established at C1-2 beam lineof JRR3M in JAERI (Tokai), Ibaraki, Japan.
The wave length and beam size of incident
neutrons was 0.7 nm and 3mm, respectively. The temperature was 25oC. Tetrachloromethane and deutrated chloroform,
dichloroethane and decaline were used assolvents.
The atom of chlorine is know to have large
absorption property of neutron. The solvents used in this study contained chlorine atoms, so that it needed to spend longtime to carry out scattering measurements.
For tetrachloromethane solutions, we musthave spent more than ten hours on one
shot measurements and could not haveenough high contrast data to analyze thescattering proﬁle to manifest the structure
after substruction of background scattering. As for deutrated dichloroethane, we
can meatured scattering proﬁle by several
hours measurement for one shot. However, as well known, its boiling point is nothigh enough to analyze the thermal transition of the gels at high temperature exceeding 50oC. In this study, we found that
deuterated chloroform can be used to measure for the thermal transition of association structure when we spend at least several hours on one shot measurement. Fromthe measurement of the deuterated chloroform sample, the gelator formed one dimensional aggregate with diameter around
3nm at room temperature. In this study,
we could not measure at the other temperatures. However, it is found that further
measurements must manifest details of the

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thermal structural change of the metal containing small molecule gelator.

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1-5-26Structure Analysis of Silicon Nanosheets Synthesized from Layered Compounds
Masashi Harada1 and Yushu Matsushita2

1 Toyota Central R&D Labs. and 2 Nagoya University

We have recently synthesized a new material ofsilicon nanosheet , which isa monolayer of silicon atoms forming a
ﬂexible two-dimensional crystalline structure with a thickness around 1 nm anda lateral size of sub-micrometer.[1] Since
silicon is one of the most important elements in the modern technology and thetwo-dimensional structure induces attractive properties from quantum size effects,
the silicon nanosheets are very promisingfor various applications. Structures of thenanosheets have been studied by transmission electron microscope (TEM) and atomic
force microscopy (AFM). Although TEM
and AFM are useful for the structure analysis of the nanosheets on grids and substrates, they can not apply for those in dispersions. Thus, measurements of smallangle neutron scattering (SANS) are employed to evaluate the structures of the silicon nanosheets in a dispersion.
SANS was measured for a hexane dispersion of the silicon nanosheets in concentration of 1 wt%. Deuterated hexane
is used to reduce the background fromincoherent scattering and to enhance thecontrast against neutrons.
The siliconnanosheets were synthesize by exfoliating layered polysilane (Si6 H6 ) by 1-hexene
with a catalyst under high temperature,
where the hexcyl groups are considered to
be grafted onto silicon monolayers. The
SANS measurements were performed at
SANS-U in JRR-3M (Tokai, Japan). The
wavelength was 7 Å and the sample-todetector distances were chosen to be 1, 2
and 8 m.
Figure 1 shows a SANS proﬁle in loglog plot obtained from a dispersion of thesilicon nanosheets. The proﬁle presents astraight line in a q range of q<0.2 Å−1 . The
slope of -1.6 indicates a fractal structure,
which is smaller than -1 for thin rods andlarger than -2 for thin disks in dimension.
At q∼ 0.2 Å−1 the line bends down. It
is evaluated from this crossover point thatthe silicon nanosheets have a thickness ofabout 30 Å (=2π/0.2Å−1 ). The size of thenanosheets can be estimated to be over 600
Å since the straight line hold at least q=0.01
Å−1 . The thickness and size are consistentof the results of TEM and AFM, although
the fractal property is unexpected.
It would be necessary to conﬁrm this interesting structure of the silicon nanosheets
by investigating more samples with various methods. Dispersions prepared in different synthesis condition will be the next
target for SANS experiments.
References[1] H. Nakano, T. Mitsuoka, M. Harada, K.
Horibuchi, H. Nozaki, N. Takahashi, T.
Nonaka, Y. Seno and H. Nakamura, Angew.
Chem. Int. Ed. 6303, 45 (2006)

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1-5-27

Mesoscopic structure in near-critical mixtures of D2 O and 3-methylpyridine withsalts
Koichiro Sadakane, Hideki Seto, Hitoshi Endo1 , and Masahiro Kojima
Department of Physics, Kyoto University, 1 Institute for Solid State Physics, The University ofTokyo
Solvation effects on phase separations associated with critical phenomena have verymuch interested many researchers not onlyin the ﬁeld of chemistry but also of physics.
A large number of papers have been devoted on this problem from theoretical andexperimental approaches. One of the mostwell-known system is an alcohol and water
mixture. Addition of small amout of salt induces interesting behavior such as the reentrant phase separation phenomenon. By
the solvation effects of ions, the clusteringof polar molecules occurs and could be theorigin of these behaviors.
The 3-methylpyridine (3MP) and water are known to mix uniformly at room
temperature and separate into two phaseswith increasing temperature, and criticalphenomena due to the density ﬂuctuation
could be observed near the critical point.
The addition of salts, such as NaBr, results in the decrease of the critical temperature and the reentrant phase separation behavior. Jacob et al. have already investigated this behavior mainly by DLS [1] andSAXS[2], and showed that clustering of water molecules around ions is induced andthe critical crossover behavior from meanﬁled to 3D-Ising is observed because the interaction responsible to the phase separation is more long-ranged due to the clustering.
Theoretically, Onuki and Kitamura considered the solvation effects in near-criticalbinary mixtures.
[3] They applied a
Ginzburg-Landau theory to the density
ﬂuctuation of ciritcal mixtures with salts,
and showed that the concentration has
a longranged Ornstein-Zernike tail representing strong critical electrostriction withapproaching the critical point. As a result, adrastic shift of the critical temperature andthe formation of large scale clusters willarise due to strong coupling of the critical density ﬂuctuation and the ions. This
theory can give a uniﬁed understanding of
the effects of salts to the phase separation
behavior associated with critical phenomena from the viewpoint of the statisticalphysics.
In this viwpoint, we have measured thedensity ﬂuctuation near the critical temperature of the binary and the ternary mixtures of 3MP, deuterated water with andwithout salts by SANS. The result of the
mixture without salt indicates that the critical phenomena belong to the standard universality class for a low-molecular weightbinary solution; the SANS proﬁles are explained by the Ornstein-Zernike function
and the critical increases of the osmotic
compressibility and the correlation length
could be explained with the critical indexof γ = 1.26 and ν = 0.63 (3D-Ising behavior). On the other hand, the SANS proﬁles from the ternary mixtures could not be
explained with the Ornstein- Zernike function. In order to analyze the data, we assumed spherical shape clusters exist evenin one phase region. Thus, we tried to apply the scattering function as follows,
I ( Q) =wheref ( R) =I0+C
1 + ξ 2 Q2
(

Z+1
Rm

) Z +1∫ ∞Z

0 f ( R)| F ( Q, R)|2 dR,(1)[

R exp −

(

Z+1
Rm

) ]
R /Γ( Z + 1),(2)
where the ﬁrst term of the ﬁrst equation corresponds to the density ﬂuctuation which is identical with the OrnsteinZernike function and the second term

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JAEA-Review 2008-067

comes from the form factor from sphericalclusters with Schultz size distribution. R is
a radius of cluster, Z is a width parameter,
Rm is a mean radius of cluster, Γ is gammafunction, and C is a constant.
Figure 1 shows the SANS proﬁle of
3MP/D2 O with small amount of KCl.
These proﬁles are well explained withthe above function, which means that themesoscopic size cluster exists in the present
system. Temperature dependences of theosmotic compressibility, I0 , and the correlation length, ξ, follow the 3D-Ising criticalbehavior.
The estimated cluster size, Rm , becomeslarger with approaching the critical point.
This evidence indicates that the mesoscopic
size cluster is formed near the critical point
and their size increases with approaching
the critical point. These behaviors werealso observed in other ternary mixtureswith NaCl and MgSO4 [4]. These are theﬁrst evidence that the coupling of the solvation effect and the critical density ﬂuctuation induces mesoscopic scale clusters.
References[1] J. Jacob, A. Kumar, M. A. Anisimov, A.
A. Povodyrev and J. V. Sengers, Phys. Rev.
E, 58, 2188 (1998).
[2] J. Jacob, A. Kumar, S. Asokan, D. Sen,
R. Chitra and S. Mazumder, Chem. Phys.
Lett., 304, 186 (1999).
[3] A. Onuki and H. Kitamura, J. Chem.
Phys., 121, 3143 (2004).
[4] K. Sadakane, H. Seto, H. Endo and M.
Kojima, J. Appl. Cryst., in press.

Fig. 1. The upper ﬁgure indicates the SANS proﬁlesnear the critical point. These proﬁles are ﬁtted witha sum of the Ornstein-Zernike funtion and the scattering from spherical clusters indicated in the lower
ﬁgure.

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1-5-28The ”swollen phase” and the ”anomalous swelling” in DPPC aqueous solution
with ethanol
Hideki Seto, Mafumi Hishida, Koichiro Sadakane, and Norifumi L. Yamada1
Department of Physics, Kyoto University, 1 Institute of Materials Structure Science, HighEnergy Accelerator Research Organization
Lipid bilayers are investigated by many
researchers in these decades as model biological membranes not only from a viewpoint of biology but also of physics. They
exhibit a richness of structures and phaseequilibria depending on their environmental conditions such as water content, ionicstrength, temperature, pressure, etc. A
ﬂuid lamellar phase (liquid-crystalline Lαphase) is a basic structure of biologicalmembranes that appears at higher temperature. In this phase, bilayers are regularly
stacked and ﬂat on average, forming multilamellar vesicles. With decreasing temperature, several thermotropic phase transitions have been observed; a main transition from the liquidcrystalline phase toa gel (Pβ� ) phase and a pre-transition
from the Pβ� to another gel (L�β ) phase. In
these gel phases, the hydrophobic tails of
lipid molecules are extended and ordered,
whereas the tails are conformationally disordered in the liquidcrystalline phase. In
the middle-temperature Pβ� phase, a twodimensional lattice structure is formed inwhich the lipid bilayers are distorted by aperiodic ripple in the plane of lamellae. Recently, the authors showed the existence of
new swollen phase , in which the thickness of lipid bilayers is almost the same asin the gel phases and only the thicknessof the water layer is larger than the otherphases, is conﬁrmed between the Lα phaseand the L βI phase. [1] This phase is induced only by increasing pressure (without adding ethanol) and only by adding
ethanol (without increasing pressure). The
nature of this phase is similar to the anomalous swelling observed between the liquid
crystalline phase and the ripple gel phase.
[2]

References[1] H. Seto, H. Nobutou, N. Yamada, T.
Takeda, D. Ihara, M. Nagao, and K. Inoue:
J. Appl. Cryst. 36 (2003) 607.
[2] N. Chu, N. Kucerka, Y. Liu, S. TristramNagle, and J. F. Nagle: Phys. Rev. E 71
(2005) 041904.

1

T=46.5°C
43.5°C
42.9°C
41.5°C

0.1

0.01

0.10

0.11

0.12

0.13

0.14

0.15

Fig. 1. The temperature dependence of the decay rate of the intermediate correlation function observed by NSE.

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1-5-29In-situ and Real-time Observation of Simultaneous Living Anionic
Copolymerization Process and Polymerization-Induced Self-Assembly by SANS,
UV-vis, GPC and NMR
Y. Zhao, N. Miyamoto, S. Koizumi and T. Hashimoto
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195

We proceeded a typical simultaneous living anionic polymerization of isoprene (I)and styrene-d8 (S) in benzene-d6 as a solvent, with sec-buthyllithium as an initiator, into a block copolymer polyisoprene-βpolystyrene-d8 .1) The difference of reactivity
between two monomers produced the block
copolymer. A specially designed combinationof four techniques, including time-resolved
small angle neutron scattering (SANS), UVvis spectroscopy, gel permission chromatography (GPC) and nuclear magnetic resonance (NMR) were employed in a single
batch, which enabled us to observe thereal-time polymerization process and thepolymerization-induced self-assembling structures during the reaction. Our results revealed three time regions, as shown in Fig.1.
(I) Region 1: On one hand, the intensityof the SANS profiles keeps as a constantand no scattering peak appears, however, themolecular weight keeps increasing, it indicates that mainly homopolymerization is going on. On the other hand, UV absorbance at
450 nm, which is only sensitive to polystyryllithium living end, does not change withtime, indicating that polyisoprenyllithium isdominant but that polystyryllithium is not.
Therefore, in region 1, mostly polyisoprene
blocks are growing. (II) Region 2: UV absorbance at 450 nm increases slowly, revealing that polystyryllithium is generated slowly
with time. A broad peak shows up on the
SANS profile, and the peak intensity is increasing slowly, which means that some PS
segments are formed. In addition, the molecular weight of the polymer is increasing slowly.
All the data demonstrates that the living
chain ends start to gradually change from isoprenyllithium to styryllithium. Further NMR
analysis offers reliable monomer conversions
原子炉：JRR-3

装置：SANS-J(C3-2)of both isoprene and styrene. The tapered
structures are confirmed. (III) Region 3: Allof UV absorbance, peak intensity of SANS
profile and molecular weight increase significantly, denoting that PS blocks are growing rapidly. With the volume fraction of a
PS block increases, polymerization-induced
microphase separation is possibly occurring.
Time-resolved SANS enables us to follow themorphology change as shown in Figure 2.

Figure 1: Three time regions defined by SANS, UV-vis
and GPC.

Figure 2: SANS profiles in Region 3.

References
1) K. Yamauchi, T. Hashimoto, et al., Macromolecules,
39, 4531(2006).

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JAEA-Review 2008-067

1-5-30In Situ Observation of the Formation of Actin and Polycation Complexes
T. Masui1 , K. Shikinaka2 , H. J. Kwon2 , S. Koizumi1 , T. Hashimoto1 ,H. Iwase1 , A. Kakugo2 and J. P. Gong2
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810
1

原子炉：JRR-3

装置：SANS-J(C3-2)

105
KCl [M]
0.40
0.35
0.30
0.25
0.20
0.15
0.10

104

10

3

10

2

101

10

0

10

-1

10

-2

10-3 34 5 6 78

0.1

2

3

4 5 6 7821

-1

q (nm )

Figure 1:
SANS profiles from the actin and
PDMAPAA-Q complexes for various KCl concentration.

3.0x10-2

9.0
8.5

2.5

8.0
2.0
7.5
1.5
7.0
1.0

6.5
6.0
0.0

Width [nm]The actin was extracted from the adductor
muscle of scallops by the method of Spudich
and as a model of ABPs we used an artificial cationic polymer PDMAPAA-Q. In Fig.1
we show SANS profiles from the actin and
PDMAPAA-Q complexes for various KCl concentration, where the concentration of actin
and polymer are kept constant. At low concentration of KCl, F-actin forms bundle structure as shown by one distinct peak at q = 0.08
Å−1 . The increase of KCl brings the peak position to lower q and sharpens its peak. By
the further addition of KCl, the SANS profiles changed dramatically at KCl = 0.35 M,
which means that the bundle structure disassemble to the native filamentous actin. From
the first peak we estimated the repeat distance of F-actin inside the bundle d and peakwidth which is the measure of the orderliness of the actin alignment(Fig.2). Our re-sult shows that the slight fluctuation of salt
concentration brings dramatic change of thecomplex structures, which is important to regulate the motility of cell.

Intensity (a.u.)

Actin is one of the most abundant cytoskeleton proteins in eucaryotic cell. They
play a crucial role in cell motility by polymerizing monomeric globular G-actin intopolymeric filamentous actin (F-actin). Withactin-binding proteins (ABPs), they form
higher order structures such as linear bundles, two-dimensional networks and threedimensional gels. It has been consideredthat these structures are controlled by ABPs.
However, a recent study has shown that the
only one kind of artificial cationic polymer canform variety of structures depending its concentration and salt concentration.1) This system is a good model to elucidate the mechanism of regulation of actin and ABPs complex structure. Based on these backgrounds,
we have investigated the effects of salt concentration on the stability and structure ofactin-polycation complexes by using a small
angle neutron scattering (SANS) technique.

distance [nm]

2

0.1

0.2

0.3

0.5
0.4

KCl [M]

Figure 2: Repeat distance of actins inside bundles andthe width of the first peak as a function of KCl concentration.

References
1) H. J. Kwon, A. Kakugo, K. Shikinaka, Y. Osadaand J. P. Gong, Biomacromolecules, 6, 3005(2005).

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1-6-1

Diversity of protein dynamic structure observed by solution inelasitic neutron
scatttering
H. Nakagawa[1], Y. Joti[2], O. Yamamuro[2], I. Tsukushi[3], K. Shibata[1] and M.
Kataoka[1,4][1] JAEA, [2] Univ. Tokyo, [3] Chiba Inst. Tech. and [4] NAIST
Protein expresses biological functions under physiological conditions, generally inaqueous solution. So far, inelastic neutron
scattering experiments of biological specimens are performed with the hydrated
powder state to avoid the strong scatteringfrom solvent. However, solution inelastic
neutron scattering experiments are emerging in the literature recently, which is stillchallenging. We performed solution scattering experiments with the AGNES using
Staphylococcal nuclease (SNase). We measured the scatterings from both native stateand heat-denatured state. We also measured the scattering from the truncated mutant. The truncated mutant is SNase without C-terminal 13 residues, which takes acompact denatured structure under a physiological condition. Figure shows the scattering proﬁles of these three samples. Heatdenatured state as well as the truncatedmutant showed larger quasi-elastic scattering intensity than the folded state, while
EISF signiﬁcantly decreases with the heatdenaturation. The appearance of quasielasitc scattering indicates that the protein
structure deviates dynamically within theobservable time scale of a few tens ps. The
difference in EISF suggests that the heatdenatured state can take wider conformational space. These results indicated thatthe truncated mutant is dynamically different from the heat denatured state, although
the truncated mutant takes a denaturedlike structure. The present preliminary dataclearly show that the inelastic scattering
study with solution sample is promising.
The quantitative analysis of solution inelastic neutron scattering will make it possible
to characterize the dynamical properties ofproteins in natural condition.

Fig. 1. Solution inelastic neutron scattering spectraof SNase in three states, native, heat-denatured andtruncated mutant.

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1-6-2

Solvent eﬀect on structure and dynamics of beta-lactoglobulin in alcohol-water
mixturesK.Yoshida and T. Yamaguchi
Department of Chemistry, Faculty of Science, Fukuoka University
The effect of alcohol on denaturation ofprotein is known in biophysics and biochemistry ﬁelds. Alcohols have a tendency
to increase the content of α-helix structure
in proteins. So far, the secondary structure of α-helix forming peptide and protein, Melittin and β-lactoglobulin (BLG),
was investigated in aliphatic and ﬂuorinated alcohols-water mixtures [1]. The denaturation effect of these alcohols changes
according to the size and nature of the hydrophobic groups of the alcohols. However, an underlying mechanism in alcohol
denaturation of proteins is still unclear. The
investigation of conﬁgurations (size, shapeand aggregation of proteins) and diffusive
dynamics of proteins in alcohol-water mixture will help us to understand the mechanism of alcohol denaturation of the protein.
In the present study, small-angle neutron scattering (SANS) of BLG in ethanoland triﬂuoroethanol(TFE)-water mixturesin order to reveal thewas measured
solvent effect on three-dimensional structure and aggregation state of BLG. Neutron
spin echo (NSE) of BLG in water was alsomeasured to reveal the diffusive dynamics of BLG. To minimize the contribution of
exchangeable hydrogen atoms of the protein, BLG powder was dissolved in D2 O
and then was lyophilized. The dried BLG
powder obtained was dissolved in ethanolD2 O and TFE-D2 O mixtures. The SANS of
BLG in both mixtures was measured at 298
K. Concentrations of BLG solutions were 5,
10, and 20 mg ml−1 for each solvent. A
sample was kept in a quartz cell of 2-mm
path length. The cell was inserted into atemperature-controlled chamber. The distances between the sample and detector
were 1 and 4 m, corresponding to Q of 0.007- 0.3 Å−1 . Measurements were also madefor background, solvent, and lupolen used

for intensity normalization. The NSE signal
for an D2 O solution of BLG of 40 mg ml−1
was measured at 298 K. A sample was kept
in a quartz cell of 2-mm path length. The
scattering vector Q covered was 0.055 - 0.12
Å−1 . The Fourier time was varied from 0.15
to 15 ns. The temperature of sample wascontrolled within ± 0.3 ◦ C with circulated
water.
Figure 1 shows SANS proﬁle of BLG
in ethanol-D2 O mixture at various ethanol
volume fractions. The peak corresponding to the correlation between proteins wasobserved at 0.08 Å−1 in ethanol-D2 O mixture of 10 vol% ethanol. With increasingof ethanol fraction, the peak position does
not change up to 30 volFor BLG in TFEwater mixtures, the position of the correlation peak between proteins drasticallyshifted to a small Q region at ∼20 vol% ofTFE. In analogy with the case of ethanolwater mixture, the speciﬁc TFE composition of the structural transition of BLG isconsistent with that for solvent structuretransition from the tetrahedral-like water
clusters to the chain-like alcohol ones for
TFE-water mixture. The NSE signal of BLG
in D2 O could be simulated by the single exThe relaxation timeponential function.
obtained at Q = 0.102 Å−1 was 13.1 ns. We
will discuss the correlation between diffusion constant and three-dimensional structure of BLG obtained from SANS. The further analysis is in progress. [1] D. Hong,
M. Hoshino, R. Kuboi, and Y. Goto, J. Am.
Chem. Soc. 121, 8427 (1999). [2] M. Matsumoto, N. Nishi, T. Furusawa, M. Saita,
T. Takamuku, M. Yamagami, and T. Yamaguchi, Bull. Chem. Soc. Jpn. 68, 1775
(1995).

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JAEA-Review 2008-067

Fig. 1. SANS proﬁles of BLG in ethanol-water mixtures at various ethanol volume fractions.

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1-6-3

Small-Angle Neutron Scattering Study on Hydrated Short Lamellar Structure in
Mammal’s Skin Stratum Corneum
H. Takahashi (A), N. Kunizawa (B), Y. Obata (C), N. Ohta (D), I. Hatta (E)(A) Gunma Univ., (B) Shiseido Co., Ltd., (C) Hoshi Univ., (D) SPring-8/JASRI (E) Fukui
Univ. Tech.
INTRODUCTION
In mammals, the permeability barrier that
restricts excess water loss is maintained bymultilamellar structure membranes localized in the intercellular space of the stratum corneum (SC), the outmost layer ofthe epidermis. The multilamellar structures
in SC are classiﬁed mainly into long andshort lamellar structures with repeat distances of about 13 and about 6 nm, respectively. In certain species, however, the shortlamellar structure is not observed by Xray diffraction. The problem whether both
long and short lamellar structures exist universally in all mammal’s SC remains unsolved. Ohta et al. [1] have proposed that
the SC permeability barrier function depends mainly on the short lamellar structures. Thus, from the viewpoints of thebarrier function, the universality of shortlamellar structure existence is an important
problem.
One of advantages of neutron scattering
techniques as compared to X-ray techniques is that one can change contrast
of samples by using isotope substances.
It is believed that there are water layers in the short lamellar structures in SC.
Thereby, it is expected that the contrast of
SC sample can be enhanced by treatingwith D2O, and that, even in undetectablecases by X-ray techniques, the short lamellar structures can be clearly detected by using small-angle neutron scattering (SANS)
techniques.

rated from a skin. All samples were driedinitially and then soaked in 100% D2O.
The water (D2O) contents of the samples
were determined by measuring the weight.
SANS measurements were performed with
the SANS-U spectrometer, (C1-2, JRR3M
in ISSP, Tokai, Univ. of Tokyo). The wavelength of the neutron beam was 0.7 nm andtwo different camera lengths (1m and 4m)
were used.
RESULTS AND DISCUSSION
Figure 1 shows SANS proﬁles from pig
SC sample containing 40% water (D2O). A
weak but relatively sharp diffraction peakis observed around Q = 1.0 nm-1 from
25 oC to 45oC. Judging from the spacing,
the peak corresponds to the short lamellar structure. For other animal samples,such peak was not observed. To get further
detailed information on the short lamellar
structure, we are planning to perform contrast variation experiments.
[1] N. Ohta, S. Ban, H. Tanaka, S. Nakata
and I. Hatta, Chem. Phys. Lipids vol. 123(2003), pp. 1-8.

EXPERIMENTAL
The SC samples used in this study wereprepared from three different animals, i.e.,rat, mouse, and pig. According to themethod reported in [1], SC was sepaActivity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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1-6-4

Analysis of F-actin dynamics
Satoru Fujiwara, Fumiko Matsumoto, Nobuaki Takahashi, Hiroshi Nakagawa, and*Toshiro Oda
Japan Atomic Energy Agency, and *RIKEN SPring8-center
Actin, highly ubiquitous protein in eukaryotic cells, plays crucial roles in various
aspects of cell motility. The actin monomers(G-actin) polymerize into ﬁlamentous form
(F-actin). This polymerization, controlled
through interactions with various proteins,and ﬂexibility of F-actin have been shown
to be the key features in the functions ofactin. It is therefore important to understand how the dynamics of actin at various levels, from the internal dynamics of Gactin to ﬂuctuation of F-actin, are related tovarious functions of actin. Here, as one ofthe projects towards ultimate understanding of the dynamics of actin at various levels, we carried out neutron spin-echo (NSE)experiments on actin. NSE spectroscopy
is a quasielastic neutron scattering technique that can study long range relaxation
processes in a macromolecule on nano-sec
timescales and nano-meter length scales.
Actin was puriﬁed from rabbit skeletal
muscles. Actin was polymerized by adding
KCl to form F-actin. In the preparation of
G-actin, actin labelled by the ﬂuorescentprobe tetramethyl-rhodamine-5-maleimide
was used to block polymerisation (Otterbein, Graceffa, and Dominguez, 2001). Solutions of G-actin and F-actin were prepared in D2O. The NSE measurements onthese solutions were carried out on the
NSE spectrometer, iNSE, run by the University of Tokyo instruments, installed at
the guide hall of the research reactor, JRR3M, Ibaraki, Japan. From the set-up ofthese NSE measurements, information on
the dynamics of actin on timescales up
to 15 nsec and on length scales from 5
to 15 nm should be obtained. Figure 1
shows the normalized intermediate scattering functions of G-actin and F-actin.
The functions at several representative Qvalues were plotted against Fourier time.

Clear differences in the spectra between
G-actin and F-actin were observed. Whilethe normalized intermediate functions of
G-actin show usual features that the decay of the functions could be ﬁt with single exponentials, the rate of decay of thoseof F-actin appears very slow. This indicatesthat there is a large difference in translational diffusion between G-actin and Factin. To make quantitative comparison of
the dynamic behaviours of G-actin and Factin, detailed analysis of these intermediate functions are currently underway.

Fig. 1. The normalized intermediate scattering functions of G-actin and F-actin.

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1-6-5

Structural evolution of human αB-crystallin on UV irradiation
M. Sugiyama1 , N. Fuji1 , Y. Morimoto1 , S. Kurabayashi2 ,T. Sato3 , K. Itoh1 , K. Mori1 and T. Fukunaga1
1 Research Reactor Institute, Kyoto Univ., Osaka, 590-0494
2 Graduate School of Science, Kyoto Univ., Kyoto, 605-8501
3 Graduate School of Engineering, Kyoto Univ., Kyoto, 605-8501
Alpha-crystallin is a human lens protein
which works as a chaperon to prevent frommaking aggregation of proteins in the lens.
This protein is a water-soluble aggregate
consisting of two kinds of polypeptides,
αA-crystallin and αB-crystallin.
Under environmental stresses,
αcrystallin makes huge aggregation andthen losses its chaperone activity. Therefore, the proteins in the lens also makehuge aggregation and ﬁnally the lens has
become opaque, namely a serious disease,cataract, has developed.
The trigger of the abnormal aggregationon α-crystallin is considered to be posttranslational modiﬁcations on the polypeptide such as deamidation, racemizationand isomerization, truncation, phosphorylation, oxidation, an increase in intramolecular disulﬁde bonding and glycation. However, the abnormal aggregation
process has not been clariﬁed so far. Therefore, we have investigated the abnormal
aggregation process of α-crystallin.
In order to reveal the abnormal aggregation process, we developed a UV irradiation system with which in-situ SANS observation can be performed. With the system, we observed the structural evolutionof human recombinat αB-crystallin under
UV irradiation with SANS-U spectrometer.
The UV light had wavelength range with
280-360 nm (UV-B) and the SANS intensity was recorded every 30 minutes for 10hours.
Figure 1 shows the evolution of SANS
patterns of αB-crystallin under UV irradiation during 10 hours. The evolution wasclassiﬁed into three stages. In the ﬁrst twohours (stage I), the SANS pattern was almost unchanged, where the radius of gy-

ration was around 55 Å. Stage I could be
an incubation time prior to making the abnormal aggregation. In the next six hours(stage II), the scattering intensity is going tobe centering. It means that αB-crystallin ismaking aggregation in stage II. In the ﬁnal
two hours (stage III), the SANS pattern wasalmost unchanged again, where the radiusof gyration was around 70 Å.
The investigation of the relation between
the chaperone activity and the structure ineach stage is now in progress.
(a)00.0 hr(b)02.0 hr(c)08.0 hr(d)10.0 hrFig. 1. Evolution of SANS patterns of αB-crystallin
under UV irradiation. (a) Before UV irradiation, (b)after 2 hrs UV irradiation, (c) after 8 hrs UV irradiation and (d)after 10 hrs UV irradiation.

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1-6-6
Defect Study of Protein Crystals by Neutron Topography
H. Koizumi, N. Ohya, M. Koishi, N. Kitajima, Y. Mukohbayashi, M. Tachibana, K. Kojima,
K. Kurihara1 and R. Kuroki1
International Graduate School of Arts and Sciences, Yokohama City University, Yokohama 236-0027
1
Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195

In common crystals, the mosaic structure
has two structure types that are a Frank network and a fine polygonization wall. Both of
the structures are composed of dislocations.
However, the mosaic structure of protein crystals has not been identified in terms of dislocation models yet. Thus, the characterizationof defects, especially dislocations, in protein
crystals is important for the understanding of
their quality of crystals. The crystallization
originating from dislocations has been investigated using atomic force microscopy (AFM).
However, AFM is limited to only local observations of the crystal surface. It is desired that the distribution of dislocations in
the whole crystal could be observed. Topographic techniques (X-ray topography andneutron topography) is one of the most powerful tools for characterization of dislocation in
the crystal. Therefore, we have performed theapplication of X-ray topography to protein
crystals1) , and consequently, we have succeed
in clear observations of the dislocation images
in hen egg-white (HEW)lysozyme crystals2)3) .
On the other hand, the application of neutron
topography to protein crystals has not been
carried out so far. Especially, effect of wateraround dislocations can be observed only using neutron topography. Therefore, to obtain
the interaction between intracrystalline waterand dislocations in protein crystals, we tried
to perform the application of neutron topography to lysozyme crystals.
The used orthorhombic HEW lysozyme
crystals were grown by a liquid-liquid interfacial precipitation technique. To avoid thehigh background coming from the incoherent neutron scattering of hydrogen atoms, thecrystallization experiments were carried out
in D2 O solution. Neutron topography was
carried out using LAUE on C2-3-3-4 at JRR原子炉：JRR-3

3. The camera length was 21 cm. Topographs
were recorded on a film instead of an imaging
plate with exposure times of about 1 week.
Figure. 1 shows Laue topographs whichwere recorded with the incident beam almost
parallel to the [110] crystallographic directionof orthorhombic HEW lysozyme crystal. Thisis the first photograph of neutron topography
applied to protein crystals. It should be noticed that a topographic image corresponds tothe shape of crystals of the lysozyme using Xray topography. In addition, this topographic
contrast attributes to dislocations observedby X-ray topography. The photo showed thelack of image of the crystal in the lower partof the crystal. This means that the qualityof crystals is not sufficient to take a clear image. More detail observation using more highquality crystals should be required to obtainthe fine structures.

Figure 1: Topographic image of an orthorhombic
HEW lysozyme crystal obtained using neutron topography.

References
1) M. Tachibana and K. Kojima, J. Synchrotron Rad.,10, 416(2003).
2) H. Koizumi, M. Tachibana, I. Yoshizaki and K. Kojima, Philosophical Magazine, 85, 3709(2005).
3) H. Koizumi, M. Shimizu, M. Tachibana and K. Kojima, Physica Status Solidi (a), (2007)(in press).

装置：LAUE(T1-4-4,C2-3-3-4)－ 291 －

分野：中性子散乱（その他）

JAEA-Review 2008-067

1-6-7
A Neutron Crystallographic Analysis of 2Zn-Insulin
W. Iwai1 , T. Yamada1 , Y. Ohnishi1,2 , Y. Kobayashi1 , I. Tanaka3 , K. Kurihara4 , R. Kuroki4
and N. Niimura1
Department of Applied Beam Science, Graduate School of Ibaraki University, Naka-Narusawa,
4-12-1, Hitachi, Ibaraki 316-8511
2
Kaken Co., Hori, 1044, Mito, Ibaraki 310-0903
3
Faculty of Engineering, Ibaraki University, Naka-Narusawa, 4-12-1, Hitachi, Ibaraki 316-8511
4
Neutron Structural Biology, Japan Atomic Energy Agency, Shirakata-shirane, 2-4, Tokai, Ibaraki
319-1195
1

Insulin is one of most important and wellknown hormones. It is used as one of themain medical treatments for diabetes because
it regulates glucose metabolism. A monomerof insulin has a mass of about 5700 Da, whichis composed of two peptide chains; an Achain (21 amino acids) and a B-chain (with
30 amino acids). This protein is synthesized
and stored in the pancreas as a hexamer withzinc ions and secreted from there in that configuration. A 2Zn insulin crystal used to collect neutron diffraction data was grown bya bach method, and the crystallization conditions are as follows: insulin (5 mg/mL),
sodium citrate (50 mM), zinc sulfate (6 mM)
and acetone (15 %). The obtained crystal
has dimensions of 1.5 × 1.5 × 1.0 mm3 (volume approximately 2.25 mm3 ). The crystal
was soaked in a supersaturated D2 O solution
for one month. The neutron diffraction experiment was carried out at room temperature using the BIX-4 diffractmeter at port
1G-B in the reactor hall, JRR-3, of JAEA.
The neutron wavelength used was 2.6 Å. The
step scan method (with increments of 0.3˚)
was used for data collection. The neutron exposure time per frame was 2 hours, and 207
frames and 280 frames were obtained at different rotation axes. The HKL software package, DENZO and SCALEPACK were used
for data processing and scaling. A total of
3,734 independent reflections were obtainedwith an overall R merge of 8.7 % from 11,755
observed reflections. The completeness of thedata set was 97.0 % in the 80 - 2.3 Å resolution range and 89.9 % for the outermost (2.3
- 2.38 Å) resolution shell. The structure refinement was carried out using the CNS set of
原子炉：JRR-3

装置：BIX-4(1G-B)

program for reflections collected and graphics
program was XtalView. The topology and parameter files for CNS had to be modified forneutron diffraction analysis to include hydrogen and deuterium atoms. The 2Zn insulin
structure (PDB ID: 4INS) determined from
X-ray data (resolution 1.5 Å) was used as an
initial model. It was assumed that the hydrogen atoms bound to carbon atoms were notreplaced by deuterium atoms. The hydrogenatoms bound to nitrogen and oxygen atoms
were not included in the initial model, andall water molecules were excluded from themodel. As the refinement proceeded, the positions of exchangeable hydrogen atoms could
be identified using 2|Fo|-|Fc| and |Fo|-|Fc| nuclear density maps, and the current R-factor
is 21.8 %, and free R is 30.1 % at resolutionof 2.3 Å. The current 2|Fo|-|Fc| positive neutron density map of His10B is shown in Fig.1
Further refinement including water molecules
is now under way.

Figure 1: His10B.

References
1) A. Wlodawer, H. Savage and G. Dodson, Acta.
Crystallogr. Sect.B, 45, 99(1989).

分野：中性子散乱（生物）－ 292 －

JAEA-Review 2008-067

1-6-8
The State of Cryptobiosis of Larvae of Polypedilum Vandezplanki Studied by
Incoherent Inelastic Neutron Scattering
H. Nakagawa, T. Okuda1 , Y. Joti2 and M. Kataoka
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
Department of Physiology and Genetic Regulation, National Institute of Agrobiological Sciences,
Tshukuba, Ibaraki 305-8634
2
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Tokyo 113-0032
1

Larvae of an African chironomid,
Polypedilum vandezplanki live in temporalrock pools and they can stand complete desiccation in a cryptobiotic (ametabolic) state1) .
One of the most characteristic phenomena
is a remarkable accumulation of trehalose in
the cryptobiotic larva. Slowly-dehydrated
larva (slow sample) accumulated sufficienttrehalose successfully entered the state of
cryptobiosis, whereas quickly-dehydrated
one (quick sample) with a small amount oftrehalose failed to do. It is suggested thatthe vitrification of the trehalose is importantfor cryptobiosis. Generally glassy materials
exhibits a boson peak, which is a broad
peak found in the low-frequency region of
inelastic neutron spectra, and a characteristic
fast relaxation process in the quasi-elastic
neutron scattering. This study aimed to
examine the vitrified state in cryptobiosis byincoherent inelastic neutron scattering using
slow and quick samples. The incoherent
neutron inelastic scattering experiments were
performed with the triple axis spectrometer,
TAS-2, in the JRR-3 reactor in Tokai, which
has an energy resolution of 0.7 meV. Theenergyrange covered was from -2.0 to 10.0
meV. The data were then collected from 100
K to 300 K. Figure 1 shows the inelastic
neutron scattering spectrum of the slow
and quick samples of Larvae of Polypedilum
vandezplanki at 100 K and 300 K. At 100 K
significant difference was not observed between the slow and quick samples, although
it seems that the slow sample may have asmall bump around 2-3 meV, boson peak.
But to discuss this further it needs the higher
statistic data. At 300 K a broardenings ofthe elastic peak due to the contribution of
原子炉：JRR-3

装置：TAS-2(T2-4)

quasi-elastic scattering were observed forboth samples, indicating the appearance ofthe relaxation processes. The difference ofthe neutron spectra at 300 K between the two
samples was detectable. The quick sample
has stronger quasi-elastic scattering than theslow one. This suggests that the relaxation
process of the slow sample is inhibited and/ or the timescales of the process is fasterthan quick one. These observations imply
that the importance of the vitrification by
the trehalose for the cryptobiosis mechanismof Larvae.

Figure 1: Inelastic neutron scattering spectra of theslow and quick samples of Larvae of Polypedilum vandezplanki at 100 K and 300 K.

References
1) T. Okuda, et al., Proc. Arthropod. Embryol. Soc.
Jpn., 39, 1(2004).

分野：中性子散乱（生物）－ 293 －

JAEA-Review 2008-067

1-6-9
Hydration Water Dynamics at Protein Dynamical Transition by Quasi-Elastic
Neutron Scattering
H. Nakagawa and M. Kataoka
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195

A protein dynamical transition around 180∼ 240 K has been observed for the hydrated
protein1) . It was reported for various proteinsthat their functions are suppressed due to theloss of unharmonic dynamics by dehydration
or by cooling down below the transition temperature. It is essential to elucidate the roleof water at the protein-water interface to understand protein dynamics and function properly. So far we found that the dynamical transition is observed only above the thresholdhydration level: h ∼ 0.2 (g H2 O/g protein).
In this study, the hydration water dynamics
were examined by quasi-elastic neutron scattering below and above the hydration level.
The scattering from the hydration water on
the protein can be selectively estimated by thesubtraction of the scattering profile of a D2 Ohydrated protein from that of a H2 O-hydrated
protein. The neutron inelastic scattering experiments were performed with a triple axis
spectrometer, LTAS, in the JRR-3 reactor in
Tokai, which has an energy resolution of 100µeV. The energy range covered was from -0.4
to 1.0 meV. Figure 1 shows the quasi-elastic
neutron scattering spectrum of the hydrationwater and bulk water at 300 K. Bulk water
has almost no elastic peak and strong quasielastic scattering, while the hydration water
has a non-negligible elastic peak, indicatingthat the hydration water is confined on theprotein surface. But the quiasi-elastic scattering profiles are different between two hydration levels, suggesting that the dynamical properties of the hydration water dependon the hydration level. The stronger quasielastic scattering observed above the threshold hydration level suggests that the hydration water has more diffusive motions thanin the case of the lower hydration. It was reported that the relaxation time of the proteinwater hydrogen bond network is 18 ps at 300
原子炉：JRR-3

装置：LTAS(C2-1)

K2) .
Therefore, we can conclude that the observed
hydration water dynamics involves such a network relaxation. The dynamical coupling between hydration water and protein is essential
for the protein dynamical transition.

Figure 1: Quiasi-elastic neutron scattering of protein
hydration water at two hydration levels and bulk water. The scattering of Vanadium indicates the resolution function.

References
1) W. Doster, et al., Nature, 337, 754(1989).
2) M. Tarek, et al., Phys. Rev. Lett, 88, 138101(2002).

分野：中性子散乱（生物）－ 294 －

JAEA-Review 2008-067

1-6-10
Neutron Diffraction Study of Porcine Pancreatic Elastase with Its Inhibitor
T. Kinoshita, T. Tamada1 , T. Ohhara1 , K. Kurihara1 , T. Tada and R. Kuroki1
Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Porcine pancreatic elastase (PPE) is a serine protease classified in the chymotrypsin
family that is possibly the most destructive
enzymes having the ability to degrade virtually all of the connective components in the
body. Uncontrolled proteolytic degradation
by pancreatic elastase (EC 3.4.21.36) causes
the fatal disease pancreatitis. Inhibitor for
PPE is typical subject of development bystructure based drug design (SBDD) becausesome elastases have similar structures of active sites. Nevertheless, many inhibitors designed by SBDD using X-ray structures still
have side effects. A more detailed structure
including hydrogen and hydration information is useful to develop highly selective inhibitors. Neutron structure analysis is the
only method to determine hydrogen and hydration of protein structures. Last fiscal year,
we collected the 2.3 Åneutron data using acrystal with a size of 1.6 mm3 .1) Here we report the collection of higher resolution datausing a larger crystal of PPE with its inhibitor.
A macro-seeding procedure was repeatedly
performed during four months by adding the
PPE-inhibitor complex in a deuterated buffer
to a seed crystal. Finally, a seed crystal
was grown to a size of 3.3 mm3 . Diffraction data were collected at room temperature using a monochromatic neutron beam (λ= 2.9 Å) and recorded on a neutron imaging plate on BIX-3 diffractometer at JRR3 in JAEA. Full data set from a rotation
about two independent axes was merged toenhance completeness. A total rotation rangeof 166.8◦ was covered by 556 oscillation images with an exposure time of 4 h/image
by a rotation angle of 0.3◦ . The data were
processed with the programs DENZO andSCALEPACK. Full data set was integrated
and scaled to 1.75 Åresolution. The num原子炉：JRR-3

装置：BIX-3(1G-A)

Table 1: Summary of refinment

R crystR f ree (5 % random)
No. of atoms
total
H and D
mean B value (Å2 )r.m.s. deviations
bond lengths (Å)
bond angles (◦ )

0.237
0.339
4,372
2,271
12.4
0.012
4.5

ber of observed reflections was 69,089, whichwere merged into 21,103 unique reflections
with an Rmerge of 0.095 and a completenessof 91.9 %. Crystallographic refinement using
by the program CNS is now in progress. The
present model, including PPE, inhibitor, twoions (calcium and sulfate), and 238 deuterated waters, which were refined to a crystallographic R-factor of 23.7 % (free R-factor= 33.9 %) to 1.75 Å resolution. Refinement
statistics are summarized in Table 1. Protonation of histidine at active site was clearly
confirmed on nuclear densities (Fig.1).

Figure 1: Nuclear densities at active sites. light: 2F oF c map (+1σ), deep: F o-F c map (+2σ).

References
1) T. Kinoshita, T. Tamada, K. Imai, K. Kurihara,
T. Ohhara, T. Tada and R. Kuroki, Acta Crystallogr. Sect. F, 63, 315(2007).

分野：中性子散乱（生物）－ 295 －

JAEA-Review 2008-067

1-6-11
Single Crystal Neutron Structure Analysis of a [NiFe]hydrogenase Model
ComplexS. Ogo1 , R. Kabe1,2 , K. Uehara2 , B. Kure1,2 , T. Nishimura2 , S. C. Menon2 , R. Harada1 ,S. Fukuzumi2 ,Y. Higuchi3 , T. Ohhara4 , T. Tamada4 and R. Kuroki4
Center for Future Chemistry, Kyushu University, Fukuoka, Fukuoka 819-0395
Department of Material and Life Science, Osaka University, Suita, Osaka 565-0871
3
Department of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297
4
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
1

2[NiFe]hydrogenase is a bacterial enzymethat catalyzes the activation of H2 into two
protons (H+ ) and two electrons (e− ). Many
synthetic modeling efforts have been devoted
to elucidating the core structure of the active form of the [NiFe]hydrogenase. A Ni(µS)2 (µ-H)Fe species is one of the candidates forthe active form. However, 10 M(µ-S)2 (µ-H)8 M
complexes [where 10 M = group 10 metals (Ni,Pd and Pt) and 8 M = group 8 metals (Fe,Ru and Os)] as models for the active form of
the [NiFe]hydrogenase have not been reported
yet.

gen atoms were determined from a differential
Fourier map and those of all atoms except anitrate ion and a solvent water were refined independently. A nitrate ion and solvent water
were refined with a rigid model. As a resultof the structure analysis, we successfully theobserved a negative peak which indicates existance of H between Ni and Ru (Fig. 2). This
result clearly shows that [2](NO3 ) has a Ni(µH)Ru structure, and strongly suggests thatthe active form of the [NiFe]hydrogenase hasa Ni(µ-H)Fe core structure. A paper including this result has recently been published.1)

Here, we report the successful determination of the crystal structure of Ni(µ-H)Ru
complex[(NiII L)(H2 O)(µ-H)RuII (η 6 C6 Me6 )](NO3 ) {[2](NO3 )}, where L =N,N’-dimethyl-N,N’-bis(2-mercaptoethyl)1,3-propanediamine by single crystal neutron
diffraction.

Figure 1: Formation of a Ni(µ-H)Ru complex from thereaction of a NiRu aqua complex with H2 .

We obtained dark-red crystals of [2](NO3 )crystals by the reaction of NiRu aqua complex [(NiII L)RuII (H2 O)(η 6 -C6 Me6 )](NO3 )2{[1](NO3 )2 } with H2 in water under ambient comditions (20◦ C and 0.1 MPa)(Fig.1).
Since this reaction is similar to the enzymatic reaction of [NiFe]hydrogenase, [2](NO3 )is thought to be a model complex of[NiFe]hydrogenase. A single crystal neutron
diffraction measurement of [2](NO3 ) was carried out using a 3.0 × 2.0 × 0.2 mm3 crystal
with the BIX-3 diffractometer at the JRR-3
reactor in JAEA. The measurement was performed using an incident neutron beam of 1.51
Å wavelength for 8 days at room temperature.
Finally, 9451 reflections including 3852 uniquereflections were observed. For the structure determination, the positions of hydro原子炉：JRR-3

装置：BIX-3(1G-A)

Figure 2: Fo-Fc map around the core structure of[2](NO3 ). The mesh between Ni1 and Ru1 indicatesthe existance of H.

References
1) S. Ogo, et al., Science, 316, 585(2007).

分野：中性子散乱（生物）－ 296 －

JAEA-Review 2008-067

1-6-12Contrast Variation Measurements of Hen Egg White Lysozyme
Amyloid Protofilaments
S. Fujiwara, F. Matsumoto and H. Nakagawa
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Amyloid fibrils are filamentous protein aggregates found in a wide variety of proteins
including disease-related proteins. An understanding the mechanism of the amyloid fibril formation is not only important for thedevelopment of therapeutic strategies against
amyloid diseases but also of considerable help
to gain an insight into the generic properties of proteins related to the mechanismsof folding and stability. It was found recently that hen egg white lysozyme (HEWL)
forms the amyloid fibrils in a highly concentrated ethanol solution1) . The HEWL-waterethanol system is suitable to study the general mechanism of the amyloid fibril formation. From small-angle X-ray and neutron
scattering (SAXS and SANS) measurements,
we showed that a pathway of the amyloid fibril
formation of HEWL consists of three stages;
the formation of the dimers, the formation of
the protofilaments, and the formation of theamyloid fibrils via a lateral association of the
protofilaments2, 3) .
In order to understand more in detail themechanism by which the amyloid fibril formation occurs, it is important to obtain moredetailed information on the structures of the
dimers, the protofilaments, and the amyloid
fibrils. In this study, as a first step towards this goal, we performed SANS experiments of the protofilaments of HEWL using
the contrast variation technique. HEWL solutions, the concentration of HEWL in which
was 2 mg/ml, were prepared in 90% ethanol,
the condition under which the protofilaments
were formed, in various fractions of thedeuterated solvent. SANS curves of these solutions of HEWL were measured with SANSJ at the guide hall of the reactor JRR-3 in
JAEA. The cross-sectional Guinier analysis of
the curves obtained was done to estimate thecross-sectional radius of gyration at each con原子炉：JRR-3

装置：SANS-J(C3-2)

trast.
The dependence of the cross-sectional radius of gyration on the contrast was analyzed
by the Stuhrmann plot4) , i.e., the plot of thesquare of the cross-sectional radius of gyration
against a reciprocal of the contrast. Figure 1
shows the Stuhrmann plot of the protofilaments of HEWL. A negative slope of a linear
fit to the data implies that a region of highdensity is located near the center of the filament.
Detailed analysis with aid of model calculation is currecntly underway.

Figure 1: The Stuhrmann plot of the cross-section of
the amyloid protofilament of HEWL.

References
1) S. Goda, et al., Protein Sci, 9, 369(2000).
2) Y. Yonezawa, et al., J. Mol. Biol, 323, 237(2002).
3) S. Fujiwara, et al., J. Mol. Biol, 331, 21(2003).
4) H. B. Stuhrmann, J. Appl. Cryst, 7, 173(1974).

分野：中性子散乱（生物）－ 297 －

JAEA-Review 2008-067

1-6-13
Hierarchical Structure for Red Blood Cells Observed by Small-Angle Neutron
Scattering with Solvent Contrast Variation
H. Iwase and S. Koizumi
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195

原子炉：JRR-3

装置：SANS-J(C3-2)

10

10

-1

I(Q) (cm )Red blood cells (RBCs) have a disk shapewith an average thickness of 3 µm and an average diameter of 10 µm and are composedof hemoglobin, cell membranes, cytoskeletons,
and glycocalyx. Except mammals, the RBC
has a nucleus. The length scale of the above
constituent elements widely.
Ranges from 1 nm to 10 µm.
It is
well-known that the hierarchical structure of
RBCs has a close relation with biological functions and diseases. To reveal the correlation between the hierarchical structure andbiological functions, we have investigated thehierarchical structure of the RBCs by using combined three small-angle neutron scattering (SANS) techniques; conventional pinhole SANS, focusing ultra small-angle neutron scattering (USANS) and double-crystal
USANS.
In this study, we presented the results of
SANS and USANS with solvent contrast variation. The solvent contrast variation method
is applied in order to selectively extract thestructural information of mainly componentsof RBC.
Chicken bloods were purchased from Nippon Biotest Laboratories Inc. The RBCs wereisolated by centrifugation at 100 G for 20 min
at 4 ◦ C and washed by resuspending in 20 mM
phosphate buffer containing 9 mg/ml NaCl
(pH 7.2) and by centrifuging for five times at2000 G for 10 min at 4 ◦ C.
SANS measurements were performed on focusing USANS spectrometer SANS-J-II andon double crystal USANS on PNO at JRR3 reactor of Japan Atomic Energy Agency,
Tokai, Japan. The covered Q range is 3 ×
10−5 - 3 × 10−1 Å−1 . SANS and USANS
measurements were performed at room temperature.
Figure 1 shows scattering profiles forchicken RBC suspension in four different

10

9

10

7

10

5

10

3

10

1

10

8

10

6

10

4

10

2

10

0

10

-1

10

-3

10

-2

10

-4

D2O/H2O=100/0=0/100=60/40-4=45/55

-2

-4
-5

10

10

-4

10

-3

-2

10

-1

Q (Å )

10

-1

10

0

Figure 1: Scattering profiles for chicken red blood cells
in 20 mM Phosphate buffer containg 9 mg/ml NaCl at
pH 7.2 (D2 O/H2 O[v/v] = 100/0, 60/40, 45/55, 0/100,
respectively).

D2O/H2O fractions (D2O/H2O [v/v] = 100/0,
60/40, 45/55 and 0/100, respectively). The
scattering profiles of D2O/H2O = 100/0,
60/40 and 0/100 showed Q−4 behavior in the
Q range from 2 × 10−4 to 1 × 10−2 Å−1 ,which is due to interface scattering between
the RBCs and solvents. The scattering profile of D2O/H2O = 45/55, on the other hand,
has an evidently different future in comparison with these for other D2O/H2O fractions.
The scattering profiles showed Q−2 behavior
in the Q range from 3 × 10−4 to 8× 10−2
Å−1 and obeys the power law of Q−4 above
Q = 8 × 10−2 Å−1 . This becomes same asthat of the unilamellar vesicles of lipids, because D2O/H2O = 45/55 is a contrast matching point of hemoglobin. All the scatteringprofiles were analyzed by fitting with a tripleshell disk model coupled with results obtainedby optical microscopy. We were able to quantitatively determine the size of a nucleus incytoplasm, the thickness of a cell membrane
and the ratio of volume fraction between the
hemoglobin and the water in the cytoplasm.
分野：中性子散乱（生物）－ 298 －

JAEA-Review 2008-067

1-6-14The Structure of 4-Repeat Tau and 3-Repeat Tau Monomer and theirSelf-Assembled Clusters
S. Naito1,2 , H. Mochizuki2 , T. Yasuda2 , Y. Mizuno2 , M. Furusaka3 ,S. Ikeda1 , M. H. Shimizu1 , J. Suzuki4 and S. Fujiwara4
KEK, Tsukuba, Ibaraki 305-0801
Dept. of Neurol., Juntendo Univ. Sch. of Med.
3
Dept. of Mech. Intell. Eng., Grad. School of Eng., Hokkaido Univ., Kita 13, Nishi 8, Kita-ku,
Sapporo 060-8628
4
QuBS Japan Atomic Energy Agency, Ibaraki 319-1195
1

2

Tau is one of the microtubule-associatedproteins. Mainly, 4-repeat tau (4Rtau) containing two cysteine residues and 3-repeat tau(3Rtau) lacking one repetition domain containing one cysteine residue are expressed innormal brain (Fig.1). The abnormal aggregation of tau often observed in Alzheimer sdisease brain causes cellular degeneration anddeath.

Table 1: The size and shape of 4Rtau and 3Rtau monomera)Radius of gyration of globular protein comprising ofn amino acids , Rg , Rg = 2.9*n(1/3) 3)b)Relation between Rg and Rh (hydrodynamic radius),

Rg = 1.51*Rh 4)c) Rh of molecular weight , M, log(Rh ) = 0.533*log(M ) - 0.682 5)

4Rtau may form a rod-like rotating ellipsoid (Rg = 850 Å, long axis, a = 1895 Å andshort axis, b = c = 105.3 Å). 3Rtau may form
random coil (slope = -2) and the Rg was estimated to be 962 Å.
Figure 1: Diagram of 4-repeat tau and 3-repeat tau.

We prepared a tau aqueous solution suggesting the monomeric dispersion1) by DLS
and confirmed that the conformation was unchanged if reductive atmosphere was maintained. The 4Rtau monomer and the 3Rtau
one are not stable and immediately selfassemble to form huge clusters comprising
several thousands of molecules. Under an oxidative environment, the cluster size of 3Rtau
increased by the formation of intermolecular
cystein crosslinkages.2) The size and shape of
4Rtau monomer and 3Rtau one are estimatedfrom the Rh values obtained by a dynamic
light scattering analysis (Table 1).
4Rtau presented a intermediary structure between globular form and random coil. 3Rtau
presented almost random coil. The size andshape of 4Rtau and 3Rtau clusters are determined by SANS-J [wavelength (λ = 1.14 nm),sample distance (L = 10 m)] and by SWAN
at KEK.
原子炉：JRR-3

装置：SANS-J(C3-2)

Figure 2: SANS profiles of 4Rtau and 3Rtau.
Figure 2 shows the SANS profiles of 4Rtau and
3Rtau below a concentration of C *.

References
1) S. Naito, et al., JAERI-Review, 2005-045, 56(2005).
2) S. Naito, et al., JAEA-Review, 2007-004, 24(2007).
3) A. Gast, et al., Biochemistry, 34, 13211(1955).
4) G. Damaschun, et al., B. B. A., 1078, 289(1991).
5) Uversky. V. N., Biochemistry, 32, 13288(1993).

分野：中性子散乱（生物）－ 299 －

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1-7-1

Development of beam splitting etalons for pulsed neutrons
M. Kitaguchi(A), T. Seki(B), K. Taketani(B), H. Funahashi(C), M. Hino(A), and H. M.
Shimizu(D)(A)KURRI, (B)Kyoto Univ., (C)Osaka Electro-Comunication Univ., (D)KEK
A large dimensional interferometer forlong wavelength neutrons has the advantage to increase the sensitivity to smallinteractions. Multilayer mirror is suitable for Bragg reﬂection of cold neutrons. We demonstrated Jamin-type interferometer for cold neutrons using beam
splitting etalons (BSEs), which enables
us to align the four independent multilayer mirrors in the interferometer withinrequired precision [1]. We are preparing for high-resolution measurement of
Aharonov-Casher effect [2,3] by using thistype of interferometer.
The interferometer for pulsed neutrons
can increases neutron counts available forAC measurement because the phase shift
is independent from the velocity of incident neutrons. Neutron interferometerwith multilayer mirrors can be applied topulsed neutrons. Neutron supermirror [4],which is a variety of multilayer mirror with
continuous lattice constants, can reﬂect
neutrons with wide range of wavelength
at a proper incident angle. In the case ofneutron spin interferometer of Jamin type,a magnetic supermirror on the one planeof the BSE reﬂects only up-spin componentof the neutrons and a non-magnetic supermirror on the other plane reﬂects transmitted down-spin component. The second
BSE with supermirrors recombines the twocomponents. High polarization of both ofreﬂected and transmitted beam for themagnetic supermirror is required in orderto split the beam into two paths according
to the spin states. We deposited magnetic
supermirrors on silicon wafers by using ion
beam sputtering instrument at KURRI for
test of BSE. Figure 1 shows measured reﬂectivity of the magnetic supermirror byscanning of incident angle instead of neutron wavelength. Test experiment was per-formed using the cold neutron beam line
MINE2 at the JRR-3M reactor in JAEA. The
beam had a wavelength of 0.88 nm and abandwidth of 2.7% in FWHM. We foundthat the magnetic supermirror can be used
as one mirror in BSE for neutrons with thewavelength from 0.52 nm to 0.88 nm at theincident angle of 1.0 degree. External magnetic ﬁeld of 17mT was required for magnetic saturation of the mirror. Strong magnetic ﬁeld in neutron spin interferometer
would decrease the visibility of interferogram due to depolarization. Magnetic supermirror for lower external ﬁeld is quite
important. The interferometer for the ACmeasurements must have perfectly separated two paths enclosing an electrode. We
are also continuing on the constructing ofinterferometer using BSEs with large gaps.
References[1] M. Kitaguchi et al.: Phys. Rev. A 67
(2003) 033609.
[2] Y. Aharonov and A. Casher: Phys. Rev.
Lett. 53 (1984) 319.
[3] A. Cimmino et al.: Phys. Rev. Lett. 63(1989) 380.
[4] F. Mezei: Comm. Phys. 1 (1976) 81.

Fig. 1. Reﬂectivity of magnetic supermirror for BSE
for pulsed neutrons.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 35－ 303 －

JAEA-Review 2008-067

1-7-2

Preliminary masurement of hydrogen content absorbed in Pd using neutroncomposite mirror
S.Taski, T.Wakita, M.Hino
Dep. of Nucl. Eng. Kyoto Univ., KURRI
Preliminary experiments on the measurement of hydrogen content in Pd using composite mirrors was performed. The
composite mirror consists of neutron a halfmirror, a gap layer, and a second halfmirror. The gap layer is made of target material Pd. The half-mirrors are Ni/Ti multilayer with the refelctivity of about 50%,
Neutrons which enters the composite mirror, is partly reﬂected by the ﬁrst halfmirror and the remaining neutron goes
through the gap layer and is reﬂected by
the second half-mirror.
Between these two reﬂected neutrons,
phase difference φ is introduced by the gap
layer. φ = 2nD sin θ/λ, where n, D are theneutron refractive index and the thicknessof the gap layer, and theta, λ are neutron
incident glancing angle and neutron wavelength, respectively.
In the reﬂectivity curve of the composite mirror interference fringes due to thephase difference is observed. When D or nchanges, the interference fringe is shifted.
In our experiment, from the shift of the interference fringes we detect the change in n
and D of the gap layer material Pd due tohydrogen absorption.
In the present experiments, two composite mirrors are arranged in (+−) conﬁguration, in order to increase the contrast of theinterference fringes.
The composite mirrors were fabricatedwith vacuum evaporation method at
KURRI. The number and mean thicknessof Ni and Ti layers in a half mirror are
6 and 10nm, respectively. The thicknessof the gap layer is 100nm. During theevaporation of top half-mirror, a meshmask is placed over the composite mirror
in order to expose partially the bare Pd gap
layer.
Neutron reﬂectivity measurements were

performed at C3-1-2-2 (MINE) beam holeof JRR-3M reactor in JAEA. Neutron wavelength and the wavelength resolution is
0.88nm and 2.7%.
The neutron reﬂectivity result is shownin Fig.1. Horizontal and vertical axis represent neutron incident angle to the second
composite mirror and the reﬂectivity, respectively. The broad peak from 0.9deg to
1.5deg is due to the half-mirror, and smallinterference fringes over the broad peak arecaused by the gap layer. The measured result is well reproduced by the calculated result.
In the present experiment, hydrogen absorption was not done because of technical reason. Experiments using hydrogen isplanned in the beginning of the next budget year.

Fig. 1. Neutron reﬂectivity of the composite mirrors
in (+−) conﬁguration.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 61－ 304 －

JAEA-Review 2008-067

1-7-3

Observation of roughness at iron-surface by neutron reﬂectometry
K. Inoue(A), T. Hirayama(B), T. Uno(B), T. Ebisawa(C), S. Tasaki(D), M. Hino(E)(A)Faculty of Science and Technology, Ryukoku Univ., (B)Faculty of Engineering, Doshisya
Univ., (C)Neutron Science Research Center, JAEA, (D)Graduate School of Engineering, Kyoto
Univ., (E)KUR, Kyoto Univ.
A new method of observation of the surface
roughness of metallic iron has been developed. Various types of surface roughness ofiron materials in air and at solid-solid interface were investigated using a neutron
reﬂectometer, MINE-2. Wave length of thebeam was adjusted to 0.88 nm. At ﬁrst,
the iron with surface roughness shown in
Fig.1 (a) was used, where the roughness
was measured by a contact-type roughnessgauge and by a two-dimensional opticalroughness gauge. To make the interface,
the iron surface was covered with Si-block
and with Al-block. The surface of the Siblock was optically ﬂat and the surface ofAl-block was polished to have roughnessof Rmax=0.07 μ m. Incident angle of thebeam to the iron surface was 0.6 °, which
is sufﬁciently smaller than the critical angleof iron, 0.805 °. The direction of the incident beam was perpendicular to the stripeof abrasive trace. Off-specular distributionof the reﬂected beam was observed by an IP(imaging plate), which was placed on thearm at 1.2 ° from the direct beam. 1 pixelof the IP was 50 μ m × 50 μ m. Distancefrom the sample to the IP was 620 mm. We
were able to obtain the two-dimensional
image of the reﬂected beam. Measured distributions of reﬂected beam for three cases
are shown in Fig.1 (b). Assuming Gaussian
distribution, the obtained half-widths were
69.3 pixels in air, 72.2 pixels with Si-blockand 76.0 pixels with Al-block. In the casesof interface, the width is slightly wider thanthat of surface in air.
Next, grating on the iron surface was prepared using a diamond bit as shown in Fig.
1 (c). The period of the grating was 50 μ m
and the depth of the grating was nearly 10
μ m, although the grating is not perfect asshown in the photograph on the left-handside. Measurement was made in air. Incident angle of the beam to the surface was
0.4°and the beam was perpendicular to thestripe. The reﬂected neutron was detectedby a He-3 counter moving against the incident beam. The result is shown in Fig. 1 (d).
We see a broad distribution due to incomplete grating and small diffraction peaks on
it corresponding to the period of the grating.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 70－ 305 －

JAEA-Review 2008-067

1-7-4

Development of a neutron focusing device with an ellipsoidal supermirror
K. Ikeda, H. Sato, K. Hirota, K. Mishima, and T. Shinohara
Radiation Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198
Quantum Beam Science Directorate, JAEA, 2-4 Shirane Shirakata, Tokai, 319-1195
We are developing an ellipsoidal focusing mirror. An ellipsoidal surface mirror
can guide neutrons those leave a small area
to another small area. That kind of mirrors works as a neutron focusing device
and makes it possible to build an experimental setup of high-resolution focusing
small-angle neutron scattering (focusingSANS). When higher Qc supermirror will
be deposited on the ellipsoidal surface ofthe mirror, the two of small area where
neutrons leave or arrive at approach nearer
without reducing the amount of neutrons
to be focused. That means the focusingSANS system becomes compact by high-Qc
supermirrors.
The original ellipsoid of the curved surface shaped on the substrate had the distance of 4000mm between two focal points
on the major-axis and the semi-minor axis
was 20mm. Some part of the original ellipsoid was ground on the borosilicate glass of
900mm × 50mm × 9mm by the Electrolytic
In-process Dressing (ELID) method. Here,the length of 900mm was achieved by threepieces of 300mm substrates.
Figure 1 (top) shows three pieces of anellipsoidal focusing mirror coated by Ni
monolayer. The Ni monolayer of 2000 Å
in thickness was successfully deposited on
the ellipsoidal surface, while 2Qc Ni/Ti supermirror of 13400 Å was peeled off thecurved surface. The reason of the peeling off seems to be due to using the detergent and scouring powder and insufﬁcientwashing by water and alcohol. The 2Qc
supermirror was successfully deposited on
the ﬂat surface of the borosilicate glasscleaned by one-hour supersonic washing in
the hot water. This cleaning method will
be applied to the substrate with the curved
surface ground by ELID method. We arealso trying to uniform the layer thickness ofsupermirror all over the curved surface, because an excess of layer thickness increases
the stress in the layers and results in peeling the layer off the substrate.
Figure 1 (bottom) shows the reﬂectivityof 2Qc supermirror deposited on Si substrate with the ﬂat surface. The sameamount of reﬂectivity will be realized on
the 2Qc supermirror successfully depositedon the curved surface.

Fig. 1. An ellipsoidal focusing mirror coated by Ni
monolayer (top), the reﬂectivity of 2Qc supermirror
deposited on Si substrate with the ﬂat surface (bottom).

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 191－ 306 －

JAEA-Review 2008-067

1-7-5
A Development of the Neutron Beta Decay Experiment with Superconducting
Tunnel Junction (STJ)s
K. Mishima, H. Sato, S. Yamada1 , T. Shinohara1 , T. Oku1 , J. Suzuki1 and H. M. Shimizu2
RIKEN, Nishina Center, Wako, Saitama 351-0198
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
2
KEK, Tsukuba, Ibaraki 305-0801

Neutron beta decay is the best reaction todetermine the coupling constant of a weak interaction, because the decay is independentof any nuclear structure and is then the simplest and only semileptonic reaction throughthe weak interaction. From the decay parameters such as lifetime or energy spectra of decay products, we can obtain Vud , a matrix element of Cabbibo-Kobayashi-Maskawa (CKM)
matrix, which describes the mixing between
quark mass eigenstates and weak eigenstates.
A CKM matrix obeys unitarity in the standard model of particle physics1) . Our researchgoal is to determine Vud by a precise spectroscopy of recoil proton and electron fromneutron beta decay.
However, the spectroscopy of a recoil proton is difficult because its kinetic energy isvery small, whose maximum energy is 752 eV,
so that it is hardly detected by semiconductive detectors like SSD. Thus, we are trying
to apply a superconducting detector for the
spectroscopy of the recoil proton. We apply superconducting tunnel junction2) (STJ)
for proton spectroscopy. Generally, STJs areworking at 300 - 400 mK, and have an energy
resolution of less than a hundred eV. These
STJs are working without a dead layer so thatthe recoil proton deposits full kinetic energy
on the detector. For this purpose, we madeSTJ array with a large area (500 µm × 500µm) at RIKEN in order to cover a large detection area. Eight STJs from 3 × 3 arrayprovide reasonable uniformity.
We installed an apparatus for the neutron
beta decay measurement with STJs at LCE(T1-4-1A). Note that we have already succeeded in measuring the neutron beta decay with conventional detectors consist of
CEM and PMTs with plastic scintillators
原子炉：JRR-3

装置：LCE(T1-4-1A)

for the recoil proton and electron detection,
respectively3) . The new apparatus is analogous with the conventional one, though it
consists of STJs in the cryostat instead of
CEM and a PMT. For the STJ experiment,a cryogen-free refrigerator was introduced torealize a long measurement time. The refrigerator was working about 20 hours continuously.
The pulseheight spectra of a STJ are shownin Fig.1. Because of a large backgroundcaused by neutrons, the beta decay event
could not be identified. The resolution of STJ
was worse due to electrical noise. By reducing the background rate and electrical noise,
we will establish an experimental environment
for low-energy proton detection.
STJ PulseHeight
Counts/Bin/Sec

1

10

Neutronwith Rejection

1

55

Fe Source

10-1
10-2
10-3
10-4
0

2

4

6

8

10
Energy [keV]

Figure 1: The pulseheight spectrum of a STJ. The
solid and dashed lines are the spectrum of neutron
beam and that without coincidense event. The dottedline is the spectrum by a checking source of 55 Fe.

References
1) H. Abele, Nucl. Instr. and Meth. A, 106, 499(2000).
2) H. Sato, et al., Jpn. J. Appl. Phys., 39, 5090(2000).
3) K. Mishima, et al., Physica B, 385-386 1219(2006).

分野：中性子散乱（基礎物理）－ 307 －

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1-8-1

Development of a Neutron Focusing Guide for High Q-Resolution Triple-Axis
Spectrometer HQR (T1-1)
S. Yamada, T. Oku, T. Shinohara, J. Suzuki and M. Nishi(A)QuBS JAEA, (A)ISSP Univ. Tokyo
For upgrading on inelastic neutron scattering in High Q-Resolution triple-axis spectrometer (HQR) at T1-1 port, a neutron focusing guide was designed to increase theneutron ﬂux at sample position and it’s focusing effect was investigated. The shapeand geometrical conﬁguration of the focusing guide were optimized to increase
the neutron intensity at the sample position by using the Monte Carlo program McStas, and the focusing guide was then determined to be a parabolic focusing mirror guide with vertical and horizontal reﬂection surfaces with the total length of1000 mm. The focusing guide is composedof supermirrors with m=3 and reﬂectivity over 85%. The neutron focusing effect was investigated by using a two dimensional position sensitive detector composed of ZnS(Ag)/6LiF scintillator and a
CCD camera. The tilting and focusing angle of PG monochrometer and the positioning and tilting angle of the focusing guidewere optimized to increase the neutron intensity at the sample position. As the result,the neutron intensity increased 4 times atthe peak position and 3.3 times at the areaof 5x5 mm2 in comparison with the casewithout the focusing guide. The quality ofthe design was conﬁrmed by the fact thatthe obtained intensity gain was consistent
with the values obtained by the simulation.
Furthermore, in an inelastic neutron scattering experiment, we observed a gain of
2.7˜2.8 in the scattering intensity by the focusing effect as shown in Fig.1. In conclusion, a neutron focusing guide was a very
powerful tool for upgrading the inelastic
neutron scattering experiments.

Fig. 1. The measured results of vanadium standard
sample in inelastic neutron-scattering conﬁguration
with and without the neutron focusing guide.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 26－ 311 －

JAEA-Review 2008-067

1-8-2

Development of resonance spin ﬂipper with high frequency
M. Kitaguchi(A), M. Hino(A), Y. Kawabata(A), H. Hayashida(B), S. Tasaki(B), T.
Ebisawa(C)(A)KURRI, (B)Kyoto Univ., (C)JAEA
Neutron spin echo (NSE) is one of the spectrometers with the highest energy resolution for measurement of quasi-elastic scattering [1]. In neutron resonance spin echo
(NRSE), the two separated neutron resonance spin ﬂippers (RSFs) replace a homogeneous static magnetic ﬁeld for spin precession in the conventional NSE [2]. The
fourier time of the NRSE spectrometer is
proportional to the frequency of the oscillating magnetic ﬁeld in the RSFs. RSFs
with high frequency magnetic ﬁeld are required for high resolution NRSE spectrometer. RSF with pure aluminum had beendeveloped in order to reduce the scattering from the surfaces [3]. The MIEZE signal
with the effective frequency of 1MHz was
observed by using the RSFs in cold neutron
beam line MINE1 in JRR-3M in JAEA [4].
The wavelength of the neutrons was 0.81
nm and the bandwidth was 10%. The visibility of the echo signal according to thephase of the RSFs was 0.4.
For practical uses of the MIEZE spectrometer, the RSFs has been upgraded (ﬁg. 1).
The static ﬁeld coil had gaps between thepure aluminum wires due to the way of
fabrication. The wires were cut out from thepure aluminum plate bonded on the cooling base. Leak of magnetic ﬂux from thegaps made the depolarization of neutrons.
The decrease of the visibility of MIEZE signals was observed when neutrons passed
through the gaps. The new static ﬁeld coilhas wider wires with the width of 20 mm
to make more ﬂat surface of the magnetic
ﬁeld. The frequency of 300 kHz of oscillating ﬁeld can be satisﬁed resonance condition with the static ﬁeld made by the current of 120A. Cooling base has been optimized to maximize water ﬂow. The temperature is kept lower than 30 degree. The
RF power supply, which is made by Meisho

Kiko co. and Noda RF Technology co., canprovide a maximum of 500W to the RF
coils. We have also made LCR resonancecircuits for the coils, which selects capacitance to enable us to ﬁnd the resonancecondition of the electric circuit in the frequency range of the frequency from 55
kHz to 300 kHz. We have develop MIEZE
spectrometer with the effective frequency
which can be change from 110 kHz to 600
kHz by using these RSFs. Remote control
system with temperature sensors for RSFs
have enabled us to perform stable operation of measurements. Some sample environments is also preparing now. We arecontinuing on developing RSF with muchhigher frequency for NRSE spectrometerwith high resolution at J-Parc.
References[1] F. Mezei: Z. Phys. 255 (1972) 146.
[2] R. Gaehler, R. Golub: Z. Phys. B65 (1987)
43.
[3] M. Kitaguchi, et. al.: Physica B 385-386,
Part 2 (2006) 1128-1130.
[4] H. Hayashida, et. al.: to be published.

Fig. 1. Resonance spin ﬂipper (left) and MIEZE signal with effective frequency of 400 kHz using the
RSFs (right). Bottom shows MIEZE setup at MINE1.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 36－ 312 －

JAEA-Review 2008-067

1-8-3

Development of ﬁne-pixel detector for UCN
T. Sanuki (A), M. Hino(B), S. Komamiya(C), S.Kawasaki(C), S. Sonoda(C),H.Shimizu(D)(A) ICEPP, Univ. Tokyo, (B) KUR Kyoto Univ., (C) Graduate School of Science, Univ. Tokyo,(D) IMSS, KEK
We are developing a ﬁne-pixel detector for
detecting UCN’s.
We selected CCD sensors as ﬁne-pixel detectors, because we can know the position
and timing precisely. The selected CCD
sensor has 512 x 512 pixels, and each pixel
has an active area of 24 x 24 micronsˆ2.
Since CCD’s cannot detect neutrons by itself, a thin converter for neutrons, such as
Li-6 or B-10, was evaporated on to a CCD
surface at KUR. The thickness of the converter was 200 nm. The CCD sensors with
the neutron converter were exposed to theneutron beam at the C3-1-2-2 beam line.
We’ve just started our analysis. Our veryquick analysis shows neutrons were successfully observed with our CCD-based detector.
Our analysis is still on the way. We will
study a detection efﬁciency and a spatial
resolution for neutrons.

Fig. 1. An examples of the observed image of neutrons. The ”height” of each bar shows total charge
deposited in the CCD.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 42－ 313 －

JAEA-Review 2008-067

1-8-4

A new layer structure for large-m polarizing neutron supermirror
M.Hino, M.Kitaguchi, H.Hayashida1, Y.Kawabata, T.Ebisawa2, T. Kume1, S. Tasaki1
Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan 1Departmentof Nuclear Engineering, Kyoto University, Sakyo, Kyoto 606-8501, Japan 2Neutron Science
Research Center, Japan Atomic Energy Agency, Tokai, 319-1195, Japan
Magnetic multilayer mirror consisting of
ferromagnetic layers and nonmagnetic layers is useful to polarize neutron beam. Polarizing supermirror is a stack of magnetic
multilayer with gradually increasing valueof the d-spacing. Several kinds of magnetic
supermirror have been developed as neutron polarizeing device.
There was no m>4 polarizing supermirror
except for our previous report[1]. Some ofauthors have succeeded in fabricating m>5
Ni(C)/Ti supermirrors and small d-spacing
multilayer monochromatorwith high reﬂectivity by using ion beam
sputter (IBS) technique [1,2].It is possible
to fabricate smmoth and small d-spacing
layer structure but it is nessesary for strong
external magnetic ﬁeld.
In the report, we succeeded in fabricating
m=5 Fe/Ge polarizing supermirror by using improved magnetic sputter target[3].
The target is well deoxidized iron target byheating it in hydrogen atmosphere.
The reﬂectivity and polarization efﬁciency
under an external magnetic ﬁeld of 45 mT
were above 0.67 and 0.90, respectively.
The reﬂectivity is very high but the polarizaition is not so high.
The durability of the sputter target was notlong enough for production. Thus we tried
improve magnetic property of the supermirror without the deoxidized iron target.
Here we noted the different magnetic property between Fe/Ge and Fe/Si multilayers.
By inserting thin Si layer in which thickness
0.5 nm between Fe and Ge layer, the magnetic property of Fe/Ge(Si:0.5nm) multilayer is better than Fe/Ge and Fe/Si ones.
We have fabricated m=4.9 Fe/Ge(Si:0.5nm)
supermirror using IBS technique and tested
the performance as a polarzing divice.
The measurement was carried out at C3-1-

2-3 port (MINE2) at JRR-3M at JAEA. The
average wavelength of incident neutron is
0.88 nm and the resolution is 2.7 % in full
width half maximum. The divergent angleof neutron beam was smaller than 1 mrad.
The strength of external magnetic ﬁeld is 45
mT. The reﬂectivity and polarization efﬁciency is estimated to be above 0.7 and 0.94,
respectively.
References[1] M.Hino, et al., Nucl. Inst. Meth. Phys.
Res. A529(2004) 54.
[2] R.Maruyama, et al., Physica B (2006)
385-386(2006) 1156.
[3] M.Hino, et al., ISSP Activity Report,
Vol. 13,ibid, Physica B (2006) 385-386(2006)
1187.

Fig. 1. Measured reﬂectivities of up (red) and down
(blue) spin neutron for m=4.9 Fe/SiGe3(Si:0.5nm)
supermirror. The green line indicates ﬂipping ratiothat reﬂectivity of up spin neutron devided by thatof down spin one.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 89－ 314 －

JAEA-Review 2008-067

1-8-5

A test of MIEZE-Reﬂectometer for study of surface and interface
M.Hino, M.Kitaguchi, H.Hayashida1 , Y.Kawabata, S.Tasaki1 , D.Yamazaki2 ,R.Maruyama2 , T.Ebisawa2 , K.Tanaka3 , N.Torikai4 , T.Kanaya5
Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan,
1 Fac. Eng., Kyoto University, Sakyo-ku, Kyoto 606-8501 , Japan,
2 Neutron Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195,
Japan,
3 Fac. Eng., Kyushu University, Fukuoka 819-0395, Japan,
4 KENS, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 Japan,
5 Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
Neutron Spin Echo(NSE) method is very
powerful spectroscopy to investigate slow
dynamics for condensed matter[1]. Neutron Resonance Spin Echo(NRSE)[2] is avariant of the NSE technique that replaces Larmor precession ﬁeld by two(RSFs).
neutron resonance spin ﬂippers
We installed MIEZE spectrometer to C31-2-2(MINE1) port at JRR-3M in JAEA[4].
MIEZE spectrometer is one of NRSE andthere is no optical component between
sample and detector. It is well suited tosmall angle neutron scattering method[3]and reﬂectometry[5]. By combining of neutron reﬂectometry and the MIEZE, it is possible to detect in- and quasi- elastic scattering on surface and interface. We installed
MIEZE spectrometer to C3-1-2-2(MINE1)
port at JRR-3M in JAEA. In this report, weshow present status of MIEZE spectrometer and the feasibility of MIEZE reﬂectometer(Fig.1(a)). Three RSFs are used on
the MIEZE spectrometer.These RSFs are set
on bootstrap arrangement. There are twokinds of detector. The He-3 point detector
is used to adjust the beam line and measurereﬂectivity by the sample. 2D-PSD is used
for the MIEZE .The two dimensional position sensitive detector (2D-PSD) is to measure off-specular scattering since inelastic
scattering component is in it. The 2D-PSD
consists of 6 Li enriched glass scintillator
and a position sensitive photomultiplier in
ﬁve inch diameter, in which position resolution is 1 mm. Magnetic guide ﬁeld coilis set from the ﬁrst DC-ﬂipper to the analyzer to avoid depolarization of neutron

spin. The length between RSF3 and 2DPSD is 0.5 m. The frequency of RSFs is 600
kHz. Fourier time is estimated to be 1 ns(〜0.6 μ eV). Fig.1(b) show measured PNSE
of specular reﬂection from m=7 NiC/Ti supermirror as a function of incident angle.
There is no decay of PNSE , we have succeeded in measuring standard elastic samples for MIEZE reﬂectometer in which Q is
up to 0.135 nm−1 .
in which frequency.
References[1] F. Mezei (Ed.), Neutron Spin Echo, Lecture Notes in Physics Vol. 128, Springer(1980).
[2] R.Golub and R.Gähler, Phys. Lett. A123
(1987) 43.
[3] M. Bleuel, et al., Physica B 356 (2005) 213.
[4] Y.Kawabata, et al., Physica B (2006) 385386(2006) 1122.
[5] M.Hino, et al., Physica B (2006) 385386(2006) 1125.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 97－ 315 －

JAEA-Review 2008-067

1-8-6

Development of miniaturized McWhan type high pressure cell for elastic andinelastic neutron scattering experiments
T. Fujiwara A , Y. UwatokoB , H. YamamotoB , N. AsoC , M. NishiC , K. HirotaC , H.
YoshizawaC
A Yamaguchi Univ., B ISSP Univ. Tokyo, C ISSP-NSL Univ. Tokyo
Over the past few decades, a considerable number of studies have been devoted
the physical properties of Ce-, Yb- and Ubased intermetallics, the so-called strongly
correlated electron systems. In these systems, an external pressure is often a key tobring about a new type of ground state accompanied with exotic physical phenomena, such as a heavy fermion superconductivity or valence transition and so on.
Accordingly, nowadays the concern with
an application of high pressure generation
techniques to various sorts of experimental
measurements has been growing remarkably. So far, most of neutron scatteringexperiments, especially inelastic neutron
scattering experiments, of strongly correlated electron electrons systems or magnetic materials have been being performed
using so-called McWhan type high pressure cell developed by Onodera et al.1
in Japan. This apparatus, however, is
not adequate to the experiments below
1 K as a cell volume is considerably large
Therefore,(100 mm φ × 140 mm height).
there is an urgent need to develop a better suited pressure cell for the elastic andinelastic neutron scattering experiments atsuch extremely low temperature to study
physical phenomena near a quantum critical point. In this work, we have newly
designed the McWhan type pressure cellwith smaller heat capacity. Cylinder was
made of an aluminum-based new hardened material, Mesoalite. An ultimate tensile strength of this material is almost twice
as high as that of conventional duralumin(A7075). Support cylinder was made ofZrO2 whose neutron transmittance is 50 %larger than that of Al2 O3 . Consequently,
we succeeded in reducing the cell volume
to one-third (66 mmφ × 92 mm height) and

improving the neutron transmittance up to
about twice comparison with those of theMcWhan type pressure cell designed by
Onodera et al.1 . A cross-section diagramof newly designed McWhan type pressure
cell for neutron scattering experiments below 1 K is drawn in ﬁgure. Pressurization examination was performed at room
temperature. Glycerin and a single crystal of NaCl were used as a pressure transmitting medium and a manometer, respectively. Generated pressures were determined based on a compressibility of NaClby estimating a lattice constant from its(200) reﬂections at various external loads.
At present, we succeed in generating pressure above 2.3 GPa by this pressure cell.
With a suitable change to the speciﬁcation,
it is possible to improve the highest pressure.
1 A. Onodera et al., Jpn. J. Appl. Phys., 26(1987) 152.

Fig. 1. A cross-section diagram of miniaturized
McWhan type pressure cell for elastic and inelastic
neutron scattering experimetns.

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 213－ 316 －

JAEA-Review 2008-067

1-8-7

Bent Perfect Silicon Crystal Monochromator for Cold Neutrons
M. Furusaka(A), T. Satoh(B), K. Tanabe(A), P. Mikula(C), K. Koyama(A), F. Fujita(A), A.
Homma(A)(A) Grad. Schl. Eng., Hokkaido Univ, (B) KUR Kyoto Univ.; (C) INR, Czech
Usually, SANS (small-angle neutron scattering) instruments are installed at an endguide position because they require rather
large space for detection system, very low
background and a wide wavelength bandof about Δλ/λ ˜ 10%. The last condition
is not easy fulﬁlled by using a conventional
crystal monochromator and therefore, atpresent a velocity selector is usually used
for such purposes. We are now developing a compact ellipsoidal-mirror focusing
small-angle neutron scattering instrument(mfSANS) employing a wide-wavelengthband monochromator, and have a plan
to install several such SANS instruments
along the guide tubes at JRR-3 reactor ofJapan Atomic Energy Agency or at manyother research reactors. In order to realize
such project, we have to develop a widewavelength band monochromator for cold
neutrons having Δλ/λ of several percents, preferably 10%.
In the case of the mfSANS instrument,
we will use a beam entrance collimator of
about 1 mm to 5 mm in diameter. When
Pyrolitic Graphite (PG) monochromator isused in such a geometry, the Δλ/λ ofthe monochromator becomes too small, ofthe order of a few-tenth of percent, irrespective of the mosaic spread of the crystal. Bent perfect crystal (BPC) of Si in the
fully-asymmetric diffraction geometry represents a good alternative for realizationof such a monochromator with required
parameters. However, there are no corresponding data available in the cold neutron
region and as far as we know, even for thebent crystal in the symmetric diffraction geometry.
Therefore, we studied neutron optical characteristics of the BPC silicon slabs in thecold neutron region. Unfortunately, we did
not have access to a white-neutron beam-port, we used the ULS instrument at theC1-3 port of the cold neutron guide C1of JRR-3. The instrument has a PG(002)monochromator, which provided us neutrons of about the wavelength of 0.47 nm.
First we measured the beam-characteristics
from the PG-monochromator using a 5inch diameter scintillation-counter basedon a resistive-wire type photo-multipliertube. With its very-high positional resolution combined with a ﬁne slit, we could
measure the phase-space intensity of thebeam, namely, not only the position dependent ﬂux, but also the angular divergencesof them.
Knowing the beam parameters from the
PG-monochromator, then we put BPC- andin Si(111) slabs on the second axis of thediffractometer for diffraction in symmetric reﬂection geometry ((111)-crystal planes
were parallel to the main face of the crystal slab) and in the non-dispersive settingwith respect to the PG(002) monochromator. We made rocking curve measurementswith various bending radii in the range of
R>2 m. First, one BPC Si slab was used,then we repeated the measurements with
two and three BPC Si slabs stacked together
as a sandwich. We successfully measured
2-dimensional images of reﬂected neutrons
with the position sensitive detector.
At ﬁrst, with changing the bending radius R from almost inﬁnity to several
meters, reﬂected beam intensity increased
without broadening of the rocking curve,
which means that the total angular changebrought about by bending is smaller thanthe mosaicity of the PG-monochromator.
However, by bending the Si-crystals furthermore, the situation distinctly changed,
the peak reﬂectivity was saturated andbroadening of the rocking curve was observed. We also observed reﬂected inten-

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 237－ 317 －

JAEA-Review 2008-067

sity enhancements when one or two crystals were added to the sandwich.
In order to check whether we could
enhance the wavelength-bandwidth further more, we conducted another typeof experiment using the pulsed neutron
source of Hokkaido University based on
a 45-MeV electron-linac. In the experiment, white cold-neutron beam was incident into several-different positions of the
BPC with slightly different angles and thewavelength-shifts were measured using atime-of-ﬂight technique.
Detailed analysis of both experiments isunderway.

－ 318 －

JAEA-Review 2008-067

1-8-8Development of High Performance Neutron Supermirrors
with Ion Beam Sputtering Technique
R. Maruyama, D. Yamazaki, T. Ebisawa, M. Hino1 and K. Soyama
1

J-PARC Center, Tokai, Ibaraki 319-1195
Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494

We have developed neutron supermirrors
by employing the ion beam sputtering (IBS)
technique because it enables the productionof layers with a high density and small grain
size. We have also demonstrated the efficiencyof the ion beam polishing technique combinedwith the IBS deposition to suppress the interface roughness, which is an important problem in the fabrication of supermirrors withlarge m1, 2) . Although the IBS technique produces high quality layers, its disadvantage isthat the deposition area and rate are relatively small. Based on the results of our development, a new IBS system with a large deposition area of 0.2 m2 (diameter of 500 mm)
has been designed and installed in JAEA. The
difference in the deposition rate over the entire deposition area has been confirmed to be
原子炉：JRR-3

装置：SUIREN(C2-2)

less than 4% 3) .
Ni/Ti supermirrors with m = 3 and 4, foruse as neutron guides in the J-PARC project,
have been fabricated using the IBS system.
The total number of layers is 403 and 1201,
respectively. The neutron reflectivities of mirrors with m = 3 and 4 at their critical angles
are 82 and 66%, respectively. Ni/Ti supermirm= 1
1.0

2

3

4

0.4

0.6

0.8
1.0
-1
Q / nm

5

6

7

0.8
Reflectivity

Neutron scattering is a useful source of
information about the positions, motions,and magnetic properties of condensed matter. Neutron scattering is important because
it provides valuable information that can not
be obtained using other techniques such as Xray scattering. In order to study a wide rangeof problems in material and life science with amuch higher neutron intensity, a new spallation neutron source (Japan Proton Accelerator Research Complex, J-PARC) is now underconstruction. The development of neutron supermirrors with high reflectivity and large m,
the ratio of the critical angle of the supermirror to that of natural nickel, is important for
the J-PARC project since it greatly increases
the available neutron intensity. For example,
a m-supermirror guide would bring about again factor of m2 in the neutron flux at theend of the guide when it is used instead of theNi guide. Neutron supermirrors consist of alternating layers of two materials with different refractive indices for neutrons.

0.6
0.4
0.2
0.0
0.2

1.2

1.4

1.6

Figure 1: Reflectivity profiles of Ni/Ti supermirrors
with m = 3, 4, and 6.7.

ror with m = 6.7, which is a record breaking
critical angle, has also been fabricated. The
total number of the layers is 8000. The neutron reflectivity at the critical angle is 23%4) . Thus, we can contribute to the J-PARC
project in which the production of neutron
guides, benders and other devices using supermirrors is planned.
References
1) K. Soyama, W. Ishikawa and K. Murakami, J. Phys.
Chem. Solids, 60, 1587(1999).
2) K. Soyama, H. Tsunoda and K. Murakami, Nucl.
Instrum. Methods Phys. Res. A, 529, 73(2004).
3) R. Maruyama, D. Yamazaki, T. Ebisawa, M. Hinoand K. Soyama, Physica B, 385-386, 1256(2006).
4) R. Maruyama, D. Yamazaki, T. Ebisawa, M. Hinoand K. Soyama, Thin Solid Films, 515, 5704(2007).

分野：中性子散乱（装置）－ 319 －

JAEA-Review 2008-067

1-8-9
Feasibility Tests on the Pressure-transmitting Media for Single-crystal
Magnetic Neutron Diffraction Experiments
T. Osakabe
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

Pressure transmitting-mediums have extremely important roles in single-crystal
diffraction experiments. Low hydrostaticityof the mediums under pressure highly depraves the crystallinity of the sample. As
a result, the diffraction intensity lowers further. In order to investigate the hydrostaticity of the mediums, we measured the mosaic
spread of NaCl single-crystal under pressure
at room temperature. The investigated mediums are graphite powder, a (1:1) mixture of
Fluorinert FC77 and FC70 (Sumitomo 3M,
Inc.), Fomblin oil (Y140/13, Solvay SolexisInc.), Si oil (KF96-50CS, Shin-Etsu Chemical Co., Ltd.), Daphne7373 oil (Idemitsu Co.,
Ltd.) 1) and glycerin. The measurements were
performed using TAS-1 spectrometer. The
pressure was applied by using an anvil-typehigh-pressure device and monitored by a standard ruby-fluorescence method.

Fig. 1(a) and (b) show the rocking curvesof the (200) Bragg reflections of the NaCl
single-crystal under pressure with the mediums of Fluorinert mixture and glycerin. In
Fluorinert mixture, the clear peaks are observed at ambient pressure, 0.4 GPa and 0.9
GPa. At 1.4 GPa, the peak suddenly extends
over more than 10 degree and the peak intensity goes down further. This indicates that
Fluorinert mixture solidifies at around 1 GPa.
On the other hand, in glycerin, the width ofthe diffraction peak increases very gently withincreasing pressure and is only 1.1 times at
3 GPa and 1.5 times even at about 7 GPa.
This shows that the glycerin medium transmits nearly hydrostatic pressure at least up to
7 GPa. Fig. 2 summarizes the experimental
results on the hydrostaticity of the mediums.
Upper limitations of the available pressuresof the mediums in the diffraction experiments
are also summarized in the figure.

Figure 2: Pressure dependence of the (200) peak widthof NaCl crystal. Each value of the width is normalized
by that at ambient pressure.

Figure 1: Rocking curves of the (200) reflections of the
NaCl crystal at the selected pressures for the mediumsof (a) Fluorinert and (b) glycerin.

原子炉：JRR-3

装置：TAS-1(2G)

References
1) K. Murata, et al., Rev. Sci. Instrum., 68, 2490(1997).

分野：中性子散乱（装置）－ 320 －

JAEA-Review 2008-067

1-8-10
Performance Test of Neutron Detector forEngineering Diffractometer in J-PARC
K. Sakasai, T. Nakamura, M. Katagiri, A. Birumachi, T. Hosoya, K. Soyama, S. Satoh1 ,E. Shooneveld2 and N. Rhodes2
J-PARC Center, Tokai, Ibaraki 319-1195
Institute of Materials Structure Science, KEK,Tsukuba, Ibaraki 305-0801
2
ISIS Science Diffraction and Muon Division, RAL, Didcot, OX11 0QX, UK
1

The fabricated detector was designed tohave a small detection pixel with a spatial
resolution of 3 mm. The detector had 120
pixels to establish a large neutron sensitivearea. Scattered neutrons were detected basedon the nuclear reaction of 6 Li(n,α) in ZnS/LiF
scintillators in the pixel. Incident neutron
position was determined by a 2 Cn coding
method. The applied voltages of PMTs areindividually set to have a gain of 3 × 107 .
The PG monochromator was used for the experiments. A collimated neutron beam was irradiated to the detector for the measurementof a spatial response. Neutron count linearity
was also measured by changing the neutron
intensity with a disperser.

In summary, the fundamental performanceof spatial resolution and the neutron countlinearity of the fabricated detector were confirmed. Other performance such as neutron
detection efficiency and uniformity are underinvestigation.



A prototype linear scintillation neutron detector originally developed in RAL was fabricated for the engineering diffractometer in JPARC. In this paper, some results of the performance test of the detector are described.

原子炉：JRR-3

装置：MUSASI(T2-3)























Figure 1: Results of spatial response.

  

Fig.1 shows the results of the measurementof the spatial response. The beam size of anincident neutron was 2 × 1 mm2 . Since a
scintillator in a detector pixel was opticallyisolated from the other pixels, the spatial resolution is the pixel width of 3 mm, in principle. One can recognize that an intense signal
was generated from only one pixel. It canbe confirmed that the detector had a spatial
resolution of about 3 mm and that there wasno coding misses and no remarkable crosstalk
between the pixels.
Fig.2 shows the results of the linearity measurement. Neutron counts were calibrated
with a 3 He gas neutron detector. As can beseen in the figure, neutron counts of both thefabricated detector and the 3 He detector were
almost the same up to 3 × 103 cps.

   























 

Figure 2: Linearity of neutron counts.

分野：中性子散乱（装置）－ 321 －

JAEA-Review 2008-067

1-8-11
Measurement of Energy Spectrum of Neutron Beam at MUSASI PortK. Sakasai, N. Metoki1 and H. Matsue2
J-PARC Center, Tokai, Ibaraki 319-1195
Advanced Science Research Center, JAEA, Tokai, Ibaraki 319-1195
2
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-11951








1.12
0.028

1.49
0.190

2.24
0.534





Figure 1: Experimental setup.











4.48
0.248










Table 1: The intensity ratios of detected peaksλ(Å)
ratios





The high-angle MUSASI beam port provides a neutron beam with a scattering angle of 82 degrees. When PG is used asa monochromator, however, neutrons withhigher harmonic ones will be generated because of the intrinsic characteristics of PG. To
provide neutron energy information to users
who adopt PG as a monochromator, neutronenergy spectrum was measured by a TOF
method.
The experimental setup is schematicallyshown in Fig. 1. An neutron beam waschopped by a chopper and the chopped neutrons were detected by a 3 He detector with aflight path of 1.27 m. Logical pulses generated by a discriminator were measured by amulti-channel scalar with a dwell time of 2 µs.
The measured neutron spectrum is shownin Fig. 2. The TOF time was converted toneutron wavelength according to the relationship between TOF time and the flight path.
One can observe four peaks corresponding toneutron wavelengths of 4.48 Å, 2.24 Å, 1.49 Å
and 1.12 Å, respectively. No noticeable peaks
was observed above 5 Å. Table 1 lists the peakratios calculated by fitting each peak with aGaussian function. The most intense component was 2.24 Å-neutrons that made up 53 %of the total beam. Note that the data were
not corrected by the neutron detection efficiency of the 3 He counter.















Figure 2: Neutron energy spectrum.

原子炉：JRR-3

装置：MUSASI(T2-3)

分野：中性子散乱（装置）－ 322 －



JAEA-Review 2008-067

1-8-12Development of High Quality Neutron Mirrors with Upgrading
Cold Neutron Bender System
I. Tamura, D. Yamazaki1 , R. Maruyama1 , K. Yamamoto, K. Nakamura and K. Soyama1
Department of Research Reactor and Tandem Accelerator Nuclear Science Research Institute, JAEA,
Tokai, Ibaraki 319-1195
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

A cold neutron bender system has been installed in the JRR-3 beam hall to increase thenumber of beam ports. In 2006, the neutron
beam transportation ability of the system was
upgraded by using high quality neutron mirrors. These mirrors have high quality Ni/Ti
multilayers with m = 3 on both side of silicon substrate and Boron float glass substrate.
The ion beam sputtering (IBS) technique enables the production of layers with a highquality and density. A large silicon substrate,
which is 40 mm in width, 105 mm in lengthand 0.2 mm in thickness, was selected in orderto improve the installation accuracy. Neutron
mirrors on silicon substrates were installed as
curved neutron guides. Neutron mirrors on
glass substrates were installed as straight neutron guides in the cold neutron bender system. In this report, we report the neutronreflectivity of mirrors with silicon substrates
and with glass substrates using the cold neutron bender system.

We succeeded in manufacturing of a highreflectivity (90%) Ni/Ti supermirror with m= 3 on the silicon substrate.

Figure 1: Neutron reflectivity on the front side of a
Ni/Ti multilayer supermirror carried out at SUIREN.

The measurements of neutron reflectivity ofa newly producted neutron mirror were carried out at SUIREN in the JRR-3 beam hall.
The incident neutron wavelength is 3.83A.
Neutron reflectivity of a Ni/Ti supermirror
on both sides of silicon substrate are shown in
Fig.1 and Fig.2, respectively. Figure 1 shows
the neutron reflectivity of a Ni/Ti supermirror on one side of the silicon substrate andFig.2 shows the neutron reflectivity on theback side of it. The reflectivities at the effective critical momentum transfer were 0.9
and 0.9 respectively. It was found that thefeatures of the reflectivities of mirrors on one
side of substrate are almost the same as thatof the other side. It was also found that thereflectivity at the effective critical momentum
transfer of the glass substrate was 0.8.
原子炉：JRR-3

装置：SUIREN(C2-2)

Figure 2: Neutron reflectivity on the back side of a
Ni/Ti multilayer supermirror carried out at SUIREN.

References
1) D. Yamazaki, et al., JAEA-Technology, 2007-030,(2007).

分野：中性子散乱（装置）－ 323 －

JAEA-Review 2008-067

1-8-13Upgrading Cold Neutron Bender System
I. Tamura, R. Maruyama1 , K. Yamamoto, K. Nakamura, K. Aizawa1 and K. Soyama1
Department of Research Reactor and Tandem Accelerator Nuclear Science Research Institute, JAEA,
Tokai, Ibaraki 319-1195
1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

In order to effectively utilize neutron beam,
we plan to increase the numbers of cold neutron beam ports that are able to install neutron beam instruments. A cold neutron bender system has been installed in the JRR-3
beam hall. The cold neutron bender system
divides a cold neutron beam line into three
beam lines. One is a straight beam line called
C2-3-1, and the other two beam lines, C2-3-2
and C2-3-3, are bend from the straight beamline. C2-3-2 beam line bend 10 degree fromthe straight beam line and C2-3-3 beam line
bend 20 degree from the straight.
However, the intensity of neutron beams
at the ends of divided neutron guides wasmuch lower than calculated one. Therefore,
the neutron beam transportation ability of
the cold neutron bender system have been upgraded using newly developed neutron mirrors .
In this paper, we report the measured spectrum at the end of C2-3-3 beam line using achopper spectrometer because Ni monolayer

mirrors were replaced with Ni/Ti multilayer
supermirrors of the straight neutron guidesection in the bender system.
Neutron spectrum was measured at the endof the C2-3-3 beam line by the time-of-flightmethod. The neutron chopper has a slit of 10mm, a disk diameter of 1400 mm and rotation
speed of 5000 rev/min. The flight path length
between the end of C2-3-3 beam line and the
chopper was 1.7 m, and the length between
the chopper and detector was 1.3 m.
The conversion factor from the time channel to the wavelength was calibrated on a dip
formed by a monochromator in the spectrum.
Figure 1 shows the neutron spectrum measured by the chopper spectrometer. The characteristic wavelength of the C2-3-3 beam lineis 5.4 A for improvement.

Figure 1: Neutron spectrum measured at C2-3-3 beam line by the time-of-flight method.

原子炉：JRR-3

装置：CHOP(C2-3-3)

分野：中性子散乱（装置）－ 324 －

JAEA-Review 2008-067

measured at depths of 2.5, 4.5, 8.5 and 12.5mm are shown in Fig.2, in which the profiles
were obtained from poled, unpoled, poled andunpoled specimen, respectively. The peak intensities of (002) reflection in the poled specimens are larger than those in the unpoled
specimens, showing that the spontaneous polarization direction is parallel to the [002]
direction. Therefore, the domain switchingproperties can be estimated from the difference between the diffraction profile of a poled
specimen and that of an unpoled one. The(002) and (200) diffraction intensity distribution with respect to scattering angle and penetration depth is plotted in Fig.3. The lowest intensity (zero) is shown by black (dark)color, and the color becomes brighter withincreasing the intensity. As shown, the firsttwo layers are profiles from the poled specimen, the next four layers are those from theunpoled one followed by four layers from thepoled one, and the last three layers are thosefrom the unpoled one. The profiles were fitted
by a convolution of Gauss and Lorenzt functions and integrated peak intensities of bothreflections were evaluated. Domain switching properties can be estimated from the integrated peak intensity ratio between (002)
and (200) reflections, i.e., I002 /I200 . Figure
4 shows the I002 /I200 value in a function ofpenetration depth. The I002 /I200 values arehigher than 1 for the poled specimen, andapproximately 0.5 for the unpoled specimen.
The I002 /I200 value of the unpoled specimen
is in a good agreement with the theoretical
I002 /I200 value, demonstrating that the neutron diffraction results have good reliability.
The I002 /I200 values are almost constant fordifferent penetration depths. This is due tothe fact that there was no treatment applied
to the specimen, and then the degree of polarization in a whole specimen is almost uniform. On the contrary, the I002 /I200 values
have fluctuations that may show the inhomogeneities of polarization in the specimen,
induced during the polarization treatments.
The results described above are difficult tomeasure by the means of XRD that only measure surface part. A combination of neutrons

having high penetration ability and a fine radial collimator can realize this kind of measurement.

Figure 3: (002) and (200) diffraction intensity distribution with respect to scattering angle and penetration depth.

Figure 4: Integrated peak intensity ratio (I002 /I200
value) as a function of penetration depth.

References
1) S. Harjo, S. Torii, A. Moriai and K. Shirakihara,
JAEA-Review (2.8.8 in this reports).

－ 325 －

JAEA-Review 2008-067

1-8-14
Test of Prototype 3 He PSDs and Related Electronics for New Spectrometers at
J-PARC
K. Nakajima1 , T. Yokoo1,2 , S. Satoh1,2 , M. Nakamura1 , N. Kaneko1,2 , Y. Kobayashi1,2 andR. Kajimoto1
J-PARC Center, Tokai, Ibaraki 319-1195
Institute of Materials Structure Science, KEK, Tsukuba, Ibaraki 305-0801
1

At MUSASI port, we have tested prototypes of detectors and related electronics,
which will be employed by spectrometers for
J-PARC. For neutron scattering instruments
planned for the new spallation neutron source
at Materials and Life science experimental Facility (MLF) at J-PARC, various novel typesof 3 He position sensitive detectors (PSDs) areconsidered to be used. Since the detector is
one of the most important key components, it
is indispensable to evaluate the feasibility andthe performance of these new detectors andrelated electronics prior to actual construction of the instruments.

A typical result of performance tests isshown in Fig. 2. The linearity of the position sensitivity is confirmed within the errorof 3 mm for all tested detectors. The resolution is less than 19 mm in FWHM. These
performances are almost equivalent to thoseof conventional short PSDs commonly usedat KENS. We have found slight differences in
the performance between the detectors provided by different venders, which are, how原子炉：JRR-3

装置：MUSASI(T2-3)

Figure 1: A 3 m length 3 He PSD on the testing standat MUSASI.

1000

18

2.5m PSD φ=2/3" p=10atm

800

16

600

14

400

12

Position Channel for PSD #1
Position Channel for PSD #2

200

0

FWHM(mm) for PSD #1
FWHM(mm) for PSD #2
-1000

-500

0

500

1000

FWHM (mm)One of the new types of the PSD is along tube PSD for 2 chopper spectrometers,
AMATERAS and 4SEASONS. The length ofthese detectors are l = 3 m and 2.5 m to minimize gaps between detectors (see Fig. 1).
They will be accommodated in the scattering chamber under the high vacuum condition (∼10−6 Torr) to reduce the background.
Therefore, new long PSDs are equipped with
newly designed vacuum couplings with SHV
connectors at the ends. A number of long
PSDs, which are deferent in lengths (l), diameters (φ), gas pressures (p), have been prepared by two different detector venders. The
detectors were set on the testing stand, andwe have examined them using neutron beam.

ever, completely acceptable to us.
According to the present results, we have
fixed the final specifications of detectors for 2
chopper spectrometers, that is, l = 3 m, φ = 1
inch, p = 10 atm PSDs for AMATERAS andl = 2.5 m, φ = 3/4 inch, p = 20 atm PSDs
for 4SEASONS.

Position Channel

2

10

8
1500

Actual Beam Position (mm)Figure 2: Position dependence of output position (position channel) and peak width of 2.5 m length, 3 He
PSDs (φ = 2/3 inch, p = 10 atm) provided by different
vendors.

分野：中性子散乱（装置）－ 326 －

JAEA-Review 2008-067

1-8-15Development of a Neutron Polarizing Device Based on a Quadrupole Magnet
and Evaluation of Its Polarizing PowerT. Oku, S. Yamada, T. Shinohara, J. Suzuki and H. M. Shimizu1
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
1
KEK, Tsukuba, Ibaraki 305-0801

So far, we have developed a Halbach-type
permanent quadrupole magnet (HQM) composed of a strong permanent magnet NdFeB
with an effective aperture size of 3.5 mm indiameter and a length of 600 mm as a neutron polarizing device1) . As a result of thecold neutron beam polarization experiment,a very high neutron polarization degree of
P = 0.9993 ± 0.0025 was obtained1) . The
polarizing device based on the HQM is considered to be a suitable polarizer for a focusing geometry small-angle polarized neutron scattering instrument using a magnetic
neutron lens because of its high polarization efficiency and high polarized neutrontransmission2) . However, for the practicalapplication to the neutron scattering experiments, an HQM with a larger aperture size
is demanded. Therefore, we have developed
the HQM with a larger aperture of 7 mm indiameter and length of the 700 mm (Fig.1).
According to the magnetic field measurement,
the magnetic field gradient was obtained to be∂ |B| /∂r = 515.8 ± 1.4 T/m inside the HQM
aperture. Neutron-absorbing cadmium (Cd)slits with an inner diameter of 5 mm were inserted between the HQM units in every 100
mm interval along the magnet length to prevent neutrons from hitting the inner surfaceof the HQM. Therefore, the effective apertureof the HQM is 5 mm in diameter.
We have performed a cold neutron polarization experiment using the HQM at thebeamline of C3-1-2-1(NOP) of JRR-3 inJapan Atomic Energy Agency. The experimental setup is shown in Fig.2. The neutron
wavelength was λ = 8.07 Å. The neutrons,
which passed through the HQM, were focusedand defocused by the magnetic neutron lensdepending on their spin polarity3, 4) , and weredetected by the 2d-detector. Figures 3 (a)原子炉：JRR-3

装置：NOP(C3-1-2-1)

Figure 1: The Halbach-type permanent quadrupole
magnet.

and (b) show the two-dimensional intensity
distributions on the detector, when the spin
flipper (SF) is off and on. The radial averagesof the intensity distributions are shown in
Fig.4 .T hepeaksappearinginthebothcasesareproducedbythepositivepo
Thus, the peak height ratio ∆ISF off /∆ISF on
corresponds to the so-called flipping ratio R.
Therefore, we get the relation5)∆ISF off∆ISF on
1 + Pi Pa (1 − D),=
1 + Pi Pa (1 − D) (1 − 2f )

R=

(1)

where Pi and Pa are the polarization efficiencies of the polarizer and analyzer, respectively. In this study, the magnetic neutron
lens corresponds to the analyzer. f is theflipping efficiency of the SF, D is the depolarization factor. By assuming Pa = 1, f = 1
and D = 0, we obtain
Pi =(∆ISF off − 1).
(∆ISF off + 1)

(2)

Based on Eq.(2), we calculated the neutron
polarization Pi of the neutrons which passed
分野：中性子散乱（装置）－ 327 －

JAEA-Review 2008-067

Figure 2: The experimental setup.

200

λ = 8.07 Å

11

10

SF Exp. Simulaiton
Off
On
B.G.

10

10
Intensity [a.u.]

through the HQM, and obtained Pi ∼ 0.999.
In conclusion, we have developed the HQM
with an aperture of 7 mm in diameter and alength of 700 mm, and performed the cold
neutron beam polarization experiment. As
the result, we obtained the highly polarized
neutron beam with a polarization degree ofPi ∼ 0.999.
(a)
2500

10

9

10

7

10

6

10

5

∆ISF∆offI f
8
10 ∆ISF∆Iondf8

0.1

x [ch]

1500

6 8

1

2

4

6 8

10

2

4

Figure 4: The radial averages of the intensity distribution, when the spin flipper is on and off.

1000

100

4

r [mm]

2000

150

2

500
0

50

References

0.48 mm/ch
50

200

100

150
y [ch]

1) T. Oku, et al., Physica B, 397, 188(2007).
2) T. Oku, et al., J. Appl. Cryst., 40, s408(2007).
3) H.M. Shimizu, et al., NIM-A, 430, 423(1999).
4) J. Suzuki, et al., J. Appl. Cryst., 36, 795(2003).
5) T.J. Jones and W.G. Williams., NIM, 152, 463(1978).

200

(b)
7
6

150

5

x [ch]

4
3

100

2
1
0

50
0.48 mm/ch
50

100

150
y [ch]

200

Figure 3: Two-dimensional intensity distributions. (a)SF is off, (b) SF is on.

－ 328 －

JAEA-Review 2008-067

1-8-16
Profile of a Neutron Reflectometer SUIREN at C2-2, JRR-3
D. Yamazaki1,2 , A. Moriai2 , I. Tamura3 , R. Maruyama1 , T. Ebisawa1 , K. Soyama1,2 ,M. Takeda2 and M. Hino4
J-PARC Center, Tokai, Ibaraki 319-1195
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
3
Department of Research Reactor and Tandem Accelerator, JAEA, Tokai, Ibaraki 319-1195
4
Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494
1

2

Specifications of the SUIREN reflectometerare collectively shown in Table 1. The intensity (* in the table) depends on the status of
the LTAS instrument operating at the C2-1
port, but can be normalized by monitoring incident neutron counts. The back-ground level(4.5 × 10−3 n/s) was measured when the local beam shutter was closed and the detector
window was covered with a B4 C rubber sheet.
Test measurements were performed before
starting operation for users. Fig. 1 shows a
specular reflectivity of a silicon wafer (3 inches
in diameter) with a fit curve for a Si wafer
with surface oxidization of 5 Å. It was foundthat reflectivity down to 10−6 (Qz  0.22
Å−1 ) can be measured unless sample itself
causes significant background. The measuring time was about 32 hours. The reflectivityof a Ni/Ti multilayer was also measured down
to 10−6 ( 0.42 Å−1 ), and Bragg peaks up to
the sixth one were identified. It took 59 hours
for the measurement.
In conclusion, the neutron reflectometer
SUIREN showed a high performance in test
measurements and has been used by industrial and academic researchers. As for futureplans, polarization analysis will be available
in 2007. Fe/Ge multilayer monochromators2)
原子炉：JRR-3

装置：SUIREN(C2-2)

Table 1: Specifications of the SUIREN reflectometer.
The intensity(*) is not fixed as described in the text.

Wavelength λ∆λ / λMaximum Beam Size
Slit1-Slit2 DistanceSample-Detector Distance
Incident Angle Resolution
Scattered Angle Resolution
Intensity*(∆θin = ± 0.04 deg)
Back Ground
Measurable Reflectivity

3.8 Å
1.3 %80H × 20W mm21450 mm1100 mm≥ 0.004 deg≥ 0.015 deg
2.3 × 104 n/s/cm2
4.5 × 10−3 n/s 10−6(coated at KUR) will be installed as a polarizing filter and an analyzer. A 1 T sample
magnet and a refrigerator (10 K ∼ RT) will
also be available.
010∆θinc=0.043deg∆θinc=0.055deg∆θinc=0.067deg∆θinc=0.118deg
Calculated

−1

10

10−2
Reflectivity

A new neutron reflectometer “SUIREN”
has been in operation at the C2-2 port of
the JRR-3 of JAEA since 2006. JAEA accepts proposals from academic and industrial
researchers. JAEA hase already provided 26days for outside researchers in 2006 and will
provide about 60 days in 2007. This instrument has vertical-sample geometry and is going to be used for studies on supermirrors1) ,polymers, magnetic thin films and other materials with solid surfaces.

10−3
10−4
10−5
−6

10

0

0.05

0.1
0.15
Qz (Å−1)

0.2

Figure 1: Measured Reflectivity from a silicon wafer.

References
1) R. Maruyama, et al., Physica B, 385-386, 1256(2006).
R. Maruyama, et al., Thin Solid Films, 515, 5704(2007).
2) M. Hino, et al., Physica B, 385-386, 1187(2006).

分野：中性子散乱（装置）－ 329 －

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JAEA-Review 2008-067－ 331 －

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JAEA-Review 2008-067

1-9-1
Polarized Neutron Inelastic Scattering Study of Spin Fluctuation inLa2−x (Sr,Ba)x CuO4
S. Wakimoto, K. Kakurai, M. Takeda, M. Matsuda, M. Fujita1 , K. Yamada1
and J.M. Tranquada2
1

Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577
2
Brookhaven National Laboratory, Upton, New York 11973, USA

The recent discovery of universal magnetic excitation in the high-Tc cuprates,
which shows a novel hour-glass shape dispersion, has provided an important insight into the magnetic origin of the superconductivity.
Among the several pictures proposed to explain the hour-glass dispersion, the stripe model is expected to
be an important candidate. We have performed inelastic polarized neutron scatteringon stripe-ordered La1.875 Ba0.125 CuO4 (LBCO
1/8) and compared the results with those of
La1.92 Sr0.08 CuO4 (LSCO 8 %) which has no
stripe order. The purpose of this experimentis to understand the effects of the stripe orderon the low energy magnetic excitations andhence have an insight into the origin of theuniversal magnetic excitation.

are confined in the CuO2 plane, that is, thea − b plane, in the stripe-ordered state.
These results demonstrate that the polarization of the low energy spin fluctuation isdifferent between the samples with and without the stripe order. A possible explanation isthat the in-plane gap of the excitation which
is observed in the non-doped La2 CuO4 is recovered in the stripe-ordered sample. Further polarized and unpolarized neutron experiments are in progress to confirm this.

The experiments have been performed at
the TAS-1 triple axis spectrometer operated
in a uniaxial polarization mode. Verticallyand horizontally focused Heusler monochromator and analyzer were used. Inelastic measurements were done with a fixed final neutron energy of 14.7 meV, and a spin-flipper
and a PG filter were placed after the sample.
Figure 1 shows profiles observed at the energy transfer 4 meV in the vertical-field (VF)spin-flip (SF) and the horizontal-field (HF)
SF channels along the A-C trajectories shownin the bottom figure. Remarkably, it is shownthat for LSCO 8 % the HF-SF signal is almost double of the VF-SF signal indicating
isotropic spin fluctuations, whereas for LBCO
1/8 both the channels show comparable crosssections indicating anisotropic spin fluctuations where those along the c-axis are suppressed. We have also confirmed by the polarized neutron diffraction that the Cu spins
原子炉：JRR-3

装置：TAS-1(2G)Figure 1: Polarized neutron scattering cross section
at the energy transfer of 4 meV observed in the VFSF and HF-SF channels. The data for LSCO 8 % aremeasured along the A (circles) and B (squares) trajectories, while those of LBCO 1/8 are measured along
the C trajectory. The bottom figures show the scan
trajectories in the momentum space and the definitionof the polarization axes.

分野：中性子散乱（超伝導）－ 333 －

JAEA-Review 2008-067

1-9-2
Magnetic Excitations in Lightly-Doped La2−x Srx CuO4
M. Matsuda, S. Wakimoto, M. Fujita1 , K. Yamada1 and J. M. Tranquada2
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195
1
Institute for Materials Research, Tohoku University, Sendai 980-8577
2
Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA.

Recently, detailed inelastic neutron scattering studies have been performed up
to high energies in various systems suchas YBa2 Cu3 O6.6 ,1) La1.875 Ba0.125 CuO4 2)
and La1.84 Sr0.16 CuO4 .3) All of them show
hourglass-shaped magnetic excitations withthe parallel incommensurate correlations at
low energies. On the other hand, there arefew studies of magnetic excitations in the
diagonal incommensurate phase in lightlydoped La2−x Srx CuO4 , although conventional
spin wave excitations were reported in the
diagonal stripe phase of La2−x Srx NiO4 .4)
We previously tried to measure magnetic
excitations in the diagonal incommensurate phase using a twinned crystal of
La1.976 Sr0.024 CuO4 .5) The results suggestthat the magnetic correlations change frombeing incommensurate to commensurate at ∼7 meV and ∼ 70 K. However, since some theassumptions are needed to analyze the datain twinned crystal, information was limited.
It is important to compare the magnetic
excitatons in both the parallel and diagonal
incommensurate phases in detail to clarify
what is the intrinsic magnetic properties inthe superconducting phase.
We performed inelastic neutron scattering
measurements on TAS-2 and LTAS using analmost untwinned crystal of La2−x Srx CuO4
(x ∼ 0.04), in which elastic magnetic peaks
are observed at (1, ±δ, 0)ortho or (0, 1±δ,0)ortho , to observe magnetic excitations in
the diagonal incommensurate phase. We observed energy and temperature dependencesof magnetic excitations in the range of 0 ≤ω ≤ 12 meV and 4 ≤ T ≤ 290 K. The results show that the incommensurability (δ)
decreases gradually with increasing energy up
to 12 meV, as shown in Fig. 1. This is qualitatively consistent with the behavior in the
原子炉：JRR-3

parallel incommensurate phase. The temperature dependence of the magnetic excitations
shows that the incommensurability gradually
decreases with increasing temperature andbecomes almost commensurate below 12 meVat room temperature.

Figure 1: Typical consant-energy spectra at T = 4
K in La2−x Srx CuO4 (x ∼ 0.04). The diagonal incommensurate peaks are observed at (1, ±δ, 0) or (0, 1±δ,0).

References
1) S. M. Hayden, et al., Nature, 429, 531(2004).
2) J. M. Tranquada, et al., Nature, 429, 534(2004).
3) S. M. Hayden, et al., Nature Phys., 3, 163(2007).
4) P. Bourges, et al., Phys. Rev. Lett., 90, 147202(2003).
5) M. Matsuda, et al., Phys. Rev. B, 62, 9148(2000).

装置：TAS-2(T2-4), LTAS(C2-1)－ 334 －

分野：中性子散乱（超伝導）JAEA-Review 2008-067－ 335 －

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JAEA-Review 2008-067

1-10-1
Intergranular Strain Pole Figure Measurement for
ECAPed Al by Neutron Diffraction
T. Suzuki1 , T. Ishibashi1 , Y. Tomota1 , H. Suzuki2 , T. Saito2 and S. Ryufuku3
1

Ibaraki University, 2 JAEA, 3 VIC Inc.

Texture and intergranular stresses are
evolved in polycrystalline materials subjected
to plastic deformation due to heterogeneous
plastic flow. In general, pole figures are measured by X-ray diffraction to evaluate theanisotropic mechanical properties of plastically deformed materials, which is not sufficient. In this study, a neutron diffraction
method has been developed to determine thetexture as well as intergranular strains called“strain pole figure” for a bulky sample.
A 4N graded pure aluminum bar with 8
mm in diameter and 60 mm in length was
ECAPed up to 8 cycles by rotating by 90
degrees at each extrusion. The (hkl ) intergranular strains and texture were measured
by using RESA at JAEA. The specimen was
rotated by 10◦ steps for texture measurement

原子炉：JRR-3

装置：RESA(T2-1)

and 45◦ steps for residual strain measurement.
And measurements were conducted a gauge
volume to measure diffractions from (111),(200) and (220) was adjusted completely inside the sample.
Figure 1 shows the results of texture andhkl intergranular strains. As shown, theECAPed aluminum shows an asymmetric texture. Residual intergranular strains are observed depending on the texture, and different in the case of three (hkl ) oriented family
grains. Although the stacking fault energyof aluminum is high, the misfit plastic strains
among grains, i.e., heterogeneous plastic flow,
seem to be yielded resulting in the generationof internal stresses.

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JAEA-Review 2008-067

1-10-2
Quantitative Evaluations of Microstructural Factors by Neutron Diffraction
for Cold Rolled austenitic Stainless Steels
H. Suzuki, T. Saito, J. Y. Tomota1 , T. Suzuki1 , P.-G. Xu1 and S. Ryufuku2
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
1
Ibaraki University, Hitachi, Ibaraki 316-8511
2
VIC, Inc, Tokai, Ibaraki 319-1112

Cold rolled stainless steels show anisotropic
mechanical properties which are dependent
on texture, substructure (dislocation structure and density) and intergranular stresses,
and hence, it is expected to determine thesemicrostructural factors as macroscopically averaged values. Neutron diffraction enables us
to measure these values for cm-ordered bulky
specimens. In this study, texture measurements and profile analysis were simultaneously performed to determine the above microstructural factors by an angler dispersion
neutron diffraction method for two stainlesssteels.
The samples used in this study were a
316 type stainless steel without N addition,
316SS, and a 0.325 mass% N bearing 310 typestainless steel, 310SS. After solution treatments to obtain a single austenitic phase, thespecimens were subjected to 25% cold rolling.
The diffraction profiles of (111), (200) and(220) reflections were measured using the neutron diffractometer for residual stress analysis(RESA) located in JRR-3 at Japan Atomic
Energy Agency in Japan. Texture and residual strains were determined by the conventional method, and the dislocation density
and the block size were analyzed for thediffraction profiles of (111) reflection using a
profile analysis software developed by Ryufuku et al.
Figure 1 shows the gradation images of
the intergranular strain pole figure superimposed on the texture contour map for (200)reflections. The textures obtained for 316SS
and 310SS are the typical rolling texture ofaustenitic stainless steels showing little difference. A significant difference between 316SS
and 310SS is found in the intergranular strainpole figure; the strain of 310SS is higher
原子炉：JRR-3

装置：RESA(T2-1)

than that of 316SS. This large difference in
the intergranular stain must be explained by
the difference in substructure which is mainly
caused by nitrogen addition. That is, theplaner dislocation array and network including Lomer-Cottrell immobile dislocations reaction has been observed in 310SS while dislocation cell structure in 316SS. Being consistent with Ikeda et al.’s work of in situ neutron diffraction study for 310SS with different N contents, higher intergranular stresses
evolve in a higher N bearing steel. Although
the dislocation structure is different in thepresent two steels, the dislocation density determined from the profile analysis was almost
the same, i.e., approximately 2.0 × 1015 /m2 ,and it gradually decreased with increase in angle from normal direction. To be noted is thecomparison of the crystal orientation pole figure and the strain pole figure, where the compressive and tensile residual strains are closely
related to the crystal orientation density.

Figure 1: Gradation images of the intergranular strainpole figure superimposed on the texture contour map
for (200) reflections of (a) 316SS and (b) 310SS.

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JAEA-Review 2008-067

1-10-3
Attempt of Residual Stress Measurements in
Multi-Purpose Thermal Neutron Application and Science (MUSASI)
S. Machiya1 , A. Moriai1 , H. Suzuki1 , N. Metoki2 , Y. Akiniwa3 and Y. Morii1
Quantum Beam Science Directorate, JAEA, 2-4 Shirakata-Shirane Tokai, Naka, Ibaraki 319-1115
Advanced Science Research Center, JAEA, 2-4 Shirakata-Shirane Tokai, Naka, Ibaraki 319-1115
3
Department of Mechanical Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku,
Nagoya 464-8601

1

2

Recently in Japan, the residual stress measurement and strain measurement for industrial use have been increasing. We feel a
growing need for a secondary residual stressanalysis port other than RESA. Therefore,
the residual stress measurement that using
MUSASI was examined.
The standard specimen was a shrink-fitted
ring and pulg made of aluminum alloy A7075.
The already-known residual stress can be introduced into the specimen by a shrink-fitted
ring and plug method, and it has used forround-robin tests of VAMAS. The monochromator was using the bending silicon crystal,and the wavelength was 0.2203 nm.
It is possible to measure the three directions of strain using neutron diffraction. In
the cartesian coordinate system, the relation
between the lattice spacing d and the strain ε
is as follows.
d(h,k,l)x,y,z − d0(h,k,l)ε(h,k,l)x,y,z =d0(h,k,l)Figure 1: Hoop stress of specimen.

Where d0 is lattice spacing for the stress freestate, and hkl is Miller’s indices for stressmeasurement.
Next, the strain and stress in the cartesian
coordinate system can be expressed as follows.
E[(1 − ν)εx + ν(εy + εz )](1 + ν)(1 − ν)E[(1 − ν)εy + ν(εx + εz )]σy =(1 + ν)(1 − ν)E[(1 − ν)εz + ν(εx + εy )]σz =(1 + ν)(1 − ν)σx =Figure 2: Radial stress of specimen.

about the resolution. In the future, improvements of the beam intensity are scheduled,and MUSASI high angle port is scheduled tooperate as RESA-II.

Figures 1 and 2 show the results of the measured residual stress. The solid line in the figure indicates the theoretical value. The measurement stress and the theoretical value arecorresponding, however it opens to dispute
原子炉：JRR-3

装置：MUSASI(T1-3)

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JAEA-Review 2008-067

1-10-4
Performance Test of Radial Collimator
Basic Performance Test
S. Harjo, S. Torii, A. Moriai1 and K. Shirakihara2
J-PARC Center, Tokai, Ibaraki 319-1195
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
2
Department of Mechanical Engineering, Suzuka National College of Technology
1

An engineering materials diffractometer
TAKUMI with time-of-flight method is recently proposed to build in Japan high intensity proton accelerator project (J-PARC).
TAKUMI needs radial collimators located between the sample position and detectors, todefine gauge sizes precisely and to control divergences of the scattered neutrons, i.e., tolimit scattered neutrons from parts except thegauge size. Since TAKUMI has a large detector solid angle surrounding the sample position, radial collimators that enable all of detector elements with different positions to observe the same gauge size are needed. However, there was not a clear description showing a relation between gauge size and collimator design parameters. Therefore, we firstly
derive both relational expressions, and thento produce a prototype radial collimator toconfirm the expression. Here, we report thederivation process of the relational expression
and a performance evaluation test result of
the prototype collimator.
The basic design concept of a radial collimator is shown in Fig.11) . Here, we ignore thethickness of the blade for simplification andthink a collimator with just twin blade. In
general, the radial collimator design parameters are: sample-collimator path length l1 , collimator blade length l2 , sample-detector path
length L2 , collimator blade intervals at the entrance s1 and the exit s2 , and angular apertureof blade α. Here, we adopted other parameters to explain the effective widths of gauge
Wg and detector Wd , geometrical maximum
widths of gaugeWgmax and detector Wdmax .
In our radial collimator design, the following
conditions were applied for the definitions of
Wg and Wgmax . (1) The scattered neutronfrom the sample shows a normal distribution
原子炉：JRR-3

装置：RESA(T2-1)

Figure 1: Definitions of radial collimator parameterscurve, and Wg is FWHM when Wgmax is assumed to have 95 % confidence interval of ±2 σ, and (2) α is assumed to be a solid angleof the detector width seen from the sample
center. First of all, equation (1) consists of
Wgmax .
Wgmax =

(l1 + l2 )s1 + l1 s2
l2(1)

By using a constant R, s1 and s2 are expressedas equations (2) .
s1
s2
Wd
=
=
R=
L2
l1
l1 + l2
s1 = Rl1∴
s2 = R(l1 + l2 )(2)

By substituting s1 and s2 in equation (1) withequations (2) l1 is obtained as follows.
(l1 + l2 )Rl1 + l1 R(l1 + l2 )l2
Wgmax l2=0
∴ l12 + l1 l2 −2R2
l22 + Wgmax l2 − l2R(∵ l1 > 0) (3)∴ l1 =
2
Wgmax =

Next, the following expressions comprise be-

分野：中性子散乱（残留応力）－ 340 －

JAEA-Review 2008-067

cause Wgmax has 95 % confidence interval of
the normal distribution, the FWHM value becomes Wg .
√Wgmax √
2ln2
FWHM = Wg = 2σ 2ln2 =22∴ Wgmax = √Wg (4)
2ln2
When Wg , Wd , L2 and l2 are set to be 1 mm,
3 mm, 2 m and 350 mm, respectively, the calculated l1 , s1 and s2 are 303.331 mm, 0.455
mm and 0.98 mm, respectively.
A prototype of radial collimator with theparameters shown above was made to have a
total angular coverage of about 5◦ considering
the cost balance. Mylar films coated by thegadolinium oxides (total thickness is 50µm)
are used for the blades. The performance
tests of this radial collimator were carried out
at RESA of JRR-3. In this measurement, thesample position of RESA was matched to a
focal point of the radial collimator, and thescattered neutron intensities from the sample
moving along the incident beam (x) direction
were observed. The used sample was a nylon
fiber of 1 mm in diameter, and the displacements with a range of x = ± 2 mm from the
focal point were given. An incident beam slit
with enough size was chosen not to give any
influences during sample movements.
Figure 2 shows the experimental result, average scattered intensities of the sample areplotted as the function of the displacement
along x direction. The focal point position isaround zero. The dotted line shows the resultof the McStas simulation using the same collimator parameters. In this simulation, since
statistics of the scattered neutrons were too
low, the neutron source with the width equivalent to the sample size of nylon was placedat the sample position, and again was moved
along the x direction. Similarly, the simulated curve is a plot of the average intensity
versus the displacement. It can be seen thatthe plotted data indicates a normal distribution function of the intensity and displacement. The FWHM of the experimental data
fitted by the Gauss function is 1.04 (1) mm,
while that of the simulated one is 1.070 (9)Figure 2: Intensity distribution of incoherent scattering from nylon with 1.0 mm diameter as a function of
displacement along the incident beam direction. The
solid line is a fitting line by Gauss function. The calculation result by McStas is shown in the dotted line.

mm. These values are very close to the design
value of FWHM = 1 mm. Therefore, it canbe concluded that the validity of the derived
relational expressions and the performance ofthe prototype collimator have high reliabilities. The peak position of the experimental
data shifts from the focal point by 0.1 mm. It
may be due to the miss-alignment of the collimator or the sample. Since we positioned thecollimator and the sample using a theodolite,
such an alignment error might have appeared.
Transmission experiments were performedby measuring the peak intensities of (110) reflection of iron wire with φ 1 mm for the caseswith and without radial collimator prototype.
The ratio of intensitiy with and without radial collimator, for (110) reflection of iron wire
was 65.6 %. It seems that this value is mostly
due to the normal distribution of beam that
goes through the radial collimator.
References
1) S. Torii and A. Moriai, Physica B: Condensed
Matter, 385-386, 1287(2006).

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1-10-5
Performance Test of Radial Collimator
Application Test on PSZ Material
K. Shirakihara, S. Harjo1 and A. Moriai2
Department of Mechanical Engineering, Suzuka National College of Technology
1
J-PARC Center, JAEA, Tokai, Ibaraki 319-1195
2
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

A relational expression between the design
parameters of radial collimators and the defined gauge sizes, which are needed to develop
radial collimators, has been established, andfrom the basic performances tests using a radial collimator prototype at RESA, the reliability of the expression were confirmed1) .
Now, this radial collimator prototype wastried to use on the real applications. As an
example of the application, mapping measurement on poled/unpoled PZT (Pb(Ti,Zr)O3 )was performed at RESA. PZT is a conventional piezoelectric ceramic containing a large
amount of Pb. Developments of new Pbfree materials having piezoelectric (domain
switching) properties as excellent as PZT
are necessary from the environmental issues.
Here, establishing materials design including
piezoelectric properties will help to design microstructures of materials in a short time andwill lead to the production of new materials
with high troughput and multi functions. The
domain switching properties of PZT are usually measured by means of X-ray diffraction(XRD) which measures only the near surface
and needs a polished surface. On the contrary, we can measure the domain switchingproperties as a whole sample or in a defined
gauge volume, by means of neutron diffraction(ND).
A tetragonal PZT (sintered at 1503 K) wasused as samples. The lattice constants a and c
are 0.40401 nm and 0.41087 nm, respectively,
and the spontaneous polarization direction is[100]. Block specimens with 4 mm width were
cut from the sintered sample and polarization treatments on the width direction with
1.9 kV/mm at 373 K were conducted for 10
min. The poled and the unpoled specimens
were serialised (layered) as shown in Fig.1.
原子炉：JRR-3

装置：RESA(T2-1)

The specimens were set on the sample table insuch a way that the scattering vector is parallel to the polarization (width) direction. The
incident beam slit with 1 mm width and theradial collimator prototype for 1 mm width
were used in the neutron diffraction experiment. The neutron diffraction scanning measurements were performed with 1 mm steps.

Figure 1: Specimen arrangement for ND measurement.

Figure 2: Typical (002) and (200) diffraction patterns of poled/unpoled PZT layered specimen shownin Fig.1.

Typical (002) and (200) diffraction patterns

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JAEA-Review 2008-067－ 343 －

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1-11-1

Hydration Properties of Low Heat Portland Cement
K. Mori, Y. Inamura*, O. Yamamuro*, K. Oishi**, K. Kimura**, T. Sato, K. Itoh, M.
Sugiyama, M. Kawai*** and T. Fukunaga
Research Reactor Institute, Kyoto University, *ISSP, University of Tokyo, **Shimizu
Corporation, ***Institute of Materials Structure Science, KEK
where the ﬁrst and second terms on theright-hand side indicate elastic and quasielastic scatterings for BW and FW, and BG
is the constant background. d(Q,E) andL(Q,E) are represented as the delta function
and Lorentzian, respectively. Note that theBW0 corresponds to the component of gypsum in the LHPC and was employed as theconstant value. The R(Q,E), which is described by Gaussian, indicates the resolution function of the AGNES spectrometer.
Finally, the excellent ﬁts between the observed and calculated patterns could be obtained for all QENS data.
The ratio of the signal from the BW1 ofbound water to the total signal of water,
BW1 + FW1, was deﬁned as BWI (= BW1/ (BW1 + FW1)), and calculated. The BWI
as a function of t is shown in Fig. 1. The
hydration process in three different stages
could be clearly observed in our experiments using QENS. In the induction period, no hydration products are created up
to ˜ 0.1 in day. The consumption of FW is ˜
20% after 1 day of hydration, and then thehydration rate decreases gradually.
0.35
0.30
0.25
0.20

BWI

Low Heat Portland Cement (LHPC) clinkers have occupied important positions inmaterials of huge buildings. The compressive strength of the hardened LHPC
may be strongly associated with the hydration properties of LHPC. Recently, quasielastic neutron scattering (QENS) technique has attracted much attention, because the QENS experiments provide us
dynamical information of water molecules
in materials. Even though cement clinkers have a lot of components, the hydration
properties can be easily investigated fromthe point of view of the bound water in thehydrated cement.
In this work, the hydration properties of LHPC were studied using the highresolution pulsed cold neutron spectrometer, AGNES. The energy resolution is 120
μ eV, using PG002 monochromator (λ =0.422 nm). The LHPC clinkers were hydrated with light water (H2O) at 28 degree
in air. The H2O to LHPC mass ratio was
kept constant at 0.5.
The time evolution of the QENS spectrumof the LHPC was obtained until 5 days ofhydration at Q ˜ 20 nm-1, where Q is themomentum transfer. The QENS spectrum
is extremely broad in the early hydration
period, while the elastic peak at around E= 0 meV is drastically grown in later hydration period. This behavior can be safely
interpreted; the hydration process changes
free water into -OH or water of crystallization. The signals of bound water (BW) andfree water (FW) in the whole QENS spectrum were separated. In the ﬁrst instance,
the QENS intensities, I(Q,E), were represented as follows:

0.15
0.10
0.05
0.00

0

1

2
3
Time / days

4

5

Fig. 1. Bound water index, BWI, of the hydrated
LHPC as a function of hydration time.

I(Q,E)={(BW0+BW1)d(Q,E)+(FW1)L(Q,E)}R(Q,E)+BG,
Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-11-2

Advanced KINKEN Triple-Axis Neutron Spectrometer, AKANE
H. Hiraka, K. Ohoyama, Y. Yamaguchi and K. Yamada
Institute for Materials Research, Tohoku University
We have completed the renewal of the former double-axis diffractometer (KSD), andreconstructed it to a conventional tripleaxis spectrometer, AKANE, last year. As asecond phase of renovation, we began to
improve its performance, in particular, toward inelastic neutron scattering measurements. This year, we set up a new Ge (311)monochromator in order to gain high-ﬂux
neutron beam. As shown in Fig. 1(a), thenew [previous] monochromator has the following speciﬁcations: (i) 20-cm height [10cm], (ii) 13 blades with each vertical size of
1.5 cm [5 blades with 2-cm height each] and(iii) tunable vertical focus [a ﬁxed bent].
As a consequence of these features, thebeam focus is improved in space and a highluminescence is produced at the sample
position. Figure 1(b) actually shows thatthe phonon intensity increases double withkeeping the resolution as well as the S/Nratio.
In addition to the conventional triple-axis
mode, AKANE has several options. First,
a horizontally focused supermirror can beinserted in the incident beam path. Second, a postion-sensitive-detector bank canbe set up after a sample under the doubleaxis mode. A combination of these new
equipments has an advantage for taking
diffraction patterns over a wide Q range
in short time by using a small crystal. Further, Ohoyama et al. performed magnetic
neutron diffraction experiments under 30T pulsed magnetic ﬁelds on AKANE usinga small MnF2 single crystal. In fact, theysucceeded in detection of magnetic signals,
which indicates a spin-ﬂop transition under high ﬁelds. Thus, AKANE is challenging to develop new techniques of neutron
scattering.

TEL: +81-22-215-2037

Fig. 1. (a) Previous and new Ge(311) monochromators. (b) Comparison of phonon intensity between
the two cases of monochromators.

Contact Person:
Haruhiro HIRAKA (IMR, Tohoku Univ.)
Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 25－ 346 －

JAEA-Review 2008-067

1-11-3

Kinken Powder Diﬀractometer HERMESKenji Ohoyama
Institute for Materials Research, Tohoku University
The main purpose of HERMES is to obtain high quality powder diffraction databy short time measurements with easy operation. HERMES is quite suitable for manycases of experiments such as measurements of a sample of a very small amount,measurements of a lot of samples, measurements at a lot of temperatures, measurements of very weak magnetic scattering.
By its user friendly GUI, even beginners
can enjoy neutron experiments on HERMES.
Recently, HERMES is an important tool for
structural investigations on hydrogen storage materials. In developments of novelhydrogen storage materials, understand ofhydrogen structure is indispensable. Fig.1
shows the one of the recent results obtainedon HERMES: the crystal structure of hydrogen compound Li2NH. Though hydrogenatoms seem to form cages centred on eachnitrogen atom, the occupancy of the hydrogen cage is much smaller than 100% so that
only one hydrogen exists around one nitrogen; owing to spatial or/and time average
operation of the diffraction technique, theaverage structure seems like that in ﬁg.1.
In 2006, the measurement system has
been replaced from the previous UNIXbase system on a workstation to the Labview base system on a Windows PC. Thisreplacement has increased expandabilityof measurements of HERMES. Thus, theIRT group has been trying development ofnovel experiments techniques using HERMES, as well as structural investigation
by normal powder diffraction experiments;
for instance, the neutron holography technique and scanning neutron diffraction
technique, development of beam focusing
device. Since these techniques need quite
high experimental efﬁciency, HERMES isthe best instrument for the experiments.
In 2006, 64 groups had experiments on

HERMES, 23 papers were published.
The detailed and latest information on
HERMES can be obtained in the Web site:
http://www.yamadalab.imr.tohoku.ac.jp/HERMES/index.html
Reference of HERMES
K. Ohoyama, T. Kanouchi, K. Nemoto, M.
Ohashi, T. Kajitani, Y. Yamaguchi,
Jpn. J. Appl. Phys. 37 (1998) 3319.
Contact person:
Kenji OHOYAMA.
Institute for Materials Research, Tohoku
Univ.

Fig. 1. Crystal Structure of Li2NH determined on
HERMES

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
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JAEA-Review 2008-067

1-11-4Present Status of Tohoku University Triple-Axis Spectrometer TOPAN (6G)
Kazuaki Iwasa
Department of Physics, Tohoku University
Up to the beginning of FY2006, the control system of TOPAN has been replaced
to the LabVIEW PXI environment common for the spectrometers owned by ISSP.
The stepping motors and the encoders
were also renewed, and the automatic diaphragms and attenuators were installed.
These upgrades were based on the ﬁnancial supports of Grant-in-Aid for ScientiﬁcResearch from MEXT and of Yamada Science Foundation.
Hereafter, some research subjects using
the IRT beam time will be reviewed.
(1) Search for electronic ordering underhigh pressure: Phase transitions of electron orbital or multipolar degrees of freedom have been topics in condensed matter physics. Collaborators of Tohoku University have studied the ordering of vanadium 3d electron orbital in RVO3 underhigh pressure (D. Bizen et al.: J. Magn.
Magn. Mater. in press (Proceedings ofICM)). In addition, collaborators of Tokyo
Metropolitan University have been interested in the drastic change of transport
properties in ﬁlled skutterudite PrFe4 P12
under high pressure, which is expected tocorrelate with switch of the order parameter of Pr-ion 4 f electrons (D. Kawana etal.: J. Phys. Soc. Jpn. 75 (2006) 113602).
In order to understand the ordering mechanisms under high pressures in these systems, we established collaborations with
JAEA group that has recently developed
a compact anvil-type high-pressure apparatus (T. Osakabe et al.: J. Magn. Magn.
Mater. in press (Proceedings of ICM)).
We have succeeded in detecting magnetic
ordering in TbVO3 up to 4.3 GPa andPrFe4 P12 up to 3.9 GPa. We obtained
the stable experimental condition with thishigh pressure cell and the cryomagnet of
ISSP producing magnetic ﬁeld up to 5.8 T.
(2) Detection of the magnetic polariza-tion of Ce ions due to octupolar orderingin Ce0.7 La0.3 B6 : Higher rank multipolar ordering has been recently observed in several f -electron systems. One of the most
attractive systems is CeB6 and La substituted ones. CeB6 has been well known for
the antiferro-quadrupolar ordering owing
to the quartet crystal-ﬁeld ground state of
Ce3+ J = 5/2 multiplet. On the other hand,
Ce0.7 La0.3 B6 shows a so-called phase IV below 1.5 K, in which antiferro-type octupolar ordering was suggested from the resonant x-ray scattering result (D. Mannix etal.: Phys. Rev. Lett. 95 (2005) 117206,
H. Kusunose and Y. Kuramoto: J. Phys.
Soc. Jpn. 74 (2005) 3139). Such ordering is accompanied by the magnetic polarization within the Ce ion without net
magnetic dipole moment, and the diffraction peaks are expected to appear in thelarge scattering vectors. The experimentfor Ce0.7 La0.3 B6 based on the collaboration with Tokyo Metropolitan University
and ISSP was carried out, and we succeeded in detecting antiferromagnetic reﬂections whose intensities become larger inthe higher scattering angles. This result is
consistent with the octupolar ordering scenario.
(3) Application of PSD to polarized neutron experiments: We have examined theinstallation of position sensitive detectors(PSD) in TOPAN for observing reﬂectionsin the wide scattering-angle. Although thebackground level is high when it is usedwith the cryomagnet, we found that it canbe applicable in polarized neutron spinﬂipping measurement at Bragg reﬂection
points. Now we are trying to install neutron polarization option together with PSD
in the LabVIEW system, to accomplish thesearch for electron ordering phenomena in
the near future.
The description of TOPAN is seen in the

Activity Report on Neutron Scattering Research: Experimental Reports 14 (2007)
Report Number: 229－ 348 －

JAEA-Review 2008-067

web site: http://sheat.phys.tohoku.ac.jp/∼iwasa/TOPAN/index-j.html. The operation of TOPAN is based on the IRT of Tohoku University shown in the web site.

－ 349 －

JAEA-Review 2008-067

1-11-5Detection of Hydrogen Trapped by Nano-scale Carbide by SANS
M. Ohnuma, F.G. Wei∗ , K. Tsuzaki∗ and J. Suzuki1
Quantum Beam Center and ∗ Structural Metals Center, NIMS, Tsukuba 305-0047
1
Quantum Beam Science Directorate, JAEA, Tokai 319-1195

The alloy was annealed at 873 K for 10800
sec for forming coherent nano-size NbC. NbC
was chosen since it has the same crystal structure as TiC while it gives a larger scattering
contrast of H compared to the TiC. 20 × 20mm2 plate samples with 2 mm thickness were
cathodically charged with H. The concentrations of H in charged samples after the SANS
experiment were 0.03 at% (6 wt ppm). Two
different SANS experiments were conducted
to determine the effect of H and to confirm
reproducibility. In the 1st experiment, twopieces of samples with and without H-charge
were adopted. In the 2nd experiment, thesample with H-charge was measured and thenannealed at 473 K for 6000 sec for desorbing
H. After the heat treatment, the sample wasre-measured as a H-free sample. Because thealloy is ferromagnetic, we applied the magnetic fields of 1 T (1st ex.) and 0.5 T (2ndex.) for separating nuclear and magnetic components of the scattering.
Figure 1 shows the nuclear components of
原子炉：JRR-3

装置：SANS-J(C3-2)

10

8
6

H-charged (1st ex.)H-charged (2nd ex.)4

without H-charge (1st ex.)annealed at 473 K (2nd ex.)

2

1
-1

Intensity [cm ]Even a trace amount of hydrogen (H) cancause a premature fracture in high strength
steels through concentrating at microstructural heterogeneity. Suppressing a diffusive
H-concentration is one of the approaches toreduce the susceptibility of hydrogen embrittlement by introducing a nano-carbide (VC,
TiC, NbC, etc.) as a H-trap site. A quantitative correlation of the dimensions of nanosized TiC to the amount of trapped H suggests that H is trapped at the TiC/matrix
interface1) . However, due to the difficulty ofdetection of H and monoatomic layer segregation, no structural evidence has been obtained
yet. SANS is one of the suitable techniques for
detecting H-segregation in a nanoscale substance. Therefore, we measured SANS of
97.62Fe-0.23C-0.25Nb-1.90Ni(at%) alloy withand without H.

8
6
4
2

0.1

8
6
4
2

0.01
0.1

2

3

4

5

6 7 8 912-1q [nm ]

Figure 1: Nuclear components of SANS profiles.  &dotted curve: without H,  & solid curve : with H

the SANS profiles obtained from parallel direction to the magnetic field. The difference between the alloys with and without H
is detected as shown in Fig.1. In both experiments, the profiles of the alloys with H
show higher intensity than those without H
with good reproducibility. In the 2nd experiment, the H-charged sample shows same profiles with that of the 1st experiment, while
the same sample shows weaker scattering intensity after annealing at 473 K. The possible
origin of the change is only the difference of
H-concentration. The difference of the intensity can be explained by both H-segregation
at the interface of TiC/matrix and trapped
H inside TiC precipitates. Although wider
q-range measurements are required for determining which trap site is dominant, the results show the high potential of SANS to detect the trapped H even in the case that the
total amount of H is in the wt ppm range.
References
1) F. G. Wei and K. Tsuzaki, Metal. Mater. Trans. A,
37, 331(2006).

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2-1
研究テーマ： ダイナミック中性子トモグラフィ流動計測技術の開発（散乱線に関る基礎的試験）
表
題：ダイナミック中性子トモグラフィ基礎試験
ダイナミック中性子トモグラフィ基礎試験
呉田昌俊１ 、熊田 博明１ 、久米悦雄 １ 、染矢聡２ 、岡本孝司２１
日本原子力研究開発機構
２
東京大学
液体金属冷却型高速増殖炉の炉心熱流動評価手法の信頼性向上に資する詳
NR Converter
Multi
Neutron細データを整備するため、ダイナミッ
Beam
Mirrorク 中 性 子 ト モ グ ラ フ ィ （ DNC T ） と 命
VisibleLight
名した 4 次元熱流動計測技術の開発にMirror
つ い て 報 告 す る 。平 成 1 8 年 度 は 、DN C T
Test Section
装 置 を 開 発 し 、 J RR -4 で 基 礎 試 験 を 実
Collimator andAbsorber
Scatter Materials
施した。
中 性 子 ラ ジ オ グ ラ フ ィ 1）を 基 盤 技 術
High-Speed
Video Camera
with I.I.
と し た D NC T 装 置 の 概 略 図 を 図 １ に 示
Camera Obscura
す 。DNCT 技術 開発では 、特 に 6 ビーム を生成させる中性子制御系の開発が重要で
図１ DNCT 装置の概略図ある。このた め、モ ンテカ ルロ解 析コー ド
MCNP を 用 い て 中 性 子 お よ び γ 線 分 布 を解析し、 中性子 制御系 を設計 した（ 図 2）。
本装置で は、投 影角度 が異な る 6 投影像 を
3 枚 のコンバ ータ上 に同時 に生じ させ、 こ
れらを 3 台の 高速度 ビデオ カメラ で同時 記録する。
JRR-4 中性子 ビーム 設備に、回 転体が 組
み込 まれ て いる 試験 体 と DNCT 装 置を 設
置して基 礎試験 を実施 した 。回転体 は、アルミニウム円柱内にカドミウム線等を埋図２ MCNP による熱中性子束解析結果
め 込 ん で あ り 、 0.5～ 1.5rps の 範 囲 で 回 転させた。 記録速 度は、 125～ 500fps で実 施した。瞬 時 CT 値分 布のデ ータ処 理結果 の一例を図 3 に 示す。本基礎 試験に より、改良の余地 はある が 6 投影分 の中性 子ラジ オ
グラフィ映像を同時に高速度で記録する
DNCT の基 本原理 が確認 できた 。
Vertical
参考文献 1) 呉田昌俊、噴流工学、Vol. 20 [3],Cadmium Bar(2003),pp.24-31
本研究は、旧電源開発促進対策特別会計法(a) Side View(b) Slice view
Instantaneous CT value distributionに基づく文部科学省からの受託研究として、
図３ 瞬時 CT 値分布のデータ解析結果例
東京大学、日本原子力研究開発機構が実施した平成 18 年度「液体金属熱流動評価のための高速度 3 次元直接計測技術開発」の成果です。
原子炉：JRR-4

装置：中性子ビーム設備－ 353 －

分野：中性子ラジオグラフィ（熱水力）JAEA-Review 2008-067

2-2
Neutron Tomography Analysis of Metal Hydride Canisterwith/without Hydrogen Charging and Discharging Cycle
Y. Fujita, T. Ebisawa1 , H. Iikura2 and M. Matsubayashi2
Muroran Research Laboratory, The Japan Steel Works, Ltd., Muroran, Hokkaido 051-8505
Machinery Research Laboratory Yokohama branch, JSW, Yokohama, Kanagawa 236-0004
2
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

1

Hydrogen is expected as an ideal clean energy medium in the future, but it is difficult to store hydrogen compactly, lightly andsafely. Metal hydride (MH) is one of thepractical hydrogen storage methods, which
can absorb and desorb a large amount of hydrogen atoms in the interstitial sites at ordinary temperatures and low pressure. MH
is commonly manufactured by vacuum induction melting, and crushed into grain for expanding the reactive area with hydrogen. The
MH grain becomes a fine powder with hydrogen charge/discharge cycle, because thelattice volume change with the cycle makes
many cracks on MH grains. This pulverizing
phenomenon makes the apparent MH volume
larger and changes the internal structure ofa MH tank. Because such structural change
may cause performance degradation, the authors tried to visualize the internal structureof MH tanks by neutron tomography analysis.

ages at dashed line. It is easy to distinguishthe six glass sleeves in MH-1 as dark straightlines in the vertical cross-section image anddark circles in the horizontal slice image, respectively. But the sleeve shapes become unclear after 1000 cycles test. The volume expansion of MH might collapse the tubular
structure of the glass sleeves. The rising of
the MH filling level also proves the MH volume expansion.
The neutron tomography analysis was carried out on 1-cycle and 1000-cycle MH canisters. The analysis revealed the filled MH
expands its volume by the charge/discharge
cycle, and collapsed the glass sleeves by hydrogen ventilation.

Two MH canisters, MH-1 and MH-2, wereprepared for neutron tomography analysis.
Both canisters’ rated hydrogen amount was
50 NL (normal liter). The dimension was
O.D. 50 mm × H 132 mm and the weight
is about 700 g. Each canister contained 330
g MH grain (composition: La-Ce-Ni-Mn-Co)
and six tubular glass sleeves (O.D. 2.8 mm)
for improving hydrogen ventilation. MH-1
had been charged and discharged hydrogenonce. On the other hand, MH-2 had undergone 1000 cycles. Both canister were discharged almost hydrogen and filled with 0.2
MPaG argon gas.
Figure 1 is the neutron tomography analysis result. The upside of Fig.1 shows the partially integrated images of the vertical crosssections of MH-1 (left) and MH-2 (right) andthe downside shows the horizontal slice im原子炉：JRR-3

装置：NRF(7R, C2-3-3-1)

Figure 1: Neutron tomography analysis result of 1cycle (MH-1, left) and 1000-cycle (MH-2, right) canister.

分野：中性子ラジオグラフィ（新素材）－ 354 －

JAEA-Review 2008-067

2-3
Development of Neutron Imaging Techniques for PEM Fuel Cells (II)M. Matsubayashi, H. Iikura and R. Yasuda
Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195

The proton exchange membrane fuel cell
(PEMFC) is a promising power source fortransportation and consumer electronics because of its efficient energy conversion. The
Japan Automobile Research Institute (JARI)
standard type PEMFC was modified for thisstudy such as replacements of stainless steel
made fastening bolts and nuts with duralumin
made ones.
Neutron images of the non-operated JARI
standard type PEMFC for computed tomography (CT) were captured by a cooled CCD
camera system. Projection images were obtained for three conditions: 1) dried condition, 2) anode side flow channel filled withwater condition(“one-side-wet”) and 3) anode/cathode side flow channels filled with water condition(“both-sides-wet”). Two types ofreconstruction calculation were applied suchas: 1) conventional FBP(filtered back projection) method, and 2) FBP method using specialized shading images as projection images
for dried condition (specialized-FBP).
All figures are 2-D vertical slices reconstructed from CT images and aligned suchas left: specialized-FBP, right: conventional
FBP. Figures 1 and 2 show the results for“one-side-wet” condition. The left image of
Fig.1 shows no water in the flow chnnel but
the right image shows residual water. This isdue to the insufficient dried-condition of thecell. Both images in Fig. 2 show water existence in the flow channel. As clearly understood, the quality of left image is better thanthat of the right one. Similar images are also
obtained in Fig. 3 and 4 for “both-sides-wet”.
The left images clearly show water condition
in both flow channels as compared to the rightones.
In this study, it was confirmed that the
specialized-FBP method is superior to theconvetional-FBP method and is useful for thevisualization of water existence in a PEMFC.
原子炉：JRR-3

装置：NRF(7R, C2-3-3-1)

Figure 1: 2-D vertical slice reconstruction at the cathode side carbon separator under anode side flow channel filled with water condition.

Figure 2: 2-D vertical slice reconstruction at the anodeside carbon separator under anode side flow channel
filled with water-condition.

Figure 3: 2-D vertical slice reconstruction at the cathode side carbon separator under anode/cathode side
flow channels filled with water condition.

Figure 4: 2-D vertical slice reconstruction at the anodeside carbon separator under anode/cathode side flow
channels filled with water condition.

分野：中性子ラジオグラフィ（その他）－ 355 －

JAEA-Review 2008-067

2-4
Evaluation Research for Long Term Stability of Metal
M. Matsubayashi, H. Iikura and H. Yishikawa1
1

Quantum Beam Science Directorate, JAEA, Tokai, Ibaraki 319-1195
Geological Isolation Research and Development Directorate, JAEA, Tokai, Ibaraki 319-1194

Neutron imaging technique was applied to
improve the estimation of the amount of corrosion in an iron-remainder left undergroundfor geologic isolation research and development.
Carbon steel (SM400B, 30 × 30 × 2 mm
thick) was macerated in simulated seawater
under atmospheric conditions for almost 5
years, and its surface was corroded as shownin Fig.1 (left). It was used as a corroded carbon steel sample for neutron computed tomography (neutron CT). Copper plate (purecopper 30 × 30 × 2 mm thick) was macerated in H2 S-contained dilute NaS solution for
3 days, and its surface was corroded as shownin Fig.1(right). It was used as a corroded copper plate sample for neutron imaging. The
neutron CT of the corroded carbon steel sample was obtained by half rotation projection
images with even angle increment. A filtered
back projection method was applied as the reconstruction calculation algorithm.
Fig.2 shows projection images of the corroed carbon steel sample and computed tomograms. Horizontal lines in the projection
image indicate the cut position of computed
tomograms. Reduction of base metal of the
carbon steel plate was clearly observed in thecomputed tomograms. Meanwhile, significant
differences were not observed for the corroded
copper plate sample as shown in Fig.3 except
boundary of flaking. Because the corrosion
layer was very thin, then the thickness of thebase metal did not change. Experimental results show the effectiveness of neutron imaging to corrosion evaluation for carbon steel
but not for copper.
This study was conducted as a collaborative
study between Quantum Beam Science Directorate and Geological Isolation Research andDevelopment Directorate.

原子炉：JRR-3

装置：NRF(7R, C2-3-3-1)

Figure 1: Sample photograph: corroded carbon steel
sample (left), corroded copper plate sample (right).

Figure 2: Projection image of corroed carbon steel
sample (upper) and computed tomograms (lower) at
the cutlines indicated in the projection image.

Figure 3: Projection image of corroded copper sample(upper) and vertically averaged plofile (lower).

分野：中性子ラジオグラフィ（その他）－ 356 －

JAEA-Review 2008-067

2-5�植物試料における水動態解析�特に根圏の研究について�
Analysis of the water statement in plant tissue.
東京大学大学院農学生命科学研究科
中西 友子

研究の目的と意�
植物体の実に 9 割は水が占め、植物におけるあらゆる生理反応は水溶液中で行われ、植物の活動は水の媒介無しにはおこりえない。特に、養分吸収や養分の転流においては水が大きな役割を果たしていることは周知の通りである。生きた植物において最も重要な役割を果たしている化学物質は何といっても水であるにもかかわらず、水そのものの知見については非常に少ない。そこで我々は、生きたままの植
物体中の水の動きや分布を探るために、中性子ラジオグラフィーを採用し、水に特異的な像を得ることを目的に実験を進めた。NRG は正確には水素の像の可視化であるが、植物試料、特に根周辺の水について詳細に調べることができる方法は NRG が唯一の手段に近い。
本研究では、マメ科植物の中で特に乾燥に耐性であるササゲを使用し、土壌中の根周辺、いわゆる根圏における水動態を観察した。これらのササゲはアフリカで自生してたササゲ約 2000 種から選抜された乾燥に耐性な品種と乾燥に感受性な品種である。
ササゲは、根付近に水が全くない状態を 2 週間以上続けても、再び水を与えると吸収を開始し生育を継続することができる植物である。しかし、なぜこのような強い乾燥耐性能を保持しているかについては不明な点が多い。一般に自然環境下におけるササゲ
は菌根菌と共生し、リン酸など必要な元素を菌根菌から受け取る代わりに、根から光合成産物を菌根菌に供与しかつ根の一部を菌根菌の住まいとして分け与えている。この際に、菌根菌からも水分をも受け取っているのではないか、もしくは、菌根菌が土壌水分保持に寄与しているのではないか、という仮説がある。そこで、ササゲと菌根菌が共生した状態における根圏水分量の測定を試み、共生が乾燥耐性に関与しているか否かについての解析を行うことを目的に研究を進めた。

根箱に播種後 6 日目のササゲを移植し、土壌水分含量を 30％に設定した砂（豊浦の標準砂）で 2 週間生育させ、その後 NRG 撮影を行った。砂の最大容
水量は 0.28ml/g、１枚の根箱に 100g 前後の砂を入れた（図１）中央にナイロンメッシュで根箱を仕切り、植物の根は上部まで、菌根菌は下部にもいき生育できるように設定した。つまり、植物根は中間ナイロ
ンメッシュよりも上部でのみ生育する一方、菌根菌は砂全面を生育場所とすることができる設定にした。
使用したササゲは、各々、選抜された乾燥耐性品
種の、11979 と感受性品種である、7778 である。菌
根菌を接種していない区とした区を用意した結果、
全 4 区の設定となった。それぞれについて 3 連ずつ根箱を用意し、合計 12 枚の根箱の撮影を行った。
撮影後、IP-Lab にて、輝度値を水分含量として検量線を作成したのち、サンプル砂中の水分含量について定量解析を行った。検量線用サンプルの土壌水
分量は、10、20、30、40％と設定した。

実験系についてササゲ(播種後６日目)

��

NRG

110mm

菌根菌(接種したもの
５枚、接種していないもの３枚を各品種ごとに用意した。)

38um ナイロン網
10mm

��
90mm
100mm

図 1a 根箱の条件設定の模式図

その研究をどのように行ったか

JRR3• 最初の土壌水分含量は30％に設定。(最大容水量は0.28ml/g、１枚の根箱に100g前後の砂を入れた。)

植物試料の水動態解析－ 357 －

JAEA-Review 2008-067の間には liniar の関係があった。しかし、その相関係数の二乗は 0.942 であり、より精度の高い解析にはさらなる検量線を求める工夫が必要であると思われる。
以後は、この検量線を基に、根箱砂中の水分含量を算出した。
図 3 は実際に撮影した図と、それに擬似カラーを施した図である。全ての画像は、左が乾燥感受性品種である 7778 で、右が乾燥耐性品種の 11979 である。
また、図 3a が菌根菌未接種、図 3b が菌根菌接種した場合の中性子線像である。一部の区では根が中央のナイロン網を突き抜けていたが、ほとんどの区では図に示されているように、根の生長は上部の砂の中にとどまっていた。菌根菌がどこまで生育しているかの判断については、中性子ラジオグラフィー撮
影用の試料はアルミ板で根箱を作成する必要があったため、撮影前の段階では確認することはできなかった。また撮影後、サンプルの放射線量が十分減衰した後日に試料箱を開封して砂を調べてみたが、砂が完全に乾燥していたこともあり菌根菌の生育状況については把握することができなかった。どのように菌根菌の生育を把握するかが今後の課題として残った。なお、撮影は菌根菌接種から 4 日目に行った。

図 1b 用意した根箱（全 12 枚＋α）

結果(菌 根菌 を接 種しな かった区 )図 1c 実際の根箱の写真
どのような��を�たか
土壌水分量と画像の輝度値（中性子の透過度）との検量線について図２示した。
y = 2.8695x - 149.94
R2 = 0.9422

土壌水分含量
(％)

検量線
50
40
30
20
10
0

50
透過度（AU/px2)

55

60

65

70

38um
ナイ
ロン
網
左7778；中央：検量線用サンプル (上から土壌最大容水量の0％、10％、20％、30％、40％の水分を含む)；右11979

図３a 菌根菌を接種しなかった場合の中性子線像。
右図は左図に擬似カラーを付したものである。画
像中の左根箱：7778（乾燥感受性ササゲ）、右根箱：
11979（乾燥耐性ササゲ） 中央：検量線用砂サンプ
ル

図 2 土壌水分量と中性子透過度との検量線

図 2 に示されるように、土壌水分量が 10％から40％までの間において、土壌水分量と画像の輝度値－ 358 －

JAEA-Review 2008-067

結果(菌 根菌 を接 種した区)

38um
ナイ
ロン
網
左7778；中央：検量線用サンプル(上から土壌最大容水量の0％、10％、20％、30％、40％の水分を含む)；右11979

図３b 菌根菌を接種した場合の中性子線像。
右図は左図に擬似カラーを付したものである。画
像中の左根箱：7778（乾燥感受性ササゲ）、右根箱：
11979（乾燥耐性ササゲ） 中央：検量線用砂サンプ
ル
画像解析では根を含まないように砂中の水分含量算出を行った。つまり、画像から該当箇所に ROI をかけ、輝度値を求め、得られた検量線を基に砂中の水分含量を％で示した。その結果を図 4 に示す。上部の水分含量は下部に比べて減少していた。その原因としては、重力により水分が下部に移動したこと、上部には根が張っているので、根が水分を吸収したことなど考えられた。また、植物を植える前の砂中の水分含量を 30%に設定したにもかかわらず、ほとんど区において水分含量が 30%以上となった。これは検量線用サンプルが撮影までの間に乾燥したこと
ならびに、今回は H を多量に含むアクリル棒を使用
して小さい検量線用サンプル箱を作成したことによる中性子の散乱効果が影響したのではないかと思われる。

性品種間でも差が見られなかった。以上のことから、当初の仮説であった菌根菌による土壌水分保持能力については確認することはできなかった。
ちなみにササゲは乾燥耐性のものは通常あまり水分を吸収しないが乾燥時において水分を多量に吸収し始める。NRG 撮影施設においては照射後砂が飛散する恐れがあるため極力試料はそのままの状態として箱の中は見なかったが、図３b では右のササゲ（乾燥耐性）の方が土壌水分量が減少していることが示された。このことは、試料が撮影した 4 日目にはかなり乾燥負荷がかかった状態ではなかったかと推察される。
菌根菌存在下におけるササゲの根の水分吸収動態についてはまだ知見が無いため、今回の予備実験を踏まえてこれからも本研究を進めていきたいと考え
ている。
成果の公表
本研究成果については、学会発表等では公表しておりません。

土壌水分含量(％)

結果(土 壌水分 量(透過 度から 推測)の 比較)
NRG0618

60
50
40
30
20
10
0
7778上部

菌根菌なし
菌根菌あり

7778下部 11979上部 11979下部

図 4 砂中の水分含量の推定値（％）
菌根菌の接種の有無で砂中水分含量には変化がほ
とんど見られなかった。また、乾燥耐性品種・感受－ 359 －

JAEA-Review 2008-067

2-6
研究課題名：造山帯の熱年代学的研究
岡山理科大学自然科学研究所

兵藤博信

岡山理科大学自然科学研究所

板谷徹丸

岡山理科大学オープンリサーチセンター

郷津

知太郎*

*現在の所属蒜山地質年代研究所

Hironobu, Hyodo, Research Insititute of Natural Sciences, Okayama University of Science
Tetsumaru Itaya, Research Insititute of Natural Sciences, Okayama University of Science
Chitaro Gouzu*, Open Research Center, Okayama University of Science, *present address*Hiruzen Institute for Geology and Chronology

目的と意義

要因から単純な解釈ができない事象も多数存在す

造山帯はそれが形成される過程において複雑な る。K-Ar年代法を改良した原子炉での放射化を用
地殻変動の歴史を経験する。その過程で形成さ いる40Ar/39Ar法はそのような場合に段階加熱法をれた岩石や変成を受けた岩石にはその記録が同 用いることで一度閉鎖系になった岩石がその後、熱位体の拡散移動や元素分布として残り、特に放 的・鉱物学的変化をうけているかを判断する基準を
射性崩壊をする同位体系ではそれを時計として 提供する。
活用し、形成年代や変動年代とともにそれらが この研究の目的は複数の事象が記録されていると起きた条件を推定することができる。それらの 予想される造山帯の未知の岩石に対し 40Ar/39Ar段
核種の中で40Kを用いたK-Ar年代測定法は、熱的 階加熱法を適用することにより精細な熱的履歴の擾乱に対するいくつかの鉱物中のアルゴン拡散 解析を行うことにある。それにより今まで測定してパラメータがよく研究されており造山帯の冷却 得られた数値を単に年代とするのではなく、アルゴ
過程でK-Ar系が閉鎖されたと考えることができ ン同位体のmobilityを活用して岩体の削剥・上昇過る温度を閉止温度と定義して直接的に推定する 程あるいは一度鉱物が形成された後でおきた事象ことが可能になっている。その半面、純粋な物 のインジケータとして地質学的意味を明らかにする。

理系では推定できないいろいろな地質学的JRR-3、HR-2 パイプ、地球科学試料放射化分析
JRR-4、TB パイプ、地球科学試料放射化分析－ 360 －

JAEA-Review 2008-067

����結果照射��
対象とした岩石・鉱物はアイルランド北部のカ
レドニアン造山運動の後期に貫入した花崗岩の母
岩におそらく花崗岩の熱水作用で生成した考えら
れる 2 段階の成長をみせるトレモラ閃石（図 1, 図
2）、エジプトのパンアフリカン造山運動に伴って噴出した火山岩の角閃石とカリウム長石の年代測定を行った。エジプトの試料については測定が完了していないので、報告に結果の詳細は記述しな 図 1

アイルランド北部試料採取地域. トレモラ

閃石は花崗岩体の周りの片岩中に形成される.

い。
対象とする鉱物を 2 ミリ径のドリル孔があいた
アルミトレイにのせ、4 - 5 段積みにしてボルトナ
ットで固定する。この試料ホルダを JRR-3 は簡易
アルミ容器、
JRR-4 は石英管に真空封入した後 0.5
ミリ厚のカドミウムを巻いて、6 時間照射を 1 – 4
サイクル行った。JRR-3 の最初の試料については

1 mm

3mm

アルミ容器の内部にカドミウムシールドを入れて照射したが、内部温度が上昇しすぎたためカドミ 図 2

パルスレーザーで穿孔したトレモラ閃石.

ウムが溶融した（>321℃）。ほとんどがアルミ製

一個のビーム径は約 50 ミクロン. 炭質物で黒色であるにもかかわらず、放熱が効率的でないために見える長方形のトレモラ閃石（右辺, コア）

考えられ、今後 JRR-3 でカドミウムを用いるにはと片理面にそって成長した結晶質のトレモラ閃

試料容器と照射用アルミ製カプセルとの熱的伝導石（透明部, リム）の二つの部分から成る. 得ら性を改善する必要がある。JRR-4 では石英容器のれた年代分布は系統的変化を占めさずアルゴン

外側にカドミウム板 0.5 ミリをかぶせたが、溶融のトレモラ閃石中での拡散現象は複雑であるこすることはなかった。各アルミトレイには未知試とを示唆する.

－ 361 －

JAEA-Review 2008-067

料の他に中性子照射量をモニターするための標準

2000
Apparent Age (Ma)

年代試料として hb-3gr を中性子束密度の偏りの有無をある程度評価できるようにトレイの外側対角に 2 個、中心に 1 個配置した。
試料と年代測定��

1500

1000

500

トレモラ閃石は黒色の炭質物を含んだコアと長39

Ar/ Ar方形のコアの長軸方向に成長した結晶質のリムか37

らなり、おそらく二つのイベントで結晶片岩中に形成されたと考えられる（図 2）。

0
50
25
0
0.0

0.2

0.4

0.6

0.8

1.0

39

Fraction of Ar released

まず約 0.4 – 0.5 ミリサイズのコアとリムそれぞれの鉱物片を連続レーザーを用いて段階加熱し希図 3 単結晶トレモラ閃石鉱物粒のガス質量分析計で 40Ar/39Ar年代測定をおこなっ

40Ar/39Ar年代スペクトルた。次の段階として 50 ミクロン厚の薄片に調整したトレモラ閃石の試料を透過光観察しながらパル トレモラ閃石はスペクトルの形状が理想的ではな
スレーザー50 ミクロン程度の穿孔径の点年代分 くまた 100-300Ma の分散した年代を示した。
析を行った。一つの分析点ではガス量が十分でな まとめ
く測定誤差が著しく大きくなるため 5 – 20 点の合計を 1 試料として扱った。

これらの結果を総合すると、一様に古い年代（12-13 億年）は過剰アルゴンの存在を示唆している。もちろん古い年代を保持していたことを排結果

複数の鉱物粒から得られた結果はコアとリムで 除する決定的根拠はないが、カレドニアン造山運予想される年代をはるかにこえた 1200-1300Ma 動という比較的変成度の高い変成作用をくぐりぬ（12 億-13 億年前）のほぼプラトー年代を示した けてトレモラ閃石が生き残ることは合理的には考（図 3）。この値はカレドニアン造山運動の平均的 えにくい。貫入岩体の付近には過剰アルゴンが形
年代 500Ma や貫入した花崗岩の年代 380Ma とは 成されることは知られており、おそらく同じよう全く異なる。これらは比較的カリウム濃度が高い なプロセスが働いたと考えられる。
試料であった。それに比べてカリウム濃度が低い

若い年代が 2 次的な事象を記録しているかどう－ 362 －

JAEA-Review 2008-067

かはまだすべてのデータが出そろっていないので いく必要がある。
早急な結論はできない。しかしトレモラ閃石がそこれらの結果はまだ公の場で発表されていなの結晶度から期待される予想に反して安定な年代 い。それは照射後 3 ヶ月以上の冷却期間をおくこの記録を失っている可能性は高い。それは貫入岩 とや、測定そのものに時間がかかること、マシン
体の年代よりも若くなっていることからおおよそ タイムが前年度からの試料を測定しているためあ推定される。すなわち貫入という事象よりさらに いていないことなどによる。従って多くの測定は軽度な地質学的事象がアルゴン拡散を引き起こし 実質平成 19 年度になってから実施されたものでてしまったと考えられる。

発表の機会を得ていない。今後学会、論文誌など

今 回 の 申 請 は 当 研 究 室 に お い て の JRR-3, に発表していく予定である。
JRR-4 での40Ar/39Ar年代測定用の初めての試料照研究の性格上、同じ年度内に具体的業績を報告

射であるので中性子束密度の均質性についても評 することは著しく困難である。今回の共同利用に価できるよう標準試料を試料サンプル内の各部に よる照射とは無関係ではあるが、参考として 18配置した。

年度以前に京都大学原子炉で行った中性子照射にまず中性子束の均質性であるが、同じ照射条件 よる40Ar/39Ar年代測定の結果から発表された論文
で水平に配置した試料はややばらつきをみせる。 を以下に参考のために列挙する。
この現象は産業総合研究所の地質情報研究部門火 1）Hyodo, H. (2007) Laser Probe 40Ar/39Ar dating:
山活動研究グループの年代研究室が行った JRR-3 History and development from technical view.
における同様の実験でも報告され、中性子束の勾 Gondwana Research, in press
配がある程度存在することを示唆している。今回 2) Kawamura, M., Uchino, T., Gouzu, C. and Hyodo,の実験では京都大学原子炉実験所の研究炉で行っ H. (2007) 380 Ma 40Ar/39Ar ages of the high-P/T
た結果と比較すると、個々のデータのばらつきは schists obtained from the Nedamo Terrane, Northeast
やや大きい。しかしばらつきはランダムであり、 Japan. J. Geol. Soc. Japan, in press.
系統的な中性子束密度の勾配による変化は特定で 3) Kunimatsu, Y., 他 14 名兵藤 6 番目, 板谷 7 番目
きなかった。今後いくつかの照射実験から集積す (2007) A new Late Miocene great ape from Kenya andる標準年代試料のデータを総合的にみて

its implications for the origins of African great apes
and humans. Preceed. Nat. Acad. Sci. USA. in press.

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JAEA-Review 2008-067

2-7�造ＣＮＲＦを利用する冷中性子ラジオグラフィのための要素技術の開発
Develo�ment o� Di�it�l Ne�tron R��io�r���y �sin� P�lse Ne�tron �e�m

���大学大学�

�学研究科

�子核�学��
�置 ��

１．本研究の�的
JRR ｰ 3M 高強度中性子ビームを利用したラジオグ
ラフィ基礎技術開発の経験を基に、大強度パルス中性子源建設進捗に合わせて,パルス中性子ラジオグ
ラフィ対応基本技術を創製して, 冷中性子と物質の相互作用の特性を生かした科学研究用解析手段となる中性子画像分光学と呼べる新たな学問分野確立に必要な技術的支援を進める。
（１）先端的中性子画像撮像システム構築にむけて
CNRF を用いて実験的に抽出した課題を解決するための要素技術開発の研究を進める。
（２）物質と冷中性子の相互作用の中性子スペクト
ルによる変化を高中性子束およびパルスＮＲの開発
によって新しい分光学的利用法開発に関する基礎研
究を CNRF で進める。
２．結果の概要
単色中性子ラジオグラフィ法の概念的および実験的検討を進めた．結果の概要を以下にまとめる．
２�１単色冷中性子ビームを利用するラジオグラフ
ィ試行実験
速度選別器による単色冷中性子ビームを用いて,
冷中性子ラジオグラフィ実験を試行した。ブラッグ
カットオフ波長(0.4nm)を挟む長波長と短波長域の透視像から,鉄溶接部の歪みの影響が可視化出来た.
（１）緒言 核種に固有の中性子全断面積を利用す
る中性子ラジオグラフィの特性は冷中性子領域ではより顕著に現れ、冷中性子を用いることによって熱中性子の場合よりコントラストの強まった画像を得ることが可能である。特にブラッグカットオフ波長域では、熱中性子領域では得られない情報を得ることができる。グラファイトモノクロメータにより得られる特定波長の中性子を用いた単色中性子ラジオ＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
ＪＲＲ－３Ｍ， ＣＮＲＦ, 中性子ラジオグラフィ

グラフィの可能性を検討した。さらに中性子エネル
ギースペクトルの影響を軽減するために速度選別器
による比較的エネルギースペクトル幅の小さい冷中性子を用いてラジオグラフィ試行実験を行い、単色
冷中性子ラジオグラフィの可能性について検討し、課題を明らかにした。
（２）実験 実験はスイスのPSI SINQの新設冷中性子照射施設ICONで行った。この施設に中性子源からの 連 続 白 色 ス ペ ク ト ル ビ ー ム の 波 長 を velocity
selector装置を通して得られるスペクトル幅の狭められた冷中性子を用い、CCDカメラにより画像を得た。
被写体としてFe、Al、黒鉛を用い、被写体のブラッ
グカットオフ波長に応じていろいろな波長のビームで撮影した。ビームの 2 次元強度分布歪みを補正して得られた画像からそれぞれの物質の中性子透過率を評価し、中性子断面積と中性子ビーム波長の関係を求めた。Feの溶接部を含む部分をブラッグカット
オフ前後の波長のビームで撮影し、溶接部の判別を試みた。
（３）結果・考察 求めたFe、Al（図 1）、黒鉛の中性子断面積は計算で求めた値とエネルギー依存では相対的に合致し、ブラックカットオフも識別できる結果を得た。断面積の絶対値としてみた場合には計算による予想値と少し異なる値を示し定量性の面では課題が多い。Feの溶接部の画像（写真(左)）もブ
ラッグカットオフ付近のエネルギーに対しては微小な断面積の差も画像として識別できるという冷中性
子ラジオグラフィの可能性を確認できた。溶接部の歪み、結晶構造,あるいは析出物の影響が可視化出来る. 本実験で用いたビームがまだ比較的広いエネル
ギースペクトルを持ち、場所によるエネルギー分布の違い(写真(右))を持っていることに由来する見かけ上の断面積の分布が現れた。定量的には熱中性子
ラジオグラフィと同様に散乱中性子の影響、γ線の＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿

��は�小され�にオフ�ット��されます。図�とも�明な��を��けて下さい。

－ 364 －

JAEA-Review 2008-067

影響も見られる。
（４）今後の課題 単色中性子ラジオグラフィの定量化を向上させるために、γ線の影響除去法、ハニ
カムコリメータを用いた散乱線の除去法、スペクト
ル幅の狭い単色中性子を得るための単結晶フィルター法などを統合し、単色冷中性子ラジオグラフィ技術の体系的な確立を図る必要がある。

断面積(barns)

10

1

文献値
計算値
実験値

0.1
0.001

0.01
エネルギー(eV)0.1

図1．Al中性子断面積の実験値と計算値、文献値との比較

写真(左) 0.4nm にピークをもつ中性子による Fe
溶接部の透視像（溶接部が明るく見える）
写真(右) 0.65nm にピークをもつ中性子による黒鉛の見かけ断面積分布（黒鉛ブラッグカットオフ波
長 0.671nm）

２-２ 相対�傾斜した単結晶群を用いる波長選別器の原理とその検証
黒鉛単結晶を傾斜させて組み合わせた波長選別器を提案・試作し、その単色冷中性子ビームを用いる
ラジオグラフィ実験を試行し、その可能性を示した.

（１） 緒言 特定波長欠損の中性子ビームを用い
る中性子ラジオグラフィ(NR)を発展させ、複数組み合わせた単結晶により、波長・スペクトル幅を任意に制御した中性子ビームを得る方法を提案する. 原
理検証と中性子波長選別器(スリット)の可能性を、
特定波長欠損および単色ビームによるNR撮像を行う
ことにより、実験的に示す.
（２） 原理 スペクトルをもつ中性子ビームは、
ブラッグカットオフ（BCO）型およびスーパーミラー(逆ブラッグカットオフ：ABCO) 形フィルターを透過する事により、スペクトル幅の狭い単色中性子ビー
ムになる(図 1). フィルターは、モザイク度相当の角度を傾けて重ねた単結晶群で構成される。透過中性子ビームは、それぞれの単結晶により特定波長の回折を起こし、幅広い波長域に欠損をもつスペクト
ルに変形する. λ1 およびλ2 に対応する回折角に設定した単結晶を基準に、BCO型フィルターでは低角
度側に、ABCO型フィルターでは高角度側に、順次単結晶を傾斜させて重ねる. 両フィルターの組み合わ
せが、λ1 からλ2 の波長域をもつ単色中性子ビームを得る波長選別器(スリット)として機能する.
（３） 実験 NRによる検証実験はJAEA JRR-3M
TNRF・CNRFで行った. モザイク度公称値 0.4、0.7、
1.0 および 2.0 度の黒鉛単結晶 4 個の設定角を種々組み合わせて、BCO型およびABCO型のフィルター、および両フィルターによる中性子波長選別器(スリット)を構成し、C-CCDおよびBAS-NDによるNR撮像系に組み込んで使用した( 図 2 は単結晶群設定例 ). まず、フィルターの機能を確認するために中性子透過率評価用のNR像を得た. さらにフィルターの中性子波長調整機能を検証するために、鉄のBCO(0.40nm)前後の波長域にわたって巨視的中性子全断面積(Σｔ)評価用のNR像を得た.
（４） 結果・考察 黒鉛単結晶のモザイク度およびその組み合わせに対応して変化する中性子透過率からフィルター効果を確認した. 傾斜させて組み合
わせた黒鉛単結晶群を透過した中性子ビームによる
鉄被写体のNR像から評価したBCO前後の鉄のΣｔは、波長フィルターの検証とスリットの可能性を示している(図３). しかし、限られた単結晶群で選別できる波長域は冷中性子スペクトルの裾野除去には不十分で、求めた鉄のΣｔの波長依存性は相対的傾向にとどまった.
（５） 今後 中性子速度選別器による波長域幅の制限およびスペクトルのTOF計測を併用して、定量的検証をすすめる.

原�は��されずにオフ�ット��されます。図�とも�明な原�を��けて�さい。

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JAEA-Review 2008-067

1.0

�．���の��

Neutron transmittance�r a�� �i� �ractions

λ 1(1)玉置 昌義、“解説 中性子ラジオグラフィ（ＮＲＴ）の将来展望”、非破壊検査 第 53 巻、2 号 、84-87 ページ（2004）．

�ra���cut�o���t��e �i�ter
1.0
�r a�� �i� �ractions

λ 2
�nt i��ra���cut�o���t��e �i�ter(2) Masayoshi Tamaki, ”Conceptual monochromatic
digital neutron radiography using continuous
cold neutron”, Nuclear Instruments and Methods
in Physics Research A32-37(2005).

1.0
�r a�� �i� �ractions

�r a�� �i� �ractions

λ 1 λ 2
Neutron �a�e�en�t� s�i(3) Masayosgi Tamaki, Kazuhiro Iida, Noriaki Mori,
Eberhard H. Lehmann, Peter Vontobel, Mirko
Estermann, “Dy-IP characterization and its
application for experimental neutron radiography
test under realistic conditions”, Nuclear
Instruments and Methods in Physics Research
A320-323(2005)

図 1 中性子波長スリットの原理

図 2 黒鉛単結晶群の角度設定例

apparent crosssection of Fe / cm

-1

1.3

1.2

1.1

1

0.9
Bragg－cut－off of Fe

0.8
0.2

0.3

0.4

0.5

0.6

0.7

Averaged neutron wavelength / nm

図 3 鉄の見かけΣｔの中性子波長依存性
原��������オフ�ット�������図������原����け�����

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JAEA-Review 2008-067

2-8
イメージングプレートを用いる定量的中性子ラジオグラフィの開発と応用研究
D���������� �� Dy-IP ��r N�u�r�� I�a���� ��r Nu���ar Ma��r�a�� u���r R�a������ C���������

����学�学�

�学研究科

原子核�学��
��

１��研究の�的
JRR ｰ 3M 高強度中性子ビームを利用したラジオグ
ラフィ基礎技術開発の経験を基に、定量性確立を進めてきたイメージングプレート・冷却型 CCD を利用する広ダイナミックレンジ・デジタルラジオグラフ
ィ画像取得・処理・解析システムの開発研究をさらに高度化するとともに、中性子と物質の相互作用の特性を生かした科学研究用解析手段となる中性子画
像分光学と呼べる新たな学問分野確立に必要な技術的支援を進める。
先端的中性子画像撮像システム構築にむけて
CNRF･TNRF を用いて実験的に抽出した課題を解決するための要素技術開発の研究を進める。具体的には、
冷却型 CCD 中性子カメラ,中性子用およびＸ線用イ
メージングプレートの併用による定量的画像情報の取得・処理・解析方法の高度化を図っていく。
２���の概要
核燃料照射後試験を念頭に、γ線不感処理式イメージングプレートの原理を提案した. 酸化ジスプロ
シウム(Dy2O3)を揮尽性発光体(PSL 体)に混ぜ込んだイメージングプレート(Dy-IP)を製作し、機能の検証、特性の評価、最適仕様の確定などを進めた. 開
発した Dy-IP を、照射後の核燃料、スポレーション
ターゲット、核融合材料の非破壊透視検査に実用的に応用した.
（１）緒言：中性子イメージング技術を科学研究手段として高度化するために、散乱中性子除去およびγ線カブリ評価に関する手法の確立につづいて、更なる中性子イメージング技術の高度化と実用的応用のために、核燃料の照射後試験に使用可能なγ線不感式撮像法の開発に取り組んだ.
_____________________________________________
JRR-3M, TNRF, 中性子ラジオグラフィ

��（２）背景：BAS-ND(酸化ガドリニウム入りIP)の開発と商品化は中性子科学研究に関わるイメージング
手法に飛躍的な高度化をもたらした。しかし、実験場におけるIP画像のγ線によるカブリは、BAS-NDにとって避けられない解決すべき課題であった(図1a). ジスプロシウム(Dy)とX線用イメージングプレート(XIP)を組み合わせる間接中性子イメージング法(図 1b)でこの問題を克服し、マルチチャンネルコ
リメータ(MC)による散乱中性子除去法を併用して科学研究への応用に必要とされる定量性の確保を検証した. この間接撮像手法を高度化するために、Dyを
XIP内に混ぜ込むことで、γ線不感処理式中性子イメージングの新概念を提案した.
（３）原理：中性子イメージングデバイスとしてのDy入りIP(Dy-IP)による撮像原理を示す(図 2 左).
中性子イメージング過程において、照射中性子線量に比例してDy-IP中のDyが放射化されると同時に、
PSL体自身もγ線やベータ線に感光する.
時には飽和して画像情報を失う. そこで中性子照射
直後に可視光線を当てて IP の潜像を一旦消去する.
続いて遮光した状態で放射化した Dy からのβ線に
よって IP を自己露光させ、二次元潜像を形成させる.
最後に IP 読み取り器でデジタル画像化し、画像解析を行う.
（４）検証：揮尽性蛍光体(PSL体：BaFBr:Eu)とDy2O3を等モル比に混ぜたDy-IPを試作し、JRR-3M TNRFにおいて、標準的には、1-10 秒間照射、5-15 分間可視光下γ線カブリ消去、遮光下 1-24 時間自己露光後、IP読み取り・画像解析を行って中性子透視画像が得られることを検証した(1). Dy/XIPの組み合わせの間接撮像法に比べてより良好な中性子イメージが得られた. 更にMCを併用して散乱中性子の影響を取り除くことによって高い定量性が確保できることを検証した.
_____________________________________________

原�は��され�にオフ�ット��され�す。図�とも��な原�を��けて下さい。

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JAEA-Review 2008-067

0.00025

0. 00 03

0.0 00 25

BAS-NDなし
BAS-NDあり
差0.0002

感度(P����)感度(P����)（５）評価：Dy-IPの感度・空間分解能の蛍光体層厚さおよび(Dy2O3／PSL体)混合比依存性を明らかにした(図 3)。さらにGd2O3 層をPSL体層に裏打ちしてIP
後方からの散乱中性子の影響を除去することで、更によい定量性が確保できることを明らかにした.
PSL体にDy2O3 を 40 モル％混合した 150μ厚さの蛍光体層と 100μ厚さのGd2O3 後方散乱中性子吸収体層からなるDy-IPが最適仕様である.
（６）応用：スイス ポールシェラー研究所（PSI）の中性子イメージング施設NEUTRA にて、照射後核燃料ピンの中性子イメージングに応用し(図 2b)、燃料ペレット・ジルカロイ被覆管の寸法、ジルカロイ
被覆管壁の水素析出物、燃料濃縮度(U-235 換算)の評価を行った(図 4). PSI中性子源SINQや世界各国のスポレーションターゲット開発のために、鉛、水銀などの照射後ターゲットの中性子イメージングに
Dy-IPを応用した(図 5). 現在,次世代ターゲットの照射後試験を進めている. また、照射後核融合炉材
料の中性子透視試験にもDy-IPを応用した.
（７）結言：開発したDy-IPは定量性を確保できる高性能中性子イメージングデバイスであり、核燃料、核融合材料およびスポレーションターゲットの照射
後非破壊透視検査に有用であることを確認した.

0. 00 020.00015

0.0 00 15

0.0001

0 .00 01

0.00005
0.
0.00 00 05

0

0
0

1 00

2 00

3 00

0

20

40

60

80

100

Dy���(�)P��体���(��)（�）Dy���の感度��性(a)P��体���の感度��性

図３ Dy-IPの感度評価
撮像系
背景成分
中性子���体

半影領域
中性子���体
散乱成分
被写体

図４ 半影法によるウラン濃縮度の評価

Rod 01_4

フィルム(またはＩＰ)
Rod 01_5

被写体
カセット

中性子

ProtonRod 02_4

コンバータ（Gd）

Rod 07_4（�）��撮像法
Rod 07_5

被写体コンバータ（Dy）

中性子

Proton

図５ スポレーションターゲットNR像と集合体内配置

転写
カセット

（�）��撮像法

フィルム（またはＩＰ）

図１ 中性子ラジオグラフィ撮像法
BaFBr:Eu2+
Dy

���

���
中性子線
γ線

��分���

��

１�分���
�������������

���り(a) 撮像手順

図�(b)Dy－IP画像情報

���研究の��
(1) Masayoshi Tamaki, ”Conceptual monochromatic
digital neutron radiography using continuous
cold neutron”, Nuclear Instruments and Methods
in Physics Research A32-37(2005).
(2) Masayosgi Tamaki, Kazuhiro Iida, Noriaki Mori,
Eberhard H. Lehmann, Peter Vontobel, Mirko
Estermann, “Dy-IP characterization and its
application for experimental neutron radiography
test under realistic conditions”, Nuclear
Instruments and Methods in Physics Research
A320-323(2005)

Dy-IPによる撮像����は縮�さ��に���ット��さ�ます。図�とも�明な��を���て�さい。

－ 368 －

JAEA-Review 2008-067－ 369 －

This is a blank page.

JAEA-Review 2008-067

3-1
Determination of Cadmium in Polymer Samples by MPGA
Y. Toh, M. Oshima, M. Koizumi, A. Kimura, K. Sushida1 and M. Sato1
Department of Research Reactor and Tandem Accelerator Nuclear Science and Energy Directorate,
Japan Atomic Energy Agency, Ibaraki 319-1112
1
Inorganic Analysis Laboratory, Toray Research Center, Inc., Otsu 520-8567

Prompt gamma ray analysis (PGA) is ahigh-sensitive, high-precision, multi-element
and non destructive method1) . The method
is used in various fields, such as geology, archaeology, earth science, industry and environmental science. However, the difficultyof quantification arises when the gammaray intensity from the trace element of interest is not strong enough in comparison
with the background gamma rays from thelarge amount of other elements in the sample.
In order to improve the sensitivity of PGA,
we proposed to introduce multiple gamma
ray detection method to the PGA, and constructed a neutron beam line for multiple
prompt gamma ray Analysis (MPGA)2–4) .
In summer 2000, the EU commission approved drafts of the guidelines for waste electrical and electronic equipment (WEEE) andthe guidelines for the restriction of the use ofcertain hazardous substances in electrical andelectronic equipment (RoHS). The guidelines
establish that users can return waste electrical and electronic equipment to the manufacturers free of charge. This regulation applies
to electrical household equipment, electrical
tools, consumer electronics, IT and telecommunication equipment, lamps and lights, toys,
medical equipment, monitoring and control
instruments as well as slot or vending machines. Lead, mercury, cadmium, chromium(VI), polybrominated biphenyls (PBB) andpolybrominated diphenyl ethers (PBDE) areprohibited. The following experimental workon the investigation of cadmium containing
polymers demonstrates the efficiency of the
MGPA technique as a screening method according to the RoHS guidelines. Cadmium
as a toxic heavy metal shows the most intensive gamma ray signal at 558 and 651 keV. A
cadmium standard sample provided by the In原子炉：JRR-3

装置：MPGA(C2-3-2)

stitute for Reference Materials and Measurements (IRMM) was measured for about 10
minutes at the JRR-3 reactor (C2-3-2). The
total event rate was about 1.7 k count/sec.
Figure 1 shows a typical signal profile of the
gamma ray of cadmium in IRMM B6 sample
on two dimensional spectrum. The IRMM B6
sample contains 54 ppm cadmium. From theexperiment, we estimated the quantification
limit of cadmium in a polymer sample to beabout 0.1 ppm with a new MPGA detector
system which consists of 8 clover Ge detectors, 4 coaxial Ge detectors and 2 twin Ge
detectors. MPGA does not require any sample preparation. Therefore, MPGA may be
used as a screening analysis for RoHS related
samples.

Figure 1: Cadmium gamma ray peak of IRMM B6
sample on two dimensional spectrum. Cadmium emits
strong gamma ray pair of 558 and 651 keV.

References
1) B.J. Allen, et al.: “Neutron Radiative Capture”,
Pergamon Oxford, (1984).
2) Y.Toh, et al., Appl. Radiat. Isotopes, 64, 751(2006).
3) M.Oshima, et al., Proc. J. Radioanal. Nucl. Chem.,
271, 317(2007).
4) A.Kimura, et al., AIP conf., 769, 792(2004).

分野：即発γ線分析実験（工業材料）－ 371 －

JAEA-Review 2008-067

3-2
火山岩，堆積岩試料の即発γ線分析
Neutron-induced prompt gamma ray analyses of volcanic and sedimentary rocks
熊本大学 大学院自然科学研究科

長谷中 利昭，三好 雅也，奈須 隆志，上村 伸樹，

高江 友佳，下野 まどか，枝村 拓也，谷田 康介，森永 麻衣子，関口 悠子，
立正大学

地球環境科学部

福岡 孝昭， 福士 裕輔， 杉内 由佳， 星 有哉，
楠野 葉瑠香，新藤 智子，

国立科学博物館

佐野 貴司，

東京経済大学新生 裕尚

我々の研究グループは 4 つの異なる研究機関に属するメンバーから構成されている．マシンタイムを100%有効に使うことが難しいので，お互いが助け合って分析準備や測定を行ってきた．しかし個々のメンバーの研究テーマは独立しているので以下に各メンバーごとに研究成果の報告をさせていただく．

A. 北部九州玄武岩類中のホウ素含有量の�間���間�変化
1．は�めに
北部九州は，四国海盆（15～26 Ma）と古いフィ
リピン海プレート（40～60 Ma））の年代が異なる二枚の海洋プレートがユーラシアプレート下に沈み込む複雑なテクトニックセッティングに置かれている．
そのような特異な構造場で，海洋プレートから放出された流体が生成するマグマ組成にどの程度反映されているのかを調べることは，地球における物質循
環を理解する上で重要である．
海洋底堆積物，変質 MORB に多量に含まれるホウ素は，他の沈み込み成分に比べ非常に流動性に富む
ため，マグマソースへの流体の寄与の良いトレーサーとなる．研究協力者の三好は，沈みこむフィリピ
ン海プレートが北部九州直下のマグマソースに与えた影響を，玄武岩～安山岩のホウ素含有量を用いて検討した．
2．分析試料
火山岩試料は，壱岐火山，玄海島，北松浦地域，
由布火山，鶴見火山，鬼箕火山，九重火山，耶馬渓
地域，阿蘇火山，雲仙火山，多良岳火山，大矢野島，
天草地域から採取し，全試料について即発γ線分析を行った．
3．分析�果���
フィリピン海プレートの北部九州への沈み込みが開始する前（11～6 Ma）に活動した玄武岩類は前弧側，背弧側の両方で低い B/Sm (0.5～1.3)，B/Zr (0.02～0.05)，B/Nb (0.2～0.5) 比を示す．特にそれらのB/Nb 比は，マントルの B/Nb 比 (0.05～0.5) と同等である (Fig. A1)．このことは 11～6 Ma の間には海洋プレートの沈み込みの影響はほとんどなかったということを示している．

Fig. A1 B/Nb 比の島弧横断方向の変化

一方，フィリピン海プレートの沈み込みが開始しJRR-3M,即発�ンマ線分析�置

中性子利用分析�即発�ンマ線分析－ 372 －

JAEA-Review 2008-067

た後（6 Ma 以降）に活動した玄武岩類のうち，火山
フロントに位置する阿蘇火山の玄武岩類は北部九州
玄武岩類の中で最も高い B/Sm (1.6～4.3)，B/Zr (0.07～0.16)，B/Nb (1.4～3.7) 比を示す (Fig. 1)．由布，鶴見，九重火山も阿蘇と同様に火山フロントに位置するが，それらの玄武岩類は阿蘇玄武岩類に比べて著しく低い B/Sm (0.9～1.9)，B/Zr (0.04～0.07)，B/Nb(0.5～0.9) 比を示す．また，背弧側に分布する玄武岩類の B/Sm，B/Zr，B/Nb 比は，フィリピン海プレ
ー ト の沈 み込 み 開始 前後 で ほと んど 変 化し ない(Fig. A1)．
阿蘇玄武岩類の B/Nb 比は，比較的古く冷たい海
洋プレート（太平洋プレート：130 Ma）が沈み込む
東北日本弧，カムチャッカ弧，伊豆－マリアナ弧などの玄武岩類と同等である．それに対し，由布，鶴見，九重火山の玄武岩類の B/Nb 比は，比較的若く
熱 い プレ ート が 沈み 込む カ スケ ード ， メキ シコ（MVB）の玄武岩類の B/Nb 比と同等である．
以上のことは，阿蘇火山直下には古い（冷たい）フィリピン海プレート，由布，鶴見，九重火山直下には若い（熱い）四国海盆がそれぞれ沈み込んでいることを示唆しているのかもしれない．
4．今後の課題
これまでの分析結果から，北部九州における海洋プレート由来物質の循環が，これまで東北日本など
で提唱された沈み込み帯物質循環モデルと大きく異なる可能性がわかってきた．今後，西南日本～琉球弧に分布する火山岩のホウ素含有量を調べ，広域的にフィリピン海プレート由来物質の循環を明らかにしたい．他に，1）地殻構成物質（特に深成岩体）のホウ素含有量分析によって，1 億年以上前の物質循
環を明らかにし，さらに，玄武岩マグマへの地殻混成作用の影響を定量的に理解すること, 2）フィリピ
ン海プレートの海洋底堆積物および海洋地殻玄武岩のホウ素含有量から,火山直下マントルに付加する
流体の化学組成を推定することが課題である．

埼玉県西部に位置する秩父市の荒川上流域における地球化学図を多元素にわたり作成してきた。その中でもホウ素は生活環境情報を知るうえで重要である。
2． 試料
試料は尾根に囲まれた流域の平均化学組成を示すものとして河川堆積物を用いた。平成 16，17，18
年度は荒川上流の中津川，河原沢川，赤平川流域から試料を採取した。
3． 分析
試料の分析手順を図 B1 に示した。即発γ線分析（PGA）用の分
析試料は分析上不都合な水を900℃で乾燥し完全脱水させたものを用いた。
4． 結果・考�
平成 16，17，18 年度の試料の分析結果を表 B1 に、その結果を元に作成した地球化学図を平成 16
年度以前の値も含めて図 2 に示した。試料採取地域の地質は砂岩・泥岩を主体として、中津川流域の

⹜ᢱ
⥄ὼੇ῎
☳ᧃൻ
㪈㪈㪇㷄ੇ῎䋨ੇ῎ེ䋩
㊀㊂᷹ቯ㪐㪇㪇㷄ੇ῎䋨㔚᳇Ἱ䋩
㊀㊂᷹ቯ䊕䊧䉾䊃૞ᚑ
䊁䊐䊨䊮ⴼ䈮ኽ౉ਛᕈሶᾖ኿䋨㪡㪩㪩㪄㪊Ἱ㪧㪞㪘ⵝ⟎䋩හ⊒㱏✢᷹ቯ

北中央部には花崗岩が分布して
図 B1．分析手順
いる。
地球化学図から、中津川流域の北中央部を中心にホウ素が高濃度であることが分かった。これは花崗岩の貫入による鉱物化作用でホウ素が濃集したためと考えられる。

河原沢川

36°04′32″
138°58′30″

中津川
赤平川

B. 即発γ線分析によるホウ素の地球化学図
1． は�めに
地球化学図は地殻表層における元素の濃度分布を示し、自然環境の固相における化学的バックグラウ
ンドの情報を得ることができる。また、人為的環境変化を評価する上での指標ともなる。立正大学地球環境科学部宇宙地球化学研究室では 2000 年度から

図 B2．ホウ素の地球化学図
5． まとめ図 B2 は 2000～2006 年度までの 224 試料の分析
結果をもとに地球化学図を作成した。2006 年度採取
地域の赤平川流域は中津川流域ほどの濃度分布差が－ 373 －

JAEA-Review 2008-067

見られない。これは背景の地質が主に泥岩を主とし似た地質であるためと考えられる。
表 B1．平成 16~18 年度までのホウ素の分析結果
試料名

分析値
ppm

試料名

分析値
ppm

試料名

分析値
ppm

0401

111

0523

72

0619

74

0402

152

0524

63

0620

63

0403

131

0525

84

0621

49

0404

132

0526

82

0622

78

0405

121

0527

83

0623

83

0406

124

0528

156

0624

79

0407

104

0529

158

0625

70

0408

103

0530

136

0626

86

0409

115

0531

114

0627

70

0410

108

0532

96

0628

43

0411

110

0533

80

0629

41

0412

130

0534

89

0630

78

0413

148

0535

79

0631

49

0414

98

0536

61

0632

56

0415

83

0537

66

0633

50

0416

111

0538

81

0634

60

0417

112

0539

76

0635

46

0418

115

0540

68

0636

33

0419

62

0541

368

0637

43

0420

146

05R01-1

3

0638

85

0421

85

05R01-2

3

0639

101

0422

91

05R01-3

nd

0640

60

0423

76

05R01-4

13

0641

73

0424

228

05R01-5

10

0642

71

0425

80

05R01-6

8

0643

74

0426

246

05R02-1

25

0644

71

0427

193

05R02-2

58

0645

63

0428

156

05R02-3

60

0646

48

0429

94

05R03

8

0647

71

0430

81

05R04

31

0648

31

0501

160

05R05

16

0649

43

0502

375

05R06

19

0650

66

0503

136

05R07

15

0651

36

0504

603

05R08

19

0652

64

0505

82

0601

94

0653

33

0506

146

0602

62

0654

47

0507

314

0603

70

0655

32

0508

256

0604

84

0656

58

0509

278

0605

66

0657

73

0510

222

0606

76

0658

54

0511

80

0607

77

0659

29

0512

141

0608

55

0660

52

0513

118

0609

71

0661

20

0514

118

0610

75

0662

38

0515

139

0611

82

0663

49

0516

94

0612

75

0664

48

0517

75

0613

80

0665

42

0518

75

0614

90

0666

52

リアと呼ばれるスコリア層を形成した（宮地，1982）．
またマグマは標高 2500m以上で溶結して山体頂部の表層をつくった．噴出量は約 0.5 km3と見積もられており（宮地，1982），山頂から噴出した最大規模の火山噴出物である．この湯船第２スコリアは新富士火山の噴火史および火山防災を考える上で，最も重要な噴火堆積物の 1 つであるが，これまでに記載岩石学的特徴や化学分析値の報告はほとんどなかった．
この理由はスコリア層の大部分が赤色~褐色であり，酸化や風化が激しいと見受けられ，マグマは噴出前の化学的特徴を保持していない可能性があると思われていたからと推定される．そこで，湯船第２スコ
リアの酸化や風化による化学組成の変化を調べた．
更に，新鮮部分について岩石記載および全岩分析を行った．
２． 分析試料
試料は山頂火口から東へ 8.5km の地点の崖から採取した（図 C1）．ここは湯船第２スコリアの等層厚線図の主軸部分であり，スコリアの厚さは 1.7 m であった．宮地（1982）で報告されているように 5 つの fall-unit が確認された．我々は下位から上位まで
順番に B から J までの 9 つの場所から大きなスコリ
ア（>2g）を採取した．

0519

51

0615

99

JB-1a 2004年

7.98

0520

100

0616

96

JB-1a 2005年

7.89

0521

75

0617

93

JB-1a 2006年

7.81

0522

76

0618

59

JB-1a 公表値＊

7.88

C．富士山の火山噴出物の即発��マ線分析
�． は�めに
富士火山における最後の山頂噴火は約 2200 年前と報告されている（宮地，1988）．この時に噴出した
マグマは山頂から東麓に降り積もり，湯船第 2 スコ

図 C1 対象試料（湯船第 2 スコリア層）の採取地点（静岡県−山梨県境）
�． ��
岩石の記載と空隙率測定を行った後、即発γ線分
析により B, Cl, Gd, Sm の定量を行った（Sano et al.,1999, 2004, 2006）．そして蛍光 X 線分析装置を用いて主成分およびいくつかの微量成分の定量も行った（佐野，2002）．また B, C, G, H, J の 5 層から採取したスコリアについては酸化・変質部分を含んだ部分の全岩化学分析も行った．

－ 374 －

JAEA-Review 2008-067

�． 結�・考�
全てのスコリアは班晶としてカンラン石（0~4vol.%）および斜長石（2~16 vol.%）を含んでいた．
みかけの密度と真の密度から計算される空隙率は20~70%と様々であった．
酸化・変質部分を含む試料の全岩化学分析値は新鮮部分と比べて MgO および Ni の含有量が低い（MgO は 10%低下，Ni は半分に低下）以外は分析
誤差を超えた差は見られなかった．従って，他の元
素は酸化や変質の影響はほとんど受けていないと考えられる．

activation
analysis,
Geostandards
andGeoanalytical Research, 28, 443-448, 2004.
Sano T., T. Fukuoka, T. Hasenaka, C. Yonezawa, H.
Matsue, and H. Sawahata, Accurate and efficient
determination of boron content in volcanic rocks
by neutron induced prompt gamma-ray analysis,
Journal of Radioanalytical and Nuclear Chemistry,
239, 613-617, 1999.
佐野貴司，蛍光 X 線分析装置を用いた火成岩中の主成分および微量成分の定量，富士常葉大学研究紀要，2, 43-59, 2002.
D．瀬戸内火山岩および外帯花こう岩のホウ素含有量について

図 C2 湯船第 2 スコリアの空隙率に対する全岩
化学組成のプロット
ハーカー図における新鮮部分の組成バリエーショ
ンは明瞭なトレンドを形成し，これは斑晶鉱物の 7%の分別により説明可能である．斑晶モードと全岩化
学組成との間に明瞭な相関は見られなかった．しかし空隙率はSiO2, TiO2, FeO*, B, Cl, Ba, Zr, Yと正の相関，CaO, Sr, Crと負の相関をなし，分化した組成のスコリアほど空隙率が高いという事実が明らかになった（図C2）．
�．�用��
宮地直道, 新富士火山における約 2000 年前の山頂噴
火とその噴出物（講演要旨）, 火山, 27, 332,
1982.
Sano T, T. Hasenaka, H. Sawahata, T. Fukuoka,
Determination of Ti, K, Sm, and Gd Values inGeological Survey of Japan Reference Materials by
Prompt Gamma Neutron Activation Analysis,
Geostandards and Geoanalytical Research, 30,
31-36, 2006.
Sano T., T. Fukuoka, T. Hasenaka, Determination ofchlorine contents in Geological Survey of Japanreference materials by prompt gamma neutron

�．試料，分析研究協力者の新正は，瀬戸内火山岩および外帯花こう岩から広域的に採集した試料について，即発ガ
ンマ線分析によるホウ素含有量の測定を行なった．
日本海拡大に伴う西南日本弧の時計回り回転直後の時期（14Ma 頃）に活動した火成岩類のうち外帯域に分布するものは大部分が珪長質～中間質の貫入岩類であり，外帯花こう岩質岩と一括される．また
瀬戸内区には，マントルに由来する玄武岩，高マグ
ネシア安山岩（HMA）および珪長質の火山岩類が分布し，瀬戸内火山岩類と呼ばれる．広域的に採取した，瀬戸内火山岩類のデイサイト～流紋岩および外帯花こう岩質岩について 30 余りの試料を選び，即発ガンマ線分析によりそのホウ素濃度を求めた．
�．結�，考�外帯花こう岩質岩のホウ素濃度は 7 ～ 426 ppmと極めて広い組成範囲をもつが，電気石を含み 100
ppm を超える極めて高いホウ素濃度をもつ試料を除外した平均のホウ素濃度は 28 (±24) ppm であった（図D1）．なおSタイプ，Iタイプ花こう岩で系統的な差はなかった．SiO2量とホウ素含有量には相関が見られず，単独の貫入岩体について複数の試料を分析した場合にはしばしば試料により大きな組成差が見られた．これらの事実から，外帯花こう岩のホウ素濃度は固結前のマグマ組成を必ずしも反映しておらず，固結時～固結後の流体等による元素移動の影響を大きく受けているものと考えられる．
瀬戸内火山岩類のデイサイト～流紋岩のホウ素濃度の範囲は 10 ～ 110 ppm で，平均は 57 (±30) ppm
であった．瀬戸内火山岩類の珪長質火成岩の一部は
四国海盆上の堆積物が深部で融解したスラブメルト－ 375 －

JAEA-Review 2008-067

でありそれがマントルウェッジかんらん岩と反応して HMA となったという提案がある（Shimoda andTatsumi, 1999）． 今回測定した瀬戸内火山岩のデイ
サイト～流紋岩は B/Nb-B プロット上で広く分散するが，高マグネシア安山岩（新正ほか，未公表）のそれと分布範囲はよく似ている（図 D2）．HMA の�．����
Shimoda, G. and Y. Tatsumi, Generation of rhyolite
magmas by melting of subducting sediments in
Shodo-Shima island, Southwest Japan, and its
bearing on the origin of high-Mg andesites, The
Island Arc, 8, 383-392, 1999.

E．��成�の公表

図 D1 外帯花こう岩類の B 量のヒストグラム（S/I タイプ
を区分）

ホウ素と液相濃集元素の B/Nb 比に大きな分散があるのは，スラブ由来成分（≒珪長質火山岩）の B/Nb
比にそもそも大きな分散があったためかも知れない．

図 D2

瀬戸内火山岩類の B/Nb-B plot���Miyoshi, M., Fukuoka, T., Sano, T. and Hasenaka, T.,
Subduction influence of Philippine Sea plate on the
mantle beneath northern Kyushu, SW Japan: an
examination of Boron contents in basaltic rocks.
Journal of Volcanology and Geothermal Research,
accepted for publication on Nov. 1, 2007.
Sano T, T. Hasenaka, H. Sawahata, T. Fukuoka,
Determination of Ti, K, Sm, and Gd Values inGeological Survey of Japan Reference Materials by
Prompt Gamma Neutron Activation Analysis,
Geostandards and Geoanalytical Research, 30,
31-36, 2006.
Sano T., T. Fukuoka, T. Hasenaka, Determination ofchlorine contents in Geological Survey of Japanreference materials by prompt gamma neutron
activation
analysis,
Geostandards
andGeoanalytical Research, 28, 443-448, 2004.
���表
Miyoshi, M., Shimono, M., Hasenaka, T., Sano, T. andFukuoka, T., 2007. Determination of boron
contents in volcanic rocks by prompt-gamma ray
analysis: an application to magma genesis in
Kyushu island, SW-Japan. 12th International
Conference on Modern Trends in Activation
Analysis (MTAA-12) (Tokyo, Japan).
Miyoshi, M., Shimono, M., Hasenaka, T., Sano, T.,
Fukuoka, T. and Shinmura, T., 2007. Temporalchanges of the subduction components in volcanic
products from Aso area, SW Japan. 17thGoldschmidt Conference (Koln, Germany).
Shimono, M., Miyoshi, M., Fukuoka, T., Sano, T. andHasenaka, T., 2007. The influence of Philippine
Sea plate on the composition of mantle beneath
Kyushu, SW Japan arc: Along-arc variation of B
data. 17th Goldschmidt Conference (Koln,
Germany).

－ 376 －

JAEA-Review 2008-067

Miyoshi, M., Shimono, M., Fukuoka, T., Sano, T.,
Hasenaka, T., 2006. Slab influence of hot
Philippine Sea plate on the subarc mantle: An
examination of Boron contents in basaltic rocks
from northern Kyushu, SW Japan. 16th
Goldschmidt conference (Melbourne, Australia).
Shimono, M., Miyoshi, M., Fukuoka, T., Sano, T. andHasenaka, T., 2006. Temporal and spatial influenceof Philippine Sea plate on the composition ofbasaltic rocks from southern Kyushu, SW Japan arc~ a study from boron analysis. 16th Goldschmidt
conference (Melbourne, Australia).
Miyoshi, M., Shimono, M., Fukuoka, T., Sano, T. andHasenaka, T., 2005. Spatial and temporal variationsof Boron contents of basaltic rocks from northern
Kyushu, SW Japan arc. American GeophysicalUnion, fall meeting (San Francisco, USA).
三好雅也，下野まどか，長谷中利昭，佐野貴司，福岡孝昭，2007．北部九州玄武岩類中のホウ素含有量の時間的・空間的変化．日本鉱物科学会，
2007 年度年会（東京大学）．
三好雅也，下野まどか，福岡孝昭，佐野貴司，長谷中利昭，2006．フィリピン海プレートの沈み込
みが北部九州のソースマントルに与えた影響－火山岩のホウ素含有量を用いた検討－．日本
火山学会， 2006 年度秋季大会（熊本県阿蘇）．
下野まどか，三好雅也，福岡孝昭，佐野貴司，長谷中利昭，2006．九州南部に産する火山岩起源物
質中のホウ素含有量の空間的・時間的変化．日本火山学会，2006 年度秋季大会（熊本県阿蘇）．
Miyoshi, M., Shimono, M., Fukuoka, T., Sano, T. andHasenaka, T. 2006. Subduction metasomatism
beneath northern Kyushu: an examination fromspatial and temporal variations of boron contents inbasalts. 地球惑星科学関連学会，2006 年合同大会（千葉県幕張メッセ）．
下野まどか，三好雅也，福岡孝昭，佐野貴司，長谷中利昭，2006. 九州南部に産する火山岩起源物
質へのフィリピン海プレートの寄与について～ホウ素を用いた研究．地球惑星科学関連学会，
2006 年合同大会（千葉県幕張メッセ）．
新藤智子，福岡孝昭他，2007,"荒川上流中津川・河原沢川・赤平川流域の地球化学図" 2007 年度日
本地球化学会大 54 回年会，2007 年 9 月．
新藤智子，福岡孝昭他，2006,"荒川上流中津川・神無川・河原沢川流域の地球化学図" 2006 年度日
本地球化学会大 53 回年会，2006 年 9 月．

新藤智子，福岡孝昭他，2005,"荒川上流中津川流域の地球化学図"2005 年度日本地球化学会大 52
回年会，2005 年 9 月．
佐野貴司，植田匡喬，2006. 富士火山から約 2200 年前に噴出したスコリアの化学組成と空隙率の関係．日本火山学会 2006 年秋季大会（講演要旨）：A27，2006 年 10 月 24 日，熊本県阿蘇市．
新正裕尚，角井朝昭，折橋裕二，長谷中利昭，福岡孝昭，佐野貴司，2005, 西南日本外帯・瀬戸内区の中新世珪長質火成岩のホウ素含有量
2005 年度日本地球化学会第 52 年会（琉球大学
西原キャンパス 2005 年 9 月 28 日）－ 377 －

JAEA-Review 2008-067

3-3

南極隕石試料の即発ガンマ線分析
Prompt gamma-ray analysis of Antarctic meteorites

海老原充、大浦泰嗣、唐牛譲、白井直樹、桑山仁、竹田光世，小岩嘉隆，高田共宏，山崎俊輔
M. Ebihara, Y. Oura, Y. Karouji, N. Shirai, J. Kuwayama, M. Takeda,
Y. Koiwa, T. Takda, S. Yamazaki
東京都立大学大学院理学研究科（首都大学東京都市教養学部理工学系）
Graduate School of Science, Tokyo Metropolitan Universityを発展させた、新しい試みである。本報告では、

１．は�めに日本原子力研究所の研究用原子炉 JRR-3 が改

このうちの１番目の課題を中心にまとめる。

造され，中性子ビームを利用した即発γ 線分析

既に述べたとおり，PGA を用いて隕石試料の（PGA）が実施可能となって以来，主に隕石試料

元素組成をほぼすべての主成分元素に対して求を分析対象として即発γ 線分析を実施してきた。

めることができる。また，PGA で利用する中性

これまでの研究を通して，PGA は隕石の全岩組

子束は通常の炉内照射で行う機器中性子放射化成（特に、主成分元素組成）を求める手段として、

分析（INAA）に比べて桁違いに低いことから，大変優れていることを実証した。それは，隕石PGA で利用した試料を再度 INAA に用いることを構成する主成分元素をほぼ全元素定量するこは可能であり，その結果，微量元素を効率よくとができる他に，PGA は全岩試料に対して非破分析することができる。その意味で，PGA と壊分析できる点で大きな利点をもつ点に集約さ

INAA を相補的に利用することにより，限られれる。

た量の隕石試料から最大限の元素組成に対する

平成 16 年度から 18 年度の間、標記課題で原研

情報を引き出すことが可能になる。本報告書で施設を利用した共同研究を行った。この 3 年の述べる結果も，PGA と INAA の併用によってえ研究期間に行った研究は２つに分類できる。１

ら得たものであり，試料によっては PGA 後の試

つはこれまでの経験を生かして、各種隕石試料

料を誘導結合プラズマ質量分析法に利用した例の非破壊分析を行ったことで、ほとんどの場合もある。

が粉末試料か、或いは塊状であっても中性子のビーム径（2cm x 2cm）以内に収まる程度の試料で、比較法により定量をおこなった。もう一つ

２．実験

は、隕石中の特定元素の存在度と存在状態を知２．１ 試料ることを目的にして行った研究で、従来の研究
エコンドライト Dhofar 007 を用いた。同隕石

酸塩相と関連があるのではないかと指摘されてはオマーンの砂漠で見つかった隕石で，約 27 kg

いた。そこで，同隕石 0.883 g を粉末にし，そのが回収された。隕石は初め集積岩ユークライト

うちの約 200 mg を用いて PGA を行った。また，と分類されたが，その種の隕石のわりには金属

粉末試料約 50 mg を INAA に，10 mg，200 mg を

相を多く含み，その結果 Ni や Co の含有量が高

ICP-MS による希土類元素，及び白金族元素の定いことから，メソシデライト（石鉄隕石）のケイ量にそれぞれ用いた。

研究施設名と装置

研究分野

JRR-3M (PGA)

宇宙化学－ 378 －

JAEA-Review 2008-067

２．２ 即発γ 線分析

示唆する。

PGA は日本原子力研究所（現 日本原子力研究

元素組成と鉱物学的観察から Dhofar 007 隕石開発機構）の JRR-3M に設置されている熱中性子の起源について考察した。同隕石の鉱物学的観

ガイドビームを用いて行った。試料約 200 mg を察からこの隕石の形成過程として以下のことがFEP フィルムに溶封し，ヘリウム雰囲気化にて推察される；(i) 母天体深部に於ける結晶化，

約 3 時間測定した。定量は比較法で行い，比較(ii) 衝突による溶融，(iii) 今回測定した岩石片

標準試料には玄武岩試料 JB-1 とスミソニアン製の再結晶化をもたらした熱的出来事，(iv) 高温

Allende 粉末試料を用いた。

での速い冷却，(v) 低温でのゆっくりとした冷２．３ その他の元素分析

却，(vi) 再度の衝突による衝突脈の形成。表１

今回は初めの粉末状試料が低く的多く準備出に示されるように，この隕石にはかなりの量の来たので，PGA に使った残りを INAA，ICP-MS

金属相と，それに伴う高濃度の親鉄性元素が含を用いた実験を行った。INAA では照射時間とまれている。これらの金属や親鉄性元素は恐ら

冷却時間を適当に組み合わせて，限られた試料

く，この隕石の母天体における衝突によってもから最大限の元素組成情報を引き出すことを心たらされたものであり，その衝突した物体（プロがけた。それぞれの方法に関して既に本研究室

ジェクタイル）は鉄ニッケル合金からなる鉄隕石から論文が公表されており，それに従って実験であったと考えられる。白金族元素の CI コンドを行った。

ライト組成（太陽系の元素組成を近似するものと考えられている値）で割った相対存在度を図２に３．結果と考察示す。Ni と Co がコンドライトの値に比べて分化

３．１

表１に定量に用いた方法と共に，元素しており，Co に相対的にとんでいることや，Os

組成のデータを示す。%で表示されている元素と Ir も分化していてメソシデライトの比に近いはすべて PGA で定量することが可能である。まことを考えると，この相対的な元素組成からは，た，そのうち Si を除く主成分元素は INAA によプロジェクタイルがメソシデライト的なものでっても定量可能であり，表１の値はこの２つのあることを示唆する。

分析方法によって定量された値をもとに，もっ以上のことより，Dhofar 007 隕石はメソシデ

とも妥当な定量値として吟味したものである。

ライトの大きなケイ酸塩質インクルージョンで後段の希土類元素（ラインタノイド）と白金族元ある可能性が考えられる。しかしながら，特殊素は ICP-MS によって求めた値である。表１でなユークライト隕石である可能性も残されてい分かるとおり，ニッケル含有量は約 1000 ppm にる。この種の隕石の化学組成を通じて，原始太も及び，通常の集積岩タイプのユークライト中陽系における物質の進化がより詳細に記述されの Ni 含有量に比べて桁違いに高いことが分かる。

ることが可能であり，今後の研究の進展が待たそれに伴って，白金族元素存在度も高く，例えれる。

ば代表的な白金族元素である It の含有量は約 50
ppb と，コンドライト隕石のもつ含有量の約半分の濃度値を示す。

研究成果（発表論文）

３．２ Dhofar 007 の起源（ 共 同 研 究 の 期 間 (2005~2007) に 報 告 し た

図１は Dhofar 007 の希土類元素存在度をコンPGA を用いて得られた研究成果）

ドライトの値で規格化した相対存在度パターン

1. P. C. Buchanan, T. Noguchi, D. D. Bogard, M.

である。図中にはユークライト隕石の存在度パ

Ebihara, I. Katayama (2005) Glass veins in the

タ ー ン も 比 較 の 為 に 示 さ れ て い る が ，Dhofar

unequilibrated eucrite Yamato 82202. Geochim.

007 のパターンは Binda 隕石のそれと酷似していCosmochim. Acta 69, 1883-1898.

ることがわかる。このことは，Dhofar 007 隕石の母天体はユークライト的なものであることを

2. H. Takeda,, A. Yamaguchim D. D. Bogard, Y.
Karouji, M. Ebihara, M. Ohtake, K. Saiki, T. Arai

－ 379 －

JAEA-Review 2008-067((2006) A deep crustal rock in a magnesianPlanet. Sci. 41, 1919-1928.

breccia: Implication for the far-side crust on the

5. L. Nyquist, D. D. Bogard, A. Yamaguchi, C.-Y.
Shih, Y. Karouji, M. Ebihara, Y. Reese, D.

moon. Earth Planet. Sci. Lett. 247, 171-184.
3. A. Yamaguchi, T. Setoyanagi and M. Ebihara

Garrison, H. Takeda (2006) Feldspathic clasts in(2006) An anomalous eucrite, Dhofar 007, and a

Yamato 86032: Remnants of the lunar crust withpossible genetic relationship with mesosiderites.

implications for its formation and impact history.

Meteor. Planet. Sci. 41, 863-874.

Geochim. Cosmochim. Acta 70, 5990-6015

4. M. Tamaki, A. Yamaguchi, K. Misawa and M.

(2006).

Ebihara (2006) Thermal history of a silicate clast
from the Mount Padburry mesosiderite. Meteor.

図１ 希土類元素存在度パターン

図２

CI コンドライトの組成で規格化した親鉄元素相対存在度－ 380 －

JAEA-Review 2008-067

表１ Dhofar 007 の元素組成
NAA/PGA
SiO2
TiO2
Al2O3
Cr2O3
FeO
MnO
MgO
CaO
Na2O
K2 O
S
Sc
V
Co
Ni
As

Dhofar 007 CG

Binda

(%)
(%)
(%)
(%)
(%)
(%)
(%)
(%)
(%)
(%)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)

46.2
0.205
12.6
0.446
15.7
0.52
9.5
11.0
0.346
0.029
4650
21.61
81.6
59.8
929
0.50

±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±

1.3
0.008
0.3
0.009
0.6
0.04
0.7
0.8
0.001
0.002
320
0.01
6.0
0.7
32
0.06

(ppm)
(ppb)
(ppb)
(ppb)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppm)
(ppb)
(ppb)
(ppb)
(ppb)

3.17
52
7.9
37
13.9
0.386
0.908
0.152
0.705
0.261
0.330
0.393
0.077
0.58
0.132
0.406
0.0611
0.427
0.067
30
49
49
9.2

±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±

0.08
1
0.2
4
0.3
0.003
0.005
0.003
0.004
0.005
0.003
0.009
0.008
0.01
0.002
0.005
0.0007
0.003
0.001
1
2
1
1.0

0.17
10.71
0.82
15.57
0.48
15.84
7.12
0.26

14.5
11.8
5.7

ICP-MS
Y
Ru
Rh
Pd
Ba
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Os
Ir
Pt
Au

*1Uncertainties for NAA/PGA are due to counting statistics and those for ICP-MS are
standard deviation of replicated measurements. *2Barrat et al. (2000).

－ 381 －

3.22

6.0
0.382
1.01
0.154
0.773
0.261
0.277
0.355
0.0705
0.507
0.118
0.356
0.387
0.0624

JAEA-Review 2008-067

3-4

固体環境試料および地球化学的試料の即発ガンマ線分析（Ⅳ）
Neutron-induced prompt gamma-ray analysis ofsolid environmental samples and geochemical samples
松尾基之・久野章仁・片岡正樹1・小豆川勝見・長谷川篤2
田野島三奈3・中村明日子・諸町大地・星野真有美4・山野孝嶺4
東京大学大学院総合文化研究科広域科学専攻
1東京大学大学院理学系研究科化学専攻
2東京海洋大学大学院海洋科学技術研究科海洋保全学専攻
3国際基督教大学教養学部理学科
4東京大学教養学部広域科学科

��は�めにその例として、千葉県の三番瀬埋め立て計画の白固体環境試料や地球化学的試料中に含有され紙撤回や、有明海の漁業不振を理由とした諫早湾

る元素を定量し、その分布を明らかにすることは、 干拓事業の差し止め訴訟などがあり、干潟と埋め試料自体の形成過程を知る上でも、試料の置かれ立てに関する事例が社会的にも大きな関心事とた環境を理解する上でも重要な課題と考えられなり、干潟の機能や役割の解明が求められている。

る。中性子誘起即発γ線分析法(PGA)は、通常の本研究では千葉県の谷津干潟と三番瀬を対象と機器中性子放射化分析法(INAA)と同様に、多元素して、干潟周辺の埋め立てが干潟底質の環境に与同時定量分析が可能なため、多くの元素の分布をえた影響を評価する。谷津干潟は四方を埋め立て

総合的に判断するのに適した分析法と言える。さられ海とは直接面していないのに対し、三番瀬はらにＰＧＡは、ＩＮＡＡでは分析が困難な H, B,

周囲で埋め立てはあったものの、現在でも広い面

S, Si 等の軽元素や Cd 等の有害元素の定量が可能

で海と面しており、この 2 つの干潟での埋め立てである、試料の誘導放射能が低く同分析法で使用による影響は異なっていると考えられる。この 2した試料を他の分析法で再使用することが可能

地点で底質試料を採取し、中性子誘起即発γ線分である、といった特長を持つ優れた分析法である。 析(PGA)、および機器中性子放射化分析(INAA)
本研究では、同法を用いることにより、次に掲げにより約 30 元素の定量を行った。また、干潟底る試料について種々の環境化学的、地球化学的な質中では嫌気性の細菌である硫酸還元菌の活動検討を行ったので、それぞれの試料ごとに研究内により硫化水素が発生し、底質中の鉄イオンと反容およびその結果を報告する。

応し硫化鉄やPyrite(FeS2)を生成することから、
メスバウアー分光法により鉄の化学状態を測定

��谷津干潟および三番瀬底質中の元素と化学状した。

態の垂直分布【実験】 試料として、東京湾奥に位置する谷津【序】これまでに多くの干潟が埋め立てられ消失

干潟の底質を垂直方向に採取した。採取には内径したが、環境浄化作用や生物多様性などの側面か6cm のアクリルパイプを用い、得られた約 50cm

ら干潟の重要性が認識されるようになってきた。

のコアを現地で 3cm ごとに切り分け、酸化を防ぐ研究施設と装置名

研究分野

ＪＲＲ－３Ｍ、即発γ線分析装置

環境化学、地球化学、分析化学－ 382 －

JAEA-Review 2008-067

ためN2中に封入した。得られた試料はN2を用いた加圧濾過により間隙水を取り除き、メスバウアー
測定とXAFS測定に用いた。また、その後、凍結乾燥を施し、めのう乳鉢で粉砕し均一にした。その中から約 200mgを精秤し、錠剤成型器を用いて直径 10mm、厚さ約 1mmのペレットに成型した。
これを中性子ビームサイズである 20mm四方以内に収まるように、厚さ 12μmのFEPフィルムに封入し、テフロン製の専用ホルダーに固定したう
えで、日本原子力研究開発機構JRR-3Mの中性子
ビームガイドに設置し、He雰囲気中で 3600 秒間
即発γ線を測定した。中性子束の変動を補正する
た め に 、 24 時 間 に 一 回 、 一 定 の Ti 板 (Ti flux
monitor)を測定して得られる 342keVと 1381keV
ピークの計数率の平均値で割り、比較標準試料について報告されているTi flux monitorの計数率で規格化した分析感度を用いて各元素の含有量を計算した。INAA法に関しては、日本原子力研究開発機構のJRR-4 にて照射を行い、大学開放研のγ線スペクロトメーターにて測定を行った。
【結果及び考察】 PGA, INAA 法により、30 数

図１．谷津干潟底質中の Cl, Mn, S, Si の垂直分布

元素の垂直分布を得ることができた。採取した谷
津干潟底質コアは深さ約 25cm までが泥質でそれ以深が砂質となっており、この変化はもともと東京湾の海岸線の一部であった谷津干潟が、四方が埋め立てられたことによって東京湾から隔離され、水の流れが変化したためと考えられる。得られた元素の垂直分布の多くも 25cm 前後で変化しており、その変化の特徴に従って 4 つのグループに分けることができた。図１に 4 つのグループの代表の元素の垂直分布を示す。表層部から徐々に減少し、25cm 以深でほぼ一定になる元素として、Cl と Br があった。これらは海水中に豊富である
ため、海水からの影響が大きいと考えられる。逆に表層部から徐々に増加し、25cm 以深で濃度が高い元素として Fe や Mn などがあった。メスバ
ウアー分光法により Fe の化学状態別の割合を求
めると、25cm より浅い部分では Pyrite が多く、それより深い部分では磁性成分が多くなっていた(図 2)。これより、埋立ての影響で水の流れが変わり、砂鉄など Fe の磁性成分を含む物質の供図２．谷津干潟底質中のPyriteと磁性成分の垂直分布－ 383 －

JAEA-Review 2008-067

給が減り、また、東京湾から隔離されたために、元素濃度変動因子を抽出した。なお、主成分分析

還元的環境下で活発に活動する硫酸還元菌が発にあたり測定誤差をもとにした加重を測定点に生する硫化水素により Pyrite が多く生成するよ

対して加えた計算を行った。

うになったことが示唆された。また、25cm より【結果及び考察】 測定を行った元素中、コア別

浅い部分で多く、それ以深で少ない元素として、に 29-36 元素の定量を行うことが出来た。定量値

S, H, B などが挙げられる。S は Pyrite を構成すから得られた主成分分析のパラメータの中から、る元素の一つであり、その垂直分布は、メスバウ

陸源元素の固有ベクトルを因子別にFig.3 に示す。

アー分光法によって得られた Pyrite 存在割合のまた、各因子の寄与率をTable 1 に挙げた。固有

垂直分布とよく一致した。また、XAFS 法を用いベクトルのパターンの挙動の類似性から因子をた S の状態分析からも、25cm より浅い部分ではGroup1 [SX09 (factor1) と SX18 (factor1)] と硫化物の割合が高く、谷津干潟が還元的状態に変Group2 [SX16 (factor1)とSX21 (factor2)]に分別化したことを示した。最後に Ca, Na, Si の濃度がした。詳細な考察の結果、Group1 は大陸起源砕

25cm 以浅で低く、それ以深で高くなっていた。

屑物(風送塵)であり、Group2 は火山岩(玄武岩)とこれらの元素は風化により岩石から溶脱しやす推定した。特にSX09 に関しては南極大陸起源のいものである。表面積の大きな泥質部分では深さ

漂流岩屑(IRD)のベクトルパターンと酷似するこに応じ溶脱が進むが、砂質部分では表面積が小さとから、その供給源が南極大陸であることが強くいため、溶脱が進まずに多くが残っていると考え推定される。また堆積物のK/Ti, Euアノーマリー

られた。

(Eu/Eu*)の挙動からもこれらの推定を支持することができた。

��遠洋性海洋堆積物表�における供給源の推定【序】 海洋堆積物中にはさまざまな供給源よりもたらされた元素が混在する。堆積物の粒径別化
SX21

学組成や同位体組成から供給源を推定する研究

0.2
0.0

報告は多数見受けられるが、プローブ以外の元素
濃度変動要因を明らかにすることは難しい。本研
究では堆積物中に異なる供給源を持つ場合、それ

-0.2
0.3

SX18

0.2

ぞれの元素組成パターンが異なるという観点か

0.1

ら、堆積物定量値に多変量解析を適応し、その供

-0.1

0.0
SX16

給源分別を試みた。

0.2【実験】 海洋堆積物は白鳳丸((独)海洋研究開発

0.0

機 構 (JAMSTEC)) に よ る KH04-05 航 海 に て
2004-2005 年にかけて西経 170 度沿いに採取した南大西洋の遠洋性コア(4 コア)を用いた。堆積物は鉛直方向に 0.5-1.0cm 毎にカットした後110℃､ 2 時間の乾燥を行った。150-200mg 程度を精秤し、直径 10mm 厚さ 1mm 程度のペレットを作成した。ペレットを清浄な FEP フィルムに内包し PGA (即発ガンマ線分析法, JRR-3M)の

SX09

SX09 IRDした。得られた定量値を多次元ベクトルとみなし多変量解析(主成分分析)を適応し、堆積物中での

Al
K
Rb
Sc
Ti

0.3
0.2
0.1
0.0
-0.1
-0.2
Factor 1

Factor 2

Factor 3

Group 1 SX09(factor1) - SX18(factor1)
Group 2 SX16(factor1) - SX21(factor2)

測定試料とした。同様にして INAA(機器中性子
放射化分析法, JRR-4)による多元素分析も適応

-0.2

0.2
0.1
0.0
-0.1
-0.2

Fig. 3.

Eigenvectors of terrigenous elementsof the South Pacific sediments－ 384 －

JAEA-Review 2008-067

Table 1. Sampling sites and factors loading from principal components analysis
SampleLocation

SX09

SX16

SX18

SX21

65.18o S

43.18o S

39.99o S

24.79o S

174.08o W

171.17o W

170.00o W

169.98o W

Variance

Factor 1

26

54

49

28

/%

Factor 2

20

26

9

22

Factor 3

12

18

7

20

K/Ti

4.39

4.89

8.33

3.34

Eu/Eu*-

1.22±0.06

1.08±0.05

1.18±0.06

��成�の�表東京大学教養学部広域科学科 卒業論文Ⅰ学術誌、紀要等(2005 年 11 月)

1. "Environmental evaluation of estuarine

7. "東京湾最奥に位置する干潟底質に関する研

sediments", M. Matsuo and A. Kuno,

究"、諸町大地、東京大学教養学部広域科学科

Analytical Applications of Nuclear Tech-

卒業論文Ⅰ (2005 年 11 月)

niques, ed. International Atomic Energy

8. "底質の化学分析から見た東京湾周辺の親水

Agency (IAEA), IAEA, Vienna, 65-67 (2004)

環境の評価"、星野真有美、東京大学教養学部
広域科学科 卒業論文Ⅰ (2006 年 11 月)

2. "放射化分析およびメスバウアー分光法による河口域堆積物の非破壊分析"、久野章仁・松尾

9. "酸性雨による土壌の酸中和能の鉛直変化"、

基之、東京大学アイソトープ総合センターニュ

山野孝嶺、東京大学教養学部広域科学科 卒業

ース、36(4), 6-8 (2006)

論文Ⅰ (2006 年 11 月)

学位論文

学会発表

3. "南極海堆積物中の元素および化学状態の垂10. "氷期および間氷期における南極海堆積物中

直分布に基づく堆積環境解析"、小豆川勝見、の Fe の状態分析"、小豆川勝見・久野章仁・松東京大学大学院総合文化研究科広域科学専攻

尾基之・三浦英樹、日本地球化学会年会 (2004

修士論文 (2005 年 1 月)

年 9 月)

4. "Elemental and state analysis on deep-sea

11. "57Feメスバウアー分光法による南極海底質中pelagic bedded chert of the GL boundary"、のFeの状態分析"、小豆川勝見・久野章仁・松田野島三奈、国際基督教大学教養学部理学科

尾基之・三浦英樹、第 48 回放射化学討論会

卒業論文 (2005 年 3 月)

(2004 日本放射化学会年会) (2004 年 10 月)

5. "元素分布と鉄の化学状態に着目した干潟お12. "汽水域底質中の重金属硫化物の分布と生成

よび運河の底質に関する研究"、長谷川篤、東に関する研究"、片岡正樹・松尾基之、北海道

京海洋大学海洋科学部海洋環境学科 卒業論文

支部 2005 年冬季研究発表会 (2005 年 2 月)
13. "元素分布と鉄の化学状態に着目した干潟お(2005 年 3 月)
6. "多摩川 中・下流域底質における元素分布とよび運河の底質に関する研究"、長谷川篤・田鉄の化学状態から見た河川環境"、中村明日子、

中美穂・片岡正樹・久野章仁・松尾基之、日本－ 385 －

JAEA-Review 2008-067

分析化学会第 54 年会 (2005 年 9 月)
14. "特異な Fe 化学種を含有する南極海堆積物の堆積環境に関する考察"、小豆川勝見・松尾基之・久野章仁・三浦英樹、第 49 回放射化学討論会 (2005 日本放射化学会年会) (2005 年 9月)
15. "干潟および運河の底質・間隙水中の元素鉛直分布に関する研究"、長谷川篤・田中美穂・久野章仁・松尾基之、日本化学会第 86 春季年会
(2006 年 3 月)
16. "南太平洋遠洋性堆積物中に含まれる元素の供給源の推定"、小豆川勝見・佐野有司・松尾基之、日本地球化学会年会 (2006 年 9 月)
17. "都市河川 中・下流域における硫酸還元"、中村明日子・久野章仁・松尾基之、日本地球化学会年会 (2006 年 9 月)
18. "放射化分析法および XAFS 法による遠洋性
海洋堆積物中の Mn 分析"、小豆川勝見・佐野
有司・松尾基之、第 50 回放射化学討論会 (2006
日本放射化学会年会) (2006 年 10 月)
19. "放射化分析法およびメスバウアー分光法による干潟底質の環境評価"、諸町大地・久野章
仁・松尾基之、第 50 回放射化学討論会 (2006
日本放射化学会年会) (2006 年 10 月)
20. "Estimation of the sources of pelagic
sediments from the South Pacific Ocean to
the Antarctic Ocean", K. Shozugawa, A.
Kuno, Y. Sano and M. Matsuo, 12th
International Conference on Modern Trends
inActivation

Analysis(MTAA-12),(September 2007)
21. "Influence of reclamation on the concentrations and chemical states of elements intideland sediment", D. Moromachi, A. Kuno
andM.

Matsuo,12th

International

Conference on Modern Trends in Activation
Analysis (MTAA-12), (September 2007)
22. "放射化分析法を用いた遠洋性海洋堆積物表層における供給源の検討"、小豆川勝見・久野
章仁・佐野有司・松尾基之、第 51 回放射化学討論会（2007 日本放射化学会年会）(2007 年
9 月)－ 386 －

JAEA-Review 2008-067－ 387 －

This is a blank page.

JAEA-Review 2008-067

4-1
研究テーマ： 放射化法による中性子捕獲断面積の測定技術開発
表
題： 安定核種の断面積測定と中性子束モニタの開発
研究炉 JRR-3 を用いた熱中性子捕獲断面積測定技術開発
中村詔司、太田雅之、初川雄一、原田秀郎
日本原子力研究開発機構

中性子捕獲断面積データは、核変換や核燃料の燃焼による生成量評価を考える上で重要である。
放射化法により断面積を測定するにあたり、照射設備の中性子束の現状を実験的に知っておく必要がある。そこで、研究炉 JRR-3 における照射設備 PN-3、PN-1、HR-1（図１)の中性子束の成分
を、Westcott’s Convention1）2) に基づいて調べたので報告する。更に、中性子束モニタ開発として、数点の安定核種の熱中性子捕獲断面積の測定を
実施した。

図１

備 PN-3：熱中性子束は、約 1×1013n/cm2s であり、十分良く熱化されていることが確認された。PN-3 を用いれば、熱中性子捕獲断面積を測定することが可能であると考えられる。このことを、モニタと一緒に照射した Mo-98 及び Zr-96 の断面積を測定することにより実証した。更に、中性子束モニタの開発という観点から、更に W-186、In-113、Sc-45、Fe-58、Cu-63の熱中性子捕獲断面積の測定を実施した。
b) 気送管照射設備 PN-1：約 5×1013 n/cm2s 程の熱中
性子成分を有し、熱外中性子成分が 0.1%しかないことを確認した。そのため、Cd 遮蔽を用いて共鳴積分を測定することは困難であると判断された。

研究炉 JRR-3 照射設備

照射設備の中性子束情報として、熱中性子束成分と熱外中性子成分の 2 成分に着目した。中性子束モニタとして、主として 197Au/Al と 59Co/Al 合金
線のセットを用い、適宜、W 箔、Mo 線を追加して中性子束情報を補足することとした。熱外中性
子成分を求める場合には Cd 遮蔽管にモニタ線のセットを入れて照射した。本実験では、Cd 遮蔽管の照射における安全性を確認する目的もあった。研究炉 JRR-3 の 20MW 定格運転において、PN-3 にて遮蔽無しで 10 分照射を行い、中性子束
モニタと一緒に数点の安定核種も照射した。
PN-1 にて Cd 遮蔽有り/無しの照射を 10 分ずつ、
HR-1 にて Cd 遮蔽有り/無しの照射を 1 時間ずつ行った。
照射後、中性子束モニタからの γ 線を高分解能
Ge 検出器で測定し、それぞれの生成放射能を求めた。モニタの放射能を、Westcott’s Conventionに基づき解析し、各照射設備における中性子束の成分を調べ図 2 の結果を得た。a) 気送管照射設
原子炉: JRR-3

装図2

Westcott’s convention に基づき測定した中性子束成分c) 水力設備 HR-1：約 8×1013n/cm2s の高い熱中性子
成分と熱外中性子成分約 1%を有することを確認した。本照射において、Cd 遮蔽管の照射の安全性を確認することができたので、本照射設備は、共鳴積分の測定に適用できることが分かった。本照射設備は、
1 サイクル(26 日間)照射が可能であるので、中性子捕獲断面積の小さい核種や生成核の半減期が非常に長い場合に対しても生成量を稼ぐことが期待される
ので断面積測定に有効である。
参考文献
1) C.H.Westcott et al., Proc.2nd Int. Conf., Geneva,
16, 70 (1958).
2) H.Chatani, KURRI-TR-432(2001).

置：気送管及び水力設備－ 389 －

分 野：放射化分析（その他）

JAEA-Review 2008-067

4-2
研究テーマ：40Ar/39Ar 年代測定による火山活動史及び地殻構造発達史の解明—日本周辺海域
及び活動的火山に関する研究—
表
題：火山岩の 40Ar/39Ar 年代測定
大陸棚限界画定調査によるフィリピン海地域の火成活動史に関する新知見
石塚治
産業技術総合研究所地質情報研究部門
本 研 究 で は 、 フィリピン海海域およびその周辺の小笠原海台や南鳥島周辺海域において，採取された地質試料に関する地球科学
的分析データ(特に岩石の形成年代)をもとに，各海域におけるマグマ活動およびマントル
ダイナミクス等を含めた火成活動史を把握することを目的とする．また本研究は現在国により準備されている国連への我が国の大陸棚限界画定申請のための調査の一環である。日本周辺海域の基盤岩の精密な形成年代を決定することを通じて、国連への提出情報作成をサポートする。
測定試料は、海底においてボーリングマシ
ンにより掘削された、あるいはドレッジにより回収された火山岩試料を用いた。火山岩のうちもっとも新鮮な石基部分を主に使用した。試料から厚さ約 1mm の板状試料を切り出し、それを軽く粉砕して約 1mm 角の小片にした。その後変質により生じている可能性のある粘土鉱物や炭酸塩鉱物の除 去を目的として、3MHCl 中で約 30 分、さらに 4MHNO 3
中で約 30 分超音波洗浄後、脱イオン水で洗浄した。洗浄時間は、試料の変質程度によって調整した。洗浄後温水中で約 2 日間脱塩処理を行った。乾燥後、顕微鏡下で変質部や斑晶の混入のない試料をハンドピックし、測定用 試 料 と し た 。 試 料 の 中 性 子 照 射 は 、 JRR4にて行った。S パイプで 6 時間照射（途中回転）を行った。またカドミウム箔による熱中
性子カットを行った。
アルゴンの同位体比分析は、産業技術総合研究所のレーザ加熱 40 Ar/ 39 Ar 年代測定シス
テムにより行った。分析法等については、
Ishizuka et al. (2003) に準じた。
今年度得られた多くの成果のうち、特に興味深いのは伊豆小笠原弧背弧地域の火山と四国海盆中軸部に存在する紀南海山列と呼ばれる火山列との関係である。紀南海山列の玄武岩類からは 7.4 -15.5Ma(1Ma は百万年)のAr/Ar 年代が得られた。現段階では年代値に地域による系統的な差は認められない。この

原子炉：JRR-4

装

置：S パイプ

年代は、四国海盆の拡大が停止したと考えら
れる 15Ma より概ね若い年代である。紀南海
山列における火山活動が、四国海盆の拡大停止後、約 800 万年間起きていたことが明らかになった。
一方紀南海山列と背弧海山列の間の海山群からは 8.9-14.4 Ma の年代が得られた。この年代値は、これまで背弧海山列で得られた年代範囲（17.3-3Ma: Ishizuka et al., 2003）と重なるが、古い時代に限られている。これらの海山が伊豆小笠原島弧の背弧域の（島弧）火山活動であることを示唆すると同時に、背弧域の火山活動が時代とともに東側、すなわ
ちより火山フロント近傍に限られていったとする従来の考え（Ishizuka et al., 2003）を支持する結果である。
上記の結果は、上記２地域の火山がほぼ同時期に活動して いたことを示している。しかしながらこれら火山の溶岩の化学的特徴は大きく異なる。紀南海山列の溶岩は、それより東の火山の溶岩が示すいわゆる島弧の火山岩が示す特徴、すなわち沈み込む太平洋プ
レート由来の物質のマグマへの寄与が全く認められない。したがっていわゆるプレートの沈み込みに伴う島弧のマグマ活動によって形成されたものではない。さらに溶岩の年
代と化学組成との間に驚くべきほど明確な相関関係が発見された。この関係は、四国海盆拡大停止後、時代とともに紀南海山列下のマントルの温度が低下あるいはマントルの上昇流が弱まることにより、マントルの溶融度が低下し、かつ低温で融けやすい部分のみが溶融してマグマを生成するようになったことを示していると解釈できる。背弧海盆拡大停止以後の背弧地域のマグマティズムとマントルダイナミクスの解明に重要な制約を与える発見と考えられる。
参考文献 1) Ishizuka, O., K. Uto, and M. Yuasa(2003), Geol. Soc. Spec. Publ., 219, 187-205.

分

野：放射化分析（地質学）－ 390 －

JAEA-Review 2008-067

4-3
研究テーマ：核破砕核種に対する線量評価法の開発
表
題：水銀中生成トリチウムの性状解明
水銀中で生成するトリチウムの化学形割合
真辺健太郎、横山須美
独立行政法人日本原子力研究開発機構 原子力基礎工学研究部門 放射線防護研究グループ

分別、回収し、液体シンチレーションカウン
タにより放射能を計測した。照射容器の形状改善により、収率はほぼ 100 %となった。図 2に、生成したトリチウムの化学形割合を試料毎に示す。
全試料の平均割合は HTO が 40 %、HT が 60 %、標準偏差は 10 %であった。
平成 19 年度は、試料容器の気相の成分を操作し、試料に不純物として含まれる酸素や水分の量を変化させ、生成するトリチウムの化学形割合に与える影響を明らかにする予定である。
100
化学種別生成割合 [ % ]大強度陽子加速器施設 J-PARC における核破砕中性子源のターゲットとして使用される
水銀中には様々な浮遊性放射性核種が生成し、特にトリチウムは生成量が多く、潜在的な内部被ばく源となる。トリチウムの吸入による
内部被ばく線量を計算する際に使用する線量
係数は化学形によって大きく異なり、トリチ
ウム水（HTO）の線量係数はトリチウムガス（HT）のそれの 1 万倍である。したがって線量を評価するにあたり、放出されるトリチウ
ムの化学形に関する知見は重要である。
昨年度、我々は、大強度陽子誘導トリチウ
ムを模擬するために、水銀に少量の金属リチ
ウムを溶解して得た液体アマルガムを試料とし、熱中性子照射して水銀中にトリチウムを生成させる方法を考案した。これにより、HTO
および HT の生成を確認した。本年度は、図 1に示すように試料を封入する容器の形状を改良して試料を直接パージすることで収率の向上を図り、水銀中で生成するトリチウムの化学形割合についてデータを得ることを目的とし、液体アマルガム照射実験を行った。
約 1 g の試料を照射容器に封入し、照射試料とした。JRR-4 中性子ビーム設備のビーム孔前に照射試料と Co フラックスモニタを設置し、熱中性子モードⅠで 6 時間照射した。放射化した Co の� 線スペクトロメトリにより求めた
熱中性子フラックスは約 1.7 × 109 cm−2 s−1 であった。生成したトリチウムは HTO と HT に
パージガスの流れ

試料
U 字型

T 字型

図1

容器形状の改良

使用原子炉：JRR-4

HTO
HT

50

0

試料1

試料2

試料3

試料4

図2

試料毎の化学形割合

成果の公表a) 真辺健太郎, 横山須美, 遠藤章. 水銀中生
成トリチウムの性状. 日本原子力学会 2007
年春の年会.
b) K. Manabe and S. Yokoyama, Ratio of tritiatedwater and hydrogen generated in mercury
through a nuclear reaction, Appl. Radiat.
Isotopes (2007), in press.
doi:10.1016/j.apradiso.2007.07.028.

装置名：中性子ビーム設備－ 391 －

利用分野：放射化分析・その他

JAEA-Review 2008-067

4-4◂✪ࢷ࣭࣏୯ᛮᏄᨲᑏ໩ฦᯊἪ࡞ࡻࡾ⎌ሾムᩩࡡฦᯊ⾪ࠈࠈࠈࠈ㢗ኬẴ࢙࢓ࣞࢯࣜ⢇Ꮔࡡ࢞ࣔࣚࢠࢰࣛࢭ࣭ࢨࣘࣤ

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ムᩩࡢࠉ7DEOH࡚♟ࡌ᭿㛣࡞ᤍ㞗ࡈࡿࡒࠊ
7DEOH
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Start

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P3

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࡞ࠉ3࡚ࡢ⢊ኬ⢇Ꮔ࡚3࡞ḗ࠷࡚9ࡡ⃨ᗐ࠿㧏ࡂ࡝ࡖࡒࠊࡆࡡ᫤᭿ࡡ$Oࡡ⃨ᗐࡢࠉୌ␊఩ࡂ
ᅰቫ⢇Ꮔࡡᙫ㡢ࢅኬࡀࡂུࡄ࡙࡝࠷ࠊࡈࡼ࡞ࠉ)LJ࡚♟ࡌࡻ࠹࡞ࠉ⢊ኬ⢇Ꮔࡡ9࡛$Oࡡ⃨ᗐẒ 9$O ࡢ3࡚௙ࡡ᭿㛣࡛Ẓ࡬࡙ಶ࡮
原子炉: JRR-3
原子炉: JRR-4

装置: 放射化分析用照射設備
装置: Tパイプ

分野 :放射化分析(環境)分野 :放射化分析(環境)－ 392 －

JAEA-Review 2008-067

4-5
研究テーマ：関東甲信静地方における浮遊粒子状物質中の金属成分濃度の把握
表
題：関東における大気エアロゾルのキャラクタリゼーション（第 26 報）
内藤季和、米持真一 １
千葉県環境研究センター１
埼玉県環境科学国際センター
関東地方環境対策推進本部大気環境部会浮遊粒子状物質調査会議

本研究では、関東地方の 1 都 9 県（関東地方

じん由来と考えられる。ナトリウムと塩素は海の１都 6 県＋山梨県・静岡県・長野県）においに近い粗大粒子で濃度が高くなり、海塩粒子のて浮遊粒子状物質の汚染実態を把握し、その濃影響と考えられた。臭素は例年微小粒子で濃度度や組成等の動向を知ることを目的とした。

が高いが、昨年度に続いて夏期の粗大粒子で高[調査方法] 平成 17 年 7 月 25～29 日(夏期)とくなり、その原因は不明である。

12 月 5～9 日(冬期)に 18 地点で行い､石英ろ紙
およびポリフロンろ紙を装着したアンダーセ
ンサンプラーにより、粒子を粒径 2.1～11μm(粗大粒子)と 2.1μm 未満(微小粒子)に分級捕集した。捕集したろ紙試料は秤量後、日本原子力研究開発機構の原子力科学研究所（茨城県那珂郡東海村）の JRR-3 原子炉において気送管（PN-3）での熱中性子放射化分析により、40 秒
照射・180 秒測定で 9 種の短寿命核種（Mg，Al，Cl，Ca，Ti，V，Mn，Cu，Br）を分析した。イ
オンクロマトグラフ法により水溶性成分、CHN
コーダー（熱分離法）により、炭素成分についても分析した。
[調査結果] (1)粒子状物質濃度：結果を図１に示した。粗大粒子の平均濃度は夏期が 11.2μ3

図１ 調査地点における浮遊粒子状物質濃度

3g/m ､冬期は 7.4μg/m ､微小粒子は夏期 12.6μg/m3 、冬期 16.1μg/m3 であった。微小粒子/(粗放射化分析と水溶性成分との比較では、ナト

大粒子+微小粒子)の平均値は夏期が 0.55､冬期

リウムはほぼ一致したが、塩素は放射化分析のは 0.69 で夏期に粗大粒子の占める割合が多か

結果が低く、カルシウムとマグネシウムは逆にった。（2）金属成分：バナジウムは東京湾岸で放射化分析の結果が高い結果となった。カルシ

高い傾向にあり、湾岸部で重油燃焼が多いこと

ウムとマグネシウムについては、非水溶性成分を示唆している。マンガンは例年同様、冬期にが多いためと考えられる。

東京湾岸で高くなる傾向があり、鉄鋼工場に由来すると考えられる。アルミニウムとカルシウ
ムは粗大粒子に多く存在し、土壌粒子や道路粉

原子炉：JRR-３

装

置：気送管

－ 393 －

分

野：放射化分析（環境）JAEA-Review 2008-067

4-6
研究テーマ：放射化分析による家畜・家禽の土壌摂取量推定表
題：家畜・家禽の土壌摂取が畜産物の生産に及ぼす影響
繁殖雌豚の土壌摂取量の推定
西村宏一 木方展治１
独立行政法人 農業・食品産業技術総合研究機構
１ 独立行政法人 農業環境技術研究所

屋外に放飼した家 畜 ・ 家 禽 は 土 壌 を 摂 取する。表 層土に吸着 されてい る重金属 や残留農薬等の有害物質が土壌摂取を介して畜産物へ移行 すると 、ヒトへ の汚染も 危惧
さ れ る 。 し か し 、 その影響は十分に検討されていない。今年度はスカンジウムを標準物質として用い、放射化分析法で繁殖雌豚の土壌摂取量を検討した。
供飼前まで舎飼いしていた繁殖成雌豚（５歳）を屋外区（３頭・平均体重 238kg）および屋内区（３頭・平均体重 237kg）に分けて群飼した。１日量 2.5kg の配合飼料を朝夕２回に分けて給与した。試験開始後 45～46 日
目（１回目）、73～74 日目（２回目）ならびに 101～102 日目（３回目）に１日 10 点以上の排糞を採取した。豚糞、給与飼料ならびに放飼場の土壌を風乾・微粉砕して試料とした。
豚糞（300mg）、給与飼料（300mg）、土壌（100mg）
ならびに標準物質のスカンジウム水溶液を吸着させたろ紙をポリエ チレン製袋に二重封入し、日本原子力研究開発機構 JRR-4 炉簡

易照射筒（熱中性子束 5.3×10 17 ×ｍ－ 2）で、
20 分間照射した。30～45 日間の冷却後、外側のポリエチレン製袋を交換し、γ線スペク
トロメトリによって 500 秒間測定した。
試料中のスカンジウム含有率と土壌含有率は表１の とおりで あった 。給与試 料中のスカンジウ ムは、試料材料 の穀実に 付着した土壌や同じく添加ミネラルに由来した も の と 考 え ら れ る 。 また、給与飼料の乾物消化率を 80％とすると、屋外区および屋内区の繁殖雌豚の１日１頭当たり土壌摂取量は図１のとおりとなった。両区の差から、繁殖 雌 豚 の 土 壌 摂 取 量 は １ 回 目 で は 109g／
頭／日、２回目では 277g／頭／ 日、３ 回目
では 232g／頭／ 日となった。この量は 繁殖
雌 豚 が 摂 取 し た 飼 料 の ４ ～ 11％ の 量 に 相当し、必 須ミネラル 欠乏によ る 異嗜行 動時のような高い 値ではな く、通 常な飼育 では
この範囲の土 壌摂取量 と考えら れる。

表１ 試料中のスカンジウムと土壌の含有率

料

給与飼料
豚糞・屋外区１回目
豚糞・屋外区２回目
豚糞・屋外区３回目
豚糞・屋内区１回目
豚糞・屋内区２回目
豚糞・屋内区３回目
土 壌

スカンジウム0.035ppm
3.95
9.58
7.92
0.39
0.58
0.37
16.3

屋外区

土 壌
0.22%
24.2
58.9
48.7
2.4
3.6
2.3
－

屋内区

300
250
土壌摂取量（ｇ／日／頭）試

畜産草地研究所

200
150
100
50
0
１回目

２回目

３回目

図１ ブタの土壌摂取量

原子炉：JRR-４

装

置： 簡易照 射筒分－ 394 －

野：放 射化分 析（農 ・水産 物）

JAEA-Review 2008-067

4-7
研究テーマ：中性子放射化分析法の農業環境研究に対する利用法の開発と適用
表
題：作物の無機元素集積能力を評価するための土壌からの移行係数算出法の開発
作物の無機元素集積能力を評価するための土壌からの移行係数算出法の開発
木方 展治 西 村 宏 一 1 藤 原 英 司 櫻 井 泰 弘 山 口 紀 子
独立行政法人 農業環境技術研究所
1
独立行政法人 農業・食品産業技術総合研究機構 畜産草地研究所

１．はじめに
土壌－作物移行係数は、土壌中に存在している対象元素が作物にどの程度移行するのかの指標であり、作物中（特に可食部）の元素の濃度を、その作物を育てた土壌中の濃度で割った値である。土壌－作物移行係数を有害元素に適用した場合には、有害成分の作物への集積しやすさの指標となり、稀少資源元素に適用した場合には、作物の資源回収能力の指標になるため、これを簡易に算出する意義は大きいと考えられる。
また機器中性子放射化分析（放射化分析と略す）は、植物と土壌を化学的な分離操作なしで、同じ条件のもとに照射、測定できるという特徴を持つ多元素同時分析法である。
植物と土壌を同時に放射化すれば、標準物質や近年放射化分析で用いられるｋo 法のような複雑な計算なしに、土壌－作物移
行係数を求めることができると考え、検討を行った結果について報告する。
２.実験方法つくば市の農業環境技術研究所畑ほ場（黒ボク土および造成土）より葉菜類・根菜類・麦類・豆類・水稲等の作物および土壌を採取し、風乾後微粉砕して試料とした。
ポリエチレン製袋に 2 重封入した試料を茨城県東海村にある日本原子力研究開発機構
JRR3 炉 PN1,PN2 気送照射孔および JRR４炉
水力 T パイプ（Ａ系統）で、短半減期核種用に 1 分、中長半減期核種用に 20 分照射し、冷却後外側のポリエチレン製袋の包み替えを行ない、同軸型 HPGe 半導体検出器を装備したγ線スペクトロメトリにより 500 秒から 24,000 秒かけて測定を行った。

３.結果および考察
短半減期核種用には作物 50mg および土
壌 10mg を秤取し、１分照射した後、３時間
から１日冷却時間を置き、500 秒の測定を行うことで、γ線スペクトロメトリにおける測定距離などの測定条件を土壌と植物とで同じにできることがわかった。
中長半減期核種用には作物 300mg および土壌 100mg を秤取し、20 分照射した後、６日以上冷却時間を置き、1000 秒から 24,000
秒かけて測定を行うことで、土壌・植物同一条件下での測定が可能であった。
半減期が１日以内の短寿命放射性核種では
40
Ｋ, 56 Mn ,24 Na 等が、半減期が１週以内の中寿命放射性核種では 82 Br, 140 La , 153Sm
等が、半減期が１週を越える長寿命放射性核種では 141Ce,60 Co, 51 Cr, 152Eu, 59 Fe, 86 Rb,
46
Sc, 65 Zn 等が検出される作物があり、移行係数が算出できた（表 1）。
表 1 の結果は、各作物で Rb および Zn の移行係数が比較的高いことを示した。短半減期核種においても移行係数が算出できるものがあった。標準試料を入れない場合には、定量に関する情報は得られないが、移行係数は算出できる（表 2）。
４.結論
以上の結果、土壌―植物移行係数の算出を容易に行う手段として、放射化分析法が有効であり、高い集積特性を有する作物のスクリーニングに使用できる可能性が示された。
参考文献
1)第 44 回アイソトープ・放射線研究発表会
要旨集,Ⅱp-01,(2007),p150－ 395 －

JAEA-Review 2008-067

表１ 同一畑ほ場から採取した各種畑作物の土壌－作物移行係数(長寿命核種からの計算値、土壌；黒ボク土)

つくば畑圃場レタス
ブロッコリーｷｬﾍﾞﾂ
葉 キャベツ菜 ﾁﾝｹﾞﾝｻｲ
類 ﾁﾝｹﾞﾝｻｲ
小松菜
3月5日ﾎｳﾚﾝｿｳ
5月10日ﾎｳﾚﾝｿｳ
根菜類 ﾆﾝｼﾞﾝ
ﾆﾝﾆｸ
芋 サトイモ（子）サトイモ（親）類
サトイモ（茎葉）
大麦
穀
燕麦
類
小麦茎葉
豆 ｿﾗﾏﾒ類 グリーンﾋﾟｰｽ
ﾃﾞﾝﾄｺｰﾝ
飼料 ｿﾙｶﾞﾑ
ｲﾀﾘｱﾝﾗｲｸﾞﾗｽ作
ｱﾙﾌｧﾙﾌｧ(参考） ホテイｱｵｲ

つくば畑圃場レタス
ブロッコリーｷｬﾍﾞﾂ
葉 キャベツ菜 ﾁﾝｹﾞﾝｻｲ
類 ﾁﾝｹﾞﾝｻｲ
小松菜
3月5日ﾎｳﾚﾝｿｳ
5月10日ﾎｳﾚﾝｿｳ
ﾆﾝｼﾞﾝ
根菜類
ﾆﾝﾆｸ
芋 サトイモ（子）サトイモ（親）類
サトイモ（茎葉）
大麦
穀
燕麦
類
小麦茎葉
豆 ｿﾗﾏﾒ類 グリーンﾋﾟｰｽ
ﾃﾞﾝﾄｺｰﾝ
飼料 ｿﾙｶﾞﾑ
作 ｲﾀﾘｱﾝﾗｲｸﾞﾗｽ
ｱﾙﾌｧﾙﾌｧ(参考） ホテイｱｵｲ

つくば畑圃場レタス
ブロッコリーｷｬﾍﾞﾂ
葉 キャベツ菜 ﾁﾝｹﾞﾝｻｲ
類 ﾁﾝｹﾞﾝｻｲ
小松菜
3月5日ﾎｳﾚﾝｿｳ
5月10日ﾎｳﾚﾝｿｳ
ﾆﾝｼﾞﾝ
根菜類
ﾆﾝﾆｸ
サトイモ（子）芋サトイモ（親）類
サトイモ（茎葉）
大麦
穀
燕麦
類
小麦茎葉
豆 ｿﾗﾏﾒ類 グリーンﾋﾟｰｽ
ﾃﾞﾝﾄｺｰﾝ
飼
ｿﾙｶﾞﾑ
料
ｲﾀﾘｱﾝﾗｲｸﾞﾗｽ作
ｱﾙﾌｧﾙﾌｧ(参考） ホテイｱｵｲ

2001年
2002年
2001年
2001年
2001年
2002年
2001年
2002年
2002年
2002年
2002年
2002年
2002年
2001年
2001年
2001年
2002年
2002年
2002年
2001年
2001年
2001年
2001年
2002年
2002年
2001年

2001年
2002年
2001年
2001年
2001年
2002年
2001年
2002年
2002年
2002年
2002年
2002年
2002年
2001年
2001年
2001年
2002年
2002年
2002年
2001年
2001年
2001年
2001年
2002年
2002年
2001年

2001年
2002年
2001年
2001年
2001年
2002年
2001年
2002年
2002年
2002年
2002年
2002年
2002年
2001年
2001年
2001年
2002年
2002年
2002年
2001年
2001年
2001年
2001年
2002年
2002年
2001年

mg/kg
189
159
13
13
14
20
9
18
4
7
25
11
36
29
8
16
9
27

Ba
Ce
Co
移行係数 mg/kg 移行係数 mg/kg 移行係数
－
40
－
40
－
－
40
－
38
－
nd
nd
0.4
0.010
nd
nd
0.3
0.008
0.07
0.6
0.015
0.4
0.011
nd
0.06
0.3
0.008
nd
0.08
1.0
0.025
0.13
0.1
0.002
1.1
0.028
nd
0.06
1.4
0.037
nd
0.1
0.003
1.0
0.027
nd
0.1
0.003
0.5
0.012
nd
0.11
0.2
0.004
0.6
0.015
nd
nd
0.5
0.012
nd
nd
nd
0.02
0.5
0.013
nd
0.03
0.9
0.022
0.16
0.3
0.007
2.7
0.073
0.07
0.2
0.004
2.5
0.065
0.23
0.2
0.005
2.1
0.055
1.2
0.031
nd
nd
0.15
0.3
0.009
nd
nd
0.5
0.011
nd
nd
0.04
2.1
0.053
0.10
0.4
0.009
1.7
0.045
0.05
0.2
0.004
1.5
0.040
－
1.5
－
3.1
－

Cr
mg/kg 移行係数
94
－
86
－
0.002
0.2
nd
nd
nd
nd
0.6
0.007
0.2
0.002
0.3
0.004
0.3
0.004
0.2
0.004
nd
nd
0.2
0.002
0.4
0.004
0.8
0.009
0.7
0.008
0.6
0.007
nd
nd
0.4
0.004
0.7
0.008
0.5
0.006
0.4
0.004
2.8
－

mg/kg
4.0
3.4
0.0
0.0
0.035
0.024
0.005

0.021
0.012

0.058

Eu
Fe
mg/kg 移行係数 mg/kg 移行係数
1.5
－
85140
－
1.4
－
78521
－
nd
96
0.0011710.0008
nd
0.007
0.005
269
0.0008620.0032nd
133
0.0064
nd
0.005
0.004
500
0.0016nd134
0.0017
0.004
0.003
282
0.0036155
0.0020nd
149
0.0019nd
nd
27
0.0003nd30
0.0003nd
22
0.0003nd
152
0.0018
0.007
0.005
367
0.0047
0.007
0.005
198
0.0025
0.009
0.006
285
0.0036nd
72
0.0008nd
81
0.0010nd
118
0.0014
0.005
0.003
320
0.0038
0.009
0.006
340
0.0043
0.018
0.013
237
0.0030
0.023
－
3988
－

表１ つづき
2001年
つくば畑圃場
2002年
レタス
2001年
ブロッコリー
2001年
ｷｬﾍﾞﾂ
2001年
葉 キャベツ
2002年
菜 ﾁﾝｹﾞﾝｻｲ
2001年
類 ﾁﾝｹﾞﾝｻｲ
2002年
小松菜
2002年
3月5日ﾎｳﾚﾝｿｳ 2002年
5月10日ﾎｳﾚﾝｿｳ 2002年
ﾆﾝｼﾞﾝ
2002年
根菜類
ﾆﾝﾆｸ
2002年
サトイモ（子）2001年
芋サトイモ（親）2001年
類
サトイモ（茎葉）
2001年
大麦
2002年
穀
燕麦
2002年
類
小麦茎葉
2002年
豆 ｿﾗﾏﾒ
2001年
類 グリーンﾋﾟｰｽ
2001年
ﾃﾞﾝﾄｺｰﾝ
2001年
飼
2001年
ｿﾙｶﾞﾑ
料
ｲﾀﾘｱﾝﾗｲｸﾞﾗｽ
2002年
作
ｱﾙﾌｧﾙﾌｧ
2002年(参考） ホテイｱｵｲ
2001年

表２ 短寿命照射（1 分）により算出されたマンガンの土壌－作物移行係数

Hf
Lu
Rb
移行係数 mg/kg 移行係数 mg/kg 移行係数
－
0.6
－
40
－
－
0.5
－
48
－
0.0
34
0.86
nd
0.0
23
0.57
nd
0.009
29
0.72
nd
nd
21
0.45
nd
nd
nd
29
0.71
0.007
28
0.58
nd
nd
25
0.53
nd
nd
0.001
18
0.38
27
0.56
nd
nd
27
0.56
nd
nd
6
0.12
nd
nd
9
0.24
nd
nd
6
0.15
nd
nd
0.005
20
0.50
nd
nd
0.0004 0.00001
15
0.32
nd
nd
19
0.39
0.004
12
0.25
nd
9
0.21
nd
nd
6
0.16
nd
nd
18
0.44
nd
nd
15
0.37
nd
nd
25
0.52
nd
nd
18
0.38
nd
nd
－
0.0092
－
15
0.39

種別

装

葉菜類

果菜類

根菜類

置：気送管,水力 T パイプ－ 396 －

作物名
フダンソウ

芋類

穀類

豆類

原子炉：JRR-3,JRR-4

Sc
Zn
mg/kg 移行係数 mg/kg 移行係数
34
－
122
－
31
－
133
－
0.013
0.0004
25
0.20
0.004
0.0001
38
0.31
0.065
0.0019
35
0.28
0.002
0.0001
20
0.15
0.030
0.0009
34
0.28
0.179
0.0058
43
0.32
0.031
0.0010
27
0.21
0.088
0.0028
42
0.32
0.040
0.0013
67
0.50
0.040
0.0013
31
0.23
0.004
0.0001
12
0.09
0.003
0.0001
18
0.15
0.003
0.0001
15
0.13
0.032
0.0009
23
0.19
0.141
0.0045
6
0.05
0.063
0.0020
16
0.12
0.095
0.00316
0.05
0.002
0.0001
46
0.38
0.004
0.0001
44
0.36
0.021
0.0006
22
0.18
0.086
0.0026
21
0.17
0.118
0.0038
58
0.44
0.072
0.0023
18
0.14
0.282
－
283
－

分

採取年

Mn

1993年

0.0411

ハクサイ

1994年

0.0177

モロヘイヤ

1995年

0.0551

カリフラワー

1996年

0.0137

ネギ

1996年

0.0094

ブロッコリー

1996年

0.0182

コマツナ

1999年

0.0263キャベツ(1/27収穫)

1999年

0.0155キャベツ(4/21収穫)

1999年

0.0233チンゲンサイ

1999年

0.0155

ホウレンソウ

1999年

0.0264レタス

2000年

0.0217

春菊

2000年

0.0188

カボチャ

1995年

0.0044

キュウリ

1999年

0.0101

オクラ

1999年

0.0075トマト

1999年

0.0071

ナス

1999年

0.0113

ピ－マン

1999年

0.0111

ショウガ

1995年

0.0241

ラッキョ

1997年

0.0038

ダイコン

1999年

0.0062

ニンジン

2000年

0.0096

ジャガイモ

1994年

0.0038

ジャガイモ

1997年

0.0036

サツマイモ

1999年

0.0052

サトイモ

1999年

0.0051

玄米

1993年

0.0686

玄米

1996年

0.0303ソバ

1995年

0.0210

トウモロコシ

2000年

0.0140

インゲン

1995年

0.0179アズキ

1996年

0.0125

ソラマメ

1999年

0.0090

キヌサヤエンドウ

1999年

0.0069

エダマメ

2000年

0.0199野：放射化分析（農・水産物）

JAEA-Review 2008-067

4-8－ 397 －

JAEA-Review 2008-067

4-9�地質特性が河川水質に��す��に関する研究�
Influence of geological characteristics on the chemistry of river water
鹿児島大学理学部 穴澤活郎・坂元隼雄・有馬一成
Katsuro ANAZAWA, Hayao SAKAMOTO and Kazunari ARIMA
Department of Earth and Environmental Sciences, Faculty of Science, Kagoshima
University

はじめに
かつて鉱山国として知られていたわが国においては，各地の廃鉱山からの流出水による水質汚濁が，深刻な環境問題を引き起こしている。それらの多くは責任の所在が不明確であることが多く，放置されている例も少なくない。ホタルの里として知られる
吉野川市美郷地区においても，旧銅山からの硫酸酸性の坑廃水が流出し続けており，下流域ではホタルの飛翔が見られないことが知られている。その原因としては，河川底質の重金属が高濃度であるため，ホタルの餌であるカワニナが生育できない環境であるとの因果関係が判明しているが，未だに坑排水の対策は採られていない。そこで本研究では，河川水質，特に溶存態重金属の挙動と底質との関係を明らかにし，得られた知見に基づいて問題解決に向けた
具体的な対策を提案することを目的に調査を実施した。

１．研究の方法
１．１ 調査地
徳島県吉野川市美郷地区は，北緯34度1分，東経134度15分を中心とし，東西13 km，南北 8km，総面積50.47 km2の四国山地の山稜にある山村である（図１）。人口は2005年現在で，1,247人。四国山地の山稜に囲まれた典型的な山村で，山稜を超えて北は吉野川市山川地区，川島地区に接し，南は木屋平
村を経て剣山山脈に連なる。南東部は柳水峠の稜線をもって神山町と境をなし，村の中心部を流れる川
田川に東山谷川が合流して吉野川中流に注いでいる。
地勢は概ね北部で険しいが，川田川から東山谷川を通り大野を経て柳水庵に至る線以南は緩やかな傾斜地となっている。
地質的には中央構造線･三波川帯に位置し，当地域を構成する三波川変成岩は，泥質片岩・砂質片岩・珪質片岩・塩基性岩(塩基性片岩・変はんれい岩)からなり，それらは褶曲しながらも大局的には北に傾斜する構造を呈している。三波川帯の結晶片岩層の中には含銅硫化鉄鉱の鉱床があり，そのいくつかは1960 年代まで採掘されていた。それらの中でも東山
谷川上流部に位置する旧東山鉱山は，黄鉄鉱・黄銅
鉱・磁硫鉄鉱を算出する阿波有数の銅山であった。
明治初期の開坑以降，1900 年から 1930 年代に最盛期を迎え，1907 年と 1908 年の２年間の精鉱産出高
は 32,694t に達した。当時，鉱山周辺には，約 1000
人の従業員と家族が居住していたという。閉山後は，鉱石残渣の小山を残して周辺は荒れ果て，今に至っている。鉱山跡地には自噴井が残されており，高濃度の重金属排水を流出している。この流出水の析出物の色から，地元ではこの自噴井からの流出水路を「赤水谷川」と呼び習わしている。
「赤水谷川」は自噴井の下流約１km の地点で，同地域の主要河川である東山谷川に合流している。本研究では，この赤水谷川と東山谷川本流を中心に河川水・河川底質の試料採取ならびに流量測定を行った。また当該水域の溶存化学成分のバックグラウンドを得るために，
東山谷川の支流，および美郷地区を流れるもう一方の主要河川である川田川の調査も併せて実施した。
１．２ 現地調査ならびに試料採取
調査は 2001 年 10 月，2002 年 4 月，2002 年 12月，2007 年 5 月の計４回にわたって実施し，美郷村東山鉱山跡および東山谷川，川田川水系において各回とも 20～25 地点から水試料を採取した。また，
2002 年 4 月ならびに 2002 年 12 月，2007 年 5 月には河川底質（河川土壌）のサンプル採取を合わせて実施した。水試料は簡易濾過の後，ポリエチレンビ
ンに採取・保存した。採水にあたっては，現地においてデジタル式pHメータ（DKK HPH-130），ECメーター（Hach社製 SensIon 5）あるいはデジタル式
pH-ECメーター（Horiba pH･EC meter D-24）によJRR－3 PN、ASC-20、地�化学試料放�化分析－ 398 －

JAEA-Review 2008-067

図１ 調査地：徳島県吉野川市美郷地区
り水温・電気伝導度(EC)およびpHの測定を行った。
なお，使用した機器は，あらかじめ日本工業規格
K0102 (JIS-K0102)にしたがい校正を行った。電気伝導度（EC）の定量限界は 0.01 mS/mであり，pH，ECともに繰り返し誤差は 1 %以内であった。また現地において，メチルレッド-ブロモクレゾールグリー
ン混合溶液を指示薬とした硫酸滴定法によりアルカ
リ度の測定を行い，HCO3-に換算した。底質試料については，チャック付きビニル袋に封入した後，冷蔵し，実験室において 60 ºCで 3 日間乾燥させた後，測定に用いた。
１．３ 化学分析
試薬類は市販の特級試薬をそのまま使用した。また，使用した水は，錫でメッキした銅製の蒸留器（高林理化株式会社製）によって得られた蒸留水をさらに Millipore 社製 Milli-Q SP 超純水システムにて処理した超純水を用いた。
主要陰イオン成分については，0.20 μm のメンブ
ランフィルターでろ過の後，イオンクロマトグラフ
ィー(Hitachi L-7470)を用いてノンサプレッサ法により測定した。主要陽イオンについては，島津製作
所 AA-646 を用い， Na+とK+はフレーム発光分析
法，Ca2+とMg2+は 1%ランタン共存下において原子吸光光度法（AA）により定量した。各イオンの定量
限界は，F-，Cl- ，PO43-，SO42-，Na+およびCa2+が5.0 µmol/dm3，NO3-が 1.5 µmol/dm3，K+およびMg2+

が 1.0 µmol/dm3であった。繰り返し誤差は全イオンにおいて 3 %以内であった。
溶存主要イオンの調査においてMg2+，SO42-などの値が明瞭に高い地点が確認されたため，川田川中流の 6 地点，東山谷川水系の 10 地点について河川
水・河川底質について重金属の分析を実施した。河
川水中の カドミウム，銅，マンガン，亜鉛について
はICP発光分光光度法を用いて，鉄についてはチオ
グリコール酸ナトリウムによる 3 価鉄還元の後に，ジピリジル発色法を用いた吸光光度法により吸収波
長 525 nmで測定した。
底質試料については，原子炉中性子を用いた機器
中性子放射化分析法(INAA)により，重金属類の多元素同時定量を行った（放射化分析研究会，2004）。
試料は，アルミナ製スタンプミルで粉砕し，さらにメノウ製ボールミルにより 20 分間粉砕した。こうして均質化した試料 100 mgをポリエチレン製の袋に入れ空気を除去した後シーリングし，さらにこれをポリエチレン製袋で二重にシーリングした。この試料を日本原子力研究開発機構の研究用原子炉
JRR-3 を用いて，気送管PN-1（熱中性子束密度：5.2×1017 m-2･s-1）で５分間照射し，試料を放射化した。核種の測定には東京大学・大学開放研究室のGe
半導体検出器ASC-20 を用いた。また，定量計算に
は検量線法，ならびに解析ソフトKAYZERO /SOLCOI（オランダ，DMS Research製）によるk0法を用いた(Simonits et al., 1975)。

－ 399 －

JAEA-Review 2008-067

またこれとは別に，ICP発光分光光度法等を用いて底質試料の湿式分析を以下の手順で行った。固体
試料 200 mg をテフロン容器に量りとり，濃硝酸 6cm3，フッ化水素酸 3 cm3を加え，マイクロ波分解装
置で 25 分間の分解を 3 回繰り返した。次に得られた溶液をホットプレート（約 250 ºC）で蒸発乾固した。冷却後，1N 硝酸 5 cm3 を加え 30 分放置し，残留物を溶解させた。その後，0.45μm メンブラン
フィルターで吸引ろ過を行い，純水で定容（50cm3 ）し，ICP発光分光光度法および原子吸光光度法にて測定した。

２．結果

２．１ 河川溶存成分：主要成分・重金属
過去４回にわたって同地点で水採取，ならびに分析を実施したが，EC の同一地点における時間変動
は，地理的な変動に比べて小さく，ほとんどの地点
において変動係数（標準偏差/平均値×100% ）は15％以内であった。これに対して空間変動について
は，同一調査期間内における各水試料の EC の変動
係数はいずれの回も 54 - 69％となり，地理的条件による水質変動が時間変動をはるかに上回ることが判明した。時間変化による水質変動が小さなことが確認できたため，以下溶存成分については各化学成分のデータが揃った 2002 年 4 月の観測値について議論を進める。
調査地域の河川成分を代表する項目として，電気伝導度（EC），pHならびに主要溶存成分の濃度を表１に示した。また，重金属類の分析結果を表２に示した。旧東山鉱山からの流出水である赤水谷川（H3）には，高濃度のアルカリ土類金属（Ca2+・Mg2+），

硫酸イオン（SO42- ），および重金属類（Cu・Fe・
Mn・Zn）が溶存している。しかし，同河川における他の元素（Na+・K+・Cl-）については，東山谷川・
川田川の各採水地点から得られた試料と同程度の濃度を示し，人為的な影響の指標となるNO3-に関して
は東山谷川・川田川の各地点に比べ小さな値となっている。また，pHが低いためにHCO3-の濃度も低くなっている。これらの分析結果から，赤水谷川の水質は，典型的な含銅硫化鉄鉱鉱床からの流出水で形成されていることが示される。なお，環境基本法に基づく水質汚濁に係る環境基準として指定されている重金属項目（Cd・Pb・As・Hg）について赤水谷
川試料の分析をしたところ（ICP: Hgは還元気化･冷原子吸光法），Cd・Asは環境基準値とほぼ同値の0.01 ± 0.001 mg/dm3となったが，Hgは 0.7 ± 0.1
ng/dm3（基準値：500 ng/dm3），Pbは検出限界以下(0.01 mg/dm3)であった。また，Cd・As・Pbについては，他の試料水についても分析を試みたが，いずれも検出限界以下であった。
２．２ 河川底質の重金属
ICP，AA，INAA による河川底質の分析結果を表２に示す。分析対象となった 11 元素(Cu, Zn, Cd,
Md, Pb, As, Fe, Ni, Cr, Co, Mo)のうち，この地域のバックグラウンドとなる川田川の含有量に比べ，赤水谷川ならびにその下流域において顕著に高い値を示した元素のみを示してある。その結果，赤水谷川
において顕著に高い値（バックグラウンドの平均値＋変動値の２σ 以上）を示したのは，Cu・Fe・Mn・Zn であった。コバルトはわが国の地殻推定含有量（Co: 15 mg/kg）に比してやや高い値（Co: 22
mg/kg）を示したが（Togashi et al., 2000），当地域

表１ 河川水の溶存主要成分 (n=2)
溶存主要成分
EC(mS/m)

K-7
K-8
K-9
K-10
K-11
K-12
H-1
H-2
H-3
H-4
H-5
H-6
H-7
H-8
H-9
H-10

13.70
14.87
17.83
15.09
14.96
15.98
12.02
13.89
51.4
18.8
12.25
15.39
10.77
16.82
17.07
16.30

pH

8.22
8.46
8.32
8.58
8.89
8.95
7.83
8.12
4.90
6.83
7.37
7.83
7.87
7.80
8.25
8.57

Na+
K+
Mg2+
Ca2+
ClNO3SO42HCO3Si（mg/dm3） （mg/dm3） （mg/dm3） （mg/dm3） （mg/dm3） （mg/dm3） （mg/dm3） （mg/dm3） （mg/dm3）

3.84
4.22
4.99
4.48
4.55
4.62
3.99
4.65
4.88
4.58
4.45
4.66
4.28
4.71
4.70
4.78

0.82
0.93
1.69
1.16
1.04
0.98
0.50
0.98
1.08
0.89
0.71
0.82
0.53
0.88
0.87
0.93

2.64
2.84
3.14
2.92
2.94
3.58
1.71
2.58
20.0
5.54
3.65
3.50
2.23
4.31
4.20
4.26

17.4
18.7
21.1
19.2
19.1
19.3
15.4
17.1
47.0
21.1
13.1
19.4
12.2
18.6
18.7
18.7

－ 400 －

3.89
4.16
6.59
4.81
4.83
4.95
3.70
4.93
2.88
4.57
5.52
3.56
3.44
4.78
4.74
5.07

3.42
3.62
11.8
5.45
4.89
4.36
2.50
4.37
0.20
2.43
2.39
4.53
1.93
3.15
3.02
3.46

11.3
13.6
16.3
14.2
14.3
16.6
8.85
11.3
224
41.9
6.98
6.84
8.67
22.6
21.2
20.3

44.7
48.1
44.9
46.4
47.6
46.2
29.5
32.9
1.0
31.7
33.2
42.2
27.6
43.4
44.7
47.6

4.06
4.06
4.06
3.73
3.69
3.81
5.02
3.85
17.0
5.40
4.98
4.19
4.52
4.69
4.56
4.60

JAEA-Review 2008-067

河川水の溶存重金属類ならびに底質中の重金属類 (n=3)
河川水
Cu
Fe
Mn
Zn
Cu
(mg/dm3) (mg/dm3) (mg/dm3) (mg/dm3)(mg/kg)K-7
0.00530.017 <0.0006
0.002939.5
K-80.00520.015 <0.0006
0.001834.1
K-90.00750.252
0.01240.003430.9
K-100.00120.094
0.00370.001124.6
K-11
0.00580.026 <0.0006
0.002233.5
K-120.00920.041
0.00630.009581.1
H-1
0.00660.078 <0.0006
0.005530.4
H-2
0.00630.035 <0.0006
0.0025
32.7
H-3
2.64
0.187
1.16
3.77
196
H-4
0.10390.015
0.0667
0.118
595
H-5
0.01150.089
0.0022
0.006
21.9
H-6
0.00820.144
0.00220.003442.8
H-7
0.00590.024 <0.0006
0.001126.2
H-8
0.02080.020
0.01730.0419105
H-90.02270.023
0.01270.031282.8
H-10
0.0142
0.026
0.011
0.018
99.9

表２

の各地点から採取された試料の平均からの変動幅１σ 以内の値となった。

３．考察

３．１ 溶存成分の挙動
旧東山鉱山から流出する重金属類のうち，当該地域のバックグラウンドに比べ，顕著に高濃度を示した
ものは Cu・Fe・Mn・Zn であった。これらの成分の一般河川（東山谷川）への流出後の挙動を明らかにするために，溶存化学成分の河川水による希釈効
果と凝集沈殿について定量的に考察した。合流前後の河川流量と化学成分との関係を以下に示す。鉱山からの流出水が東山谷川と合流し，単純希釈される
場合，各成分濃度と流量とは以下の関係式で表現できる。

{Cus ( Fds − Ftr )+ Ctr Ftr }/ Fds = C *

ds

(1)

ただし，C :溶存成分濃度，F :流量，us :東山谷川
上流（坑廃水流入前），tr :赤水谷川（坑廃水），ds :東山谷川下流（坑廃水流入後）である。
下流域における，ある化学成分の濃度(C)が上流域での主流と支流との単純混合だけで決定づけられる

河川底質
Fe
Mn
(g/kg)(mg/kg)
38.3
504
22.7
566
20.5
418
20.5
470
32.4
893
29.0
649
12.1
423
24.5
350
40.0
503
22.3
465
17.5
304
32.7
432
16.4
170
25.1
650
30.3
578
48.0
1074

Zn
(mg/kg)
81.3
71.4
62.8
57.9
76.3
186
59.6
70.0
206
808
60.0
78.1
60.3
232
203
251

場合，上記濃度計算値(C*)と実測値(C)との比率(C/C*)は１となる。これに対して，主流と支流の合流により，沈殿作用のような溶存化学成分の水相からの除去反応が発生した場合は(C/C*)<１となる。
この式に従い，坑廃水の流路である赤水谷川(H3)が東山谷川(H2)へ流入する地点から約 700 m 下流の H4 地点での各化学成分の濃度を算出し，化学成分ごとの計算値と実測値との比率(C/C*)を図２に示した。その結果，主要成分については理論値と実測値とがほぼ一致し，同地点での溶液組成は坑廃水と東山谷川との単純混合で説明できた。しかし重金属類については，実測値が理論値の 20 - 40％程度と小さな値を示し，重金属の水相からの除去が示された。
また，河川底質については，Cu・Zn の実測値が 7 10 倍程度と顕著に高い値を示した。このような現象については以前の熱力学的な研究により，東山谷川との合流に伴う pH 上昇が，これら重金属類の中和沈 殿を誘発するためと説明されている（Anazawa
et.al., 2004）。今回の調査結果もそれを裏付けるものとなった。なお，Fe・Mn については，周辺岩盤の主要成分であるため，中和沈殿による濃度上昇が明瞭には検出されなかったものと考えられる。
３．２ 対策－ 401 －

Cds(measured) / C*ds(calculated)

JAEA-Review 2008-067

1.5Conservative mixing line
1

Heavy metals
0.5

Major elements0

図２

EC Na K Mg Ca Cl NO3 SO4 HCO3 Si
Dissolved chemicals

Cu Fe Mn Zn

H4 地点における溶存化学成分の濃度計算値(C*)と実測値(C)との比率(C/C*)。上流域のH2 と H3 との単純な混合で濃度が決定される場合は C/C* = 1 となり，沈殿反応が発生する場合は C/C* < 1 となる。

重金属廃液の処理法には，主に凝集沈殿法や吸着除去法などが採用され，各々特色を生かした処理が行われている(石油天然ガス・金属鉱物資源機構，
2006a など)。新たな施設の設置による周辺環境への悪影響や保守に関わるコストを考慮すると，処理費用の負担責任者が不在のまま含重金属廃水が大量に流れ続ける当調査地において，これら産業廃液処理用の施設を設置するのは，環境保全の観点からも経済的にも適切な方法とはいえない。重金属類を完全に除去する努力をするよりも，重金属による環境負荷を軽減するための，安価で周辺の自然環境に即した重金属除去法を用いることが肝要である。そのためには，上記天然河川での重金属類の中和沈殿反応に習い，流出口における坑廃水の pH を高めて重金属を沈殿・除去する方法が有効であろう。具体的には石灰石等の投入と，その結果生じた沈殿物の除去を繰り返すことが挙げられる。
本調査地域と同様に強酸性の坑廃水が流出し，中和処理を継続的に行っている例としては，岩手県旧
松尾鉱山，鳥取県旧岩美鉱山などが知られている。
このうち旧松尾鉱山跡からは，pH2.3 の強酸性の坑廃水が毎分 18 m3の割合で流出しており，日量 20
tonの炭酸カルシウムを使った中和処理が行われている（石油天然ガス・金属鉱物資源機構，2006b）。
本調査地域では上記例に比べると坑廃水の流出量は1.6 m3/min（27 dm3/s）と小さく，酸性度もそれほど強くない(pH 4.7)。したがって対策としては，流出水の完全な中和を図るのではなく，重金属の凝集沈殿を促進するための小規模な中和沈殿槽を設置することが考えられる。
そこで，石灰石などの炭酸カルシウム(CaCO3)を坑廃水に投入し，重金属類を中和凝集沈殿させた場
合のCaCO3の必要量，重金属の除去効率，および発生する沈殿物の量を試算した。まず，坑廃水の流量（A地点における流量）と各重金属濃度の積を求め，各重金属の流出量を算出した。次に，主要イオン濃度およびイオン強度を考慮した上で，坑廃水（赤水谷川：A）が中和された場合の理論溶液の成分組成
を溶解度積から算出した。このとき，中和反応による凝集沈殿物として，Cu4(OH)6SO4，Fe2O3，MnO2，
ZnSiO3を想定した。また，反応効率については，赤水谷川と東山谷川との合流付近（H２）と同程度の割合でpH上昇が進むものとして，CaCO3の溶解度
積の 1/10 量のCa2+が溶出すると仮定した。重金属の除去効率を求めるための理論凝集量は，溶液中の溶存態重金属の濃度と流量の積を坑廃水の重金属流出量から差し引いて算出した。計算に使用した熱力学
データは，米国地質調査所（USGS）が提供する
Wateq.datを用いた(Parkhurst and Appelo, 1999)。
その結果，各重金属の除去率は，銅 77％，鉄 100％，
マンガン 100％，亜鉛 99％となった（表３）。また，
凝集沈殿物の年間発生量は，Cu4(OH)6SO4が 3.1 ton，
Fe2O3が 0.23 ton，MnO2 が 1.57 ton， ZnSiO3 が6.88 tonとなり，10 m3程度の沈殿槽を設置した場合，理論的には１～２回／年程度のスラッジ処理で済む試算となった。この処理によって新たに発生する環境負荷としては，石灰石からのCa2+の溶出が挙げられるが，その理論溶出量は 32.4 ton/yrであり，調査－ 402 －

JAEA-Review 2008-067
表３ 中和処理による坑廃水の組成変化と重金属の除去効率（理論値）1)
Solution
Precipitation
Chemical
Pre-treated water Treated water
Removal(t/yr)
Formula(mg/dm3)(mg/dm3)
efficiency (%)
Ca
Cu
Fe
Mn
Zn

52.97
2.64
0.19
1.16
3.77

91.02
0.59
0.00
0.00
0.04

－
77
100
100
99

CaCO3
Cu4(OH)6SO4
Fe2O3
MnO2
ZnSiO3－81.0 2)
3.10
0.23
1.57
6.88

1) [Ca2+][CO32-] = 0.1 Ksp (calcite)として算出
2) 溶出のため負値となっている。

時における下流域（H3）のCa2+流量（369 ton/yr）の 10％以下となった。これはH3 地点におけるCa2+の時間変動（CV 15.5％）の範囲内であり，環境に対する悪影響はほとんどないものと考えられる。

おわりに本研究では，廃鉱山からの流出水中の重金属類の挙動を，溶存態成分と底質中成分の両面から考察した。その結果，天然河川で中和凝集沈殿作用により水相から除去される過程を熱力学的・量論的に説明することができた。またこの原理による簡易中和沈殿槽を設置した場合の重金属類の除去率や環境負荷を試算した。

activation analysis, J. Radioanal. Chem., 24
31-46.
Togashi, S., N. Imai, Y. Okuyama-Kusunose, T.
Tanaka, T. Okai, , T. Koma, and Y. Murata(2000) Young upper crustal chemicalcomposition of the orogenic Japan Arc.
Geochemistry Geophysics Geosystems(Electronic Journal of the Earth Sciences),
Vol.1, November 27, Page number
2000GC00083.

成果報告
穴澤活郎・篠村善徳・冨安卓滋 (2007) ほたるの里
徳島県吉野川市美郷地区における坑廃水の重金属挙動と対策試案，環境情報科学論文集 21,601-606.

引用文献
Anazawa, K., Y. Kaida, Y. Shinomura, T.
Tomiyasu and H. Sakamoto（2004）
Heavy-Metal Distribution in River Waters andSediments around a “Firefly Village”,Shikoku,
Japan :Application of Multivariate Analysis．
Analytical Sciences, No.20,79～84.
放射化分析研究会（2004）放射化分析ハンドブック-確度の高い多元素同時微量分析への実践-（伊藤泰男・海老原充・松尾基之編），pp.138，日本ア
イソトープ協会，東京
Parkhurst, D.L., C.A.J, Appelo (1999) User’s
guide to PHREEQC (version 2) – A computer
program for speciation, batch-reaction,
one-dimensional transport, and inverse
modeling. U.S. Geol. Surv., Water-Resour.
Investig. Rep. 99–4259.
石油天然ガス・金属鉱物資源機構 (2006a) 坑廃水処
理の原理，石油天然ガス・金属鉱物資源機構，神奈川.
石油天然ガス・金属鉱物資源機構 (2006b) 松尾鉱山
坑廃水処理における省エネルギー技術開発の成果，金属資源レポート 2006.1，732-737.
Simonits, F., De Corte, J. Hoste (1975)
Single-comparator methods in reactor neutron.

－ 403 －

JAEA-Review 2008-067

4-10�植物・土壌試料の元素分析�
Elemental analysis of plants and soils
東京大学大学院農学生命科学研究科
中西 友子
研究の�的と��当研究室では、植物および土壌試料中の元素濃度を非破壊状態で調べるために、放射化分析を採用してきた。具体的には、食の安全性が重要視されるな
か、元素濃度から産地の判別をしようという試みがあり、農産物中の元素を非破壊でマルチに測定するために、放射化分析を用いた。現在も本研究は遂行中であるが、今までに得られた結果について報告したい。
近年、農作物の原産地について消費者の関心は高まるにつれ、信頼ある情報を提供することが求められている。これまでに、GMO 混入については日本で開発された DNA マーカー等を利用した技術が、国際基準になってきている。しかし同じ品種の作物については DNA が等しいため遺伝子を用いる判別法では原産地を特定することはできない。そこで、農作物の産地特定のためには、様々な情報を得て複合的に解析するシステムが求められる。複数の元素パターンや同位対比などを駆使し、統計処理をする
ことで産地を特定する技術の開発では、一部の農産物については判別が可能になってきている。この元
素パターンによる判別システムでは、通常 ICP-AES
もしくは ICP-MS が利用されるが、定量対象とする元素の範囲を拡大できれば、産地特定の精度の向上が期待できる。本研究では、次の利点を持つ放射化分析法を導入する；1)ICP-MS 等の前処理である溶液化が必要ないことから、極微量元素の混入が最小限に抑えられる。2)高感度に定量できる元素が多くある。3)多元素同時分析を行うことができる。これらの利点を最大限活かし、これまで測定できなかった
農作物や食品中の超微量元素の検出を試み、そのデータから高精度な産地特定法の開発を試みる。分析
対象としては、産地の明確な試料として農水省の消費技術センターが他の課題で入手するタマネギを利用する。これまでに食品総合研究所で蓄積されてきた知見に本研究の成果を融合させていくことにより、高精度な産地特定システムの構築が期待できる。
その研究をどのように行ったか

消費技術センターより産地が明確なタマネギサン
プルの提供を受けた。タマネギの前処理方法としては、以下の通りである。
1. オレンジ色または茶色をした外側の皮と上端、及び基部から上 1cm までを除去した白または緑色をした部位を採取した。
（外皮をとり、純水で洗浄後、上端と基部から上１cm までを除去した）。
2. 個数は 10 個で 1 サンプルとした。
3. 10 玉全てを均質化することができない場合は，10 玉を対象に 4 等分，あるいは 6 等分，8 等分など，縦方向に切り分け，対角線部分を採取して試料とした。
4. 分析対象とする元素のコンタミをできる限り少なくするため粉砕機にはチタンコート刃のフー
ドプロセッサーなどを用いた。ステンレスなどの金属部分はできるだけ試料に触れないように粉砕機を使用した。
5. 水分測定は下記の統一した方法により測定した。
1） ルミ箔カップの秤量容器の重さを測る。
2） 粉砕・均質化試料を 5～6g 秤量容器に取り，重さを測った。
3） 70℃で 24 時間常圧乾燥した。
4） デシケーター中で放冷後，重さを測り，水分を求めた。
5） 測定は 3 点併行で行った。
以上の方法で前処理したタマネギは、60℃で常圧乾燥を 1 週間行い、粉末状に粉砕した後、高純度ポリ
エチレン袋に 2 重に封入して放射化分析に供した
どのような結果を得たか
北海道産タマネギを 14 種類、佐賀産タマネギを 20
種類について、放射化分析で測定を行った。一方で並行して同サンプルを PGA 測定も行った。産地の詳細な場所と品種については、Figure 1 に記した。
PN-3 による短半減期を対象とした放射化分析については、24Na, 27Mg, 28Al, 38Cl, 42K, 49Ca and 56Mnの核種が検出ができた。一方、PGAではB, S, Cl, Kの元素

JRR-3 PN-3,PN-2 放射化分析－ 404 －

農作物の元素分析

JAEA-Review 2008-067が検出ができた。

a) INAAb) K 0 -PGA

Hokkaido

Figure 1 onion producing
distincts in Japan andcultivars.
Two cultivars described as A and B
were grown in Hokkaido and 7
cultivars described as C, D, E, F, G,
H and I were grown in Saga.

得られた結果について、主成分解析を行いグルー
ピングのモデリングを行ったところ、Figure 2 に示されるように、北海道産と佐賀産の区別がつくことが判明した。既に、ICP-AES や ICP-MS による元素分析データからこの 2 つについては区分されることが示されていたが、放射化分析もしくは PGA で得られるデータのみでも、産地の判別を行うことが可能であることが判明した。さらに、放射化分析と PGAのデータをあわせると、より明確に区別ができることも示された(Figure 3)。図では黄色字が北海道産、
赤字が佐賀産のタマネギを示す。
さらによいモデリングを探るために、モデルへの寄与の少ないデータについては、削除し、残りの主

S-29

H-14 H-3
H-13
H-7
H-5H-8H-1
S-24

H-12

H- 6 S-21

Factor1

S-11
S-34 S-32
S-33

S-26

S-7

S-12 Factor3
S-10
S-25
S-28
S-27
S-6

S-8

H-3

S-28

S-31

H-10 H-2
H-9

H-11

S-30
S-21
S-23
S-6 S-34 H-10
S-31
Factor1
S-10
S-8
S-25 S-7
H-1
S-11
S-27
S-12
S-26
H-5
H-6 H-9
H-7
H-14
H-8
S-24
H-2
Factor3
Fa
ctor3
S-29
H-12
H-13
H-11 H-4

S-30
S-23
S-9

Figure 2: PCA by with data set of
INAA (a) or k 0-PGA (b).

H-10

H-7
H-6
H-9 H-8
H-13
S-34
S-21 Factor1
H-5
S-29
H-14
Factor3 H-3
H-1
H-12
S-6
S-9
S-8

INAA

H-11

K0-PGA

S-32
S-31
S-30

H-2

H-4

Modeling Power

S-33

Factor2

S-24

S-10
S-26
S-12
S-11
S-23
S-25
S-28

S-7

S-27

a) INAA & K 0 -PGA

H-4
H- 11

H-12
H-14
H-5

H-1

S-33

S-30
Factor1

S-32
S-29
S-34
S-21

S-11
S-12
S-28
S-24
S-26 S-10S-6
S-8
S-25

S-7

S-27
S-23

b) INAA & K 0 -PGA
(Al and Mn omitted)

S-9

0.350
0.503
0.764
0.415
0.512
0.094
0.594
0.377
0.294
0.210

Modeling Power

S-31

Factor2
H-2
H-7
H-10H-6
H-8
Factor3
H-9
H-13H-3

B/K
S/K
Cl/K
24
Na
27
Mg
28
Al
28
Cl
42
K
49
Ca
56
Mn

K0-PGA

cultivarA:
KAIRYO-OKHOTSK No.1
B:
SUPER KITAMOMIJIC:SIPPO-W ASE No.7
D:
TAZAN
E:
MOMIJI No.3
F:
SIPPO-KAN70
G:SATSUKIH:
NEOEARTHI:
ANSW ER

H-4

S-32

S-9

INAA

Saga

Saga
No. cultivar
S-1
C
S-2
C
S-3
C
S-4
C
S-5
C
S-6
D
S-7
D
S-8
E
S-9
E
S-10
F
S-11
G
S-12
H
S-13
I
S-14 D or G
S-15
E
S-16
E
S-17
E
S-18
E
S-19
E
S-20
E

Factor2

S-33

Factor2

Hokkaido
No. cultivar
H-1
A
H-2
A
H-3
A
H-4
A
H-5
A
H-6
A
H-7
A
H-8
B
H-9
A
H-10
A
H-11
A
H-12
B
H-13
B
H-14
A

B/K
S/K
Cl/K
24
Na
27
Mg
28
Cl
42
K
49
Ca

0.418
0.421
0.776
0.506
0.544
0.606
0.356
0.435

Figure 3: PCA bywith data set of
INAA and k 0-PGA(a) or Al and Mnomitted data (b).

成分解析を行うことにした。つまり、得られた Alや Mn のデータを除いてグルーピングを行った結果
が、Figure 3B であり、より明確な判別が可能である
ことが示された。
これらのデータ解析から判明したことの一つに、モデリングパワーから読み取れる、産地判別に寄与の大きい元素として、塩素があることである。モデ
リングパワーとは、そのモデルに対する寄与度を、最大値を 1 として算出した数値である。今回注目される塩素は酸分解を必要とする分析方法では揮発したり、試料を可溶化させる際に加える酸に含まれていたりなど、検出することが困難な元素である。しかし、非破壊分析である放射化分析を用いることにより、塩素の測定は容易に行うことができ、かつ今まで知られていなかった塩素の産地判別への寄与が－ 405 －

JAEA-Review 2008-067

大きいことが判明した。
このように、放射化分析は非破壊分析が可能でありその点が大きな利点である。そして放射化分析法
を産地判別の手段として用いて元素定量分析を行う
ことは、これまでは見過ごされてきた元素が判別に重要な役割を演じていることを明らかにできる可能性が示された。塩素は農産物に広く存在する元素であることから他の農産物に対しても広く応用できるのではないかと思っている。
今回用いたタマネギについて、さらに、佐賀産、
北海道産、それぞれの地域におけるいろいろな品種を入手して実験を行った（Figure 1）。その結果、タマネギの品種が多岐に渡っているのにもかかわらず、
北海道産と佐賀産を区別することができたということの意義は大きい。つまり元素による産地判別方法
は、品種間差を考慮しなくても可能であることが示されているからである。言い換えれば農作物中に含まれる元素の濃度のパターンは生育する土壌に含まれる元素濃度を大きく反映しているからである。

尚 、 本 成 果 に つ い て は 、 現 在 、 Journal ofRadioanalytical and Nuclear Chemistry に投稿し、審査を受けているところである。

継続する��は、今後の方�
本課題は H19 年以降も継続する予定である。今度は、農作物の中でも偽装の多いものや、野菜以外の農産物への本手法の適用を目指して実験を行っていく予定である。また今回は時間の関係で行えなかったが、長期の放射化を行うことで、長い半減期を持
つ核種、微量重金属元素にも着目した産地判別の可能性の検討についても今後の課題としたい。
成果の�表
本成果については、H19 年 8 月に行われた「The 12th
International Conference on Modern Trends in
Activation Analysis (MTAA12)」において、ポスター発表を行った。
ポスターナンバー：P019
題 目 ： Studies of Elements in Onions, Specific to
Producing Districts through Instrumental Neutron
Activation Analysis and Prompt Gamma-Ray Analysis
演者：K. Tanoi1, H. Matsue2, H. Iikura2, T. Saito1, Y.
Hayashi1, Y. Hamada1, H. Nishiyama1, N. I. Kobayashi1,
T. M. Nakanishi1
1 Graduate School of Agricultural and Life Sciences, The
University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo
113-8657, Japan
2 Japan Atomic Energy Agency, Tokai-mura, Naka-gun,Ibaraki-ken 319-1195, Japan－ 406 －

JAEA-Review 2008-067

4-11
大気試料の�成分およ�海�試料の放射化分析
Activation analysis of ma�or element in overland and marine aerosols

永井尚生

齊藤 敬 山形武靖 吉田忠英(日本大学文理学部)

H. Nagai T. Saito T. Yamagata T.Yoshida
College of Humanities and Sciences, Nihon University
1. はじめに本 研 究 は 宇 宙 線 生 成 核 種 7Be (T1/2=53.3 d),
10
Be(T1/2=1.5×106 y), 36Cl (T1/2=3.0×105 y) の大気中における移動についての情報を得るために,中性子放射化分析(NAA)を用いて土壌起源の指標となるAl, 海塩の指標となるNa, Clの測定を行うことを目的としている。
1) 再浮遊10Beの見積もり
宇宙線生成核種7Be, 10Beは高層大気において宇宙線と窒素、酸素の相互作用によって生成する。生成後はエアロゾルに吸着し移動するため, 高層大気のエアロゾルのトレーサーとして用いることが出来ると考えられる。また7Be, 10Beは同位体であるため大気中での挙動は同じであり、10Be/7Be同位体比は滞留時間のみによって変化するため、エアロゾルの滞留時間の指標として用いることが出来る。エアロゾルの平均滞留時間が大気の混合に対し短いために大気中の7Be, 10Be濃度は時間的, 空間的に不均一な分布を示す。そのため、緯度分布等の空間的な変化を観測することに加え、定点観測により季節変動を観測することが必要となる。しかし陸上において観測を行うと、10Beは土壌における滞留時間に対し非常に長い半減期を持つために、一度地表に降下した後、再浮遊する成分によって大気中の10Be濃度が過大評
価されている可能性が指摘されている。そこで本研
究では再浮遊による影響を土壌粒子の指標であるAlの濃度から定量的に見積もることを試みた。
2) エアロゾル状36Clの測定法の開発
宇宙線生成核種36Clは高層大気において宇宙線とアルゴンとの相互作用によって生成する。大気中ではClの安定同位体と混合し、大気中にNaClなどのエ
アロゾル状、HCl、Cl2などの無機ガス状、CH3Cl、CFCsなどの有機ガス状で存在していると考えられているが、36Clの大気中の挙動についてはっきりとしたことはまだわかっていない。本研究では36Clを高層大
気からのClのトレーサーとして用いる可能性を探る

ために、2006 年 4 月から雨水、エアロゾルの回収し、Clの測定を行ってきた。エアロゾル状36Clの測定は水抽出を行い水溶性エアロゾルの36Clを測定する方法を用いたが、エアロゾル状全Cl量を把握することは非常に重要なことである。そこで全Cl量を中性子放射化分析で水溶性Clをイオンクロマトグラフィー(IC)で測定し、水溶性エアロゾルの割合を調べることを行った。

36

2. 実験
1)試料
東京都世田谷区の日本大学文理学部 5 号館屋上においてハイボリュームエアサンプラー(紀本電子製
AS-1400)を用いてペーパーフィルター(whatman No.
41)にエアロゾルを回収し試料とした。回収期間は約
1-2 週間、積算流量は 4500-10000m3であった。回収
した試料は八ツ折りにし、非破壊ガンマ線スペクト
ロメトリーによって7Be(E γ =477.6 keV)の定量を行った。その後、ろ紙の 1/2 を36Cl測定用、1/4 を10Be測定用、2×2 cmを中性子放射化分析用とした。36Cl
測定用試料は細かくちぎり、50mLのイオン交換水で15 分間超音波洗浄を 3 回行った。試料はそれぞれイ
オンクロマトグラフィーを用いてCl- の定量を行った。その後HNO3とAgNO3を添加し、AgClとして東京大学MALTのAMSシステムにおいて36Cl/Clの分析を行った。大気中のエアロゾル状36Cl濃度はAMSによって求められた36Cl/Clと安定同位体Clから求めた。10Be測定用試料はBe担体 1mgを加え、硝酸を用いて湿式灰化を行い、分解溶液の一部について誘導結合プラズ
マ発光分光分析法(ICP-AES)によって組成分析を行った。その後陽イオン交換でBeの単離を行い東京大学MALTにおいて10Be/Beの分析を行った。大気中10Be
濃度は10Be/Beと加えた担体量から求めた。
2)中性子放射化分析
2×2 cmに切断したろ紙をHNO3、エタノール、イオ
ン交換水を用いて洗浄したポリ袋に 2 重封入し、ろJRR-4 気送管、地球化学試料放射化分析－ 407 －

JAEA-Review 2008-067

紙の大きさを測定した。2×2 cmに切断した場合、試料が不均一であると、定量結果に大きな誤差を含むことになる。そのため試料の均一性の確認のため 1
つの試料について試料採取面を 4×5 ブロックの片に分割し、同様の測定を行った。また 2×2cmに切断したろ紙(ADVANTEC No. 5C)に標準溶液を滴下し、Al
標準試料(Al 70μg), NaCl標準試料(Na 110μg、Cl170μg)を作成した。作成した試料は 10 グループに分割しAuフラックスモニター(Au 17μg)とともにカプセルに封入しJRR-4 気送管において 100 kW、1 分間の照射を行った。照射した試料は直ちに取り出し、2 台のGe半導体検出器を用いた非破壊ガンマ線スペ
ク ト ロ メ ト リ ー を 50 秒 間 の 測 定 を 行 い
28
Al(1779keV)の定量を行った後、300 秒間の測定を行い24Na(1369 keV)、38Cl(1643 keV)の定量を行った。
3. 結果と考察
1)気送管中性子フラックスの安定性
Au フラックスモニターの測定結果から算出した
気送管中性子フラックスの安定性を表 1 に示す。照射は 2006 年 12 月 25 日 12 時 17 分から開始した。合計 10 回の照射を行ったが、気送管中性子フラックス
は実験中において標準偏差 1σで 2%と安定していた。
2)試料の均一性
試料の均一性を示した図を図 1 に示す。x軸、y軸はそれぞれろ紙の中心からの距離、z軸はろ紙のブ
ランクを差し引いた 1 cm2あたりの元素量を表す。
表 1 JRR-4気送管における中性子フラックスの変動
照射番号
照射開始
相対中性子フラックス
1
2002/12/24 12:17
0.997 ± 0.023
2
2002/12/24 12:41
0.981 ± 0.023
3
2002/12/24 13:04
1.006 ± 0.023
4
2002/12/24 13:24
1.036 ± 0.024
5
6
7
8
9

2002/12/24 13:47
2002/12/24 14:05
2002/12/24 14:28
2002/12/24 14:52
2002/12/24 15:15

1.015 ±
0.977 ±
0.976 ±
1.008 ±
0.985 ±

10

2002/12/24 15:40
平均

1.019 ± 0.024
1.000 ± 0.020

表 2
Al濃度/μg m-3

0.023
0.023
0.023
0.024
0.023

中心部のAlを除き、ほぼ一様であることが確認された。Na/Cl比は全試料において一定であったが、Al/Cl
比、Al/Na比は中心部が高くなっていた。中心部のAlについては、7Beのガンマ線スペクトロメトリーを行
うため、ろ紙を折り畳んだ際に中心部に粗大な土壌
粒子が集まっていることが目視により確認されていることから、中心部に集まった粗大土壌粒子を観測してしまい、Al量が多くなったと考えられる。このことから折り畳んだ試料の中心部を用いて測定することは避けるべきであることが確認された。
3)土壌粒子の影響
2006 年 4 月から 12 月までの中性子放射化分析から求めた大気中Al濃度と10Be分析用に酸抽出した試料から求めたAl濃度、36Cl測定用にイオン交換水で超音波洗浄した水溶性エアロゾルの大気中Al濃度の季節変動を図 2 に示す。東京におけるAl濃度は 4、6
月に 4μg m-3と高い値を示した他は 1-2μg m-3 程度であった。4 月の後半に黄砂が観測されたことを除くと大規模なダストイベントは無く、東京におけるAl濃度はグローバルな供給より近隣土壌からのローカルな供給の影響を強く受けていると考えることが出来る。中性子放射化分析により求めたAlが全量だとすると、酸抽出によって 43.4-58.5%、水溶性エア
ロゾル中には 0.9-14.6%のAlが存在することがわかった。
土壌中の10Beは土壌表面に吸着して存在しているため、比較的容易に酸で抽出されることが確認されている。しかしAlは緑泥石などの酸に可溶なAlとア
ルミノケイ酸塩などの酸に不溶なAlが存在する。
ICP-AESを用いた測定はNAAより簡便であるが、土壌全量推定のためには全Al量が必要であるため、NAAで求めたAl量を用いることが適当であると考えられる。以下の式から土壌からの 10Be量を見積もり、
10
Be/7Beを求めた結果を表 2 に示す。
C10 = (CAl/SAl)×S10
式中のC10は補正した大気中10Be濃度、CAlは大気中全Al濃度、SAlは土壌中Al濃度(8.93%)、S10は土壌中の10
Be濃度を表す。土壌中10Be濃度は採取値付近で採取した土壌中 10Be濃度と中国レスの 10Be濃度の結果から 5×108 atoms g-1とした。この式から求められた
大気中 10Be濃度に対する再浮遊した 10Beの割合は

大気中Al濃度から再浮遊成分の補正を行った10Be濃度と10Be/7Be

06NH-01

3.95 ± 0.21

Be濃度/104 atoms m-3
補正12.21 ± 0.44
9.99 ± 0.46

( 18.1% )2.04 ± 0.10

補正1.67 ± 0.09

06NH-02
06NH-03

2.24 ± 0.13
0.88 ± 0.03

12.30 ± 0.48
7.64 ± 0.27

11.04 ± 0.49
7.15 ± 0.27

( 10.2% )( 6.5% )2.16 ± 0.11
1.83 ± 0.09

1.94 ± 0.11
1.71 ± 0.09

06NH-04

1.27 ± 0.04

11.85 ± 0.45

11.14 ± 0.45(

2.29 ± 0.10

2.15 ± 0.10

試料名

10

－ 408 －

10

Be/7Be( 再浮遊 )

6.0%)

JAEA-Review 2008-067

6-18%となった。
4)大気中のエアロゾル Cl 濃度
大気中全エアロゾル Na 濃度、水溶性エアロゾル
Na 濃度、また全エアロゾル、水溶性エアロゾル Cl
濃度を表 3 に示す。酸抽出した Na は水溶性 Na と非常に良く一致した。全エアロゾル中から抽出される
Na は 57.6-90.1%であった。抽出残渣中の Al/Na 比は
1.9-6.0 で関東土壌の Al/Na 比(9.7)より低く、花崗岩(2-3)や玄武岩(3-5)と同等であった。このことか
らも抽出残渣は酸不溶な鉱物であると考えられる。
全エアロゾル中、水溶性エアロゾル中のNaとClの関係を図 3 に示す。図中の実線は海水中のNa/Cl比を示す。水溶性エアロゾルについては海水中Na/Cl比と一致したが、全Na/Cl比は海水と同等かNaが過剰になっていた。このことは、水溶性エアロゾルは海塩の影響を非常に強く受けていることに対し、全エアロ
ゾルは水溶性エアロゾルに難溶性の土壌鉱物が付加されていると考えることが出来る。水溶性エアロゾ
ルに含まれる36ClのAMS測定を行ったところ、36Cl/Cl
は海水から作成したブランク試料に対し有意に高い値を示した。このことから、水溶性エアロゾルは海塩の影響を強く受けているものの、大気中に存在する間にClが交換している可能性が示唆された。
4. まとめ研究炉 JRR-4 の気送管を用いた中性子放射化分析
で大気エアロゾル中の Al、Na、Cl 濃度を測定した。
測定中の中性子フラックスは標準偏差が 2%と安定していた。フィルター上の元素分布の均一性を確認したところ、放射化分析の前段階においてろ紙を折り畳んだ際、粗大な土壌粒子が中心に集まった影響
により Al のみ中心に偏った分布を示したため、ろ紙の中心部を使った測定は避けるべきであることがわかった。
中性子放射化分析を用いて測定したAl濃度を用いて大気中10Be濃度の再浮遊成分の補正を行ったとこ
ろ、東京において大気中の10Be濃度は 6-18%過大評価されていると算出された。
大気中全エアロゾルNa/Cl比と水溶性エアロゾル
Na/Cl比を比較すると水溶性エアロゾルNa/Cl比は海

試料名

水中Na/Cl比と一致することに対し、全エアロゾル
Na/Cl比は海水よりNaが過剰に存在していた。また全エアロゾルから水溶性を差し引いた残渣中Al/Na比
が土壌成分より岩石成分に近かった。このことから
水溶性エアロゾルは海塩粒子の影響を強く受けている と 考え られ た 。し かし 、 水溶 性エ ア ロゾ ル中
36
Cl/Clは海水より有意に高く、大気に存在する間にClが交換している可能性が示唆された。
［成果の公表］1. 山形武靖、杉原真司、森長一朗、永井尚生, "東京と福岡における大気エアロゾル中の Be-7,
Be-10 濃度の同期観測", Proceedings of the Seventh
Workshop on Environmental Radioactivity, 125-128(2006)
2. 山 形 武 靖 , 齊 藤 敬 , 松 崎 浩 之 , 永 井 尚 生 ,"2002-2003 年における東京都心と八丈島における大気中の7Be, 10Be", Proceedings of the 8th Japanese
Symposium on Accelerator Mass Spectrometry, 17-20(2006)
3. 山形武靖,齋藤 敬,松崎浩之,永井尚生, "東京都
心 と 八 丈 島 に お け る 大 気 中 の 7Be,10Be 濃 度 と
10
Be/7Beの比較", Proceedings of the Sixth Workshop
on Environmental Radioactivity, 45-48 (2005)
4. T. Yamagata, W. Tada, T. Saito, M. Murayama, N.
Momoshima. H. Matsuzaki and H. Nagai,"Atmospheric Concentrations of 7Be, 10Be and 210Pb
in Northeast Asia", Asia-Pacific Symposium onRadiochemistry-05, Beijing, China (2005.10)
5. T. Yamagata, T. Saito, H. Nagai, H. Matsuzaki,"Seasonal variation for 7Be and 10Be concentrations in
the atmosphere at Tokyo and Hachijo-Island during
the period of 2002 to 2003", 10th International
Conference on Accelerator Mass Spectrometry,
Berkeley, California, U.S.A. (2005.9)

表 3 大気中Na濃度とCl濃度
Cl濃度 / μg m-3
Na濃度 / μg m
-3

ICP-AES ( 水溶性 )IC( 水溶性 )

06NH-01NAA
2.37 ± 0.14

1.527

( 64.3% )NAA
3.82 ± 0.12

2.615

( 68.5% )06NH-02
06NH-03

1.81 ± 0.11
1.27 ± 0.07

1.697
0.744

( 93.6% )( 58.6% )2.71 ± 0.09
2.64 ± 0.08

2.825
1.531

( 104% )( 57.9% )06NH-04

1.66 ± 0.10

0.960

( 57.8% )3.01 ± 0.10

1.767

( 58.8% )－ 409 －

JAEA-Review 2008-067b)

Na量 (μg)

Al量 (μg)

a)

中心
からの
距離

離
距
の
ら
か
心
中

(cm)

m)
(c
中心
からの
距離

離
距
の
ら
か
心
中

(cm)

m)
(c

c)
z

y

Cl量 (μg)x

図1 ろ紙上の各元素の分布. 左端がろ紙の中心となり,
x軸, y軸はそれぞれろ紙の中心からの距離, z軸はろ紙のブ
ランクを差し引いた1 cm2あたりのa) Al b) Na c) Cl量を表す.

(cm)

-3

Al concentration (μg m )54

6
Cl concentration (μg m-3)

中心
からの
距離

離
距
の
ら
か
心
中

m)
(c

NAA
acid leachingwater soluble

3
2

NAA
IC

5
4
3
2
1

1

0
0

1

2

3

4

5

6

7

8

9

10

11

12

0

1

2

3

4
-3

month

Na concentration (μg m )図 2 大気中Al濃度の季節変動

図 3 大気エアロゾル中のNa濃度とCl濃度の関係－ 410 －

JAEA-Review 2008-067

4-12

中性子放射化分析法による鉄隕石中の53Mnの定量
Determination of 53Mn in Iron Meteorites by Neutron Activation Analysis
首都大学東京 大学院理工学研究科 分子物質化学専攻
Department of Chemistry, Graduate School of Science and Engineering,Tokyo Metropolitan University
大浦泰嗣，橋詰二三雄
Yasuji Oura, Fumio Hashidume53

1. はじめにMnは，主として鉄の核破砕反応により生成する

隕石は宇宙空間を飛行している間に高エネルギー

宇宙線生成核種で，半減期 3.7×106年でEC壊変するな宇宙線の照射を受け，核反応，主に核破砕反応に核種である．EC壊変に伴うガンマ線を放出しないのよりさまざまな核種が生成する．この中で，半減期で，Crの特性X線(5.4 keV)を測定しなければならなが長い放射性核種(10Be, 26Al, 36Cl,53Mnなど)や希ガ

い．しかし，X線エネルギーが低く正確な定量は難し

ス安定核種を宇宙線生成核種として隕石中で検出すいし，測定に長時間を要する．そのため，実用的にることが可能である．これらの宇宙線生成核種を利は中性子放射化分析法にて定量が行われる．すなわ

用して，宇宙線照射年代や，地球に落下した年代を

ち，中性子照射により53Mnを半減期 312 日の54Mnに変得ることができる．また，複数の核種の濃度から，換することにより，放射能強度を桁違いに増すこと

その隕石の落下前の大きさや，宇宙線照射環境を推ができ，さらにガンマ線測定が可能となる．しかし，定することも可能である．

照射前と照射後に化学操作によりMnを濃縮ならびに

主な宇宙線生成放射性核種は，その半減期が数 10
万年〜数 100 万年と非常に長く，また，存在量がわ

精製しなければならず，その操作が煩雑なためか，
最近は53Mnに関する報告はほとんどない．

ずかなこともあり，その放射能は非常に小さく，放1836 年にナミビア共和国で発見された鉄隕石ギ

射線測定による定量は難しい．また，測定が容易な

ベオンは，総重量が 26,000 kg 以上あり，この隕石

ガンマ線を放出しない核種も多く，さらに放射線測は宇宙空間で大きかったと予想できる．この隕石中

定の困難さを増している．そのため，近年は，加速の宇宙線生成核種，10Be，26Al，36Clならびに3,4Heが器質量分析(AMS)法を用いた測定が主流である．日本

系統的に隕石表面から深部まで測定されているが，においても，10Be，14C，26Al，36Clの測定はAMS法に可53

能である．しかしながら，宇宙線生成放射性核種のと思われる試料が見つかったが，高感度である希ガ一つである53Mnは，我が国ではAMS法による測定は不ス同位体測定も限界に近く，核破砕標的である鉄の可能で，海外においても，53Mnを測定可能なAMS施設

質量数に近く，より生成率の高い53Mnの測定に期待は非常に限られている．

がもたれる．また，鉄隕石中には不均質にFeS鉱物やMn のデータは少ない．最近，非常に表面から深いJRR-3 DR 孔，宇宙化学的試料 放射化分析－ 411 －

JAEA-Review 2008-067

ケイ酸相が含まれていることが知られている．10Be

熱濃縮し，ジイソプロピルアルコール-HCl溶液に溶

や3,4Heなどはこれらからも生成するが，これらの相解し，陰イオン交換樹脂に通し，0.5M HClにてMnをの分析に供する試料中での存在をあらかじめ知るこ

溶離した．溶離液は，加熱濃縮し，H2Oにて溶解後，とは不可能であり，過剰評価した結果が得られるこ陽イオン交換樹脂に通した．Mnを 2M HClにて溶離し，ととなる．一方，53Mnは鉄またはニッケルからしか加熱濃縮した．残渣をH2Oにて溶解後，Al箔に滴下乾生成しないため，このような過剰評価は生じないた

燥させて，照射用試料とした．

め，53Mn濃度を得ておくことは重要である．この隕石で現在報告されている最も低い 10Be 濃度は 6×

照射は，JRR-3M DR 孔にて 1 サイクル(25 日間)行
った．

10-5 dpm/kg であり，これに相当する 53Mn 濃度は

照射 1 ヶ月後に，Al箔とともにガンマ線を測定し0.05 dpm/kg と推定され，当研究室の瀬戸口の方法

たところ，Ir, Ag, Coがまだ十分に除去されていなによる定量限界値 0.4 dpm/kg の約 1/10 である．

かったことがわかった．そこで，放射性トレーサ，

本課題申請時は，最深部と思われる試料中の53Mnの54

定量を計画していたが，ここしばらく本定量実験を

射後のMn精製操作を行い，これらの元素の除去率と行っていなかったため，いきなりこれまでの定量限Mnの回収率を調べた．除去率は十分であったが，Mn

界にせまる，あるいはそれ以下と推定される試料のの回収率が悪かった．AgをAgClとして除去した際の分析は無謀であると考えた．そこで，これまでにまろ過方法が適当でないことがわかったため，ろ過方だ53Mnの定量が行われていない深度の試料を分析す

法を回収率が低下しない方法に改めた．

Mn，60Co，110mAg，192Irを用いて，従来行っていた照ることにより，現在の方法の定量限界を再確認し，照射後，Al箔表面に添着させたMnのみ溶解し，Ag

ギベオン隕石のより深部における低濃度の 53Mn ををAgClとして除去した後，照射前の濃縮操作と同様測定するために必要な改良方針を得る事を目的としの陰イオン交換と陽イオン交換によりMnの精製を行て実験を行った．

った．Mnフラクションは濾紙上に滴下・乾燥し，54Mn
測定試料とした．
Mnの化学収率は， 54Mn測定終了後，再放射化法

2. 実験方法
試料として 3 つの鉄隕石ギベオン #204, #1122,#99 を 0.5 g 〜 1 g用いた．これらの10Be 濃度は(JRR-4 PNにて 30 秒間照射)により求めた．回収率は，13〜83%であった．

測定されており，10Be 濃度と 53Mn 濃度の相関より，これらの試料の 53Mn 濃度は，約 1/10 づつ小さく

3. 結果と考察
現在，信頼できる 53Mn標準溶液がないため， 53Mn

なると推定される．
試料は表面を洗浄後，秤量し，100μgのMn担体と濃度が報告されている#99 試料を比較標準試料とし2mgのCl担体を添加後，1:2 HNO3で加熱溶解した．塩て定量を行った．その結果を表 1 に示す．#1122，#204

素をAgClとして分離した後，7M HCl溶液とし，ジイ

ともにこれまでの53Mn濃度の深度分布と矛盾しない

ソプロピルエーテルで鉄を抽出除去した．水層を加値が得られた．

－ 412 －

JAEA-Review 2008-067

らの妨害はそれぞれ 0.1 dpm 53Mn/μgFeと 3.4 dpm
表 1 53Mnの定量結果

53

Mn/100μgMnであった．照射前分離操作では，まだ試料 No.

濃度 [dpm/kg]

Mn 収率[%]

#99
#1122
#204

196 ± 12

12.5
82.9
57.9

73.0 ± 5.1
8.29 ± 0.59

約 1μgの鉄が残っており，また，Mn担体を 100μg使用したため，0.05 dpm/kgの53Mnを含む試料を想定すると，FeならびMnからの54Mnの寄与は，53Mnからの54

Mnに対して，それぞれ約 2 倍と約 70 倍となる．50%

53

ガンマ線スペクトルから本定量法での Mnの定量までの寄与率を許容できるとすると，照射前の濃縮限界を求めた．鉄隕石を 1g用いて，収率 80%でMnが操作において，鉄の除去率をさらに 1/2 にすること，回収できたと仮定すると，0.2 dpm/kgが定量限界でまた，用いるMn担体の量を 1μg程度にまで減らす必ある．定量を予定している試料の53Mn濃度の推定値
要がある．しかしながら，このMn担体量では，回収は，0.05 dpm/kgであるから，現状では定量が困難で率測定の際に鉄隕石にもともと含まれているMn量をある．計数率を向上されることが，定量限界を下げ
無視しえないこととなる．そのため，あらかじめ鉄
るには手っ取り早いが，現状ではさらに相対効率の隕石試料に含まれているMn量を評価する必要がある．
よいGe検出器を準備することは難しい．次に有効な
また，化学操作中のMnの汚染についても評価する必のは，バックグランド計数を減少させることである．
要がある．
照射後のMn精製操作は非常に有効で，測定試料中に
現在の 53Mn 定量方法においての定量限界は、収52存在する鉄隕石由来の放射性核種は Crのみである．
率 80% のとき 0.2 dpm/kg であり，目標とする 0.05
52

Crのガンマ線(320 keV)は54Mnからのガンマ線(835
dpm/kg の 4 倍である．定量限界を下げるには低バッ

keV)の測定の妨害にはならない．そのため，現在，クグランドな環境にてガンマ線を測定することが必
定量限界を左右する大きな要因は天然放射性核種に要である．また，正確に 0.05 dpm/kg の試料を測定由来するコンプトン散乱による計数であると考えらするには試料量を 7g 以上，収率 80% 以上，Mn 担れる．そのため，検出限界を下げるには，より低バ
体量は 1μg，照射前化学分離において Fe を 0.1μg
ックグランドな環境で測定することが必要である．
まで除去することが必要である．
この低バックグランドな測定施設として，金沢大学
今後は，この条件をみたす化学分離操作に改良すの尾小屋地下測定室が考えられる．この施設でのガるとともに，鉄隕石中のMn元素濃度定量法の開発，
ン マ 線バ ック グ ラン ドレ ベ ルは 当大 学 施設 の約53

Mn標準溶液の調製を行いながら，より深部の53Mn濃1/160 であるため，単純に比較すると，地下測定室
度の定量を目指す．
にて測定すれば検出限界は 0.03 dpm/kgとなる．
本研究実施に当たり東京大学名誉教授本田雅健氏
中性子放射化分析法にて正確に53Mnを定量するにから鉄隕石試料を提供していただくとともに，貴重は，妨害反応の補正が必要である．すなわち，54Fe(n,な助言をいただいた．ここに感謝する．
p)反応と，55Mn(n, 2n)反応により生成する54Mnを補
4. 成果の公表
正しなければならない．本実験でのFeならびにMnかなし－ 413 －

JAEA-Review 2008-067

4-13

地�環境������分�・�環�研究— ������ —Geoenvironmental assessment by INAA analysis ofchromium and arsenic for a large number of stream sediments伊藤知子（ITOH Tomoko）1)・田中 剛(TANAKA Tsuyoshi)1)・南 雅代(MINAMI Masayo)1)・山本鋼志(YAMAMOTO
Koshi)1)・浅原良浩(ASAHARA Yoshihiro)1)・三村耕一(MIMURA Koichi)1)・竹内 誠(TAKEUCHI Makoto) 1)・柴田信之介(SHIBATA Shin-nosuke)1)・小島 久(KOJIMA Hisashi)2)
1) 名古屋大学大学院環境学研究科地球環境科学専攻, 464-8601 名古屋市千種区不老町
Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya 464-8601, Japan
2) 名古屋大学アイソトープ総合センター, 464-8601 名古屋市千種区不老町
Radioisotope Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan��������

Geochemical map was studied in many institutes for the specific purpose of environmental assessment. Especiallyin late years, this map is used to discriminate anthropogenic elemental pollution among primary geoenvironmental
factors.

Where arsenic shows high concentration gold and antimony also shows similar behavior as arsenic in

geothermally affected area. High arsenic concentration was found in Mesozoic and Paleozoic area in western part ofTajimi city, Gifu prefecture but gold abundance is not so high on the geothermal area.

This study was intented toclarify the behavior of arsenic and gold in the Mesozoic and Paleozoic area, and to clarify controlling factors of arsenic
and gold in this area. Ninety-one stream sediments are analyzed by instrumental neutron activation analysis and X-ray
fluorescence spectrometry.

The results are expressed in geochemical map. Analytical data are treated by factor

analysis to find controlling factors of the element in study area.

Constituent minerals of the stream sediment samples

were examined, to find control factors of arsenic and gold distribution in the Mesozoic and Paleozoic area.
Analytical data in the study area examined in referring to three distinctive geology, i.e., clastics area in Mino belt, chertarea in Mino belt and Tertiary and Quaternary formation area. Although several sites clastics area in Mino belt havehigh arsenic concentration between 60ppm and 177ppm, the area generally shows low arsenic concentration.

Tertiaryand Quaternary formation area has not much notable difference. .
Factor analysis shows elemental distribution in this area is controlled by monazite, biotite, zircon, pyroxene,
feldspar and material including cobalt and arsenic.

Monazite, pyroxene and potassium feldspar control the elemental

distribution in Mesozoic and Paleozoic area. Arsenic and gold in the study area doesn’t show similar correlation eachother as is Tsugu region.

This indicates that the factor controlling arsenic and gold distribution in the area is different

from the factor of Tsugu region.

Minerals that show high arsenic concentrations in the Mesozoic and Paleozoic

formation area are prospected a kind of pyrite with red or black features.

These minerals analyzed by INAA, showhigh arsenic concentration but not for gold.
These fact indicate that arsenic concentration in this Mesozoic and Paleozoic area have relatively low concentration,
but high arsenic concentration leastways in the area is shown including arsenic minerals in sedimentary rocks. Arsenic
and gold are indicated have different carrier, arsenic have high concentration although arsenic shows low concentrationin this study area.

装置：JRR-3気送管、JRR-4気送管・T・Sパイプ、

分野：中性子利用・放射化分析、地球化学、環境化学－ 414 －

JAEA-Review 2008-067

��調査地域

1�はじめに
地球化学図は，古くから鉱床の探査に使用されてきた(西山, 1991)。近年になり，分析機器の進歩により，多試料中の多元素が迅速に分析できるようになった。そのために，迅速な対処が必要な土壌汚染の評価などの基礎資料となる環境評価を目的とした地球化学図の作成が進んだ。地球化学図は，人為汚染による元素濃集とバックグラウンドである本来の地質的要因を区別することを期待されており，環境基盤図として使用されている。
ヨーロッパでも，全土での地球化学図が作成されている (例えばWebb et al., 1978、Fauth et al.,
1985、Haslam et al., 2000など) 。また，日本では，
産業技術総合研究所(今井ほか，2004)を始めとして様々な機関で広範囲の地球化学図が作成されている。(例えば，椎川ほか, 1984、太田ほか, 2002)
愛知県での地球化学図は，東部や北東部，瀬戸市のものが局地的に作成されている。その中でも，
戸上ほか(1997)は愛知県北東部・津具地方の地球化学図を作成している。戸上らは，地球化学図のデータに因子分析を適用し，熱水活動に関わる金・ヒ
素・アンチモン・亜鉛・セシウム，銅などの元素が金鉱床周辺で高濃度を持つことを示した。
ヒ素が他の地点より高い濃度の場合，金も同様の傾向を示すことはよく知られている。しかしながら，名古屋大学地球化学講座で作成された地球化学図(2003)では，岐阜県多治見市西方でヒ素が他の地点より高濃度にも関わらず，金はほとんど検出されなかった。そこは，中・古生層分布地域であり，これまで研究された地域とは異なった元素の挙動があることが推測される。
地殻にヒ素は，平均約1.7mg/kg含まれている(文献)。日本の表層地殻の平均は1.3～10.1ppmであり(Togashi et al., 2000)，アメリカ合衆国の河床堆積物・土壌中では約5～8mg/kgで，平均7.4mg/kgである(Gilpin et al., 2006)。また，ヒ素の濃集は母岩の鉱物の形態や，風化環境により大きく異なる。硫化物や硫砒化合物，特に硫砒鉄鉱に含まれていることが多い。珪酸塩では，As3+ によってFe3+ とAl3+ が置換され，マグマから生じた初生の造山鉱物に組み込まれる。AsO43-はPO43-などの陰イオンに類似している
ために，As5+はアパタイトなどのような燐酸石の中のP5+ と置換し，燐酸塩に濃集する (Haslam et al.,2000)。ヒ素は火成岩の中に特に豊富に含まれているというわけではない(Haslam et al., 2000)。しかし，熱水活動の結果，豊富になる傾向が見られる。
また，高いヒ素の異常は，浅熱水・中熱水金鉱床の特色と共通している (戸上ほか, 1997)。堆積岩においてヒ素は，泥・沈殿物・硫化物・有機物や2次鉱物である鉄酸化物の存在する所に濃集している。ヒ素は粘土部分や含水した酸化鉄や酸化マンガン・硫化化合物や燐酸塩に強く吸着されているので鉄マンガンノジュールや類似した堆積物に濃集している。また，As2O2やAs2O5は酸性の水に穏やかに溶ける。しかし，硫化物・砒酸塩からはヒ素が遊離しにくい(Haslam et al., 2000)。また，ヒ素は、粗粒堆積物に比べ，細粒堆積物に濃集することが知られている(寺島ほか, 1993)。
本研究では，本調査地域におけるヒ素と金の濃度を規定する要因を考察するとともに，中・古生層におけるヒ素と金を中心とした元素の挙動を知ることを目的とした。
P��� 調査範囲
これまでに名古屋大学地球化学講座で調査された地域に隣接し，中・古生層の分布する愛知県北部
から岐阜県南部にかけての東西約15km，南北約10kmを調査地域とした。本研究地域は，庄内川の上流域である土岐川に流れ込む河川と，人工池である入鹿池に流れ込む五条川の集水域である。五条川
流域にはキャンプ場，そのほかの地域には住宅地・建造物・ゴルフ場が多く点在する。特に，第三紀・第四紀層分布地域には住宅地・工場が多い。また，
入鹿池東と春日井市南部にそれぞれ土砂採掘所が存在する。また，多治見市北部から可児市南部には工業団地があり，その他の場所にも工場が点在している。本調査地域及び試料採取地点をFig.1に示す。

Gojyou-riverToki

Tajimi

ri
kiTo

ver
ki
To

er
riv

Gifu-Pref

InuyamaTajimi
NagoyaAichi-Pref

䇭䇭5km
KasugaiFig. 1 Study area and sampling sites of stream sediments.
Ninety-one samples were collected in the area of 15km×10km.

��� 地質調査地域の西部と北部の一部に，中・古生層である美濃帯砕屑岩・チャートが分布している。それ以外の地域には海成層である中新世の瑞浪層群及び湖成層である第三紀鮮新世の瀬戸層群およびが分布している。瑞浪層群は砂岩・泥岩，瀬戸層群は砂礫層を主体とし，少量の粘土や火山灰を含む(日本地質学会, 2005)。また，多治見市では陶土の採掘が行われている。また、第四紀完新世・更新世の沖積層
や砕屑岩層が多治見市・土岐市の中心部周辺に分布している。本調査地域の地質図をFig.2に示す。

Toki

TajimiInuyamaKasugai

5km

Fig. 2 Geology in this study area.
Compiled after geological map by Geological Survey of Japan.

－ 415 －

JAEA-Review 2008-0673�試料と分析法
3.1 試料
3.1.1 試料の採取
地球化学図を作成するための分析試料には，土壌(Kadunas et al., 1999,)，湖沼堆積物(Kadunas et al.,1999,) ，氷河堆積物(Bolviken et al., 1986)，更には地下水(Slowansk, M.Sc., 1997) ，雪塵・雪解け水(Kadunas et al., 1999)などが用いられている。しかしながら，これらの試料にはそれぞれ問題がある。岩石や土壌は場所に依存する不均質性が大きいと考えられる。また，地下水・湖沼堆積物・氷河堆積物
は，本研究地域では採取することが困難である。そこで，土地所有権の問題が無く，地域代表性が良く，均質的である河床堆積物を用いた。河床堆積物の均質性については，3.3.2で詳しく述べる。試料採取は伊藤ほか(1991)と同様の手法で行った。河床堆
積物は，現地の流水を使い，80メッシュの篩に通し，粒径180μm以下の粒子を集めた。流れの速いところには重鉱物，遅いところには軽鉱物がたまりやすい。また，流速により，酸化還元状態が異なる。そのために，極端に流れの早いところや，よどんでいる地点は避けて，試料採取した。
また，地球化学図の描写のためには，試料を地理的にできるだけ均等な分布になるよう採取することが望ましい。本研究での試料採取は，できるだけ均等に採取したが，2.1に述べたように住宅や工場が多い。それらの近隣では，三面工事の行われている地点が多数あった。そのような地点では，工事のなされていない上流に遡って採取した。しかしながら，それでも工事がなされている場合は，堆積物が多く堆積しているところで採取した。また，河川の合流点では、隣の河川からの汚染がないように，数十m遡った地点で採取した。また，河川横の崖崩れが起こっており，特定の土砂が河川に流れ込んでいる地点は避けた。約150km2 の範囲内で，91地点で試料を採取した。
3.1.2 分析試料採取した試料は，実験室に持ち帰り揮発しやす
い元素を失わないように40℃で乾燥させた。また，均質性を高めるためにメノウ製のボールミルで30分程度粉砕し，これを分析試料とした。
河床堆積物を構成する鉱物の分析を目的とした鉱物分離用の試料として，やや粗い粒子を含む350μm以下の河床堆積物を採取した。上記の試料と同様に40℃で乾燥させたのち，250μm,180μm,150μm,125μm,75μm,38μm,25μmのふるいを使って8つの粒度別フラクションに分離した。そのうち，340～250μm,250～180μmに分画された量の多い7試料
は，アイソダイナミックセパレータを用いて強磁性のものを取り除いた。それらの試料と，UI46地点で採取した1mm～180μmの試料について，ヨウ化
メチレンで比重が3.211以上の鉱物を分離した。各
フラクションは実体顕微鏡下で，ヒ素を含む可能性の高い非珪酸塩質の不透明鉱物3種類，①黒光りしている鉱物②赤い鉱物③黒い鉱物をハンドピックによりそれぞれ数十個～数百個集めた。これらの鉱物
は①黄鉄鉱②黄鉄鉱に鉄がコーティングされた鉱物③黄鉄鉱を含む様々な鉱物と鑑定された。

3.2 分析
測定は，中性子放射化分析(上岡・田中, 1989、
柴田ほか, 2001)と蛍光X線分析(杉崎ほか, 1977，山本ほか, 2000)によって行った。
中性子放射化分析(INAA)では，河川堆積物約125mgをポリエチレン袋に2重に封入し，日本原子力開発機構のJRR-3気送管で中性子を5分間照射した。
標準物質には地質調査所のJB-1aを使用した。ヒ素
や金などの，JB-1a中に乏しい元素は，濾紙に含ませた試薬を標準物質として用いた。また，ハンドピ
ックした鉱物試料は，石英管に封入し，JRR-4 Sパ
イプで中性子を6時間照射した。照射後の試料のγ線を，名古屋大学アイソトープ総合センターのGe半導体検出器で6日後と約1ヵ月後の2回定量した。測定結果が2回得られた時は，荷重平均データを用いた。半減期より，ナトリウム・カリウム・ヒ素・ル
ビジウム・バリウム・ランタン・サマリウム・ジス
プロシウム・イッテルビウム・ルテチウム・タング
ステン・レ二ウム・金・ウランは一回目，クロム・鉄・コバルト・亜鉛・セレン・ストロンチウム・ジ
ルコニウム・アンチモン・セシウム・セリウム・ユーロピウム・テルビウム・ツリウム・ハフニウム・
タンタル・トリウムは2回目の測定結果が好ましいと考えられる。しかしながら，金・レ二ウムは，2回目に真の値ではない架空の測定値が出てくるので，これらの元素は1回目の分析結果のみを用いた。
蛍光X線分析（XRF）では，主成分元素10元素を定量した。有機物などを取り除くために1000℃で強熱減量した河川堆積物0.7gに，四ホウ酸リチウムを6.0g の 割 合 で 混 ぜ 合 わ せ た 。 そ の 混 合 粉 末 を ，1050℃で熱し，ガラスビードを作成した。それを，島津蛍光X線分析装置SXF-1200を用いて分析を行った。但し，試料量の少ないVI10については，必要量に足りなかったことから，XRFによる分析は行わなかった。
分析値は、別途公表をおこなう。
3.3 分析値の��3.3.1 中 性 子 放 射 化 分 析 (INAA) と 蛍 光 X 線 分 析(XRF)による分析結果の比較
鉄・ナトリウム・カリウムの3元素は，INAAとXRFの両手法で測定されている。どちらがより確かな濃度分布を示すか考察した。3元素についてINAAとXRFによる分析データの比較図をFig.3(a)～(c)に示す。この2つの方法による分析値を比較すると，
鉄・ナトリウムは2つの手法間での違いが少ない。
測 定 結 果 が ， 鉄 の 含 有 量 の 10 ％ 程 度 ま で は ，
INAA、XRFともに、ほぼ一致。鉄は、XRFにおいて，高濃度になるにつれて検量線作成域を超えるた
め、確度が低くなると考えられる。しかし，そのような試料の数は少なく，こでは，試料量の多いXRFのデータを採用するのが考えられる。同様に，河床堆積物中のナトリウムは，岩石試料や海洋試料と比較して含有量が少ないため（0.03～1％）に，XRFでは確度が低くなる傾向が見られる。INAAでは，
0.03～1％の含有量でも，一回目の測定で， 24Naの十分な強度が得られるので，精度が高い。逆に，カリウムはINAAでは強度が小さく，ピークを見ることが難しい。そのために，INAAではデータが大き
くばらつく。そこで，今回は，双方の測定値を参考に，ナトリウムはINAA，鉄・カリウムはXRFにより得られたデータを採用した。

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組成変動②保存瓶中の不均質性による組成変動がある。
柴田ほか(2001)は，INAAによって，BCR-1を標準試料としてJB-1aを多数回分析した。柴田らは，その結果を推奨値と比較したところ，ナトリウム・
スカンジウム・鉄・コバルト・ランタン・セリウ
ム・サマリウム・ユーロピウム・イッテルビウム・
ルテチウム・ハフニウム・タンタル・トリウムは±5％以内，クロム・亜鉛・セシウム・バリウム・ネ
オジム・テルビウム・ウランは±10％以内の精度・確度で分析可能であると述べている。これが，分析誤差を表す。
また，田中ほか(1995)は同じ地点で，多数回河床堆積物試料を採取，分析した。その結果，同じ地点での変動は，チタンは±100％，ナトリウム・カ
リウム・ニッケルは±20％，その他の元素においては±50％程度であった。したがって，その変動幅を超える違いについては真の違いであると言えると述べている。Minami et al. (2005)は，同一地点において1994年から2004年まで各年度で複数回採取した試料をXRFにおいて再測定した。その結果，チタンやリンも同様に±20％の範囲でばらつきがあることを示した。
本研究での試料は1地点1試料であることから，保存瓶中の不均質性を見ることを目的とした。加えて，測定結果には測定誤差も含まれていることから，このデータは，保存瓶中の不均質性と測定誤差を合わせたばらつきを見ていると考えられる。同一
サンプル瓶中から5回はかりとり，分析したデータの平均値と分析値に対する変動をFig.4に示す。
亜鉛・セレン・ルビジウム・アンチモン・セシ
ウム・ネオジム・サマリウム・ジスプロシウム・ツ
リウム・トリウム・タンタル・タングステン・レ二
ウム・金は試料によって大きくばらつく。特にルビジウムは，±50％の変動があった。これは，不均質性と，試料に含まれている各元素の少なさが大きな
変動の原因と考えられる。放射化されにくい元素
は，含有量が低ければ，さらに変動が大きくなる。
しかしながら，そのほかの元素は±10％以内の誤差であった。したがって，これらの変動と誤差を明確にし，化学組成の違いを解釈する必要があると考えられる。

Fig. 3 Comparison of analytical data for Fe, Na and K withINAA and XRF.

����� 試料の均質性・分析の確度
地球化学図のデータを使用する上で，分析誤差とともに考慮しなくてはいけないのが試料の地域代表性である。それには①同一地点で採取した試料のFig. 4 Concentrate fluctuation of repetition analyses in asingle sample bottle.
x: elements, y:concentration except Na(ppm), Na(%).
This figure shows average values and variations.

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JAEA-Review 2008-067

��結果・考���� 地球化学図��地質に�う元素濃度の相違
地球化学図の描画には，稲吉(2005)の地球化学
図プログラムを用いた。本研究地域でのヒ素・金・主成分元素の地球化学図を，Fig.5に示す。
本研究では，調査地域の地質を美濃帯砕屑岩分
布地域，美濃帯チャート分布地域，第三紀・第四紀
層分布地域の3地域に分け，議論を進める。また，その議論では，絶対値ではなく相対的に比較を行った。
美濃帯砕屑岩地域では，美濃帯チャート地域と比較するとナトリウム・コバルト・亜鉛・タングス
テン・金・ケイ素が低く，チタン・マグネシウムは高い濃度を示す。また，第三紀・第四紀層地域と比較すると，ナトリウム・クロム・アンチモン・ルテ
チウム・ヒ素・カルシウム・リンは低い濃度を示す。特に金は，0.006~0.014ppmであり，第三紀・第四紀層地域のように，0.1ppm以上の高い値は見られなかった。ヒ素は第三紀・第四紀層分布地域と比べ，比較的低濃度の地点が多いが，顕著な違いは見られない。美濃帯チャート地域では，第三紀・第四紀層地域に比べ，コバルト・タングステン・マンガ
ン・ケイ素が高い濃度を示す。
これら3つの地質分布地域のうち，美濃帯チャート地域では，他の地域に比べ濃度が比較的大きくばらついている。また，希土類元素は，地質による違いはあまり見い出されない。
中・古生層は，第三紀・第四紀層に比べ，より古い地層であるために，風化により溶脱しやすい元
素は，年月をかけて既に河川中に流出していると考えられる。その結果，溶脱しやすい元素は濃度がより低くなったと考えられる。同様に，溶脱しにくい
元素は，河川堆積物中により多く残留している可能性があると考えられる。しかしながら，これらのデータからは，定量的な議論を行うことができなかった。

Fig.6 Factor loadings of analysis data in all
sampling site.

Fig.7 Distribution of factor score.

��� 因子分析
Gilpin R. et al. (2006)は，約4000試料のデータを
non-parametric法を用い補正を行い，地球化学図の濃度分布を決定した。またSiegel-Tukey Testを用
い，全サンプルのうち，濃度が，主にどの範囲に分布しているかを記号で表し，解釈を行っている。しかしながら，本研究ではそれらに比べて，検討に加え得る試料数が少なく，これらの数値解析はできなかった。本研究では，因子分析を用い，解釈を行った。因子分析は多変量のデータによって表される変動をより少数の，基本的，仮説的変動によって指標の単純化を図るものである。本研究では，北関東の地球化学図（上岡ほか，1991）や津具地方（戸上ほか，1997）で用いられたものと同様に因子数は6とし，バリマックス法で軸を直交回転させ，補正を行った。因子は，因子負荷量・因子得点分布を元に解釈した。しかしながら，本研究では試料数が少ない
ので，寄与率の小さい第五因子以下は，信頼度が低
いと考えられる。各因子の因子負荷量をFig.6に，
因子得点分布をFig.7に示す。

【第一因子】
第一因子は，ランタン・セリウム・サマリウ
ム・ユーロピウムなどの軽希土類元素・スカンジウ
ム・トリウム・カリウム・マグネシウム・アルミニ
ウム・セシウム等への寄与が大きい。寄与率は，23.4％である。因子得点は，中・古生層分布地域に高得点域があり，この地域におけるそれらの元素の規定要因であると考えられる。第一因子は、モナザ
イトと黒雲母だと考えられる。また，ヒ素の因子負荷量はやや高いが，金は無いと考えられる。
【第二因子】
第二因子はハフニウム・テルビウム・ルテチウ
ム・トリウムの寄与が大きい。寄与率は12.9％で，ほとんどが第三紀・第四紀層で高い因子得点を示す。これは，ジルコンを表す因子だと考えられる。
また，ヒ素と金の因子負荷量はともに非常に少ない。

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JAEA-Review 2008-067

Fig.5

Geochemical map in this study areas.

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JAEA-Review 2008-067【第三因子】
第三因子は，マンガン・コバルト・ヒ素の寄与が大きい。寄与率は11.6％である。因子得点は，中・古生層分布地域に高得点域が集中している。そのため，この第三因子も本研究地域の主な規定要因であると考えられる。また，鉱物であると特定するのは難しい。そのため，これはコバルトとヒ素を含む物質であると考えられる。また，第一因子と同様に，ヒ素の因子負荷量はやや高いが，金は無いと考えられる。
【第四因子】
第四因子は，ナトリウム・カルシウム・カリウ
ム・マグネシウムの寄与が大きい。寄与率は10.2％である。因子得点の分布は，中・古生層と第三紀・第四紀層の間では違いが見られない。この因子は長石類を表す因子だと考えられる。金の因子負荷量は高いが，ヒ素はほぼ無いと考えられる。
中・古生層は，堆積層であり，変成作用を受けな
い限り，その堆積層中に存在する鉱物そのものが河床堆積物の濃度に影響を及ぼすと考えられる。因子分析の結果より，本研究地域においてはヒ素と金の規定要因は異なることが示された。また，ヒ素は第一因子と第三因子を構成する元素、金は第四因子を構成する元素と同様の挙動をする可能性が示唆された。
��� 河川堆積物における粒径別の化学組成変化
今井(1986)は，粒径別に分けた河川堆積物試料
中 の 化学 組成 が どの よう に 変化 する か 調べ た。
ICP-AESを用いた分析の結果，細粒の試料になるほど銅・鉛・亜鉛・クロムで明確な濃縮傾向を示すことがわかった。またコバルトは各粒度であまり変化が無いと述べている。
本研究ではINAAを用いて粒度別の元素分析を行った。分析結果をFig.8に示す。
その結果，ほとんどの微量元素で細粒になるほど濃集する傾向が見られた。これは，SiやAlなどの主要化学成分は石英や長石などの粗流な鉱物を形成
し，粗粒部分に濃集しているが，ここで分析された微量元素は微小な不透明鉱物や鉱物粒界の細粒部分に濃集しており，細粒フラクションほど細粒部分が多くなることによると考えられる。この分析データに粒径ごとの重量の割合をかけると，この鉱物試料の全体の濃度を知ることができる。その結果，ボールミルで粉砕し分析した試料に比べ低い濃度であった。実際に地球化学図として分析している試料は，比較的細かな粒子まで十分に沈めた試料が採集されたことによると推測される。また，重鉱物・軽鉱物
以外にも，細粒フラクションの多い地点で試料を採取すると，濃度が相対的に高くなると考えられる。
しかしながら，試料全体の重量に対しもっとも細粒な部分の重量は全体の1％以下であるため，それほど分析結果への影響は少ない。
ハフニウムは，最も細粒の25μm以下の粒径ではなく，38~25μmの粒径部分に高い濃集が見られた(Fig.8)。ハフニウムはジルコンなどの鉱物に含まれるので，この地域のジルコンは38~25μmの粒径が卓越しており，河床堆積物として堆積したと考えられる。

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Fig.8 Concentration on comparing minerals.

JAEA-Review 2008-067

���� ヒ素を含む鉱物について�
中・古生層のバックグラウンドを明確に表すと考えられる五条川流域の地点の中でヒ素が比較的高い濃度を示す地点で試料を採取した。3.1.2に示した手法でヒ素を含む可能性が高い鉱物を分離・分析した。鉱物別の分析結果をFig.9に示した。
(a)光沢を持つ黒色鉱物：鉱物の外見から黄鉄鉱と鑑定されたものに準じ、同じ外観をもつ鉱物をハ
ンドピックしたもの
ヒ素はさほど多くなく，100ppm以内にあり，最も高いヒ素の濃度は78.4ppmである。金は2地点で検出された。しかしながら，そのほかの試料では検出限界0.39ppm以下であった。また，鉄が26.3～40.8％を示した。このことから，この鉱物は黄鉄鉱及び輝石などの不純物が付着したものと推測される。
(b)赤褐色鉱物：(a)の黄鉄鉱に類するが、表面が赤褐色を示すもの
ヒ素は，92.8ppm～540ppmの高い濃度を示している。また，金も4地点で検出されており，0.09～
1.69ppmと比較的高い。また，鉄は26.6～45.3％を示した。1地点を除く4地点の鉄濃度は，(a)の鉱物に比べ高くなっている。これは，黄鉄鉱にヒ素と鉄が吸着された鉱物だと考えられる。
(c)黒色鉱物
ヒ素は1地点で901ppmという高濃度を示した。
しかしながら，他の4地点では32.7～123ppmと比較的低い濃度であった。また、ヒ素の濃度が最も高い
地点では，金が2.1ppm検出された。金はこの地点を入れた2地点を入れた2地点を除き、そのほかの鉱物では検出限界以下であった。鉄濃度は13.6～44.8％とばらつきが大きいことから，様々な鉱物が採取されたと考えられる。
粉砕した河床堆積物の分析結果でヒ素が高濃度を示す地点ではヒ素を高濃度で含む黄鉄鉱などの不透明鉱物が存在することが確認できた。このことか
ら，ヒ素は，本来の地質的要因に加え，ヒ素を含む
特定の鉱物の存在の多少がヒ素の規定要因になっていると考えられる。また，多くは高濃度のFe・Crを伴う。そのために，黄鉄鉱，もしくは鉄酸化物が生成し，その表面に固着・沈殿している可能性も示唆される。
しかしながら，これらの鉱物は，全体の重量の1％以下である。そのために，As全体の濃度は，標準的な濃度，もしくは少し高い程度にしかならな
い。また，鉱物により，全体の濃度が高くなるためには，非常に多量の鉱物，もしくは細粒になった鉱物が多量に入っていることが原因だと考えられる。

－ 421 －

Fig.9 Concentrate fluctuation of repetition analyses inthese minerals.

JAEA-Review 2008-067

�� まとめ近年，地球化学図は環境基盤図として用いられつつあり，土壌汚染など環境問題の評価に大きな役割を担っている。本研究では，愛知県北部・岐阜県南部の中・古生層分布地域における化学的バックグ
ラウンドを知り，ヒ素と金をはじめとする元素の挙動を調査し，考察した。その結果、風化に強いと考えられる元素が河床堆積物中に残留し，弱い元素
は，河川水中に溶出したことが，河川堆積物中の主要化学成分濃度が変化する一因だと考えられる。
また，因子分析を行い，元素存在度を規定する因子を推定した。抽出された因子は，モナザイト，
黒雲母，ジルコン，コバルトとヒ素を含む物質，長石類に対応すると考えられる。また，本研究地域の
ヒ素と金の規定要因は異なることがわかった。その規定要因を特定するために，粒径別分析及び鉱物分離して分析を行った。その結果，細粒になるほどほ
とんどの微量元素で濃集傾向が見られた。これは，主成分元素が粗粒部分に含まれるため，細粒部分には，微量元素が濃集することがわかった。また，Hfに関しては，その傾向にあてはまらず，その元素を多く含む鉱物の粒径で，特定の元素の濃縮が進むことが推測できた。
ヒ素が多く含まれている地点の不透明鉱物をハ
ンドピックし，①黒光りしている鉱物②赤い鉱物③
黒い鉱物を見ることができた。また，これらを中性子放射化分析で定量したところ，特に②には高濃度のヒ素を含むことがわかった。
以上より，本研究地方の中・古生層におけるヒ素は，比較的低濃度な地点が多く，第三紀・第四紀層と比べ，大きな違いは見ることができなかった。
本研究地域においてヒ素が高濃度であるのは河川堆積物中に含まれる上記の3鉱物を含むことによって，高濃度のヒ素を伴うようになったと考えられる。また，ヒ素と金の規定要因は異なると考えられるため，本調査地域では，ヒ素が低濃度であっても金が高濃度を示すことがわかった。

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53, 15-32.
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領域研究「セム系部族社会の形成」ニュースレター
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Crystal structure control of the dissolution of rare earth
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Jour.vol.40 , 437-446.
Asahara, Y., Ishiguro, H., Tanaka, T., Yamamoto,K., Mimura, K., Minami, M. and Yoshida, H. (2006)
Application of Sr isotope to geochemical mapping
and provenance analysis: the case of Aichi Prefecture,
central Japan. Applied Geochemistry. vol. 21, 419-436.

Senda, R., Kachi, T. and Tanaka, T. (2006) Multiple
records from osmium, neodymium and strontium isotope
systems of the Nikubuchi ultramafic complex in the
Sambagawa metamorphic belt, central Shikoku, Japan.
Geochem. Jour. vol.40, 135-148.
Minami. M., Tanaka, T., Yamamoto, K., Mimura,K., Asahara, Y., Takeuchi, M., Yoshida, H. and Yogo, S.
and Inayoshi, M.(2005) Database for geochemical
mapping of the northeastern areas of Aichi Prefecture,
central Japan –XRF major element data of stream
sediments collected in 1994 to 2004– Jour. Earth Planet.
Sci. Nagoya Univ. vol. 52, 25-67.
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Kim, K.H., Nagao, K., Tanaka, T., Sumino, H.,
Nakamura, T., Okuno, M., Lock, J. B., Youn, J. S. andSong, J. (2005) He-Ar and Nd-Sr isotopic compositionsof ultramafic xenoliths and host alkali basalts from the
Korean peninsula. Geochem. Jour. Vol.39, 341-356.
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vol.39, 21-28.
Wallis, S., Tsuboi, M., Suzuki, K., Fanning, M.,
Laili. J. and Tanaka T. (2005) Role of partial melting
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－ 423 －

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� � � � � � � � � �� � � � � �� � �
Takeda, M. and Tanaka T.(2007) Isotope diluted
NAA for accurate determination of iridium and osmiumin the crustal materials. 12th International Conference on
Modern Trends in Activation Analysis, Sept.16-21,
2007, Tokyo Metropolitan Univ. (口頭)
Tanaka, T., Minami, M., Shibata, S., Ito, T. and
Takeda, M. (2007) INAA multi-element analysis on
multi-sampleforgeochemical
mapping.
12th
International Conference on Modern Trends in
Activation Analysis, Sept.16-21, 2007, Tokyo
Metropolitan Univ.(招待講演)
Nakao, T., Tanaka, T. and Kojima, S. (2007) Rb-Sr
single bed isochron dating with evidence of isotopic
equilibrium. 17th V. M. Goldschmidt Conference,
Aug. 20- 24, 2007, Koln.（ポスター）
Tanaka, T., Wakaki, S., Tanimizu, M. and Asahara,
Y. (2007) Elemental and isotopic fractionation in someorgans of bamboo. 17th V. M. Goldschmidt Conference,
Aug. 20- 24, 2007, Koln.（ポスター）
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M. Goldschmidt Conference, Aug. 20- 24, 2007, Koln.
（ポスター）
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and Sr isotopic and chemical compositions of ultramafic
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（口頭）

Wakaki, S. and Tanaka, T.(2006) Precise
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and Adachi, M.(2005) Geochemistry of Precambriancarbonate intercalated in pillows and its host basalt:
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Hayashi, T., Tanimizu, M. and Tanaka, T.(2005)
Origin of negative Ce anomalies in Barberton
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JAEA-Review 2008-067

4-14
Ko 放射化分析法を用いた河川の水質階級と指標生物の重金属濃度に関する研究

Investigation on elemental concentrations of aquatic insect larvae in river in relation to water quality by INAA
with k0 standardization method
九州大学アイソトープ総合センター 百島則幸

N. Momoshima (Radioisotope Center, Kyushu University)
熊本大学大学院自然科学研究科

豊嶋 孝浩、福田 紋子、日比野啓一

T. Toyoshima, A. Fukuda, K. Hibino (Graduate School of Science and Technology, Kumamoto University)

１．はじめにやそれらの餌との関係についての詳細な研究は少な

環境指標生物としてこれまで様々な生物が利用さ

く、水生昆虫に含まれる重金属濃度を環境評価に利れてきている。環境水中の重金属や農薬などの環境用するための基礎的な知見についての情報は多いと汚染を評価するために利用する場合は、多くの生物はいえない。水生昆虫は、孵化して年を越えて成長が環境水中のこれらの汚染物質を生物濃縮する性質

し夏前に羽化して水から離れる。このような特徴をを利用している。水中の汚染物質濃度を直接定量す持つ水生昆虫の重金属濃度の季節変化や河川の上流ることが困難な場合でも、生物濃縮により濃度が高から下流に沿った金属濃度の変化に関して基礎的なめられている生物を分析すると検出が容易になる。

情報を得ておくことは指標生物として利用する際に一般に重金属は生物により濃縮されることが多い。
したがって生物中の重金属を分析することは、水中は不可欠である。
環境試料の分析には様々な分析法が用いられるが、に存在する重金属を高感度で分析することに等しい

生物を環境指標として用いる場合、より多くの元素といえる。水中の重金属濃度が変動しているようなを定量することが望ましい。k0放射化分析法は、目場合でも、ある程度の時間平均として濃度を評価で的元素ごとの比較標準試料を必要とせず多元素を同きる利点もある。生物は重金属を代謝するとき、代時に分析できるという利点を持っており、環境試料

謝に要する時間に関連した体内濃度を持つので、河の分析には魅力的な手法である。本研究は、k0放射

川水の重金属濃度が変動していてもある程度時間平化分析法で行なった。

均された体内濃度になる。河川の水質を月平均ある
いは季節平均として評価したい場合、指標生物の利2.

用は有効な方法である。

2.1. サンプリングと試料処理実験

本研究では水生昆虫を河川水における金属汚染の水生昆虫は熊本県内を流れる白川で採取した。白

環境指標として利用するための基礎的なデータを得

川は阿蘇カルデラに源を発し全長 74kmで流域面積ることを目的として行った。一般的には水生昆虫は480km2を有し、有明海に流れ込む河川である。定点

きれいな河川に生息しているので、生息する水生昆のサンプリングポイントとして河口から 14km上流

虫の種類や数自体を用いて環境を評価することも行の熊本大学に近い場所として黒髪ポイントを選定しわれている。しかし、水生昆虫の金属濃度と環境水た（図１参照）。白川流域は、水田や野菜などをも

JRR－4 S-パイプ、環境試料放射化分析－ 425 －

JAEA-Review 2008-067

っぱら生産している田園地帯であり、黒髪ポイント行った。菊陽は黒髪の 10km 上流、大津は 21km 上流

は熊本市内の人口密集地帯より上流側に位置し、黒にある（図１）。

髪ポイントより上流には大きな工場などの汚染源はない。

採取した水生昆虫は、実験室に持ち帰り種類別に分類した後、デシケーター中で乾燥させた。藻は河川水で洗った後、水生昆虫と同様にデシケーター中で乾燥させた。水中の重金属濃度を明らかにするために、河川水を蒸発乾固させて残渣を回収した。

2.2. 照射と測定
水生昆虫と藻の乾燥試料及び河川水の残渣は、石英管及びポリエチレン袋に封入して照射試料とした。
照射は日本原子力研究所の原子炉 JRR-4 で 10 分と 3
時間を行った。10 分照射試料は、照射 6 時間後にガ

図 1 サンプリング地点
黒髪ポイントでは 2004 年 1 月～2005 年 12 月の期間について水生昆虫の採取を行った。ただし、水生昆虫が確認されるのは、10 月から翌年の 6 月頃までであり、10 月は個体サイズも小さく生息数も少ない。
また、５月頃からは羽化により個体数は減少する。
黒髪ポイントで採取した水生昆虫を表１に示す。

表１

黒髪ポイントで採取した水生昆虫

Ecdyonurus yoshidae

コカゲロウ

Baetis sp.
Macrostemum radiatum

ヒラタドロムシMataeopsephus japonicus

ルの測定を行った。ガンマ線スペクトルは、東京大学原子力研究総合センター大学開放研究室の高純度
ゲルマニウム半導体測定システムで測定した。解析には解析支援ソフト「SAMPO90」と「KAYZERO/SOLCOI」
を用いた。

3.1

藻、河川水、水生昆虫の金属濃度

石の表面に成長していた藻に含まれる金属濃度と河川水中の金属濃度を表２に示す。Ca、Fe、K と Na

ヤマトフタツメカワゲラ Neoperla niponensis
オオシマトビケラ

照射 1 週間後と 2-3 週間後の 2 回ガンマ線スペクト

3. 結果と考察

エルモンヒラタカゲロウ Epeorus latifolium
シロタニガワカゲロウ

ンマ線スペクトルを測定した。3 時間照射試料は、は藻に％オーダーで含まれているが、他の金属は微量であった。サンプリングポイント間で大きな差は観察されず、最大でも大津と菊陽の Mn の 2.4 倍であ水生昆虫は、河川敷の流れに洗われている石の表面に見られた。石の表面には短い褐色の藻が成長しているが、たとえ石が水中にあっても藻が成長していない石には、水生昆虫は確認されなかった。従って、水生昆虫は藻を餌にしていると思われる。藻に含まれる重金属と水生昆虫に含まれる重金属の関係を調べるために、2005 年 12 月に黒髪ポイントで藻と水生昆虫の採取を行った。また、場所による違いを調べるために、2005 年 12 月に、黒髪ポイントの上流に位置する菊陽と大津で藻と水生昆虫の採取をった。黒髪で 2005 年 10 月と 12 月に採取した藻に含まれる金属濃度の違いは少なく、最大でも Br の 3倍であった。以上の結果は、藻に含まれる金属濃度
は、採取地点や採取時期で大きな変化がなかったことを示している。一方、河川水中の金属で主要なものは、Ca、K と Na で藻と同じであった。しかし、Feは藻に比べると河川水では少ない。Br や Rb は河川
水と藻は同じ程度であり、Co、La、Mn、Sc の水中濃度は低い。河川水に検出された Zn と Se は藻では検出限界以下であった。

－ 426 －

JAEA-Review 2008-067

表２

石表面に成長した藻および河川水中の金属濃度

River water

Attached algaeŌzuKikuyō

Kurokami

Kurokami

Kurokami

Dec. 2005

Dec. 2005

Dec.2005

Oct. 2005

May 2004

As

20 ± 934 ± 627 ± 515 ± 2Br

60 ± 355 ± 557 ± 319 ± 1035Ca37500 ± 4700

37400 ± 5600

39200 ± 7200

57600 ± 9200

21500

Co

23

26 ± 223 ± 326 ± 10.13

Cr23 ± 521 ± 329 ± 926 ± 6Cs

3.6 ± 0.7

4.5 ± 0.4

3.8 ± 0.3

4.0 ± 0.3Eu

1.3 ± 0.1

1.4 ± 0.1

1.0 ± 0.1

1.3 ± 0.1Fe71800 ± 2000

90400 ± 6800

78400 ± 6200

73400 ± 9300

480K

13200 ± 200

11500

11500 ± 800

17100 ± 3400

59000

La

19 ± 323 ± 1

21 ± 223 ± 6

0.11

Mn

2200

5200

2900

3200

35

Na

14800 ± 200

13800

12700 ± 1200

20600 ± 4700

20700

Rb

51 ± 1045 ± 550 ± 2071 ± 2118.5

Sc

12 ± 112 ± 1

11 ± 113 ± 2

0.04

Se

0.72

Zn

4.8

藻と同時に大津、菊陽、黒髪で採取した水生昆虫の違いは見られていない。採取地点で金属濃度に違のシロタニガワカゲロウに含まれている金属濃度をいがないシロタニガワカゲロウの傾向は、藻に観察

図２に示す。シロタニガワカゲロウは白川で見られされた傾向と同じである。しかし、大きな違いとしる代表的な水生昆虫である。K と Na 濃度は高く、Mn、て、Zn はシロタニガワカゲロウでは検出されたが、Zn と Br 濃度は中程度であり、採取地点による濃度

藻では検出されていない。2005 年 12 月に大津、菊陽、黒髪で採取した他の種類の水生昆虫でも Zn は検出されていることから、シロタニガワカゲロウの Znが、この種に特徴的なものとは考えられない。

黒髪ポイントで 2004－2005 年に採取したシロ
タニガワカゲロウの金属濃度の季節変化を図３に示す。年が変わっても金属濃度には大きな違いはない。金属濃度の平均と範囲は次の通りである。
Br：51 ± 26 μg/g (24 – 105)、Fe：2790 ± 1350 μg/g
(1060 – 5700)、K：9450 ± 3940 μg/g (3300 – 18100)、
Na：4120 ± 1370 μg/g (1650 – 6380)、Rb：33 ± 14μg/g (16 – 69)、Sc：0.5 ± 0.2 μg/g (0.2 – 0.9)、Zn：
図２

シロタニガワカゲロウの金属濃度

370 ± 120 μg/g (250 – 720).

－ 427 －

最も大きな差は K のJAEA-Review 2008-067

5.5 倍である。水生昆虫は毎年羽化することから、金属濃度を、それぞれの試料について金属ごとの濃度はその年に生息していた個体の金属濃度を比を計算し濃度比マトリックスを計算する。ここ示していることになる。採取時期による大きな濃で、X は試料であり、a は試料 X の各金属濃度で度変化が観察されていないことから、白川水系のある。

水生昆虫の金属濃度に関して 2004－2005 年は安定していたといえる。

⎡ ( a 1 / a1 )⎤⎢⎥(a / a ) (a 2 / a 2 )⎥X ij = ⎢ 2 1⎢( a 3 / a1 ) ( a 3 / a 2 ) ( a 3 / a 3 )
⎥
⎢
⎥
−
−
−⎦
⎣ −

得られた試料 A の濃度比マトリックス X と試料
B の濃度比マトリックスを用い、それぞれの金属濃度の比についてマトリックス比 Y を計算する。
図 3

黒髪のシロタニガワカゲロウの金属濃度

の季節変化

3.2

⎡ ( X 11 ) A /( X 11 ) B⎢( X ) /( X 21 ) B ( X 22 ) A /( X 22 ) B
Yij ( AB ) = ⎢ 21 A⎢( X 31 ) A /( X 31 ) B ) ( X 32 ) A /( X 32 ) B⎢−−⎣( X 33 ) A /( X 33 ) B
−

⎤
⎥
⎥
⎥
⎥
−⎦

水生昆虫と藻及び水生昆虫と河川水の金属
ここでは、マトリックス比 Y として、水生昆虫の関係
水生昆虫は、藻が成長していた石の表面に生息/藻と水生昆虫/河川水を求めた。水生昆虫と藻あしていたことから、藻は餌になっていると考えら

るいは水中の金属濃度の分布及び濃度は異なっれる。また、水生昆虫は流れてくる懸濁物やあるているのが普通であるが、仮に濃度は異なっていいは水中の金属も取り込むと考えられるので、どるが、その分布が同じであった場合、すなわち、

れが水生昆虫の金属濃度により影響を与えてい

例えば、水生昆虫が水中のすべての金属を等しくるかを濃度比解析から行なった。

生物濃縮していたとしたら、マトリックス比 Y の藻、河川水及び水生昆虫の各試料に検出された

図４

すべて成分は１となる。従って、水生昆虫/藻と水マトリックス比の分布、上段（水生昆虫/藻）、下段（水生昆虫/河川水）－ 428 －

JAEA-Review 2008-067

生昆虫/河川水のマトリックス比 Y を比較したと金属濃度に、場所による違いは観察されなかった。

き、より１に近い成分を多く含む方が、より水生また、2004－2005 年に測定した限りでは、黒髪生物と金属の分布が近くいと言える。すなわち、

では季節による差は見れていないことから、白川

水生昆虫はより大きな影響を受けていると考えの水質環境にその間変化はなかったといえる。

ることができる。これにより餌として藻の影響と水生昆虫の金属濃度は、河川水よりも餌からの生息環境としての河川水の影響を比較すること

影響をより大きく受けていることから、水質環境ができる。図４に黒髪で採取した水生昆虫についの指標として利用する場合には、このことを考慮て求めたマトリックス比を示す。図４では、上段して利用することが必要である。

に水生昆虫/藻の分布を、下段に水生昆虫/河川水の分布を水生昆虫の種類ごとに示している。分布成果公表

がより１に集まっているほど水生昆虫の金属濃国際会議発表度に影響を与えていると判断される。ヤマトフタ(1)

ツメカワゲラ以外の水生昆虫では、明らかに上段

Nakamura, ”Metal concentrations of aquatic insectに示している水生昆虫/藻の分布がより１に集中

larvae and attached algae inhabiting stone surfaces in

した分布を示していることがわかる。多くの水生unpolluted stream”, 12th International Conference

昆虫は草食性であることが知られているので、図on

４は水生昆虫は餌と考えられる藻の金属により

21, 2007 at Tokyo Metropolitan Univ., Hachioji-shi,

近い金属分布をしていると言える。カワゲラの一Tokyo, JAPANN. Momoshima, S. Sugihara, K. Hibino, Y.

Modern Trends in Activation Analysis, Sep. 16-

部の種類は雑食性であることが知られている。ヤ
マトフタツメカワゲラが雑食性であるかどうか

Publications

は不明であるが、ヤマトフタツメカワゲラ/藻のマ(1) Momoshima, N., Toyoshima, T., Matsushita, R.,

トリックス比の分布が他の水生昆虫よりばらつ

Fukuda, A. and Hibino, K. (2007) Metal

きが大きいのは食性の違いを反映している可能concentrations in Japanese medaka, mosquitofish

性がある。

and insect larvae living in uncontaminated rivers in
Kumamoto, Japan. J. Radioanal. Nucl. Chem., 272,

4．まとめ

495-499.

水生昆虫は、河川水に含まれる金属より、生息している石に成長していた藻の金属の分布に、よ(2) Momoshima, N., Sugihara, S., Hibino, K.and

り近い金属分布を持つことが明らかになった。こNakamura, Y. (2008) Elemental concentrations of

れは藻が水生昆虫の餌であることと関係していaquatic insect larvae and attached algae of stone

ることを示唆しているが、雑食性と思われる水生

surface in uncontaminated stream, J. Radioanal.

昆虫では異なっていた。藻の Zn 濃度は検出限界

Nucl. Chem., submitted.

以下であったにも関わらず、いずれの水生昆虫にも高い濃度で Zn が検出された。このことは、必須元素については、餌以外からの金属の取り込みがあることを意味している。白川の上流から下流までの 20km 程度の範囲では、水生昆虫及び藻の－ 429 －

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JAEA-Review 2008-067－ 431 －

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JAEA-Review 2008-067

5-1
研究テーマ：フィッショントラック法による環境試料中の核物質検出表

題：フィッショントラック法の保障措置環境試料パーティクル分析への応用

フィッショントラック法の保障措置環境試料パーティクル分析への応用

李 致圭、井口一成、伊奈川潤、鈴木大輔、江坂文孝、間柄正明、桜井 聡、篠原伸夫、臼田重和

日本原子力研究開発機構 原子力基礎工学研究部門 環境・原子力微量分析研究グループ

フィッショントラック（FT）－表面電離質

粒子の濃縮度だけではなく粒径にも依存する。熱

量分析（TIMS）法によるパーティクル分析法は、

中性子の数と粒径が同じである場合、FTのエッ

2 次イオン質量分析器（SIMS）では測定が難しい

チング速度はその数が多い高濃縮度のウラン粒

粒径 1 μm以下の核分裂性物質を含む微小粒子に子ほど早くなる。これは、高濃縮度のウラン粒子

対しても同位体比分析が可能であることから、保ほど短い時間でエッチングされることを意味し、障措置上有効な分析手法とされている。フィッシ

エッチング時間の制御によってウラン粒子の濃ョントラック法では熱中性子照射により起こる

縮度別検出が可能であることを示唆する。2)

核分裂の痕跡（フィッショントラック、飛跡）か検出器のエッチング時間の制御によりウラら核分裂性物質を高感度に検出できる。我々がこン粒子を濃縮度別に検出するためには、濃縮度ごれまでに開発したFT-TIMS法では、核分裂性物質とに検出されるエッチング時間を求める必要がを含む粒子をFT検出器の中に閉じこめるので（1ある。その結果を図 1 に示す。実験では、粒径の層式FT 試料調製法）、高い検出効率、試料調製違いによる影響をできるだけ小さくするために、の簡便さなどの長所がある。しかし、検出器のエ

2 段式粒子吸引法によりウラン粒子の粒径を 1～

ッチングの際、ウラン粒子の一部が溶解すること

3 μmにした。図 1 は、熱中性子照射後、エッチンがある。そこで、粒子保持層とFT検出器部を分グによりFTが検出されるまでのエッチング時間

離した 2 層式FT 試料調製法の開発を行った。このウラン粒子の濃縮度依存性を示しており、濃縮の方法では粒子層と検出器の一端を固定するこ

度が高くなるほどFT検出までのエッチング時間とにより、粒子溶解の問題だけではなく、従来のが短いことが分かる。この関係を利用して、ウラ2 層式 FT試料で見られた検出器でのFTと粒子層

ン粒子の濃縮度別検出の実証実験を行った。試料

での目的粒子との位置ずれを解決し、目的粒子のは天然組成のウラン（NU）と 35%濃縮ウラン

検出効率を向上させた。今回は、本法の長所であ（U350）を混ぜて作製した濃縮度混合試料を用る、検出器の繰り返しエッチング後でも目的粒子いた。濃縮度別検出のためのエッチング時間は、の同定が正確で簡便であることを利用して、保障U350 のみが検出される時間である 2.5 分と、NU

措置上重要な高濃縮度のウラン粒子を優先的にが十分検出される時間である 7 分を用いた。それ

1)検出できる方法の開発状況について報告する。

ぞれのエッチング時間で検出した粒子のTIMSにウランの同位体において熱中性子照射によよる同位体比測定の結果を図 2（a）と（b）に示

235

り核分裂が起きるのは Uであるので、FTの数は

原子炉：JRR-4

す。図 2（a）に示すように、エッチング時間 2.5装置：気送管－ 433 －

分野：その他（フィッショントラック法）

JAEA-Review 2008-067分で検出した粒子はすべてU350 の認証値（235U/
238

6.0 x 10 -1

U：0.5465）に一致している。一方、エッチンのエッチング後でU350 が検出されたのは、2.5 分のエッチングで検出されなかった粒径の小さい
U350 粒子の出現に起因することであり、これは7 分のエッチングにより現れたFTの形状から確

235U/ 238U

グ時間 7 分で検出された粒子は、図 2（b）に示
すように、NUとU350 の双方が検出された。7 分(a)5.8 x 10 -1
5.6 x 10 -1
5.4 x 10 -1

U350

5.2 x 10 -1
5.0 x 10 -1（認証値： 0.5465）

0

1

2

3

認できる。図 3（a）と（b）にエッチング時間 2.5
分と 7 分で現れたFTの典型的な形状を示す。写

6.0 10-1

分のエッチングにより現れたNU（10, 11）とU350（16,17）はFTの形状から、両者は明確に区別できる。図 3（b）の写真 16 と 17 のFT形状（トラ235U/ 238U

真の番号は、図 2 の粒子番号に対応している。7

8

9

10

(b)

5.0 10-1
4.0 10-1

U350（認証値： 0.5465）

NU(7.25x10-3)

1.7 10-2

3.4 10-3

NU（10, 11）の形状よりも、2.5 分のエッチングにより現れたU350 のFTと同様な形状をしている。

完全な濃縮度別検出に至らなかったが、FT の形

7

1.0 10-2

ックの本数）は、同じエッチング時間で出現した

このように、エッチング時間の制御だけでは

4 5 6
粒子番号

10 11 12 13 14 15 16 17 18 19 20 21 22
粒子番号

図 2 濃縮度混合試料（NU+U350）において、エッチング時間 2.5 分（a）と７分（b）で検出された粒子の TIMS による同位体比。

状を比較することにより高い割合で濃縮度別検出が可能であることが示された。

1

2

����
1) C.G. LEE et al., Jan. J. Appl. Phys. 42 (2006)
L1121-L1123.
(a)2) C. G. LEE et al., NIMB 245 (2006) 440-444.
100

11

16

17

図3

(b)
濃縮度混合試料（NU+U350）において、エ55℃,
55℃,6M-NaOH
6M-NaOH80
濃縮度 (%)

10

60
40
20
0
0

1

2

3

4

5

6

7

8

エッチング時間 （分）図１

種々の濃縮度のウラン粒子における、FTが検出されるまでのエッチング時間の濃縮度依

ッチング時間 2.5 分（a）と 7 分（b）で検出され存性。

た粒子の FT 形状の例。写真の番号は、図 2 の粒
子番号と対応する。

－ 434 －

JAEA-Review 2008-067

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JAEA-Review 2008-067

5-4

ԑದҺӛҵҡҚҵҳӥҢၓџѼѿިଟา৳੔ᆍඨྑᆘӎӟӥѢࠑੳObservation of the ultra small amount boron in various steel materials by
α particle track etching method
東京大学大学院工学系研究科マテリアル工学専攻

朝倉健太郎、長崎千裕、小関敏彦

Department of Materials Science, Faculty of Engineering, The Univ. of Tokyo
K. Asakura, C. Nagasaki and T. Koseki

��研究の目的と������研究の目的
ボロン（以下 B）は極微量でも鉄鋼の性質を向上させることが知られており、非常に多くの鋼で利用されている。さらに今後ますます重要となる環境問題、資源・エ
ネルギー問題に対処できる鋼としてB添加鋼の重要性の認識が高まっている。
著者らは日本原子力研究開発機構(JAEA と略称)の医療用照射設備を用いて熱中性子とボロン 10 の反応を利用したα線トラックエッチング（以下、ATE と略）法について実験を進めてきたが近年、医療本来の需要、ないしは動物実験のマシンタイムが増しているため、ATE 法のマシンタイムが減少傾向にあった。
この3 年間は、ATE
法を利用できる気送管による照射システムを立ち上げた。またフェライト系耐熱鋼および Cu-Sn 含有鋼について B の状態分布について研究を進めてきたので報告する。
��研究成果��������� �� ����4 �������������
�����������������������
����������
����
ボロンを極微量添加することによって鉄鋼の諸性質を向上させる研究は盛んに進められている1)、2)など。古くはArmijoらの論文があるが、当初はオーステナイト鋼中のボロンを検出するために使用された3)。またボロン添加鋼における焼入れ性とオーステナイト粒界へのボロンの非平衡偏析4)や、粒界偏析におけるボロン欠乏域の幅か
ら非平衡偏析が説明されている4,5)。さらにボロンはNbの有無によりそれらの効果が異なることが明らかにされてきた6)。しかし鋼中のボロンの挙動については不明な点が多く、さらに高性能な鋼を開発するためには、ボロンの詳細な挙動を明らかにする必要がある。

一方で、ボロンのような軽元素の可視化や、定量分析
を機器分析で行うことは容易ではない。最近はEDS(Energy Dispersive X-ray Spectroscopy)検出器の高性能化に伴い、X 線吸収の少ない有機高分子膜の
UTW(Ultra-Thin Window)が開発され、ボロンまでの分析
は原理的には可能であるが、濃度が 0.2mass％以下であると定量分析は難しい。
他方、EELS(Electron Energy Loss
Spectroscopy)で精度よく分析するには試料の最適膜厚が 50nm以下と制限されるため、薄くした際にバルクとの組成比の相関性や、バックグランドが高いために微量元素の分析には適さないなどの問題もある3)。
α線トラックエッチング（以下ATEと略称）法は中性子照射による10B（ｎ,α）7Li反応を利用することにより、ppmオーダー以下で検出できる高感度を有している唯一の可視化法である。このための中性子照射源を有した立教大学原子炉は、2000 年 3 月をもって閉鎖された。この問題に対応できる機関として、我が国では日本原子力研
究開発機構(JAEAと略称)しかない。著者らはJAEAにおいて、これまで立教炉で行われてきたような便利さで、ATE法が利用できるシステムを立ち上げることを目指して実験を行い、医療用照射設備を転用することで、従来とくらべて遜色のない鋼中ボロンのATE像が得られる照射条
件を明らかにしてきた4)､5)。
しかし近年、JAEA 炉の医療用照射設備は医療本来の需要、ないしは動物実験のマシンタイムが増しているため、ATE 法のマシンタイムが減少傾向にある。そこで JAEA 炉の照射設備として比較的容易に使える JRR-4 の簡易設備
T パイプ、N パイプについて検討したが、秒単位で照射束をコントロールすることができないため、気送管による照射を試みた。著者らは過去に、気送管照射の短所として、①炉心まで輸送している途中に振動（衝撃）が原因
でフィルムのはく離が生じる、②照射線源に対して試料が平行であった場合、α線の放射化確率が低下する、③ボロン像を観察するには、非常に正確な照射時間が必要である。④速中性子束（ファストニュートロン）やガン

JRR-3（気送管照射設備）、JRR-4（医療用照射設備）、鉄鋼材料工学、ボロン状態分布観察－ 445 －

JAEA-Review 2008-067

マ線量が高いことなどから気送管による照射を断念してきた経緯があった4)。
にもかかわらず医療用照射設備は、前述したようにマシンタイムの制限が生じているため、より簡便な気送管を用いた ATE 法について積極的に検討を進めた。
��実験方法��� ATE 法によるボロン分布の��
ATE法を用いるには、
核反応によりα線をつくり出す必要がある。10B（ｎ,α）7Li反応は、中性子照射によって熱中性子と対象とする元素との間で核反応を起こさせ、α線の放射を生じさせる。この核反応が生じる頻度は放射化散乱断面積によって表される。放射化断面積の大きい核種は10B（4017born）であり、6Li（945born）、17O（
0.4born）がこれに続く。Li、Oは鋼中の濃度が少ないため、10B（ｎ,α）7Li反応を生じる同位体の量も小さい。
したがって、他元素の影響を無視して、10Bのみが、(1)式の10B（ｎ,α）7Li反応によってα線が放射されると考えて良い。
10B＋1n → 7Li＋4He(α)＋2.4MeV ・・・・・(1)
核反応中に放射されるα線の鋼中の飛程は数μｍであるため、ボロンの分布および形態情報は試料表面から数μｍ以内に存在したボロンといえる。
ATE像の撮影までの手順をFig.1 に示す。試料を 0.2～
1mm厚に切り出し、片面のみをエメリー紙研磨にて粗研磨を行い、その後、鏡面に仕上げる。鏡面仕上げした面に
酢酸メチル、あるいはアセトンを滴下した後、工業用硝酸セルロースフィルム（以下フィルムと略）を試料に貼り付けるが、フィルムと試料表面の間に気泡が入らないようにする。中性子照射後は、試料の残留放射能が減衰するのを待ち、試料からフィルムをはく離する。303K、
2.5mol・ｌ-1のNaOH溶液中で約 1.2×103s～2.4×103s程度
エッチング処理を行う。その後、フィルムを水洗後乾燥し、光学顕微鏡によってATE像を撮影する。

ATE 法のための照射条件を JAEA 炉で見出すには、はじめに中性子フルエンスおよびカドミニウム比を選定しなければならない。カドミニウム比は、共鳴中性子が熱中
性子中にどの程度混在するかを知る簡便な方法としてカドミウム被膜の有無による中性子検出器における計数の比が用いられている。共同利用者らが使える気送管としては原子炉 JRR-3M（出力 20MW）と JRR-4（出力 3.5MW）がある。しかし JRR-4 のカドミニウム比は 3.6 と低い。
JRR-3 の気送管には PN-1、PN-2 の照射路があり、カドミ
ニウム比が 23 である。また、同じ気送管でも PN-3 は放射化分析用照射設備として用いられている照射路であるが、カドミニウム比は 290 と高い。
気送管による照射は、Fig.2 に示すキャプセル内に対象試料（以下試料と略）を入れて窒素ガスで炉心に送り、任意の時間照射した後、再び窒素ガスを流して試料取出し口にキャプセルを戻す。気送管照射は短時間で照射が終了するため、照射料金も安価ですむという利点がある
反面、窒素ガスで炉心まで送気するため、試料からフィルムがはく離しやすいという欠点もある。これまでの実
験の経験上から、確率的に 30％程度がはく離すると考えた方が無難である。なお JRR-3 の気送管キャプセルの内径は PN-1 用(φ23.5×72L)、PN-2 用（φ28.5×82L）、
PN-3 用（φ10×21L）であり、JRR-4 の気送管キャプセ
ルがφ20.5×67L である。なお、キャプセルの大きさに拘わらず試料重量は 10ｇ以下に制限されている。

Fig.2

JRR-3 及び JRR-4 の気送管キャプセル

��� 熱中性子照射の�備
2.3.1 化学成分と熱処理条件用いた供試鋼の化学成分を Table 1 に示す。熱間圧延材を施した B10 鋼は、ボロン濃度が 19ppm の極低炭素
1.7Mn 鋼である。B140 鋼はボロン濃度が 140ppm の0.024C-9Cr-0.14Mo-2.5W-1.9Co-0.08Nb-0.19V-Fe のフ
Table 1. 供試鋼の化学組成 (mass%)
C

Fig.1 ATE 像の撮影までの手順
��� 中性子照射��－ 446 －

Cr

Mo

Co

V

B

B10

0.004

-

-

-

-

0.0019

B140

0.035

9.0

0.14

1.8

0.19

0.0143

JAEA-Review 2008-067

ェライト系耐熱鋼である。両鋼はボロン濃度が大きく異なる。熱処理条件はB10 鋼が 1373K、3.6×103s加熱後、空冷処理を施した。B140 鋼には 1373K、3.6×103s焼ならし、1053K焼もどし処理を施した。
2.3.2 試料照射と照射時間
JRR-3 の気送管による中性子照射条件は、Table 2 で示すように熱中性子束を制御するために照射時間を調整した。これまで立教炉で行ってきた最適と考えられる中性子フルエンス 6.5×1014n・cm－２を参照にした。以下、
このフルエンスを“参照フルエンス”と呼ぶ。PN-1 とPN-2の最小照射時間は原子炉の構造上から 30sであるため、それぞれ 14×1014n・cm－２と 15.6×1014n・cm－２であり、参照フルエンスの 2 倍以上になっている。PN-3 の熱中性
子束は 4.4×lO9n・cm－２s－１であるため、中性子照射を30s～53sの間で照射を行ったが、計算上は 43sが参照フ
ルエンスにもっとも近い。

だし試料とフィルムが密着していない場合は、Fig.3(b)に示すように粒界がより不鮮明になるので、ATE 像の良否については容易に識別できる。もちろんフィルムが試料からはく離した場合には、ATE 像を観察することはできない。PN-2（JRR-3 気送管照射）における ATE 像を
Fig.3(c)に示す。PN-1 に比べて、ほぼ似たような結果を示したが、鮮明さは PN-1 に比べて良好であった。
PN-3（JRR-3 気送管照射）におけるATE像をFig.4 に示す。30s照射における中性子フルエンスは 4.5×1014n
・cm－２であり、参照フルエンスに比べて約 70％低い。
Fig.4(a)に示すように粒界析出、粒内析出および粒界偏析を確認することができたが、わずかにフェライト粒界
は太めで、析出物が大きめに観察された。33s～36sでは粒界・粒内析出物が比較的鮮明に観察できた。

(a)

(b)

(c)

(a)PN-1(30sec 照射)

Table 2. JRR-3 気送管の中性子照射条件
Irradiation

Neutron fluencecadmiumtime (sec)(1014n・cm⁻²)

ratio

PN-1

30

15.60

23

PN-2

30

14.00

23

30～40

4.50～6.00

290

43

6.45

290

46～53

6.90～7.95

290

PN-3

(b)PN-1(30sec 照射);
はく離したケース
100�m

JRR-4 の気送管による熱中性子照射条件をTable 3 に示す。前述したようにカドミニウム比が 3.6 と小さい。
照射時間を 10s～28sとすると中性子フルエンスは（3.2～8.96）×1014n・cm－２になる。参照フルエンスにもっとも近い照射時間は 20s（6.4×1014n・cm－２）である。なお、フィルムをはく離するまでの冷却時間（放射能減衰）は、
JRR-3 およびJRR-4 ともに 3.6×105s以上とした。

Fig.3 JRR-3 気送管 PN-1,PN-2 における B10 鋼の ATE 像

Table 3. JRR-4 気送管の中性子照射条件
Irradiation time

Neutron fluence(sec)(1014n・cm⁻²)

10～18

3.20～5.76

3.6

20

6.40

3.6

22～28

7.04～8.96

3.6(c)PN-2(30sec 照射)

(a)

(b)

(c)

(d)

cadmium ratio
100�m(a)30sec 照射 (b)40sec 照射 (c)43sec 照射 (d)53sec 照射

Fig.4 JRR-3 気送管 PN-3 における B10 鋼の ATE 像
����結果��１ B10 鋼の ATE 像
PN-1（JRR-3 気送管照射）における B10 鋼の ATE 像を
Fig.3 に示す。中性子フルエンスは参照フルエンスの 2倍以上あったので、ATE 像は Fig.3(a)で示すように、粒界析出、粒内析出および粒界偏析が不鮮明であった。たまたFig.4(ｂ)に示すように 40s（6.9×1014n・cm－２）
において、最も鮮明にATE像を観察することができた。また 43s以上になるとフィルム面上に、トラック以外のしみ状の影響が顕著になる。
これらの結果は当たり前のように思われるかもしれな
いが、これまで JAEA 炉における気送管による ATE データ－ 447 －

JAEA-Review 2008-067

は皆無であり、参照フルエンスに妥当性があったと言える。
JRR-4 の気送管照射ではFig.5 に示すように、PN-3 の結果（Fig.4）に比べて、10～28sの照射時間（中性子フルエンス：3.2～8.96×1014n・cm－２）の全範囲においてATE像は不鮮明であった。なかでもFig.5(d)～(e)に示したATE像は、20～24sにおいて不鮮明さが顕著であった。
本来であれば、
20s前後の照射時間は参照フルエンスにほぼ一致していることから、鮮明に観察されてもよいはずである。他方、Fig.5(f) に示したように 28sでは、ATE
像の鮮明さがわずかに回復している。なお、この不鮮明に見えたATE像は剥離に起因した像形態ではなかった。
これらのことから“気送管照射の短所”で述べたように、照射線源に対して試料が偶然にも平行になったため、α線の放射化確率が低下し、像質が不鮮明になったものと考えられる。

PN-2（JRR-3 気送管照射）における ATE 像を Fig.6(b)に示す。鮮明さについては、B10 鋼と同じように PN-1 に比べて良好であった。
PN-3（JRR-3 気送管照射）におけるATE像をFig.7 に示す。参照とした中性子フルエンス（6.5×1014n・cm－２）に最も近い照射時間は 43sであるが、36～53s（中性子フルエンス：5.25～7.95×1014n・cm－２）の範囲においても、
粒界偏析と粒内析出物が比較的良好に観察できた。
他方、JRR-4 による気送管照射においては Fig.8 に示
すように、B10 鋼と同じように、10～28s の照射時間の全範囲において ATE 像は不鮮明であった。JRR-3 気送管照射の PN-1～PN-3 で観察された粒界偏析が、JRR-4 気送管
照射では観察されなかった。

(a)

(b)

(c)

(d)

�����

(a)10sec 照射 (b)14sec 照射 (c)18sec 照射 (d)20sec 照射(e)24sec 照射 (f)28sec 照射(a)30sec照射 (b)40sec照射 (c)43sec照射 (d)53sec照射Fig.5 JRR-4 気送管における B10 鋼の ATE 像

Fig.7 JRR-3 気送管 PN-3 における B140 鋼の ATE 像

３�２ B140 鋼の ATE 像
PN-1（JRR-3 気送管照射）における B140 鋼の ATE 像を
Fig.6(a)に示す。B140 鋼の ATE 像は B10 鋼に比べて、ボロン濃度が７倍以上高いことから、また後述するカーボ
ン抽出レプリカ像からも推測できるように、多くの析出
物（ほう化物）が観察できる。粒界偏析は、それほど鮮明ではないが旧オーステナイト（γと略称）粒界に相当する領域に沿ってφ10μm 程度の大きさで観察できる。
これらの結果より、粒内析出と粒界偏析を確認することができた。中性子フルエンスは、前述したように 2 倍以上であったが ATE 像は比較的良好に観察できた。

(a)10sec 照射 (b)14sec 照射 (c)18sec 照射 (d)20sec 照射(e)24sec 照射 (f)28sec 照射

Fig.8 JRR-4 気送管における B10 鋼の ATE 像

(a)

(b)

�����

(a)PN-1(30sec 照射) (b)PN-2(30sec 照射)

Fig.6 JRR-3 気送管 PN-1 および PN-2 における B140 鋼の ATE 像４�考察
ATE像の撮影までの手順はFig.1 に示したように、
2.5mol・l-1のNaOH溶液中で適当な時間エッチング処理した後に、光学顕微鏡によってATE像を撮影している。観察倍率としては 100～200 倍程度が最適である。
しかし光顕の観察倍率から換算した析出物の粒子径や、実測誤差などについての報告は皆無であり、これまでに、どのような像コントラストで結像されているかについての議論は－ 448 －

JAEA-Review 2008-067

Air cooling
ATE image

４�１ 気送管の照射�性
JRR-3 気送管（PN-1～PN-3）とJRR-4 気送管を用いてATE像を比較した。比較した気送管におけるカドミニウム比の違いは 3.6、23 および 290 であった。
この結果、Fig.3～Fig.8 に示したように、カドミニウム比が高いPN-3（JRR-3）の像質が最も優れており、カドミニウム比の低かったJRR-4 の像質は不鮮明であった。一つのトラックは(1)式の10B（ｎ,α）7Li反応に対応しているために、熱中性子の照射条件を最適化することによって、ppm以下という微量濃度のボロンでも検出可能である。
前述したようにカドミニウム比は、その照射孔における共鳴中性子に対する熱中性子の存在割合を示すので、カドミニウム比が高いPN-3 の照射孔は、熱中性子の相対的割合が高いといえる。他方、ATE像のバックグランドは
LiやOなどの元素から生じるα線の影響のほかに、
速中性子によるフィルム中のCやHの反跳があげられる。さらに
10B（ｎ,α）7Li反応は、速中性子よりもエネルギーの低い熱中性子の照射により生じる反応であるため、カドミ
ニウム比は大きい方がよいと言える。
したがってJAEA炉によるATEの像形成としては、
カドミ
ニウム比が高いPN-3 により最もきれいなATE像が得られた。この理由を考えるとボロンは熱中性子に対する放射化断面積が大きいので、ボロンと反応する熱中性子の数が増えれば、7Liに変わってα線を放出する確率があがり、フィルムに損傷を与えるためと考えられる。
さらに重要なことは、原子炉の出力（熱中性子束）は常に変動している。JRR-3 照射設備は連続運転であるため、熱中性子束が非常に安定しており、変動率は約１％程度である。他方、JRR-4 は毎日 6 時間の定時運転であるため出力は１回照射当たり±４％、１日の照射中においても±10％の出力変動が生じることが JAEA の調査でわかっている。この変動要因は原子炉の臨界を一定に保つために、絶えず制御棒 C1～C5 のうち C5 を小刻みに動かしており、これが原因でフラックスが変動する。また
C5 の稼働範囲を越えると C1～C4 を動かすが、出力変動はこのときに顕著になる。
このような出力変動があるため照射日によって出力変動が生じ、熱中性子束にも変動が生じる。このため ATE
像からボロンのマトリックスへの固溶、偏析、それに析出物の状態分布を議論する場合は同じ照射ロッドで、フィルムのエッチング温度、時間を同じにすることが重要である。

の分布状態をフィルム上で観察できるので、黒点はすべてボロン由来の分布および形態情報であるといえる。しかし、熱中性子照射によってフィルムにつけられた痕跡
は、このままの状態では光顕レベルの倍率では観察できないほど小さい。
そこで NaOH エッチング液によって痕跡を広げることにより、光顕で可視化できる。
B10 鋼を 1323K で加熱後、水冷（冷却速度：230K/s）
および空冷（冷却速度：13K/s）処理を行った。PN-3 （JRR-3）の参照フルエンスで中性子照射した後、所定の手順でフィルムにつけられたα線トラック（痕跡）を、ATE
像と SEM 像によって比較した写真を Fig.9 に示す。なお
SEM 像は試料に貼り付けたフィルム面側を、カーボン蒸着を施してから観察した。

Water-cooled
(b)

(a)

(c)
SEM image

医療用照射および気送管照射に係わらず、これらを理解していないことによって生じるいくつかの誤りについても考察した。

(d)

a

d

c
b

10μm

10μm

(a),(c): 結晶粒界上への偏析(冷却速度 230K/s)(b),(d): 結晶粒界・結晶粒内への析出(冷却速度 13K/s)

Fig.9 照射後 B10 鋼の ATE 像と SEM 像
冷却速度 230K/s の ATE 像は、
Fig.9(a)に示すように旧
γ粒界にボロンの偏析が見られる。また、同じように空冷した場合は、Fig.9(b)のように粒界偏析と粒内析出
物（ほう化物）が観察できる。1373K で空冷したときに見られる粒界偏析の状態は、たとえば Fig.4 とは異なり、未固溶のほう化物も観察できる。
Fig.9(a)に示したATE像の粒界偏析をSEM観察すると、
Fig.9(c)に示すように、フィルム表面には多くの穴が観察できる。結晶粒内にも多くの穴が観察できるが、とくに粒界に沿った領域には微細な連続穴が空いており、結晶粒界への偏析（表記ａ）と理解できる。また、Fig.9(b)(a)

４�� SEM による ATE 像の観察
基本的には照射条件を最適に選択すれば、微量ボロン－ 449 －（b）2μm(a) 偏析 ATE 像 (b) 析出 ATE 像
Fig.10 Ｂ10 鋼における AET 像の拡大 SEM 像

JAEA-Review 2008-067

あるいは粒内析出物をSEMに示したATE 像の粒界析出物、観察すると Fig.9(d)に示すように、フィルム表面には孤立した大きな穴（表記ｂおよび表記ｃ）と、連続した穴（
表記ｄ）が観察できる。表記ｂは粒界析出物、表記ｃは粒内析出物、そして表記ｄは粒界偏析に相当する。
Fig.9(c)および(d)を拡大したSEM像をFig.10 に示す。１μm程度の大きな析出物ほど、析出物中に固溶している
10Bがα線を四方八方に放射するため、大きな穴を形成していることがわかる。
このように ATE 像の実体は、フィルムにつけられたα線トラックを NaOH のエッチング液によって痕跡を広げることにより、光顕で可視化している。したがって ATE
像の実体は Fig.10 に示したように「穴」の状態変化か
らボロン偏析や、析出状態を間接的に観察している。つ
まり金属組織のように試料をエッチングして観察した直接像ではなく、間接像にすぎない。とはいえ、ボロンの状態分布を 1ppm オーダーで捉えることができる情報源としては、何ものにも代え難い観察手段である。

Carbon extraction replica image

ATE image

(b)

(c)

Steel B10

(a)

100nm

0.5μm

(e)

(ｆ)

1000
2μm

250nm

Precipitation diameter in carbon
extraction replica image(nm)Steel B140

(d)

100μm

Fig.11(b)に示す。B10 鋼の多くの析出物は中央部に見えるフェライト粒界には観察されず、結晶粒内に微細分布している。しかし倍率を上げて観察すると、わずかではあるがFig.11(b)に示すようにフェライト粒界にも観察できる。析出物サイズは約 25nmと小さい。B10 鋼のATE
像はFig.11(c)に示すように結晶粒界には、ボロンの粒界偏析が観察され、粒内には微細な析出物が多く観察できる。この微細析出物の大きさを単純に倍率換算すると、
約 5～10μmになる。ATE像による析出物の大きさは、カーボン抽出レプリカ像から得られた析出物の大きさと比較すると、200～400 倍の大きさになっている。
また B140 鋼の析出状態は、
カーボン抽出レプリカによると Fig.11(d)および Fig.11(e)に示すようになっている。微細な析出物は 100nm 以下であるが、粗粒になると約１μm のものが観察できる。Fig.11(e)には 250nm サイズ（中央部）と、20nm サイズ（右上）の析出物が混在して観察できる。ATE 像は Fig.11(f)に示すように、多くは微細析出物からなる。ボロンの粒界偏析が観察され、粒内には微細な析出物が多く観察できる。B10 鋼と同じように析出物の大きさを倍率換算すると１μm の場合は 13倍、250nm の場合は約 50 倍、25nm の場合は 650 倍と開きが大きくなる。
Fig.11(f)で観察された粒内の超微細な点状析出物（母相を黒くしている要因）を１μm として換算すると、1～65 倍に縮まる。

100μm(a),(b) ,(c)： Steel B10 (d),(e) ,(f)： Steel B140
Fig.11 B10 鋼とB140 鋼におけるカーボン抽出レプリカ
像と ATE 像の比較
４�� ATE 像による粒子径と誤差
ATE 像から得られた析出物（ほう化物）やボロンを含んだ介在物粒子の大きさ（サイズ）を知ることは、材料の特性や強化メカニズムを議論するには重要な情報となる。ATE 像からはボロンの粒界偏析やほう化物の粒界析
出、および粒内偏析や粒内析出などの状態分布などを知ることができる。他方、ほう化物の大きさを正確に知るにはカーボン抽出レプリカ法や透過電顕（薄膜透過像）法がある。しかし ATE 法のようにボロンの固溶やボロンの状態分布を知ることはできない。このように実際のほう化物の粒子径と、ATE 像から求めた粒子径との誤差を求めるには、カーボン抽出レプリカ法と ATE 法による実測が不可欠になる。
B10 鋼とB140 鋼を、1373Kから空冷した後のカーボン抽出レプリカ像を観察するとFig.11 のようになる。また
ATE像も比較のために掲載した。
カーボン抽出レプリカ法
10)によって観察したB10鋼の析出状態をFig.11(a)および

800
B140
600
400
200
0
0

B10
10

20

30

40

Precipitation diameter in ATE image( μm）

Fig.12

ATE 像とカーボン抽出レプリカ像による析出
物サイズの相関性

B10 鋼と B140 鋼のカーボン抽出レプリカ像と ATE 像の析出物サイズを比較すると、Fig.12 のように両者は大きく異なる。また析出物（ほう化物）の大きさや、ボロン濃度によっても誤差が生じる。たとえば、ボロン濃度が高い（放射化確率が高い）B140 鋼の場合、100nm サイ
ズのほう化物が、ATE 像では 5～6μm の大きさに観察できる。しかしボロン濃度が低い B10 鋼の場合には、15μm－ 450 －

JAEA-Review 2008-067にもなる。この理由はエッチングによって可視化する際に、ボロン濃度が低い（放射化確率が低い）と、エッチ
ング時間をより長くする傾向にあり、このため見掛けのサイズが大きくなると考えられる。このように Fig.12において、B10鋼とB140鋼の曲線の中点から求めた100nmのほう化物は ATE 像では 10μm になり、おおよそ 100 倍程度のサイズ誤差が生じる。
４�４ ATE 像のコントラスト
ATE 像を観察する際に注意することは、焦点合わせとコントラストの選択である。これまで示した ATE 像の写真から、ボロンが結晶粒界に偏析している場合は黒い線、
析出物（ほう化物）であると黒点として観察してきた。
しかし、本当に正しい像コントラストであるかを確認する必要がある。たとえば、B10 鋼を通常コントラスト（
ブラックコントラストと略）で観察すると Fig13(a)に示
すようになる。しかし、観察場所を変えないで焦点位置だけを変化させると、粒界偏析は Fig13(b)のように白い線（ホワイトコントラストと略）として観察できる。どちらのコントラストも正しいように思われるかもしれな
いが、よく見るとホワイトコントラストには黒点の析出物が観察されていない。つまり本当は存在するのに、あたかも存在していないようなコントラストになってしまう。フィルム表面を SEM 観察した結果、多数の穴があいていたことから、黒線あるいは黒点が ATE 像としては正しいコントラストであることが理解できる。
(a)

(ｂ)

�����

(a)ブラックコントラスト

Fig.12(b)ホワイトコントラスト

B10（1373K）におけるＡＴＥ像のコントラ
スト比較

��結�
日本原子力研究開発機構において、ATE 法が利用できる気送管システムを立ち上げるための実験を行った。結果をまとめると以下のようになる。
(1) ATE 用照射設備としては JRR-3、PN-3 気送管の像質が優れており、
JRR-4 気送管の像質は不鮮明であった。カドミニウム比はそれぞれ 290、3.6 であった。
(2) カドミニウム比は、その照射孔における共鳴中性子に対する熱中性子の存在割合を示すので、カドミニウ
ム比が高い PN-3 の照射孔は、
熱中性子の相対的割合が高いといえる。
(3) JRR-4 気送管の 20～28s 間で ATE 像が不鮮明であった原因は、照射線源に対して試料が偶然に平行になったため、α線の放射化確率が低下し、像質が不鮮明になったものと考えられる。
(4) カーボン抽出レプリカ像と ATE 像からほう化物（析出物）サイズを比較すると、両者で大きく異なる。ATE像によるほう化物の大きさは、真の大きさよりも約
100 倍のサイズ誤差を生じる。
(5)ほう化物の大きさはボロン濃度によっても誤差を生じる。これはエッチングによって可視化する際、ボロン濃度が低いあるいは放射化確率が低いとエッチング
時間が長くなる傾向にあり、見掛けのサイズが大きくなるためと考えられる。
(6) フィルム表面に観察できるコントラストは黒点が析出物（ほう化物）、黒線は粒界偏析に相当する。
参考��1) 日本鉄鋼協会：鉄鋼材料の組織と特性に及ぼすボロンの影響、(1999)
2) 日本鉄鋼協会：鋼中微量ボロンの挙動と性質への影
響、(2003)3) J.S.Armijo and H.S.Rosenbaum:J.of Appl.Phys.,385(1967)2064-2069
4) X.L.He and Y.Y.Chu: Appl.phys.,16(1983)11451158
5) X.L.He,Y.Y.Chu and J.J.Jonas:Acta metal mater.
37,1(1989)147-1989
6) X.L.He, M.Djahaz, J.J.Jonas and J.J.Jonas:Acta
metall.mater. 39,10(1991)2295-2308
7) 朝倉健太郎、平坂雅男、為我井晴子編著：失敗から学ぶ電子顕微鏡試料作製技法 Q&A, (2006)、199、ア
グネ承風社
8) K.Asakura, K.Shibata, H.Sawahata, M.Kawate and
S.Harasawa :Tetsu-to-Hagane, 89, (2003), 369-374
9) K.Asakura, K.Shibata, S.Harasawa, H.Sawahata
and M.Kawate :Tetsu-to-Hagane, 89, (2003),
375-38010) 堀内繁雄、弘津禎彦、朝倉健太郎編著：電子顕微鏡
Q＆A(1996),174、アグネ承風社

研��：� �� ������������� � ���１���
石炭焚き火力発電プラントの高効率化が国内外で推進されており、超々臨界圧（USC）の蒸気条件も 650～760℃の利用に向けて研究が推進されている。
欧米では従来、主として ASME P91 が使用されてきたが温度上昇、経済性などから現在では ASME P92 が使用されるようになった。
しかし 650℃、35MPa 以上の蒸気条件を達成するには、これまでの高 Cr フェライト系耐熱鋼のクリープ破断強度－ 451 －

JAEA-Review 2008-067

２��験方法２－１ 試料の化学成分
高 Cr 耐熱鋼の長時間クリープ破断強度に及ぼす供試
鋼の化学組成を表1に示す。
T11鋼は0.087C-10.9Cr-2.6W-2.6Co-V-Nb(47ppmB)であり、C9 鋼は 0.035C-9Cr-2.4W1.8Co-V-Nb(70ppmB)の組成である。そのほかの主要合金
元素は 0.15Mo、0.07Nb、0.20V を添加している。両鋼とも 50kg を真空溶解し、Mn と Si によって脱酸した。鍛造
比は約 10 である。
表１ T11 鋼と C9 鋼の化学成分（mass%）
C

Cr

W

Co

T11

0.087

10.87

2.6

2.61

C9

0.035

9.06

2.4

2.44

Ni

N

B

Al

0.10

0.046

0.0047

0.006

<0.01

0.070

0.00700.001

ログラムにより定量分析を行った。分析時のビーム径は15～25nm であった。透過電子顕微鏡は日本電子製のJEM-4010（加速電圧 400kV）を用いて、倍率 20,000～
100,000 倍で撮影した。
２－３ ATE 法によるボロン状態分布観察
Bの挙動はα線トラックエッチング（ATE）法を用いて、析出形態および分布を調べた。
ATE法は熱中性子とボロンとの間で核反応を起こさせ、α線によって試料の表面に貼った硝酸セルロースフィルムの表面に痕跡を生じさせる。10B＋1n→7Li＋4He（α）の反応によって、Bの分布状態を観察することができる。
この方法はBの観察にもっとも有力な手法のひとつであり、検出感度もB含有量が1ppm以下の試料でも観察が可能であるなど優れた長所を有している2)。つまりBの存在位置（たとえば粒界、粒内）
や形態（たとえば偏析、析出）状態を比較的容易に観察することができる。
ATE 用の試料はクリープ破断した試験片を輪切りにして観察した。中性子照射は日本原子力研究開発機構の原
子炉 JRR-4（3.5MW）を用いた。
３�研究��と考察
３－１ クリープ破断曲線の腰折れ挙動
T11 鋼のクリープ破断曲線は図１に示すように、1000hを超えるあたりから腰折れが認められ、100N/mm2において破断寿命は 4000h程度であった。T11 鋼は、後述する逆Ｓ字クリープ現象が見られたC9 鋼に比較してCr、C量が高く、NiおよびAl量が高い。
1000

11CrWCo steel, 650℃

Stress ( N/mm2 )をしのぐ Ni 基超耐熱合金の開発が必要とされている。
しかし、これらの発電プラントは経済性に課題があることは明らかである。
そこで現在最もすぐれていると考えられるボイラ用９Cr耐熱鋼の化学成分、熱処理および予想される 550℃～
650℃、105時間のクリープ破断強度を推定した。このボ
イラ用９Cr耐熱鋼を使用すれば、主蒸気圧力 35MPa／主蒸気温度 650℃／再熱蒸気温度 650℃、1000MW級の火力発電プラントの建設が可能になり、最も安価な電力を得ることができ、しかも現用の火力プラントより大幅にCO2を減少させることができ、環境にすぐれたものを得ることができると考えられる。
9～12Cr耐熱鋼においてAl、Niを低下させると 650℃、105時間のクリープ破断強度を高めることが明らかになっているが、従来発表されているAl、Niの単独および複合添加の影響を調べた。一部のフェライト系耐熱鋼については１万時間未満においてクリープ破断曲線の腰折れ（折れ曲がり）が認められる鋼がある。他方、１万時間付近でわずかに強度低下を示しながら再びクリープ強度維持（逆Ｓ字クリープ現象）1)を示す鋼がある。ここでは主としてB（ボロン）の挙動と、Al、Ni添加量が及ぼすZ相析出、それに関連したLaves相の粗粒化抑制と、MXの微細化からクリープ破断強度因子を特定することを目
的とした。

100

10
1

２－２ ミクロ組織
T11 鋼と C9 鋼のミクロ組織観察は透過電子顕微鏡（日立製 H-800：加速電圧 200kV）によって行った。析出物の個々の組成分析は EDS（エネルギー分散型スペクトル分光器）を用いて行った。マトリックスの影響を除去するために各種破断材からカーボン抽出レプリカを作製し、EDS を用いて組成分析を行った。EDS 分析はトレイコア・
ノーザン社製のエネルギー分散型 X 線分析装置を用い、SMTF（Standardless Metallurgical Thin File）補正プ

10

100

1,000

10,000100,000

Time to rupture ( h )図１ T11（11Cr-W-Co）鋼のクリープ破断強度
３－２ 逆Ｓ字クリープ破断曲線
他方、C9 鋼は図２に示すように１万時間付近でわずかに強度低下を示しながら逆Ｓ字クリープ破断現象を示した。100N/mm2における破断寿命は 30,000h以上ある。
朝倉ら3）はNi添加量が高いとフレッシュマルテンサイトを生成し、このため焼もどし時における硬さを上昇させ、短時間側のクリープ破断強度を高めるが、長時間側強度を低下させることを指摘している。一方、T11 鋼および－ 452 －

JAEA-Review 2008-067

C9 鋼の初期組織に大きな違いが認められることから、変態温度の違いが転位密度、マルテンサイトラス幅、析出
挙動など下部組織に与える影響も考えられる。
1000

2

Stress ( N/mm )650°C
Normlize/Temper
1,050/780°C
C9-A 1,050/780°C
1,100/780°C

ブグレイン）が観察され、析出物も大きなものでは約１μｍにもなる。
T11 鋼における 650℃-7,158h破断材平行部の抽出カー
ボンレプリカ像からMX型（NbC）の析出物を同定した。ここで観察されたMX（NbC）のサイズは 50～70nmであった。
このほかにM23C6、Laves相およびZ相が同定された。

Reverse-S（２）C9 鋼のミクロ組織
C9 鋼の特徴は写真 2 に示すように、マルテンサイトラ
スの形態が破断時間 11,000h 付近でも鮮明に見られる。
ラス内部の転位密度も 2,000h 程度では as NT（焼ならし/焼もどし）
まま材に比べ、
遜色のない転位密度であった。

100(

Running)

10
1

10

100

1,000

10,000100,000

Time to rupture ( h )図２ C9（11Cr-W-Co）鋼のクリープ破断強度
３－３ クリープ破断曲線のミクロ組織
マトリックスの組織変化については薄膜法、M23C6、
Laves相、Z相およびMXなどの析出に関しては薄膜法とカーボン抽出レプリカ法、そしてATE法を併用して観察するが、ここでは主として薄膜法について簡単に触れ、ATE法について詳述した。
（１）T11 鋼のミクロ組織
写真１にクリープ破断強度の腰折れが認められた T11
鋼の TEM 組織を示す。写真１(a)～（f）は撮影倍率 5,000
倍の比較的低倍で観察したミクロ組織である。
0.6h～17h
破断材において旧オーステナイト（γ）粒界およびマルテンサイトラスの境界には多くの析出物が密集して観察される。短時間側で破断した試験片であるにもかかわらずラス内部の転位密度が低い。クリープ破断強度の著しい低下が認められた 1,632h 破断材では、写真 1(c)に示したようにラスの形態が崩れ、ラスの幅にも広がりが見られる。
約 3,000h になるとラスの形態は残っているがラス幅は広がり、析出物も写真 1(d)に示したように粗大化(a)as NT (b)4.7h(c)75.2h (d)484.5h(e)1,604h (f)2,168h (g)8,715h (h)11,424h
写真 2 C9 鋼における 650℃破断材平行部の TEM 組織
8,700h 破断材では、
写真 2(g)で示すようにラスの形態は残っているが、転位密度の低い領域も認められた。このまま下部組織の回復が進行すれば腰折れの原因になると思うが、11,000h 破断材では写真 2(h) に示すように、１μｍ程度の亜結晶粒が多数観察され、微細な析出物にピンニングされた転位が多数観察される。
つまり 1 万時間加熱でも高い転位密度が観察される。
この領域を高倍率（撮影倍率 50,000）に拡大すると写真���
写真 3 C9 鋼における 650℃ｰ 11,424h 破断材平行部のTEM 組織(a) 0.6h (b) 16.9h (c) 1632h (d) 3030h(e) 4898h (f) 7158h
写真１ T11 鋼における 650℃破断材の TEM 組織している。5,000h 以上の破断材では、写真 1(e)および写
真１(f)に示したように回復が著しく進んだ亜結晶粒（サ

3 に示すように約 200nm、また 10～12nm 程度の微細析出物にピンニングされた転位が多数観察される。このように下部組織の回復が著しく抑制された下部組織が母相と－ 453 －

JAEA-Review 2008-067

なり、逆Ｓ字クリープ現象を示したものと考えられる。
11,000h付近になると微細析出物の密度が高くなるのに加えて、再び転位密度の上昇が認められる。また、短時間側で認められなかったFe2W型金属間化合物Laves相が観察される。T11 鋼では比較的短時間で析出したのに比して、C9 鋼では遅れて析出する傾向が認められた。さらに析出物サイズもここで示したように大きなものでも300nm程度で、Laves相（Fe2W）の粗大化が抑制されていることが確認された。
３－４ ATE 法による B の挙動
Bの挙動を調べるために主としてATE法によって調べた。
ATE法で析出物を観察すると黒いコントラストがついて見える。前述したように、この方法は熱中性子により核反応10B（ｎ、α）7Li反応をつくり、α線を放射させる。
この反応が生じる頻度は放射化散乱断面積によって表される。
放射化散乱断面積の大きい元素がB(4017barn)であり、Li(945barn)、O(0.4barn)と続く。Li、Oは鋼中の含有量が少ないため、B（正確には10B）だけが10B（ｎ、α）
7
Li反応を生じて、α線を放射する。したがって、このコ
ントラストはBのみによって形成されたコントラストと考えてよい。
（１）T11 鋼の ATE 像
B添加によってM23C6やLaves相の粗大化が抑制され、MXが微細化されることは、すでに多くの研究報告があるたとえば４)。他方で、Bは旧γ粒界上や旧γ粒界近傍のM23C6中に濃化されており、Bの大半がM23C6中に含まれると報告されている５)。そこでT11 鋼、650℃破断材のB分布状態をATE法によって調べた。この結果を写真 4 に示す。

(a)

(b)

(c)

(d)

(e)

(f)

���� �

(a)0.6h(b)16.9h(c)1,632h(d)3,030h(e)4,898h (f)7,168h
写真 4 T11 鋼における 650℃破断材平行部の ATE 像
塊状の析出物は、0.6h～7,168h 破断材のすべてで観察できる。低倍率では微細析出物の存在はわからないので、倍率をあげて観察すると写真 5 になる。写真 5 は 4,898h
破断材であるが、ここでは３種類の形態が観察できる。
棒状、塊状（球状）、点状（黒点）である。
棒状に見えるほう化物は薄膜、カーボン抽出レプリカ
観察から類推すると、M23C6、Laves相およびZ相の析出M�
M�������e3����)����2 ��a�e�、��p�a�e

M23C６
���

写真 5 T11 鋼における 650℃-4,898h 破断材の ATE 像物群が旧γ粒界を被うように連続析出したことで、棒状の形態様を示したことも考えられるが、カーボン抽出レ
プリカによって観察をおこなった結果、写真 5 の左下に示すような棒状形態の析出物が観察できた。サイズは直径 1～1.5μｍ、長さ 10μｍであった。構造については電子線回折とEDS分析で調べた結果、Fe3(SiB)あるいはSiB6に相当する介在物であった。
塊状および球状の析出物はM23C6、点状（黒点）はMXに相当する。よってBはM23（CB）6のみに濃化されるのではなく、すべての析出物に濃化することを示唆している。
またBの析出物（ほう化物）中への固溶、あるいはマトリックス中への固溶については、マトリックスのコントラ
ストからBはマトリックスにも固溶している。
さらに析出
物をよく観察するとBは析出物とマトリックスの界面に濃化（析出物が黒くフチ取りされている。これがBの偏析である）していることがわかった。仮にBが析出物中にすべて固溶していれば、
黒い棒状あるいは黒点になるので、この差は歴然である。したがってT11 鋼のBはマトリック
スにわずか固溶しており、析出物（M23C6、Laves相、Z相）とマトリックス・析出物界面に濃化し、微細析出したMXにも濃化していると考えられる。
なお著者らは 0.05C-3Mn-B鋼を用いて、オーステナイ
ト粒界に析出したほう化物(200～250nm)と粒内に微細析
出(100nm)したほう化物について、得られたATE像とカーボン抽出レプリカ像から大きさの比較を行った６)。この
結果、１個のほう化物（黒点１個）が 5～10μmに観察されることから、ATE像は 10～100 倍に拡大されて観察されることになる。
このように処理条件によって１μmのほう化物は、10～100μm（0.1mm）の大きさに観察されるので、単純には析出物（ほう化物）の大きさを議論することはできないことを指摘している。つまり、直径１μmのほう化物においては間隔がおよそ 100μmより広く離れていないとATE像では２つの析出物としては観察できないこともある。
（２）C9 鋼の ATE 像
ATE 法によって C9 鋼の As NT および 650℃-5h～－ 454 －

JAEA-Review 2008-067

11,424h 破断材の B 分布状態を調べた。結果の一例を写真 6 に示す。球状の析出物は As NT～11,424h 破断材のすべてに観察できる。○で囲んだ領域は他の領域に比べて明らかに析出物の再固溶が認められる。低倍率では微細析出物の存在はわからないので、倍率をあげて観察した例を写真 7 に示す。ここでは T11 鋼に見られたような棒状や球状のほう化物はみられず、点状（黒点）に微細
析出していることがわかる。つまり B はほとんどの析出
物中に固溶した状態で存在すると考えられる。
(a)

(b)

(c)

(d)

100��

(a) 1,604h (b) 2,168h (c) 8,715h (d) 11,424h
写真 6 C9 鋼における 650℃破断材平行部の ATE 像

Ǵ㨙

写真 7 C9 鋼における 650℃-11,424h 破断材の ATE 像
さらによく観察すると、どの破断材においても旧γ粒界に相当する領域に B の偏析（矢印）が観察できる。これは B が旧γ粒界に偏析することにより、結晶粒界エネ
ルギーを下げて、粒界析出を抑制（析出物の微細化）す
る効果を促進し、あるいは B の拡散速度は比較的速いた
めに、結晶粒の成長速度を下げていること（他の溶質原子とのサイトコンペティション）の傍証とも考えられる。また B のマトリックス中への固溶については、マト
リックスのコントラストから旧γ粒界だけではなく、マトリックス中にも固溶していると推定できる。

3-2-5 逆Ｓ字クリープ現象とミクロ組織
C9 鋼において、逆Ｓ字クリープ破断現象が認められた。そこで本項では、逆Ｓ字クリープ破断現象について
ミクロ組織の視点から考察する。C9 鋼のクリープ変形にともなう組織変化としてはクリープ強度の低下が認められた 8,715h 付近において転位密度の減少、局所領域での亜結晶粒の成長と不均一な回復が認められた。しかし、
11,000h 付近において再びミクロ組織にも変化が見られる。
つまり微細析出物の増加と転位密度の上昇が生じた。
このことが C9 鋼の逆Ｓ字クリープ現象を生じさせた要因と考えられる。
C9 鋼のクリープ強度因子をまとめると、①析出物の粗大化は 75.2h と 8,715h で認められ、それ以降の 485h と11,424h において析出物の細粒化が認められた。②すべての析出物中に濃縮するボロンが認められ、これが析出物の凝集粗大化を抑制。③旧γ粒界、フェライト粒界およびフェライト粒内にも、B の固溶（偏析）が認められる。④析出強化が重要と考えられているが、C9 鋼では固溶強化も十分に寄与していると考えられる。
��結 �
9～12Cr 耐熱鋼の長時間クリープ破断強度に及ぼす
Al、Ni、P などの影響について調べた。また Al、Ni を低減した 9Cr 耐熱鋼の長時間クリープ破断強度の強化機構を検討し、以下の結果を得た。
(1) Al、Ni を低減すれば析出物の成長、粗大化を抑制
でき、クリープ強度が維持できる。このことにより Cr、
Mo、W、V、Nb および B などマトリックス中の固溶量が増し、マトリックスが強化される。
(2) 析出物中への Al、Ni 濃化は当然、その制御量によって異なる。T11 鋼（11Cr）では、ほとんどの析出物
中に Al、Ni の濃化が認められたが、一部の Z 相で Niの無濃化が認められた。C9 鋼（9Cr）では Al 濃化が少ないのは Laves 相、MX であり、一部の MX（VNbCN）に
Ni の無濃化が認められた。
(4) Al、Ni量が比較的高い高Cr耐熱鋼を 650℃、数 1000
～ １ 万 時 間 程 度 加 熱 す る と 、 析 出 物 M23(CB)6 、Laves相Fe(Mo, W)2B、Z相などの周囲にAl、Niが拡散して、析出物の成長、粗大化を促進させるため、クリー
プ強度を低下させるものと考える。
(5) 固溶度の比較的小さい Nb、V が 10～50nm 程度の MX型炭窒化物として析出し、クリープ強化する。
(6) ボロンは主として析出物中、あるいは析出物とマト
リックスの界面に偏析して、析出物の凝集粗大化を抑制（微細化）することによって、析出強化する。
参考��1）佐藤 恭、田村広治、福田祐治、朝倉健太郎、藤田
利夫：CAMP-ISIJ, 19(2006) 565
2）朝倉健太郎、柴田浩司、澤幡浩之、川手 稔、原澤

－ 455 －

JAEA-Review 2008-067

進：鉄と鋼、89、(2003), 369-374
3）朝倉 健太郎、藤田利夫、山下幸介：鉄と鋼、66(1980),
1375-1382
4）東 司、三木一宏、田中泰彦、石黒 徹：鉄と鋼、88、(2002), 678-685
5）千波潤之、阿部富士雄：耐熱金属材料委員会研究報
告 46、1(2005）,1-12
6）朝倉健太郎、柴田浩司：鋼中微量ボロンの挙動と性質への影響、（社）日本鉄鋼協会、材料の組織と特性部会、(2003)、25-33

研������������������������
����������
１．緒言
我が国では鉄スクラップ量は年々増加している１）。このため廃棄物量の縮小とCO2ガスの排出抑制という環境問題の観点から、スクラップをなお一層再利用することが日本における鉄鋼生産プロセスの中で重要になっている。鉄スクラップ中にはCuやSnなどのトランプエレメン
トが含まれ、その濃度は年々増加している。
しかし、鉄スクラップ中に含まれる銅が熱間圧延時に表面割れを引き起こすため、鉄スクラップの利用促進には大きな障害となっている。銅を含有する鋼スラブを熱間加工するときに酸化雰囲気中で高温加熱され、鉄の選
択酸化により鋼と酸化層界面に銅濃化相が生成する。
1083℃以上になると銅は液相になり、熱間圧延での変形
中にオーステナイト(γ)結晶粒界に浸入し、表面割れを発生させる。この現象は銅起因表面赤熱脆性と呼ばれている２）。また、Snは表面赤熱脆性を助長させることが報告されている３）。
これまで鉄スクラップ中から銅を分離する研究や製鋼プロセスで溶鋼中から銅を除去する研究が試みられてきたが、現在の技術では銅を鉄鋼中から安価に取り除くことは非常に困難である。そこで銅を含む鋼の熱間加工において、材料学的方法により銅起因赤熱脆性の抑制法を探ることは重要で、かつ有益な課題である４）。
本研究では、大気中および LNG 燃焼ガス雰囲気において、Cu と Sn を含有する炭素鋼の銅起因表面赤熱脆性に及ぼすボロン(B)添加の影響について調べた。
２．実験方法
２．１ 供試鋼
供試鋼の組成を Table １に示す。Cu を 0.3%、Sn を 0.04%含有
する 0.05%炭素鋼であり、B 量を 50ppm まで変化させた。
約 20 kgを真空溶解した後、熱間圧延した厚さ 16mm の板材を供試材とし
た。

B1
B2
B3
B4

Table 1 供試鋼の化学成分 (mass%).
C
Mn
Cu
Sn
B
0.28
0.05
0.31
0.044 0.0002
0.05
0.30
0.31
0.037 0.0011
0.05
0.28
0.31
0.044 0.0030
0.05
0.29
0.31
0.042 0.0051

２・２ 高温引張試験
各鋼の熱間圧延材より、その圧延方向と軸方向が一致するように平行部長さ 30 mm、直径 6 mm の丸棒引張試験片に加工した。
高温引張試験はArガス、
大気中およびLNG燃焼ガス雰囲気で行った。LNG燃焼ガスに相当する混合ガスの組成は74%N2－16%H2O－8%CO2－2%O2とした。ガス流量は 2 l/minである。室温から 0.33K/sで昇温し、1100℃で 1.8 ks
保持後、ひずみ速度 1.0×10－２ s－１で引張変形させた。
高温引張試験の荷重－のび曲線における最大荷重から、以下の式を用いて脆化感受性パラメータを算出した５）。
Ep=（PAr －P）／PAr
・・・・（１）
Ep' =（PAr －P'）／PAr ・・・・
（２）
ここで、PAr はArガス中での最大荷重、Pは酸化雰囲気中での最大荷重、P' は酸化による試験片の有効断面積の減少分を補正したときの最大荷重である。
２・３ 光学顕微鏡による組織観察
鋼と酸化層界面に生成する銅濃縮相の量や存在サイトを観察するために光学顕微鏡による組織観察を行った。
熱間圧延材から 10 mm×10 mm×10 mm の立方型試験片を切り出し、エメリー紙で＃1200 まで表面を研磨した。
加熱試験は、
大気および LNG 燃焼ガス雰囲気において、室温から 0.33 K/s で昇温し、1100℃で 1.8 ks もしくは
5.4 ks 保持した後、炉冷した。酸化させた試料を樹脂に埋め込み、切断面を観察した。腐食液として 4%ナイター
ルを用いた。
２・４ ATE 法によるボロン分布の観察
ボロンの分布はα線トラックエッチング法（以下、ATEと略す）により調べた。試料の形状および採取方法は光学顕微鏡観察と同一である。加熱は、大気および LNG 燃
焼ガス雰囲気において、室温から0.33 K/sで昇温し、1100℃で 1.8 ks 保持した後、水冷した。試料中央部を 1 mmに切断し、切断面をバフ研磨した後、硝酸セルロースフ
ィルムを貼り付けた。
硝酸セルロースフィルムを貼り付けた試料に中性子照射を行った。ボロンに中性子を照射すると、１０B＋１ｎ→
７
Li＋４He（α）の反応によりα線を放射し、セルロース
フィルムに痕跡を残す。このセルロースフィルムのみを回収し、2.5 mol・ｌ-1のNaOH溶液中でエッチング処理した後、フィルム表面を光学顕微鏡により観察した。

－ 456 －

JAEA-Review 2008-067

２・５ 銅インプラント高温引張試験
銅液相のγ結晶粒界への浸入性を評価するために、Cu
合金インプラント高温引張試験を行った。鋼の熱間圧延材より、圧延方向と軸方向が一致するように、平行部長
さ 20 mm、その外径 10 mm、内径 4 mmの中空型丸棒引張試験片を作製した。この中空型試験片の中に径 3.9 mmの
Cu－9.3%Sn合金の棒を挿入した。Cu合金は、無酸素銅（
純度 99.99％）、高純度すず（純度 99.9％）を用い、真空溶解炉で溶製した。溶製した試料を熱間鍛造や熱間圧
延により板材にした後、スウェージング加工により丸棒にした。試験は、Arガス雰囲気において、室温から 0.33
K/sで昇温し、1100℃で 1.8 ks保持後、ひずみ速度 1.0
×10－２ s－１で引張変形させた。
３．実験結果および考察
３・1 表面赤熱脆性
鋼の脆化感受性パラメータに及ぼすＢ添加の影響をFig.1 に示す。大気中、LNG 燃焼ガス雰囲気とも、B 量が増加するにつれて脆化感受性パラメータの値が小さくなっている。LNG 燃焼ガス雰囲気では、Ｂを 11ppm 添加したときに Ep の値を約 10%低下させ、表面赤熱脆性を抑制するのに有効である。大気中では、B 添加量 11ppm では
脆性抑制効果が小さく、50ppm まで添加すると脆性抑制に有効である。LNG 燃焼ガス雰囲気のほうが大気中より脆化感受性パラメータの値がやや大きくなっている。

30

(a)

(b)

Scale

Cu

Cu

Steel
(d)

(c)

Cu

Cu

50μm

(a) B1, (b) B2, (c) B3, (d) B4
Fig.2 LNG 燃焼ガス中における鉄/スケール界面の銅濃縮相
３・３ ボロンの分布挙動
大気中で 1100℃、1.8 ks 加熱後水冷した試料の ATE
像を Fig.3 に示す。B 量が少ない鋼 B1 と鋼 B2 の表面部には B の粒界偏析が見られない。一方、B 量が 30ppm 以
上の鋼 B3 と鋼 B4 では表面部に粒界偏析が確認される。
LNG 燃焼ガス雰囲気で 1100℃、1.8 ks 加熱後水冷した試料の ATE 像を Fig.4 に示す。B 量が 30ppm 以上の鋼 B3と鋼B4では大気中と同様にLNG燃焼ガス雰囲気でも表面部の粒界に B が偏析している。また B を 11ppm 添加した
鋼 B2 でも表面部にわずかに粒界偏析が見られる。
一方、試料内部では大気中と LNG 燃焼ガス雰囲気による違いは全く見られなかった。B 量が増えるとともに粒界偏析量が増加している。また、B 量が 30ppm 以上で粒内析出が顕著になり、B 量が 50ppm で粒界析出も現れる
ようになる。

Ep, Ep' (%)

LNG (Ep)
20

（a）

（ｂ）

（ｃ）

（ｄ）

air (Ep)10
air (Ep')010

20 30 40 50
B content (ppm)60

Fig.1 脆化感受性パラメータに及ぼす B の影響
３・２ 鋼と酸化層の界面付近の組織
LNG 燃焼ガス雰囲気において、1100℃、1.8 ks 保持したときの鋼と酸化層界面付近の組織を Fig.2 に示す。いずれの鋼でも鋼と酸化層界面に銅濃縮相がフィルム状に生成している。B 量が増加しても銅濃縮相の量や形態に変化は見られなかった。

100μｍ(a) B1, (b) B2, (c) B3, (d) B4
Fig.3 1100 ℃-1.8 ks（大気中）処理における ATE 像－ 457 －

JAEA-Review 2008-067

（a）

（ｂ）

（ｃ）

（ｄ）

100��

(a) B1, (b) B2, (c) B3, (d) B4
Fig.4 1100 ℃-1.8 ks（LNG ガス燃焼ガス雰囲気）処理
における ATE 像
３・４ 銅濃縮相の粒界浸入性
各鋼に Cu-9.3%Sn 合金を挿入し、インプラント高温引張試験をしたときの応力－ひずみ曲線を Fig.5 に示す。ひ
ずみを付加すると応力が徐々に増加し、ある臨界点に達すると応力が急激に低下する。この臨界点で銅液相が鉄粒界へ急速に侵入したと考えられる。このときの臨界応力を破断応力とし、臨界ひずみを破断ひずみとする。B
を 11ppm 添加した鋼 B2 では、Ｂが 2ppm の鋼 B1 と破断ひ
ずみはほぼ同じである。また、B が 30ppm の鋼 B3 は鋼 B1
や鋼 B2 と破断応力はあまり変わらないものの、破断ひず
みは増加している。さらに B 量が 51ppm に増加した鋼 B4は、破断応力、破断ひずみとも増加している。B 添加量が増えると、銅液相のγ粒界への侵入性が抑制されることがわかる。

30

True stress (MPa)15←B4(51ppmB)←B3(30ppmB)10←B2(11ppmB)5←B1(2ppmB)0

４．結言
本研究では、0.3％Cu と 0.04％Sn を添加した炭素鋼を用いて、大気中と LNG 燃焼ガス雰囲気における 1100℃での銅起因表面赤熱脆性を調べ、赤熱脆性に及ぼす微量 B
添加の影響を調べた。
(1) 大気中、LNG 燃焼ガス雰囲気とも、B が増加すると大気中ではともに鋼の表面赤熱脆性は低下していく。
50ppm の添加で表面割れが抑制できる。一方、LNG 燃
焼ガス雰囲気では、11ppm の B 添加が有効である。
(2) B を添加した鋼では表面部においてもB が粒界に偏析している。B は粒界偏析により粒界エネルギーを低下させ、γ粒界への浸入性を抑制するためであると推
察される。
参考文献
1) W. Tamaki, S. Hayashi and Y. Tomota; 29(2004), 1897
2) A. Nicolson and J. D. Murray: J. Iron Steel Inst.,
203(1965), 1007
3) N. Imai, N. Komatsubara and K. Kunishige: ISIJ
Int., 37(1997), 217
4) K. Shibata, S. -J. Seo, M. Kaga, H. Uchino, A.
Sasanuma, K. Asakura and C. Nagasaki: Mater.
Trans., 43(2002), 292
5) S. – J. Seo, K. Asakura and K. Shibata: ISIJ Int.,37(1997), 2326) 長崎千裕、柴田浩司、朝倉健太郎：鋼中微量ボロンの挙動と性質への影響、日本鉄鋼協会編、(2003), 174.

2520

３・５ 表面赤熱脆性に及ぼすボロンの影響
以上の結果より、鋼表面部における B の粒界偏析と表面赤熱脆性の低下が非常に良く対応していることが明らかとなった。銅すず含有鋼の表面赤熱脆性は B を添加す
ると低下し、大気中では一定量以上の B を添加すると表面赤熱脆性は完全に抑制された。鋼への B 添加により表面赤熱脆性を低下させているときには、鋼表面部の粒界に B が偏析していることが ATE により確認された。
また、鋼への B 添加は、Cu－Sn 合金を挿入したインプラント引張試験での破断応力や破断ひずみが上昇させ、粒界浸入性を抑制させている。
したがって、B添加による脆性抑制効果は、鋼表面部においてBが粒界偏析することによりγ粒界エネルギーを低下させ、銅濃縮相の粒界浸入性を低下させることによるものと考えられる。このようなB添加による効果はSn
無添加銅含有鋼でも認められていたが６）、同様に粒界浸入性の抑制に起因するものであると推察できる。

0.02 0.04 0.06 0.08 0.10 0.12
True strain

Fig.5 各鋼に Cu-9.3%Sn 合金をインプラントした試験
片の高温引張試験における応力－ひずみ曲線

�．結果の�表1) E. El-Kashif, K. Asakura and K. Shibata： Role boron
in preventing intergranular fracture in steels,－ 458 －

JAEA-Review 2008-067

Intern. Forum for the Properties and Applicationof IF Steels, IF STEELS, 2003, 188-191(2003)
2) Emad El-Kashif, K. Asakura, T. Koseki and K.
Shibata：Effects of Boron, Niobium and Titanium on
grain Growth in Ultra High Purity 18% Cr Ferritic
Stainless Steel, ISIJ Intern., 44, 1568-1575(2004)
3) 朝倉健太郎、柴田浩司、小関敏彦、妹尾政臣：低炭素鋼における B の偏析・析出に及ぼす Mo の影響, CAMP-ISIJ, 17, 496 (2004)
4) 佐藤 恭、田村広治、福田祐治、朝倉健太郎、藤田利夫: USCボイラ用９Cr-W－Co 耐熱鋼の逆Ｓ字クリープ
破断材挙動と強化機構, CAMP-ISIJ, 19, 565, (2006)
5) C. Nagasaki, K. Asakura, T. Koseki and K. Shibata：Effects of boron and tin on surface hot shortness
due to copper in low carbon steel, CAMP-ISIJ, 19,
501, (2006)
6) 佐藤 恭、田村広治、福田祐治、朝倉健太郎、藤田利夫：USC ボイラ用９Cr-W－Co 鋼の長時間クリープ強度とクリープ中の析出物変化の定量化、CAMP-ISIJ, 19,1173, (2006)
7) 朝倉 健太郎、小関敏彦、藤田利夫、佐藤 恭：高 Cr
耐熱鋼の長時間クリープ破断強度に及ぼす Al, Ni の影響と強化機構、耐熱金属材料 123 委員会研究報告、
47、3(2006)、329-344
8) 朝倉 健太郎、小関敏彦、藤田利夫、佐藤 恭：高 Cr
耐熱鋼の長時間クリープ破断強度に及ぼす Al, Ni 及
び B の影響と強化機構、CAMP-ISIJ, 20, 549(2007)
9) 朝倉 健太郎、小関敏彦、川手 稔、石本光憲：JRR-3
及び JRR-4 の気送管設備を用いたα線トラックエッ
チング法による鋼中ボロンの状態分布観察法の確立と問題点、鉄と鋼、93(2007) 634-641

10) 朝倉 健太郎、小関敏彦：日本原子力開発機構における気送管設備を用いたα線トラックエッチング法による鋼中ボロンの状態分布観察法の確立と問題点、
CAMP-ISIJ, 93(2007)
��今後の��
原子力機構炉（医療用および気送管設備）を用いてATE 法の手法をほぼ確立した。そこで今後については以下の研究について遂行する。
(1) 積層鉄鋼材料を用いて、硬質／軟質界面における Bの状態分布挙動の調査を行う。
(2) 溶接構造用鋼の基本成分に C, Nb, B を変化させ、真空溶解にて試験片を作製する。その後、溶接熱影響部相当の熱サイクルを付与しacicular フェライトを含む溶接部組織を再現し、組織観察を行うとともに、ボロンの存在位置の調査研究を行う。
(3) Cu および Cu 合金(Cu-Ni-Si-0.02B)を用いての研究も併せて遂行する。高周波加熱溶解炉で純銅中に B
量を 25ppm、50ppm、100ppm 添加し、種々の熱処理における B 分布について調査研究を行う。

謝�：
本研究の中性子照射に関する一部は東京大学大学院原子力専攻の川手 稔氏、石本光憲氏、澤幡浩之氏の協力によった。またデータと試料の一部は日立バブコック㈱の好意により掲載した。ここに感謝の意を表します。

－ 459 －

JAEA-Review 2008-067

5-5ホウ素ナノカプセルを用いた中性子捕捉治療
Development of boron nano capsules for BNCT

学習院大学理学部化学科 中村浩之、上野学、Hyun Seung Ban、Jong Dae Lee、鍋山航
筑波大学人間総合科学研究科

中井啓、鶴田和太郎、松村明

大阪大学大学院医学研究科 金田安史

現在まで長期にわたりＸ線によるがん治療が行われ本研究では、目的数値を達成するためにドラッグデリているが、Ｘ線療法とホウ素中性子捕捉療法の治療効

バリーシステムに用いられているリポソームに注目し果を比較すると後者の治療方法の方が治療効果が高い

た。リポソームとは脂質二分子膜からなるナノキャリと言うデータも示されている。

アーであり内部に薬剤などを封入し、患部に送達させホウ素中性子捕捉療法とはホウ素化合物を予めがんることで知られている。リポソーム内部にホウ素化合

細胞に集積させ、そこに熱中性子を照射してホウ素(Ｂ

物を封入することは報告されているが目標数値は達成

10)と中性子の核反応により局所的にがん細胞だけを死出来ていない。脂質二分子膜は分子間相互作用により滅させる治療法である。熱中性子による正常細胞への自己集合化しているため密度が高い。そこで本研究で影響が少ないこと、核反応から生じるエネルギーが細はリポソームを構成する脂質二分子膜にホウ素導入を

胞 1 つ分だけを破壊することから、極めて副作用の少指向したホウ素イオンクラスター脂質の開発を行った。

ないがん治療法である。したがって高い治療効果を得

この脂質を用いることでキャリアー自身をホウ素薬剤

るためにはホウ素の癌細胞選択性、蓄積性が求められとし、さらに内部にホウ素化合物を封入出来ることかており、がん細胞へ 40ppm以上のホウ素濃度、さらにら、高濃度でホウ素をデリバリーできる。また、この腫瘍/正常組織のホウ素濃度の比が 5 以上を蓄積させホウ素リポソームの内部にホウ素化合物ではなく抗がる必要がある。この数値を達成することが可能となれん剤を封入し、中性子照射を行うことにより抗がん剤

ば現在開発中である病院施設内に設置可能な小型加速のリリースを狙い、中性子捕捉療法と化学療法を同時器(中性子源)を用いて、ホウ素中性子捕捉治療が身近に行うコンビネーションセラピーの検討を行う。

な治療法となり、この治療で治るがん患者が増えるで

我々は脂質の親水性部位に親水性ホウ素イオンクラあろう。

スターを導入したホウ素イオンクラスター脂質(6)のJRR-4、中性子ビーム設備－ 460 －

JAEA-Review 2008-067

ム(7.2mg/kg 10B,14.4mg/kg 10B)をそれぞれ静脈注射し、合成に成功した。

72 時間後に 37 分間中性子照射を行い、照射後の生存
さらにこのホウ素脂質とコ曲線を調べた。

レステロール、DSPC、PEG を用いて逆相蒸発法によりト
ランスフェリン修飾型ホウ
図1 ホウ素リポソーム

素リポソームの調整に成功した。(図 1)
調整したトランスフェリン修飾ホウ素リポソームを用いてマウス内での各臓器におけるホウ素分布を測定した。ヨウ素 125 ラベルしたイヌリンを含むホウ素リ
ポソームを左足に Colon26 細胞を移植した Balb/c マウス(6 週齢、18～20ｇ)に静脈注射した後、1～72 時間においてマウスの血液、肺、肝臓、腎臓、脾臓、腫瘍を

図 2 ホウ素リポソームとトランスフェリン修飾型ホウ素
リポソームのマウス体内分布

各々取り出し、各組織の放射活性を測定した。(図 2)
血液中の濃度変化は、ホウ素リポソームおよびトラン

ホウ素リポソームを投与していないマウス(コントロ
スフェリン修飾型ホウ素リポソームとも速やかに低下ール)では中性子照射後の平均寿命が 22 日であったのした。一方、肝臓、腎臓、脾臓ではトランスフェリンに対し、 トランスフェリン修飾型ホウ素リポソーム
修飾型ホウ素リポソームの方が高濃度で蓄積している(7.2mg/kg 10B)投与したマウスでは、平均寿命が 32 日
ことが分かった。腫瘍では非修飾型ホウ素リポソームと約 1.5 倍の延命効果が得られた。しかし投与量をは時間に伴い濃度が減少しているのに対し、トランス
14.4mg/kg 10Bにしたところ急性毒性が見られた。このフェリン修飾型ホウ素リポソームでは時間経過と関係ことから毒性を改善した新しいホウ素脂質を分子設計なく蓄積しており、72 時間後でも非修飾型ホウ素リポ
し、合成することを試みた。
ソームと比較し約 3 倍の濃度であることが分かった。
我々は中性子捕捉療法において臨床応用されている
左足にColon26 細胞を移植したBalb/cマウス(6 週歳、BSH(ホウ素イオンクラスター化合物)を親水性部位に18～20ｇ)にトランスフェリン修飾型ホウ素リポソー－ 461 －

JAEA-Review 2008-067

導入した新しい低毒性ホウ素脂質(12)の合成に成功した。(Scheme 1)
Br
O

Br
O

O

OH

O

O

Br

MeOH ,
p-TsOHBrO

8

CH 3 (CH 2 )n CO2 H
DMAP , DCC
CH 2 Cl 2

O

9

O

quant

7
OH
HO

O

Py , THF

38 %CH 3 (CH 2)nCH 3 (CH 2 )nO

61-75 %

O

図４ 細胞用照射器具(Cyborg 480)a : n=16
b : n=14c : n=12

O
O
O

Br
O

10a-c

22 Me 4 NO

CNS
CH 3 CN

CH 3(CH 2)nCH 3(CH 2)n O

Me 4N
O

2-

O

O

S

O
11a-c

NC

O
Me 4NOHac etoneion exchange r esin

CH 3(CH 2) n
CH 3(CH 2 )n O

2-

O

O
3 steps 46-68 %

2 Na

O

S

O
12a-c

Scheme 1 BSH を導入した脂質の合成
図５ 細胞レベルにおける第二世代ホウ素リポソームの中

また、合成した第二世代ホウ素脂質、コレステロール、

性子捕捉療法効果

DSPC、PEG を用いてホウ素リポソームの調整に成功しその結果、no wash の条件ではホウ素リポソームは濃た。調整したホウ素リポソームの中性子捕捉療法効果
度依存的な細胞増殖阻害活性が見られた。BSH と比較を細胞レベルにおいて no wash,wash の二つの条件で検しても同程度、もしくはそれ以上の効果を示している。
討した。
no wash での方法は Colon26 を 20 時間培養し、一方 wash 条件では、
BSH は活性が見られないのに対し、
ホウ素リポソーム存在下さらに 30 分間培養する。その
ホウ素リポソームは no wash の条件と活性がほとんど後、中性子照射を 30 分行った後 3 日後の MTT assay に変わらないことが言える。このことよりホウ素リポソより細胞増殖阻害活性を調べた。Wash 条件ではホウ素ームは BSH よりも細胞に多く蓄積していることが示さ
リポソーム処理 30 分後に培地を交換し、その後中性子れた。今後はこの第二世代ホウ素リポソームにトラン照射を行った。図 4 には、ハイスループットスクリー
スフェリンを修飾し、マウスに投与した後中性子照射
ニングのための新しい細胞への中性子照射システムをを行い、腫瘍の完全消失を目指す。
示した。この、システムは現在ある「弥七」システムと異なり、一度に 480 サンプルを照射できるため、薬剤開発の効率化が可能となる。

－ 462 －

JAEA-Review 2008-067

5-6
αトラック法による硼素薬剤の細胞内局在計測法の開発
Development of boron drug localization measurement method inside biological cellsby neutron-induced alpha track mapping technique
東京大学・大学院工学系研究科 中沢正治、雨宮邦招（現・産総研）、藤田薫、高橋浩之
東京大学・先端科学技術研究センター 江里口正純、柳衛宏宣、久智行
国立療養所香川小児病院 中川義信
東京大学・大学院農学生命科学研究科 西澤直子、長坂征治
独立行政法人産業技術総合研究所光技術研究部門 眞島利和
独立行政法人放射線医学総合研究所基盤技術センター 安田仲宏
１� 研究目的硼素中性子捕捉療法

時に硼素薬剤の分布が変化しないような試料調整法
1）（Boron Neutron Capture

Therapy： BNCT）は、硼素を含む化合物に腫瘍集積を確立・データの信頼性を保証することが肝心となる。

性を持たせ、外部から照射される少量の熱中性子と細胞内の放射線感受性は細胞核（感受性高）と核の核反応で生ずるα線・Li反跳核を用いて腫瘍細胞外（感受性低）とで大きく異なる6)上、荷電粒子タイにダメージを与える新しいタイプの放射線がん治療

プの放射線はその飛跡に沿って極めて狭い範囲に高法である。BNCTの特徴は生成したα線・Li反跳核の密度な損傷をもたらす性質があるため、細胞内での飛程が細胞１個分程度（～10μm）であり、放射線エ

α・Li粒子の発生分布を知ることは、BNCTの治療効

ネルギーの全てを細胞１個の範囲内に落とすため殺果を判定する上で薬剤の腫瘍選択性にも増して重要細胞性が極めて高いことである。また硼素薬剤が腫な情報である。本研究が開発を目指す手法を用いる

瘍細胞のみに集積していれば、隣接する正常細胞をことで、BNCTで急務とされる新規硼素薬剤開発のた

傷つけることなく腫瘍のみを選択的に撃退できるための硼素薬剤の詳細な局在情報が得られるものと考

め、浸潤の激しい腫瘍（悪性脳腫瘍・悪性黒色腫等）

えられる。

を患部の機能を温存したまま根治できる画期的な治細胞内硼素分布測定法としては現在、αオートラ療法である。現在、BSH及びBPAと呼ばれる腫瘍集積

ジオグラフィ法のほか、硼素化合物の抗体を用いた性硼素化合物が見出されており、さらに十分に集積免疫染色法7,8)および二次イオン質量分析法9)（SIMS）

比・取込量を上げるべく硼素薬剤の化学修飾や新規や電子線エネルギー損失スペクトル法10)（EELS）に

硼素薬剤の開発が盛んに行われているが、その取りよる元素分布マッピングが主流である。しかし現状込み機構は必ずしも解明されておらず、またそれをの方法では細胞内構造まで画像化するには難がある、調べるための細胞内微小器官のレベルでの硼素薬剤

固定・染色などの処理を必要とする場合に水溶性硼

の分布測定法自体も開発途上の段階にある。

素薬剤が溶出する可能性がある、などの問題を抱えそこで本研究では硼素分布測定法のひとつであるている。本研究で提案する手法は高分解能な上、固中性子誘起αオートラジオグラフィ法2-5)を高度化

定・染色を施すことなく処理することが可能で、よし、詳細な細胞構造イメージ中に硼素分布をマッピ

り信頼性の高い細胞内硼素分布計測が可能になるもングする手法を開発・要素技術を確立して各種硼素のと期待される。

薬剤によるBNCTの治療効果の評価や硼素薬剤の輸送

前年度までの研究で、αオートラジオグラフィのメカニズムの解明に資するデータを取得することを立場からは細胞内硼素分布計測に向けて一定の成果目的とする。具体的にはFig.1 に示すように、硼素

を挙げることができたとも言えるが、それでも以下－中性子反応により発生したα・Liトラックとともに挙げる 2 点についての検討が必ずしも十分ではなに、紫外線暴露により細胞の“影絵”をプラスチッ

かった。ひとつは、Fig.1(b)に示されているようなクポリマー上に記録、同時観察する手法を開発する

画像はオルガネラレベルでの硼素薬剤分布計測を必ことであるが、これを高分解能化し細胞内微小器官

要としている向きには解像度がいまだ不十分であるのスケールで観察できるようにすること、また処理点である。確かに細胞核へのヒットの有無について

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JAEA-Review 2008-067は確認できる。しかし BNCT に限らず薬剤の開発や特るのだが、広く一般的に行なわれている化学的固定性評価に当たっては分子生物学的な視点を避けて通法を採用してしまうと、細胞内の硼素薬剤分布が実れない。硼素薬剤も分子標的で設計されるから、細際の生体内での分布と変わってしまう可能性がある。

胞内オルガネラレベルでの分布情報が創薬において我々は Fig.1 の手法開発後も解像度不足および試料鍵となるのである。

調整法の信頼性不足を克服するために様々な工夫をもうひとつは使用している細胞切片試料の調整法してきた。ここでは特にその成果について報告する。

についてである。本手法は細胞試料の切片化が不可
欠で、切片作成にはやわらかい細胞組織を固定・樹脂包埋して固化してからナイフで薄切する必要があ

熱中性子

熱中性子

a)

（１）細胞切片を CR-39 にマウント、切片厚 1μm

細胞切片

熱中性子照射αトラック~ 1014 /cm2 程度

殺菌灯（２）試料を殺菌紫外線に暴露
10W 殺菌灯
1cm の距離で 5 時間

潜在 UV 像AFM
カンチレバー（３）エッチング細胞像

7N NaOH 70℃で 2 分

レリーフ

原子間力顕微鏡観察

エッチピット

汎用タッピングモード AFM
（鳥瞰図）

b)

c)

＜凡例＞

（断面図）

細胞核・
クロマチン構造

細胞質

細胞外領域

エッチピットFig.1：a) 開発した BNCT マイクロドシメトリ用αオートラジオグラフィ手法の手順。
b) 本手法で得られた画像の例（硼素薬剤BSHを 16 ppm-10Bの濃度で含む腫瘍細胞切片を使用）。
c) は b) の画像の説明図。画像サイズは 20 μm x 20 μm。

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JAEA-Review 2008-067

以前の報告では、エッチングを短時間にすること��細�内オ���ラの解像度向�

で試料のごく近傍の像を現出させて読み取れること
����試料厚さが紫外線顕微鏡像に��す��
11,12)を示した4)。その一例として、Fig.2 に直径 100 nmのアナロの標準ポリスチレンラテックス粒子の紫外線顕微鏡

ジーで筆者らが新規に開発した手法である。殺菌に像を示す（本図ではラテックス粒子による紫外線吸用いられる紫外線灯の波長は 254 nmで、生体内の核収像というよりも、球体の粒子がレンズのように働酸の吸収ピークに相当するため、殺菌線の透過像は

き紫外線が屈折され集光されたような像になってい核酸による吸収コントラストがつく。一方、CR-39て、粒子のあった場所が掘れた状態になっている）。

プラスチックは紫外線に対して感度を有しており、

100 nmを切る解像度があるため、ラテックス粒子も暴露量に比例してエッチング速度が増加する。した十分解像できていることがわかる。一方、エッチン

がって吸収コントラストがエッチング後のレリーフ

グ時間を短縮したとしても、試料とCR-39 基板とのとして現出するのでこれをAFMで高解像度に観察で密着度が不十分な場合には高い解像度が得られない

きる。軟X線顕微鏡法と比べ、紫外線顕微鏡では安価ことがある。近接場とはせいぜい数十nmの領域をさに大量処理が可能となるため、硼素薬剤分布計測のすためである。Fig.3 でその様子を説明すると、珪ようなスクリーニング目的に向いているといえる。

藻のように湾曲した試料はCR-39 基板と完全に密着

しかし使用している波長が比較的長いため、100 nm

させることが難しく、それゆえ解像度にムラが現れ

以下の微細構造を解像するには近接場を用いて回折ているのがわかる。

紫外線顕微鏡法は、軟X線顕微鏡法

限界を打ち破る必要がある。

a)a)Fig.2：a)直径 100 nm のポリス
チレンラテックスの AFM 像。
b)ラテックスの UV 顕微鏡像
（矢印）
。試料はφ3mm のコリ
メータ越しに 10W 殺菌灯から1mm の距離に設置し、24 時間照射。エッチング時間は 70℃の
7N NaOH にて 15 秒で溶出厚は 50nm。Bar=100 nm.

b)

b)
解像度良好

密着不良

解像度不良

密着度良好

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
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密着度良好

Fig.3：a) 珪藻殻の紫外線顕微鏡像。70℃の 7N NaOH にて 15 秒エッチング。30μm 角
スキャン。
b)で示すように珪藻は湾曲した構造になっており、CR-39
基板との密着度の良否に差があるため、紫外線像にも解像度にムラが生じている。

JAEA-Review 2008-067

αオートラジオグラフィの際には厚さ 1μm 程度

厚さに比例して減少することになる。硼素濃度数十の細胞切片を用いているため、100 nm 解像度を得る

ppm程度の治療条件下において、αトラックの統計量ことが困難となっていたものと考えられる。そこでを稼ぐには 1μm程度の試料厚が必要と試算されるより薄い試料として 300nm 厚の切片について紫外線ので、紫外線像の解像度とはトレードオフの関係に顕微鏡法の適用を試みた。Fig.4(a)にその結果を示あるといえる。また細胞内オルガネラの解像には膜す。1μm 厚切片の使用時（Fig.4(b)）と比べて、解構造の可視化が不可欠と考えられるが、生体膜の主像度が向上したのがわかる。しかし電子顕微鏡像成分である脂質の吸収ピークは紫外線灯の波長とは（Fig.4(c)）に見られるようなオルガネラの解像ま異なり、また他の成分との吸収コントラストがつきでには残念ながら至っていない。さらなる高解像度にくい13)という特徴を有しており、原理的にも解像を得るにはより薄い試料の適用が必要と考えられるが難しい。この点では軟X線を用いてもコントラスト

が、一方でαオートラジオグラフィを同時に行なう確保は難しく、波長による回折ボケ以前の問題であことを考えた場合、試料に含まれる硼素の絶対量が

る。

a)

＜凡例＞
細胞核・
クロマチン構造

細胞質

細胞外領域
エッチピット
（本図中にはナシ）b)ミトコンドリア

細胞膜

Fig.4：a) 300 nm 厚のエポン樹脂
包埋細胞切片の紫外線顕微鏡像。
b) 1 μm 厚のエポン樹脂包埋細胞切片の紫外線顕微鏡像。いずれも 2
分エッチング、20μm 角。試料を薄くすることで解像度は高まっているが、c)の電子顕微鏡画像内に見られるようなオルガネラ構造までは解像できていない。
（右の各図は細胞構造の説明用）。

c)

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
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JAEA-Review 2008-067

����細胞切片��の AFM 直接観察法の�用

αオートラジオグラフィ用にCR-39 上にマウント済

紫外線顕微鏡法の解像度が不足する状況では、別みの切片試料を観察すれば確実に同一の試料につい途なんらかの方法で細胞組織像を高解像度で得る必て議論できるので間違いないのだが、TEMは使えない要がある。Fig.5 に考えられる手立てを図解する。

ため観察法が限られる。最も一般的なのは通常の光一つの手段として、ミラー切片法が考えられる。ま学顕微鏡観察であるが、これは解像度が低いためオず測定対象となる細胞切片を作成する際に連続切片

ルガネラ観察には不向きである。近年、こうした細を次々に作成しておく。連続する 2 枚の切片はほぼ胞切片をAFMで直接観察してTEM並みの画像を得よう

同じ断面を有しており、片方を Fig.1 でも示したαという試みが何件か報告された。切片化した試料でオートラジオグラフィ法に使用し、もう片方は透過あるため、通常のAFMで観察してもフラットな像が得型電子顕微鏡（TEM）観察に回す。それぞれで得られられるだけであったが、試料の粘弾性分布が計測でた画像を照らし合わせ、TEM の高解像イメージ中にきる特殊なAFMを用いたり14)、試料を薬品15)や電子線

αトラックマッピングするという手法である。しか16)

し TEM 用、αオートラジオグラフィ用の切片厚はそが表出し、TEMに迫る解像度で観察できたというもの

れぞれ 50nm, 1μm であり、一桁以上も厚さの異なるである。

で処理したりすることで細胞内オルガネラの構造

連続切片を作成して選別するのは技術的にもかなり難しいため、効率が悪いと考えられる。

連続切片作成ミラー切片

従前のαオートラジオグ
ラフィの流れ（Fig.1 と同じ）

TEM

光学顕微鏡

切片の AFM
直接観察

エッチング後画像の比較、重ね合わせ

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
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Fig.5：詳細な細胞組織
像内でのαトラックマ
ッピングを達成するた
めの手立てを図解したもの。実線の丸で囲んだ部分が今回採用した「AFM による細胞切片の直接観察法」である。

JAEA-Review 2008-067

今回、筆者らはαオートラジオグラフィ時に切片アや小胞体といったオルガネラ構造までもが十分解

試料の AFM 直接観察法を応用することを試みた。ま像できており、TEMとほとんど同等の画像が得られた。

ず CR-39 上にマウントした切片試料を、一般的なタαオートラジオグラフィ試料では、このあとでCR-39

ッピングモード AFM で観察した例を Fig.6(a)に示す。

基板をエッチングしてαトラック像の分布を計測し未処理の切片はナノメートルレベルでフラットであておき、細胞紫外線像をガイドとして先程の細胞組

り、TEM 並みの解像度には遠く及ばない。しかし、織AFM像と位置合わせすることで細胞組織像中のα紫外線顕微鏡法と同じ条件で UV 照射を施した後にトラックマッピングも可能になる。一例として、細切片を AFM 観察したところ、Fig.6(b),(c)に示すよ

胞切片直接観察像と同じ位置に生じたCR-39 上の紫

うに細胞内構造まで明確に可視化できることがわか

外線像を並べて示したのがFig.7 である。Fig.7 のった。紫外線吸収により変質した細胞内成分の一部(b),(c)については、αトラックとの同時観察も実証

が揮発等で除去され、平坦だった切片表するために、241Amからのα線を照射してオートラジ

面にこのような細胞内構造が現出したものと考えら

オグラフィを模擬した例を示している。ガイドとしれる。これにより核内のクロマチン構造や細胞膜のて紫外線顕微鏡像を用いているため、同一箇所の探存在が明らかとなったばかりでなく、ミトコンドリ

索や画像のアライメントが容易なばかりでa)Fig.6： a)エポキシ包埋切片を AFM
で直接観察した像。30μm スキャン。
細胞らしき影も見て取れるが、切片は通常 nm レベルで平坦であるため、凹凸像として得られる情報は少ない。

b) エポキシ包埋切片をAFM で直接観察した像（撮像前に UV 照射処理を施した場合）。30μm スキャン。c)は b)内のカコ
ミ部分を拡大した像（10μm スキャン）。
ミトコンドリアやその他
細胞内オルガネラの膜構造などが見て取れ、電子顕微鏡で観察したものと遜色ない解像度が得られている。
※右の画像は説明図（凡例 は Fig.4 を 参 照 の こ
と）
。

b)

c)

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JAEA-Review 2008-067

なく、高精度な位置合わせが可能となるという特長

片が利用できるため、今回のαオートラジオグラフも有している。これにより、真に細胞内オルガネラ

ィ法との親和性が高い。TEM 試料作成に必要なウラレベルでの硼素薬剤分布計測法を確立することがでンや鉛イオンを用いた電子染色も不要で環境にもやきた。

さしい。AFM のスキルのみで作業が可能であるため本手法は TEM を全く用いずに TEM レベルでの計測

測定者の負担も軽減できる点も有利である。

が可能となる特色があり、1μm 程度の比較的厚い切

a)

b)

c)

Fig.7：エポキシ包埋切片のAFM直接観察像と（左）、CR-39 プラスチック上に焼き付けられたUV像を現像して得られたレリーフ（中央）。右は細胞内構造の説明図（凡例はFig.4 のものを参照）。b), c) については241Amからのα線を 107/cm2程度照射し、αトラックとの同時観察も試みた。UV像をガイドに細胞組織像を位置合わせし画像をオーバーラップさせることで、オルガネラレベルで粒子飛跡マッピングが可能となる。

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
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JAEA-Review 2008-067

Fig.8：フォトリソグラフィ用マスクの UV 透過像を CR-39
表面に焼き付け現像した様子
を AFM 観察したもの（30 μm
スキャン）。段差は 70nm 程度。
右は使用したマスクと同じ素材の光学顕微鏡像（石英基板にクロム蒸着し、電子線描画でパターニングしたもの）。Fig.7 で示した画像の位置合わせを容易にするためのガイドとして利用できる。

μO

スクリーニングのように大量のデータを取得してた場所から流れ出てしまう懸念がある。このように統計を稼ぎたい場合は、画像の位置合わせも効率よ

溶液処理による試料の信頼性低下が心配される場合

く行なう必要がある。Fig.8 に示すように、測定をには、組織試料をまるごと急速凍結し、凍結のまま始める前にCR-39 上にあらかじめフォトマスクなど

クライオスタット中で切片化する手法が取られる。

を通して紫外線パターニングを施しておくとよい。

ただし、組織試料は必然的に水分を多く含むため、区画のナンバリング等も行なうことで、低倍率画像

凍結する際に膨張しながらスパイク状に氷晶が形成

から所望の箇所へのアクセス・画像拡大が容易になされることよって組織が破壊されることがある。こると考えられる。以前、CR-39 上にフォトリソグラ

れを防ぐには氷を結晶化させずにアモルファス状にフィでアルミパターニングする手法を提案したこと凍結する必要がある。アモルファス氷生成には、大17)がある が、アルミは反応性が高くCR-39 に少なか気圧下では 10000 度/秒もの冷却速度で凍結する必らず影響を与えるため、Fig.8 のような単に段差を要があるが、それでも破壊を免れるのは組織表面かつけるだけのマーキングの方が使い勝手もよいと考らごくわずか分のみである。近年、2000 気圧の高圧えられる。

下で 1mm ほどの大きさの組織試料全体を健全に急速凍結できる装置が市販されるようになった。そこで

��高圧凍結固定法による高信頼性試料��法の利用

この高圧凍結装置を用いて作成した試料について、
αオートラジオグラフィ法の適用可能性を試験した。
使用したのは BAL-TEC 社の HPM 010 高圧凍結装置で二つ目に検討すべき項目は細胞試料の健全性に関ある。本装置では組織試料を半球状の小さな銅製カする問題である。例えば TEM で細胞内オルガネラをップで両側から挟み、その外側から対向して液体窒観察する場合、ただ漫然と組織試料を樹脂で固めて素の高圧ジェットを吹き付けることによって、2000

薄く切り、TEM の機械にかければよいというもので気圧もの高圧印加と同時に急速凍結を達成している。

はなく、適切な固定処理が必要とされる。固定とは摘出した腫瘍組織を 1mm 角以下の大きさとし、同装切片化のための樹脂包埋とは別に、細胞の形を保ち置で急速凍結したのち、水分をアセトンで凍結置換続けるための処理をさす。細胞は生ものであり、組した。切片化するためにエポン樹脂に包埋した後は、織を摘出した瞬間から劣化が始まるため、何らかの（１）切片の直接観察と、（２）紫外線顕微鏡像およ方法でその進行を防がねばならない。通常 TEM 用試

びαトラックとの同時観察がこれまでの化学固定試料の場合はグルタールアルデヒドでたんぱく質を変料を用いた場合と同様に行なえるかどうかを確認し性固定し、四酸化オスミウムによって脂質が固定さた。Fig.9 にその結果を示す。切片の直接観察像はれる。こうした処理は溶液中で行なわれるため、もFig.6,7 と比べると細胞内オルガネラの解像が一部し組織中に含まれる成分、たとえば硼素薬剤が溶液不足しているが、これは高圧凍結固定が通常の化学に溶解する性質を有していると、処理中にもとあっ固定と比べて高い技術を要求されるためで、使用すJRR－3M7R 中性子ラジオグラフィー装置、医工連携
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JAEA-Review 2008-067

Fig.9：a) 高圧凍結固定した組織のエポキシ包埋試料を切片化し、UV 照射後にAFM 直接観察した像。
b), c) 高圧凍結固定・エポキシ包埋試料の切片についてUV顕微鏡を適用した例。
c)については 241Amからのα線を 107/cm2程度照射し、αトラックとの同時観察も試みた。
右は細胞内構造の説明図。
いずれも 20μm スキャン。
細胞内薬剤分布についてより現実に近いと考えられる
凍結固定試料を用いても高解像度でαトラックマッピ
ングが実現できる目処がつ
いた。

a)

b)

c)

る組織の性質に合わせた固定・後処理の条件出しに��おわりに検討の余地があると考えられる。細胞核や細胞膜などは細かく解像できており、また適切な条件下では
18)

BNCT の鍵は、硼素薬剤の分布特性にかかっている

オルガネラの解像も可能であるとの報告もある 。

ことは序論でも述べた。薬剤自身の設計・開発がそ一方、紫外線顕微鏡像のほうは全く問題なくこれまの大部分を決定付けることになるのだが、実際に開でと同じ解像度が得られており、α線との同時観察

発された薬剤が細胞内でどのような分布を示すのか、も達成できている。こうして高圧凍結試料の切片を組織ごとに分布特性がどのように違うのかといった用いることで、オルガネラレベルでの解像度を持た情報がフィードバックされてこそ、薬剤開発の進展、せつつ、試料の信頼性も高い条件で硼素薬剤の分布

そしてひいては BNCT が治療として確立されていく

計測が行なえる見込みが十分得られたと考えられる。

ことにつながる。これまで高解像度の硼素分布計測技術が不足していたが、αオートラジオグラフィ法の立場からは今回ついに細胞内オルガネラレベルでの分布計測が可能となる手法を提案・確立できたと

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
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JAEA-Review 2008-067

考えている。ただし人命に関わる計測である。ただ

7)T. Kageji, S. Nagahiro, B. Otersen, D. Gabel,「測れる」だけではなく、計測した結果の信頼性に

M. Nakaichi, Y. Nakagawa, Journal ofも責任を持つ必要がある。これについても当初のよNeuro-Oncology 59 (2002) 135.

うな試料の信頼性不足を克服できる可能性を示せた。

8) M. Neumann, U. Kunz, H. Lehmann, D. Gabel,

しかし、これでようやくスタートラインに立てたばJournal of Neuro-Oncology 57 (2002) 97.

かりである。本手法を活用し、さまざまな硼素薬剤

9) D.R. Smith, S. Chandra, R.F. Barth, W.L. Yang,

について、組織ごとの分布特性データを蓄積していD.D. Joel, J.A. Coderre, Cancer Research

くばかりでなく、時間的な分布状況の変化に関する

61 (2001) 8179.

情報も収集することで硼素薬剤の特性把握を進め、

10) J. Michel, W. Sauerwein, A. Wittig, G.

BNCT の確立に向けて貢献していく必要がある。これ

Balossier, K. Zierold, Journal ofらの研究を通じ BNCT が近い将来、がん患者さんたち

Microscopy-Oxford 210 (2003) 25.
11) T. Tomie, H. Shimizu, T. Majima, M. Yamada,の希望となるよう願ってやまない。

T. Kanayama, H. Kondo, M. Yano, M. Ono,
Science 252 (1991) 691.

謝�
本研究を遂行するにあたり、非常に多くの共同研

12) K. Amemiya, et al., Nuclear Instruments &究者の方々に大変お世話になりました。本研究の研究

Methods in Physics Research Section

代表者であられました故・中沢 正治 東京大学教授におB-Beam Interactions with Materials andAtoms 187 (2002) 361.

かれましては、2006 年3 月10 日に永眠されました。偉大な研究者・教育者であるとともに人格者でもあった中沢先生

13) T. Ito, A. Ito, K. Hieda, K. Kobayashi,
Radiation Research 96 (1983) 532.

のご冥福をここに改めてお祈り致します。
東京大学大学院工学系研究科原子力専攻共同利用管理本

14) N. Matsko, M. Mueller, Journal of Structural

部（大学開放研究室）の皆様には実験準備段階から諸手続
きに至るまで懇切丁寧にご指導・ご協力を賜りました。末Biology 146 (2004) 334.
15) B. Tiribilli, D. Bani, F. Quercioli, A.

筆ながらこの場をお借りして感謝の気持ちを表したいと存

Ghirelli, M. Vassalli, Ultramicroscopy

じます。

102 (2005) 227.
16) T. Osada, H. Arakawa, M. Ichikawa, A. Ikai,

�考文献

Journal of Microscopy-Oxford 189 (1998)
43.

1) Y. Nakagawa, K. Pooh, T. Kobayashi, T. Kageji,
S. Uyama, A. Matsumura, H. Kumada, Journal17) K. Amemiya, H. Takahashi, M. Nakazawa, N.

of Neuro-Oncology 62 (2003) 87.

Yasuda, M. Yamamoto, Y. Nakagawa, T.

2) W.S. Kiger, P.L. Micca, G.M. Morris, J.A.

Kageji, M. Nakaichi, K. Ogura, Nuclear

Coderre, Radiation Protection Dosimetry

Instruments & Methods in Physics Research

99 (2002) 409.

Section B-Beam Interactions with

3) H. Yanagie, K. Ogura, T. Matsumoto, M. Eriguchi,

Materials and Atoms 159 (1999) 75.

H. Kobayashi, Nuclear Instruments &18) N.B. Matsko, Ultramicroscopy 107 (2007) 95.

Methods in Physics Research Section
a-Accelerators Spectrometers Detectors

成果の公表

and Associated Equipment 424 (1999) 122.

原著論文

4) K. Amemiya, et al., Radiation Measurements 40[1] K. Amemiya, et al., “High-resolution nuclear
track mapping in detailed cellular histology(2005) 283.
5) 雨宮 邦招、放射線、31 (2005) 41.

using

6) T.R. Munro, Radiation Research 42 (1970) 451.

technique”, Radiat. Meas. 40, p283 (2005).

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
JRR－4 中性子ビーム設備、医工連携－ 472 －

CR-39

with

the

contact

microscopy

JAEA-Review 2008-067

依頼投稿

imaging in detailed cellular histology”, 12th

[1] 雨宮 邦招, “がんの硼素中性子捕捉療法におInternational

けるマイクロドシメトリ手法”, 放射線, (印刷Therapy, Takamatsu, Kagawa, Japan, 9-13, Oct.,

中).

2006.

学会発表
[1] K. Amemiya et al., “Atomic force microscopic
neutron-induced alpha-autoradiography of boron

JRR－3M7R 中性子ラジオグラフィー装置、医工連携
JRR－4 中性子ビーム設備、医工連携－ 473 －

Congresson

NeutronCaptureJAEA-Review 2008-067

5-7���� 6123 �悪性脳腫瘍に対する非開頭硼素中性子捕捉療法�
Boron neutron capture therapy without craniotomy for malignant brain tumors
東京大学 医学部 脳神経外科 藤堂 具紀
稲生 靖
田中 実
大阪医科大学 脳神経外科 宮武 伸一
筑波大学臨床医学系能神経外科 松村 明
Department of Neurosurgery, Department of Neuro-oncology and Molecular therapeutics
University of Tokyo, Tokyo Japan, Department of Neurosurgery Osaka medical college,
Osaka, Japan, Department of Neurosurgery, Institute of Clinical Medicine, University ofTsukuba, Tsukuba city, Japan（�） 研究の目的と意義が少ない。BNCT 後の摘出組織の検討では、BNCT の治

目的：悪性脳腫瘍患者に対し、BSH(Borocaptate)とBPA(Boronophenylalanin)の同時併用投与下に熱外中性子を非開頭で照射する「硼素中性子捕捉療法」(Boron Neutron Capture Therapy; BNCT)を行い、頭部皮膚および正常脳組織に対する安全性を確認するとともに腫瘍制御と生存期間の改善を目指す。

療域に一致した necrosis を認めた。共同研究者の松村は原研東海研究所において、悪性脳腫瘍に対する
開頭下での BSH を用いた BNCT を多くの症例に行った経験を有し、最近非開頭による BNCT を開始した。本研究は、熱外中性子を利用することにより、非開頭で深在性腫瘍に対する治療を可能とし、さらに BSHの高い腫瘍選択性と BPA の高い腫瘍細胞集積性を合意義：悪性脳腫瘍は、腫瘍細胞のＸ線感受性が低い
ことや周囲脳組織への広範な腫瘍細胞浸潤などから難治疾患であり、この数十年間治療成績の改善がほわせて利用することにより抗腫瘍効果と安全性の向上を図る。悪性脳腫瘍に対する効果的か
つ実用的な新しい治療法となりうる。

とんど見られていない。BNCT は、腫瘍細胞を選択的かつ生物学的効果の高い粒子線にて治療するため、
通常のＸ線分割照射に比べ高い治療効果が期待できる。BPA 投与量の増加や、BNCT 後にＸ線分割照射を追加することにより、腫瘍縮小後の再増大の抑制の面で更なる改善が見られている。生存期間の延長については今後の追跡調査が待たれるが、少なくとも腫瘍縮小効果に関しては従来のＸ線分割照射よりも反応率が高く、非開頭にもかかわらず頭皮への影響

東京大学

方法：悪性脳腫瘍患者に対し、医学部研究倫理委員会で承認されたプロトコールにより症例を登録し、非開頭で硼素中性子捕捉療法を行う。
京都大学研究用原子炉(KUR)で施行されていた臨床研究プロトコール（2001 年６月 12 日 KUR 原子炉医療委員会承認）を基に、プロトコールを作成し東京大学医学部附属病院の倫理委員会にて承認を得た。
KUR では、臨床研究プロトール「“熱外中性子”ビー

医学部 脳神経外科－ 474 －

JAEA-Review 2008-067

ムを用いた悪性神経膠腫に対する非開頭硼素中性子

る。神経学的所見と画像の経時的観察により、抗腫捕捉療法」が承認施行された。ただし、KUR は平成瘍効果と生存期間に対する評価を行い、一方で照射

18 年 2 月以降点検のため約２年間操業を停止してお野内に皮膚および脳組織への影響を調査して安全性り現在では東海村が唯一の治療原子炉となっている。

の評価を行う。適応の判断を迷うような症例に対し腫瘍摘出術施行後の病理診断の確定した悪性脳腫瘍ては都立老人医療センターにて BPA の PET 検査を追患者を対象に、多施設共同研究として、非開頭の加し、L/N 比 2 以上をもって適応と考えることとす

BNCT の開発研究を行う。平成 16 年度から BNCT の臨る。

床研究プロトコールを東京大学医学部付属病院の倫理委員会に申請し、規定様式の同意書を作成した。

（２） 研究成果

平成 18 年 2 月 21 日に倫理委員会にて承認を得た（研

平成 17 年度〜19 年度文部科学省科学研究費補助金

究課題名：脳腫瘍に対する非開頭硼素中性子捕捉療（基盤Ｂ）「熱外中性子を用いた悪性脳腫瘍に対する法、受付番号 1312）。

次世代 BNCT」（研究代表者：松村明、研究分担者：

本研究では、KUR での経験に基づいた臨床研究プロ

藤堂具紀、森田明夫ほか）が採択された。平成 18

トコールを用い、腫瘍摘出術施行後の病理診断の確年度に倫理委員会を通過した後に適応症例が 3 例あ定した悪性脳腫瘍患者を対象に、BSH と BPA の２種ったが、１例は BPA- PET で T/N 比が 2 以下であっの硼素化合物投与を行った上、熱外中性子モードにた為 BNCT は行わなかった。またもう 1 例はちょうよる非開頭での硼素中性子捕捉療法を施行する。

ど９月半ば頃の症例で原研が点検で使用できず断念

腫瘍は最新のナビゲーションシステム（ステルス）した。平成 18 年 12 月 19 日、膠芽腫再発例の患者

および神経生理学的術中モニタリングを駆使し、新に本プロトコールによる硼素中性子捕捉療法を東海

たな神経障害を生じない範囲で可及的に大きく摘出

村の JRR-4 で行った。東大脳神経外科の 4 症例を含する。腫瘍摘出後の病理診断において膠芽腫と診断

めて、既に多数例の悪性脳腫瘍患者に対し非開頭でされ、かつ年齢が 10 歳から 80 歳までの症例で、術の治療を行っており、大多数の症例で２日〜７日後

後残存腫瘍が確認され、脳表より比較的浅部にあるまでに腫瘍の縮小を認めている。今回の症例も硼素症例で、本人および家族に対して本治療法の説明を

中性子捕捉療法後翌日、２日後、６日後に行った頭倫理委員会により承認された説明文により行い、同部 MRI では腫瘍の縮小を認めた。この間に症状の一意を得られた場合に、研究協力を依頼している筑波

時的な改善を認めた。しかし、本症例はその後髄腔

大学医学部附属病院へ転院し、必要な検査および内播種を合併し１ヵ月後に死亡している。

BSH および BPA の点滴を行う。JRR-4 において熱外中性子ビーム照射時の腫瘍内推定硼素―10 濃度は（�） 成果の�表

50ppm 以上を目標とし、血中濃度を即発ガンマ線分I.

Publications

析によって測定する。照射後線量分析に応じて、東1.

Tanaka M, Ino Y, Nakagawa K, Tago M, Todo T:

京大学医学部附属病院にて放射線分割照射を追加す－ 475 －

High-dose conformal radiotherapy forJAEA-Review 2008-067

supratentorial malignant glioma: a

オーマに対する高線量局所照射の治療成績

historical comparison. Lancet Oncology―60G 照射と比較した 184 例の解析―。第 64 回

6(12): 953-960, 2005.

日本脳神経外科学会総会（横浜）、2005 年 10 月
5-7 日

II. 学会発表
1.

2.

藤堂具紀、田中実、稲生靖、高橋雅道、斎藤延

7.

人：星細胞腫の長期治療成績からみた治療スタ

astrocytoma の放射線治療の意義 119 例の検ンダードの検討：130 例の解析。第 66 回日本脳討。
第 63 回日本脳神経外科学会総会（名古屋）、

神経外科学会総会（東京）、2007 年 10 月 3-5 日

2004 年 10 月 6-8 日

藤堂具紀、稲生靖、田中実、丸山啓介、鎌田恭輔、斎藤延人：悪性神経膠腫に対する多角的先端医療の実践。第 65 回日本脳神経外科学会
総会（京都）、2006 年 10 月 18-20 日

3.

田中実、稲生靖、斉藤延人、藤堂具紀：Recursive
partitioning analysis を用いた悪性グリオー
マ高線量局所照射の治療解析。第 24 回日本脳腫瘍学会（阿寒湖）、2006 年 10 月 1-3 日

4.

田中実、稲生靖、藤堂具紀：テント上悪性グリ
オーマに対する高線量局所照射の治療成績―60G 照射と比較した 184 例の解析―。第 23 回
日本脳腫瘍学会（鹿児島）2005 年 10 月 30 日-11
月1日

5.

田中実、稲生靖、藤堂具紀：Low-grade
astrocytoma の放射線治療の意義 119 例の検討。第 22 回日本脳腫瘍学会（松島）、2004 年
10 月 17-19 日

6.

田中実、稲生靖、藤堂具紀：Low-grade

田中実、稲生靖、藤堂具紀：テント上悪性グリ－ 476 －

JAEA-Review 2008-067

お わ り に
本報告書は、研究炉（JRR-3、JRR-4）を利用した利用者の協力を基に、研究炉の成果を提出して頂き、研究炉利用課で編集したものであります。この成果を公表する事で、研究炉の今後の有効利用並びに利用拡大に役立つ事を期待します。

編集委員

編集委員メンバー和田茂（研究炉利用課長）

広瀬彰（研究炉利用課）

吉永

真希夫（研究炉利用課）

高橋俊行（研究炉利用課）

渡辺

広子（研究炉利用課）－ 477 －

JAEA-Review 2008-067

謝辞

本報告書の発刊にあたり、多くの皆様から多大なご協力を頂きました。
原稿を提出して頂いた利用者の皆様のご協力に感謝するとともに、今後も研究炉が有効に利用され、種々の研究がさらに進展されることを期待します。
編集に際し、ご協力頂いた、研究炉加速器管理部長 山下清信氏、研究炉加速器管理部
JRR-3管理課課長 寺門義文氏に深く感謝致します。

－ 478 －

JAEA-Review 2008-067－ 479 －

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JAEA-Review 2008-067

付 録

原科研研究炉の利用設備一覧
１．ＪＲＲ－３
１）実験設備
実 験 孔
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実
験
装
置
高分解能粉末中性子回折装置（ＨＲＰＤ）
生体高分子用中性子解析装置（ＢＩＸ－Ⅲ）
生体高分子用中性子解析装置（ＢＩＸ―Ⅳ）
三軸型中性子分光器（ＴＡＳ－１）
中性子トポグラフィ及び精密光学実験装置（ＰＮＯ）
汎用三軸型中性子分光器（ＧＰＴＡＳ）
偏極中性子散乱装置（ＰＯＮＴＡ）
東北大学中性子散乱分光器（ＴＯＰＡＮ）
中性子ラジオグラフィ装置（ＴＮＲＦ）
中性子偏極回折装置（ＨＱＲ）
単結晶中性子回折装置（ＫＳＤ）
粉末中性子回折装置（ＫＰＤ）
即発ガンマ線分析装置（ＰＧＡ）
多重即発ガンマ線分析装置（ＭＰＧＡ）
ＴＯＦ型中性子反射率計（ＴＯＦ）
中性子ラウエ回折装置（ＬＡＵＥ）
中性子ベータ崩壊基礎測定装置
残留応力測定中性子回折装置（ＲＥＳＡ）
中性子４軸回折装置（ＦＯＮＤＥＲ）
多目的単色熱中性子ビームポート（ＭＵＳＡＳＨＩ）
高分解能三軸型中性子分光器（ＴＡＳ－２）
高エネルギー分解能三軸型中性子分光器（ＨＥＲ）
二次元位置測定小角散乱装置（ＳＡＮＳ－Ｕ）
超高分解能後方散乱装置（ＵＬＳ）
冷中性子散乱実験デバイス開発装置（ＬＴＡＳ）
高Ｑ領域対応中性子反射率計（ＳＵＩＲＥＮ）
中性子スピンエコー分光器（ＮＳＥ）
多重即発ガンマ線分析装置（ＭＰＧＡ）
即発ガンマ線分析装置（ＰＧＡ）
冷中性子ラジオグラフィ（ＣＮＲＦ）
パルス中性子機器開発装置（ＣＨＯＰ）
ＴＯＦ型中性子反射率計（ＴＯＦ）
中性子ラウエ回折装置(ＬＡＵＥ)
高分解能パルス冷中性子分光器（ＡＧＮＥＳ）
中性子光学システム評価装置（ＮＯＰ）
多層膜中性子干渉計／反射率計（ＭＩＮＥ）
中性子小角散乱装置（ＳＡＮＳ－Ｊ）－ 481 －

JAEA-Review 2008-067２）照射設備
水 力 照 射 設 備

ＨＲ－１,２

気 送 照 射 設 備

ＰＮ－１,２放射化分析用照射設備

ＰＮ－３

均 一 照 射 設 備

ＳＩ－１

回 転 照 射 設 備

ＤＲ－１

垂 直 照 射 設 備

ＶＴ－１,ＲＧ－１～４
ＢＲ－１～４,ＳＨ－１

２．ＪＲＲ－４
１）実験設備プール

中性子ビーム設備
散 乱 実 験 設 備
冷却水循環ループ
医療照射設備（ＢＮＣＴ）
即発ガンマ線分析装置
２）照射設備Ｔパイプ（水力）Ｓパイプ
簡 易 照 射 筒
Ｄパイプ
Ｎパイプ
気送管照射設備

ＰＮ－ 482 －