bluuebunny/crossref_metadata_2025 huggingface dataset:
X-Ray Absorption Spectroscopy Investigation of Amorphous and Crystalline As2S3 up to 30 GPa
Authors: Itie J. P. , Polian A. , Grimsditch M. , Susman S.
Published: March 2014

Pressure behaviour of crystalline and amorphous As2S3 has been studied up to 35 GPa by x-ray absorption spectroscopy at the As K edge using the energy dispersive spectrometer of LURE. In the crystalline sample, a modification is observed at 10.6 GPa. In both materials, a transition to higher coordinance seems to occur above 30 GPa, associated with an increase of the first neighbours distance.
X-ray Absorption Near Edge Structure (XANES) Studies of Diluted Magnetic Semiconductors (DMS) Zn1-xYxS (Y=Mn, Fe, Co) Systems
Authors: Pong W. F. , Mayanovic R. A. , Wu K. T. , Tseng P. K. , Bunker B. A. , Hiraya A. , Watanabe M.
Published: March 2014

X-ray absorption near edge structure (XANES) spectra of the Diluted Magnetic Semiconductors (DMS) system Zn1-x
Mn
x
S have been measured at the Zn LII,III-edges and of Zn1-x
Y
x
S (Y = Mn, Fe, Co) at the S K-edge using total electron yield mode. The Zn LIII-edge results for Zn1-x
Mn
x
S reveal a dramatic reduction in intensity of the first prominent feature, just above the edge, in the XANES spectra. Analysis of the S K-edge XANES spectra for Zn1-x
Y
x
S revealed an increase in a pre-edge peak and a corresponding decrease in the first above-edge peak with increase in transition metal content in the alloys. These results are consistent with more S 3p- transition metal (Y) 3d(t2) hybridized states and less S 3p- Zn 4(s,p) and S 3p-Zn 3d hybridized states becoming available as transition metal content increases in the alloys.
Coordination of Cr3+ Ion in α-Al2O3
Authors: Emura S. , Maeda H. , Kuroda Y. , Murata T.
Published: March 2014

The local arrangement of a substitutional Cr3+ ion for an Al3+ ion in corundum is studied by means of a Fluorescence XAFS method. The large single crystal is used and the removal method of the diffraction peak at various energy is described. The Cr3+ ion is coordinated in the nearly same structure as Cr2O3..
Off-Center Position of the Cu+ Ion in NaBr
Authors: Emura S. , Murata T. , Maeda H. , Nomura M. , Moriga T.
Published: March 2014

The off-center of a Cu1 ion in a NaBr:Cu+ system is directly confirmed. One of the off-center parameters, an off-center distance, is analyzed from the observed Cu-Br distance. A preferential off-center direction is along <111> axes. It is suggested that the cage consisting of 6 Br- ions is deformed.
XAFS Study of SiX (X=C or N) with Poor Crystallinity
Authors: Imamura Motoyasu , Shimada Hiromichi , Matsubayashi Nobuyuki , Sato Toshio , Yoshimura Yuji , Hanaoka Takamasa , Sasaki Motoi , Nishijima Akio
Published: March 2014

X-ray absorption spectra of several silicon compounds with high S/N ratios were obtained over a wide energy span, up to 950 eV above the silicon K-edge monitoring total electron yields from the sample. EXAFS analysis of a CVD thin film of Si3N4 elucidated the presence of contaminated Si metal in the α-Si3N4 structure. EXAFS and XANES analyses detected SiC crystallites in a CVD thin film of SiC, which could not detected by X-ray diffraction.
XAFS Study of the bcc-hcp Transition of Iron
Authors: Wang F. , Ingalls R. , Crozier E. D.
Published: March 2014

An XAFS study of metallic iron at room temperature and pressures to 21.5 GPa has been performed. The data show the transition from the α (bcc) to the ε (hcp) phase. With increasing pressure a mixed phase region is found to mainly exist between 13 and 20 GPa, and between 15 and 11 GPa with decreasing pressure. We report the XAFS derived results for the coordination numbers, the near neighbor distances and the associated Debye-Waller factors.
XAS Investigation of the Structural and Electronic Changes Induced by Hydrogen Absorption in CeFe11Ti
Authors: Chaboy J. , Marcelli A. , Bozukov L.
Published: March 2014

We present an extensive study using X-ray absorption spectroscopy on CeFe11 TiHx at variable hydrogen concentration. Cerium L3-edge, iron and titanium K-edge EXAFS and XANES spectra have been measured. We have investigated the influence of hydrogen absorption in electronic localization and local structure around the metal atoms as well as on the electronic state of cerium. The structural and magnetic changes in the hydrides are discussed in terms of the modification of the 4f-3d coupling strength via 3d-5d hybridization.
Fermi-Edge Singularity in One-Dimensional Metals: Effects of Hole Recoil and Electronic Correlation
Authors: Ogawa Tetsuo , Furusaki Akira , Nagaosa Naoto
Published: March 2014

The Fermi-edge singularity in optical spectra is studied theoretically for one-dimensional (1D) metals. Using the intermediate-coupling method, the critical exponent is obtained analytically for an arbitrary mass of an optical hole. The electronic correlation is also taken exactly into account by the Tomonaga-Luttinger's bosonization technique. The exponent is found to be independent of the hole dynamics in 1D, which is in striking contrast to the 2D and 3D cases. Weak repulsive interaction among the conduction electrons sharpens the power-law peak in the edge spectrum.
XAFS Analysis of Sm2Fe17Nx Magnetic Compounds
Authors: Yamashita Seiichi , Konishi Tokuzou , Kobayashi Kurima
Published: March 2014

Sm2Fe17Nx magnetic compounds were obtained by nitrogenation in NH3-H2 mixed-gas atmosphere; the local structure around central Sm atom in the compounds was studied from XAFS analysis. It was suggested that three or more N atoms are situated at the first neighbor of Sm atom, forming a distorted local structure around Sm atom in the Sm2Fe17N4.5 compound.
Gold Silver Sulfide Structure on the Surface of Silver Halide Microcrystals
Authors: Murata Takatoshi , Harada Katsuyuki , Emura Shuichi , Nakayama Tomoyuki , Takada Hiroshi , Tsuchiya Nobuyuki , Maeda Hironobu , Nomura Masaharu
Published: March 2014

The structure of the Au clusters dispersed on the AgBr microcrystals is investigated by fluorescence EXAFS technique. The results show the definite similarity between the sample and Au metal foil. The formation of small Au metal clusters on the surface of the AgBr microcrystals is suggested.
Structural Studies of Vapour Phase Transport Reactions Using X-ray Absorption Spectroscopy and Matrix Isolation
Authors: Young Nigel A.
Published: March 2014

The vapour above heated ferric chloride (Fe2Cl6) been isolated in nitrogen, argon and neon matrices. The XANES features are indicative of iron in a tetrahedral environment and the interatomic distances from the EXAFS data for the nearest neighbour shells are in good agreement with the vapour phase electron diffraction data. In the case of the nitrogen matrix isolated species the Fe...Fe distance has been determined, indicating the potential usefulness of matrix XAS for the study of vapour phase intermediates. The reasons for the non-observance of this shell in argon and neon matrices are considered.
Ar 2p and Ar 1s Spectroscopy of Free Argon Clusters
Authors: Rühl E. , Heinzel C. , Baumgärtel H. , Drube W. , Hitchcock A. P.
Published: March 2014

Ar(2p) and Ar(1s) total electron yield and total ion yield spectra of supersonic beams of Ar clusters with average size between 1 and 750 atoms are reported. The near edge features evolve with increasing cluster size from atomic-like Rydberg states to solid-like excitonic states. EXAFS in the Ar(2p) and Ar(1s) continua of Ar clusters is analysed.
EXAFS Characterization of Manganese(III) Dihydrogen Triphosphate Dihydrate H2MnP3O10·2H2O
Authors: Chaboy J. , Garcia J.
Published: March 2014

The study of local structural environment of the manganese in H2MnP3O10.2H2O has been performed by using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy at the K edge of Mn. Results from the analysis of the EXAFS spectra show an axially distorted octahedral environment of manganese due to the Jahn-Teller effect, being larger in H2MnP3O10.2H2O. The inclusion of multiple scattering contributions into the theoretical simulations is shown to be indispensable in order to obtain a right structural determination.
A XAFS Study of Rb- and Sr-Salts of Crowned p-(2,4-Dinitrophenyl)azophenol
Authors: Kaneda Takahiro , Takahashi Masao , Emura Shuichi , Sakata Yoshiteru
Published: March 2014

The rubidium and strontium salts of crowned p-(2,4-dinitrophenyl)azophenol 1 were prepared in 69 and 77 % yields, respectively. The VIS spectrum of the Sr salt showed a remarkable blue-shift of 48 nm compared to that of the Rb salt. The present XAFS experiments provided the evidence for host-guest complexation between the Sr ion and the chromogenic ligand, by which the observed blue-shift can be interpreted.
XANES Spectroscopic Study of Chemical Bonding in Amides and N-Salicylideneanilines
Authors: Oichi Kazuyoshi , Ito Eisuke , Seki Kazuhiko , Araki Tohru , Narioka Satoru , Ishii Hisao , Okajima Toshihiro , Yokoyama Toshihiko , Ohta Toshiaki , Inabe Tamotsu , Maruyama Yusei
Published: March 2014

Resonance and tautomerism by proton transfer were studied by N and 0 K-XANES spectroscopy in two systems with coupled NH and CO groups: amides and salicylideneaniline derivatives. In amides, where tautomerism is mostly absent with OH form dominating the equilibrium, effect of resonance clearly appears in the N K-XANES spectra as the 1s → π* resonance showing the double bond nature of the CN bond. In salicylidenaniline derivatives, N and 0 K-XANES spectra gave consistent results about the tautomerism in N,N'-disalicylidene-1,6-pyrenediamine (DSPY) and di(2-hydroxy-1-naphthylidene)-p-phenylenediamine (DNP), with DSPY primarily in OH form and DNP in both OH and NH forms. These results are consistent with those from X-ray diffraction and NMR measurements, showing the usefulness of XANES as a method of studying resonance and tautomerism in organic systems.
XAFS Study of Metal-Formazan Compounds
Authors: Honda Kazumasa , Uchiumi Isao Kojima Akira , Eyama Tomohisa
Published: March 2014

XAFS studies have been performed to clarify the relationship between the corresponding pH, color and the structural changes of metal(Cu, Ni)-(o-PHF)n [o-PHF=1-(2-hydroxyphenyl)-3-phenyl-5-(2-pyridyl)formazan; Fig.1] complex. The structural change of the Cu(o-PHF) complex has been attributed to the change of bonding mode of the -OH group in the formazan ligand to the metal. The Ni(o-PHF)n complex has been proved to form different structures, 6-coordinated 1:2 complex and 4-coordinated 1:1 complex in acid and alkaline media, respectively.
Splice Method in the EXAFS Analysis Applied to Cuprous Halide
Authors: Ono Izumi , Yokoyama Toshihiko , Sato Hitoshi , Kaneyuki Kentaro , Ohta Toshiaki
Published: March 2014

The splice method in the EXAFS analysis, which was recently proposed for the direct determination of a radial distribution function (RDF), was applied to the systems with large disorder. The 4th-order cumulant expansion method cannot reproduce a strongly asymmetric RDF, while the splice method successfully gives the original RDF. Temperature dependence of the 1st nearest neighbor Br-Cu RDF in CuBr was investigated by analyzing the Br K-edge EXAFS with the splice method.
New routes of XAFS with the low emittance storage rings.
Authors: Fontaine A.
Published: March 2014

New routes of XAFS should come from the extreme focusing and the polarization tunability of the new storage rings. It is certainly of interest to recall that fundamental ideas in X-ray absorption spectroscopy should come from direct soft X-ray excitations, currently accessible with the national facilities but also via inelastic scattering by electronic excitations more relevant of the new storage rings. Because of the ESRF proximity, references come from the European development, but it is only due to my ignorance if pertinent quotations of the American and Japonese efforts are missing.
Future Prospects of XAFS Researches Using High Brilliance Photon Sources
Authors: Oyanagi Hiroyuki
Published: March 2014

Future prospects in XAFS researches to be developed by high brilliance photon sources are discussed. Above a dilute limit, sensitivity and time resolution are enhanced with the increase in brilliance, detector effeciency and focusing capability. It is shown that a multipole wiggler and multi-element solid state detector improve both sensitivity and time resolution by an order of magnitude. Applications to structural studies of dilute systems, in particular, surface and interfaces are presented. A “tunable” X-ray undulator inserted in an ultra-low (<10 nrad) emittance storage ring, which covers a hard X-ray (4-30 keV) region using the fundamental and third higher harmonic radiations, further improves the present limitations on sensitivity and resolutions in time, space and energy. Feasibility of a variable gap/bandpath undulator combined with new quick scanning techniques for applications in time-resolved studies is discussed. By optimizing an undulator band width for a scan, without varying undulator gap, XAFS is obtained by simple scanning of monochromator (Q-scan I). A new quick scanning technique for time-resolved studies on dilute systems based on an energy dispersive geometry (Q-scan II) is proposed. Design considerations of a “tunable” X-ray undulator XAFS beamline at SPring-8 are presented, in which either a high flux or a microfocus high energy resolution beam is obtained by a fixed-exit double-axis (2+2) crystal monochromator followed by crossed eliptical mirrors. A concept of “ring” detector for microfucusing in a fluorescence detection mode is also proposed.
Investigation of the Local Thermal Behaviour of GaAs by the Cumulant Analysis of EXAFS
Authors: Burattini Emilio , Dalba Giuseppe , Diop Djibril , Fornasini Paolo , Rocca Francesco
Published: March 2014

EXAFS at the K edges of Ga and As in crystalline GaAs has been measured in the temperature range 77-450 K. The temperature dependence of the second and fourth cumulants of the distance distribution of Ga and As in the first three coordination shells has been determined from the EXAFS amplitude analysis. The influence of anharmonicity in the shells beyond the first one has been revealed.
The Effect of Anharmonicity on the EXAFS Coordination Number in Small Metallic Particles
Authors: Clausen Bjerne S. , Topsøe Henrik , Hansen Lars B. , Stoltze Per , Nørskov Jens K.
Published: March 2014

By use of a newly developed model, a more accurate determination of metal particle size from a standard analysis of an EXAFS experiment is now possible1). The model is based on a set of molecular dynamics simulations from which the pair correlation function of small metallic particles can be obtained. The model allows an estimation of the errors arising from the standard EXAFS analysis, in particular the errors due to the exclusion of the low momentum information as well as the non-transferability of the amplitude function.
Cu K-edge XANES and Electronic Structure of Trivalent, Divalent, and Monovalent Cu Oxides
Authors: Akeyama Koichi , Kuroda Haruo , Kosugi Nobuhiro
Published: March 2014

To elucidate the electronic structure of copper oxides with formally trivalent, divalent and monovalent Cu, x-ray absorption spectra were measured for NaCuO2, CuO and Cu2O by using synchrotron radiation. These XANES spectra were investigated by performing ab initio quantum chemical calculations based on the cluster-CI theory. The ground state of NaCuO2 demonstrates strong covalent bonds between the Cu 3d and O 2p orbitals, resulting in small contribution of Cu(d8) configuration and large contribution of Cu(d9) configuration. The final-state effect in the Cu K-shell excited states of NaCuO2 is similar to that of CuO, which explains that the overall structure in the spectrum of NaCuO2 resembles that of CuO. On the other hand, the ground state of Cu2O demonstrates covalent bonds between the Cu 3d, Cu 4s and O 2p orbitals, resulting in a contribution of the Cu d94s configuration. This configuration causes another type of final-state effect in the Cu K-shell excited states of Cu2O.
Epitaxial Growth of Wide-Gap Chalcopyrite Materials –Current State and Future–
Authors: Kukimoto Hiroshi
Published: March 2014

The world-wide current state of the epitaxial growth of wide-gap chalcopyrite materials, especially of I-III-VI2 (I=Cu, Ag; III=Al, Ga; VI=S, Se), is reviewed with emphasis on outstanding progress and problems. An optimistic view of the future development directed toward device applications, which includes conductivity control and heteroepitaxial growth, is also presented.
Characterization by Photoluminescence of ICB-Grown CuInSe2 Thin Films
Authors: Ushiki Takehito , Ueno Akira , Yano Takayuki , Sano Hiroyuki , Usui Hiroaki , Sato Katsuaki
Published: March 2014

CuInSe2 thin films were prepared by the ICB (ionized cluster beam) technique on glass substrates. It is found that the apparent grain size increased more than 1 µm when Cu cluster is ionized, even in In-excess CuInSe2 films which usually shows a specular surface with a small grain size of less than 0.2 µm. These films were characterized by photoluminescence (PL) spectra employing Ar and YAG lasers as excitation sources. In those films with a slightly In-excess composition, the 0.85 eV-peak was observed, which has been correlated with the good solar cells performance. The PL peak gained intensity with the increase of acceleration voltage of In-cluster up to 2 kV. It is concluded that ICB is a promising technique for preparation of good quality CuInSe2 thin films for solar cells.
A criterion for Applying Chalcopyrite Semiconductors to Optical Line Elimination Filters
Authors: Horinaka Hiromichi , Mononobe Shuji , Yamamoto Nobuyuki
Published: March 2014

The optical line elimination filter consisting of a birefringent, optically active crystal and two polarizers has a narrow band at the wavelength of the accidental optical isotropy of crystal. Chalcopyrite semiconductors applicable to this filter are predicted from the contribution of anisotropy of transition intensity to birefringence. CuAlS2, AgAlS2, AgAlSe2, AgAlTe2 and AgInS2 are thought to satisfy the condition of the filter, i.e. the accidental optical isotropy. Experimental results show that CuAlS2 had the optical isotropic wavelength at 378 nm. The dependence of center wavelength of AgIn
x
Ga1-x
Se2 filter on x is estimated from the band parameters. The center wavelength of AgIn
x
Ga1-x
Se2 filter (x=0.5) is shown experimentally to be adjusted to the emission line of Nd:YAG laser.
Structural and Electrical Investigations of the Anion Exchange in Polycrystalline CuIn(S, Se)2 Thin Films
Authors: Walter T. , Schock H. W.
Published: March 2014

The transition from the selenide to the sulfide in coevaporated CuIn(S, Se)2 thin films is investigated regarding morphology, structural properties, incorporation of sulphur versus selenium, the existence of secondary phases and electrical properties. The segregation behaviour of secondary phases in In-rich and Cu-rich films and the influence on the film growth are discussed. Measurement techniques involve SEM, XRD and acceleration voltage dependent WDS.
Practical Use of Easy Raman Spectrometer Equipped with AgGaSe2 Filter and GaAlAs Laser Diode
Authors: Yamamoto Nobuyuki , Huang Wen-Zheng , Horinaka Hiromichi
Published: March 2014

A new type of easy Raman spectrometer equipped with AgGaSe2 crystal filter and single mode GaAlAs diode laser exciter is constructed. Because the Rayleigh scattering light can be effectively eliminated by the crystal filter, both Stokes and anti-Stokes Raman scattering lines can be measured through a single scan of wavelength. Performance test of Raman scattering measurement for some typical samples is demonstrated.
Predictions of New Semiconductor of Transition Metal Structures and Their Properties
Authors: Zunger Alex
Published: March 2014

I describe how one can use the “Cluster Expansion Method” to predict systematically what are the thermodynamically stable crystal structures on a given lattice type. The method is used to illustrate how hitherto unsuspected ordered compounds can be identified, including new transition metal intermetallics and ternary semiconductors.
Improvement in Layer Quality of CuGaS2 Grown by Vapor Phase Epitaxy with Metal Chlorides and H2S Sources
Authors: Tsuboi Nozomu , Isu Takehiro , Ando Yoshihide , Sawada Masayuki , Iida Seishi
Published: March 2014

In vapor phase epitaxial growth of CuGaS2 on GaP substrates under simultaneous feeding of H2S and metal chlorides, two-step growth was found to be useful for obtaining thick layers with single orientation of c-axis of the chalcopyrite normal to the substrate. Under alternate feeding of H2S and mixed gas of the chlorides, saturation behavior of growth rate was observed for the feeding amount of copper chloride and that of gallium chloride, and also for the supplying period of H2S gas. These results strongly suggest atomic layer epitaxy of CuGaS2. The layers grown under alternate feeding as well as layers by the two-step process under simultaneous feeding showed strong free exciton emission at low temperatures, indicating high quality of these layers.
Molecular Beam Epitaxial Growth and Properties of CuInSe2
Authors: Niki Shigeru , Makita Yunosuke , Yamada Akimasa , Obara Akira , Misawa Syunji , Igarashi Osamu , Aoki Kazuhiro , Kutsuwada Noboru
Published: March 2014

CuInSe2 (CIS) films with Cu/In ratios (γ) ranging from 0.81 to 1.81 have been grown by molecular beam epitaxy on (001)-oriented GaAs substrates at a substrate temperature of T
s=450°C. It is found that Cu-rich films tend to become Se-poor, and In-rich films tend to become Se-rich. X-ray diffraction patterns obtained from these films have shown the peaks with respect to CIS {n00} planes, clearly indicating epitaxial growth. Optical properties of the CIS films have been characterized by means of photoluminescence (PL) spectroscopy at 2 K. Many distinct emission lines including a band edge emission were present on PL spectra obtained from Cu-rich films. A broad emission (λ∼1.45 µm) appeared at γ=1.04, then became dominant with further decreasing γ.
Time Resolved Study of Laser Induced Crystal Growth and Phase Transformation
Authors: Joshi N. V. , Quintero P. , Martin J. M.
Published: March 2014

Laser assisted crystal growth and phase transformation of CuInSe2 from thin layers of copper, indium and selenium have been examined in time domain. Such study has not been reported before for any system. Transmitted intensity at wave length of maximum transmittance of CuInSe2 was recorded at the interval of 0.5 ms during the entire process of phase transformation. It has been found that for a threshold power of 160 W/cm2, 500 ms are reguired to convert a system into a thin film of CuInSe2. The final product was examined by Raman spectroscopy. Substantial intermixing of the constituent elements takes place at about 300 ms. If the film is further radiated, then defect states are created causing a considerable reduction in the transmittance.
Effect of Fluid Flow on the Concentrational Nonuniformities in LiNd1-xYxF4 Compound
Authors: Grasza K. , Pawlowska M. , Jabloński R. , Hofman W. , Luczyński Z. , Kowalczyk E. , Radomski J.
Published: March 2014

In this work we have investigated the effect of convective melt flow on structural and compositional nonuniformities of LiNd1-x
Y
x
F4 crystal grown by the Bridgman-Stockbarger technique. The crystal was studied by the scanning electron microscopy. The Nd3+ distribution in the crystal was analyzed using electron spin resonance spectroscopy. The structure of convection vortices was investigated at various stages of crystal growth.
Crystal Structure and Properties of Ag7-xTaSe6-xIx (0≤x≤1)
Authors: Wada Hiroaki , Ishii Motohiko , Amiel Olivier , Sato Akira
Published: March 2014

A new argyrodite-type compound Ag7-x
TaSe6-x
I
x
(0≤x≤1) has been studied in terms of crystal structure and properties. Depending on x value, two types of cubic phases were obtained: one with S.G. P213 is in the range 0≤x≤0.2 and the other one with S.G. F4̄3m is in the range 0.2≥x≤1. Single crystals were prepared by solid state reaction at 900°C for 2 weeks. Crystal structure analyses were performed with CAD-4 four-circle X-ray method using Mo Kα radiation.
Solid Solubility Determination and Single Crystal Preparation of New Quaternary Solid Solution System of (Pb1-xGex)(S1-zSez)
Authors: Kimoto Kazuhiko , Masumoto Katashi , Noda Yasutoshi , Kumazawa Kazutoshi , Kiyosawa Teruo , Koguchi Nobuyuki
Published: March 2014

For the quaternary (Pb1-x
Ge
x
)(S1-z
Se
z
) solid solution system, the solubility limits of Ge in the system were investigated using powder X-ray diffraction and the solubility region were clarified. From the results, the relationship between the lattice constant and the energy gap was derived in the solid solution region, which will serve to fabricate double hetero laser diodes lattice-matched to PbS. The (Pb1-x
Ge
x
)S single crystals were prepared by chemical transport and characterized by Hall effect measurements.
Defect Chemistry of CuInSe2
Authors: Chang D. Y. , Ueng H. Y.
Published: March 2014

The defect chemistry model is developed as a function of the nonmolecularity (Δ
X) and nonstoichiometry (Δ
Y), and the formation energies of defects are also considered. In this model, the p-type conductivity can occur in the region with Δ
X<0 and Δ
Y<0 and n-type conductivity can occur in the region with Δ
X>0 and Δ
Y>0. For above given regions, it could be possible to define a critical relation as Δ
X
c=8Δ
Y/(1-2Δ
Y). The p-type conductivity occurs in the Δ
X (more negative value)<Δ
X
c region at a constant Δ
Y value. As the decreasing of Δ
X negative value, the type conversion appears near the Δ
X equals to Δ
X
c region, and then it was dominated by n-type conductivity.
Electronic Structures and Properties in Strongly Correlated Electron Systems: Perovskite-like Titanates
Authors: Tokura Yoshinori
Published: March 2014

The Ti3+ (3d
1) based oxide compounds are mostly Mott-Hubbard insulators or barely metallic due to the strong correlation between 3d electrons. With use of distorted perovskite-like structures RTiO3 (R=rare earth) and their R-site substitution with alkaline earth (A=Sr or Ca), we can systematically control the effective electron correlation (U/W) and the band filling of the 3d states. With decrease of the filling or with “hole-doping”, the systems show the insulator-metal transition. Recent progress in experimental investigations on the metal-insulator transition is reviewed.
Magnetic Properties of Intermetallic Compounds Mn3PtCx (x=0–0.1)
Authors: Kaneko Takejiro , Kanomata Takeshi , Kikuchi Makoto , Yoshida Hajime , Abe Shunya
Published: March 2014

Antiferromagnetic ordered alloy Mn3Pt with a Cu3Au-type structure has a triangular spin structure (D phase) below T
t=365 K and a collinear one (F phase) between T
t and the Néel temperature T
N(F)=475 K. The effect of carbon addition to Mn3Pt on magnetic properties is studied for Mn3PtC
x
by measuring the magnetic susceptibility and pressure effect on the magnetic transition temperatures. The results show that (1) the lattice parameter expands with x, (2) both T
t and T
N(F) decrease with x, (3) T
t decreases and T
N(F) increases with pressure, (4) the F phase disappears at high pressures. The P–T magnetic phase diagrams are presented.
Spin Arrangement and Electronic Structure of Mn3MC (M=In and Sn)
Authors: Ishida Shoji , Fujii Shinpei , Maeda Michiharu , Asano Setsuro
Published: March 2014

It is shown from the electronic structures of Mn3MC (M=In, Sn) that there are two types of Mn atoms with different magnetic moments and a novel spin arrangement in Mn3MC, though the Mn atoms are equivalent in crystallography.
Electronic Structure and Ferromagnetic-Antiferromagnetic Transition in Cubic Perovskite-type Compound Mn3GaC
Authors: Shirai Masafumi , Ōhata Yoshifumi , Suzuki Naoshi , Motizuki Kazuko
Published: March 2014

First-principles band structure calculations are performed by using a self-consistent linearized augmented-plane-wave (LAPW) method for the non-magnetic, ferromagnetic (FM) and antiferromagnetic (AFM) states of Mn3GaC, in order to provide the basis for understanding the origin of the FM–AFM transition of Mn3GaC. Total energies for both the FM and AFM states are calculated as a function of the unit cell volume and compared with each other. The stability of these magnetic ordered phases is discussed and pressure effects on magnetic properties are predicted.
Magnetic Properties of MnZnSb
Authors: Mori Sin-ichi , Kanomata Takeshi , Yamauchi Hiroshi , Sakatsume Shinichi , Kaneko Takejiro
Published: March 2014

Magnetization measurements are made on a single crystal of ferromagnetic MnZnSb from 4.2 K to 325 K in order to determine the uniaxial anisotropy constant K
1. The easy and hard directions of magnetization are c-axis and c-plane, respectively. The saturation moment and K
1 extrapolated to 0 K are 1.5 µB and 6.7×106 erg/cm3, respectively.
Transport Properties of Ternary Magnetic Compounds Mn3-xMxGaC (M=Cr and Fe)
Authors: Harada Takashi , Nishimura Koichi , Kanomata Takeshi , Kaneko Takejiro
Published: March 2014

The electrical resistivities (ρ) and the thermoelectric powers (S) of Mn2.95Fe0.05GaC and Mn2.95Cr0.05GaC are studied to investigate the mechanism of the antiferromagnetic (AF)-ferromagnetic (F) transitions. The substitution of Fe or Cr for Mn decreases and increases the first order transition temperature, respectively. The experimental results suggest that the magnetic transitions of Mn2.95Fe0.05GaC and Mn2.95Cr0.05GaC should be discussed in terms of itinerant magnetism.
Spin Arrangement and Electronic Structure of Mn3GaX (X=C and N)
Authors: Ishida Shoji , Fujii Shinpei , Sawabe Akihiro , Asano Setsuro
Published: March 2014

The electronic structures of Mn3GaX (X=C, N) were calculated for the ferromagnetic, antiferromagnetic and triangular spin arrangements. It is found that the difference of the hybridization between the spin states in the three magnetic states produces differences in the magnetic moments and the total energies.
Magnetic Resonance on Cr2Te3
Authors: Konno Hiroshi , Adachi Yoshiya , Yuzuri Motoyoshi
Published: March 2014

The compound Cr2Te3 is ternary for including the ordered vacancies. On the compound, magnetic resonance absorption with 9.3 GHz microwave has been observed. The absorption intensity is small below 198 K, the ferromagnetic Curie temperature of the compound. But it rather increases rapidly above the temperature, then it decreases sharply at 335 K. Landé's g-factor shows anomalously large value from 198 K to 335 K, the maximum is almost 7 at 300 K, then approaches to 2 at higher temperatures. From the results, it is shown that true Curie point is 335 K, and 198 K is another kind of magnetic transition point.
Peculiarities of Galvanomagnetic Effects in Ternary Magnetic CuCr2X4 Single Crystals Near Magnetic Phase Transition
Authors: Tsurkan V. V. , Radautsan S. I.
Published: March 2014

The observed results on the magnetoresitance and Hall effect in ternary ferromagnetic spinel CuCr2Se4 single crystals with anion and cation substitution are presented. Charge carrier scattering mechanisms at different temperature intervals are discussed.
Magnetic Properties of R2T17 Type Y2Fe17-xAlx Compounds
Authors: Itoh Kazuo , Ohkubo Naoki , Kanematsu Kazuo
Published: March 2014

Magnetization and Mössbauer measurements on R2T17 type compounds Y2Fe17-x
Al
x
were performed. The crystal structure is of Th2Ni17 type for x≤4 and Th2Zn17 type for 5≤x≤7. With increasing Al content, the magnetization decreases and the Curie temperature increases for x≤3 and decreases for x≥3. The composition dependence of the hyperfine field is discussed in conection with the substitution of Al for Fe.
Effect of Interstitial Beryllium Atoms for the Magnetic Properties of R2Fe17Be
Authors: Horikawa Yoshiharu , Tokita Satoshi , Kanematsu Kazuo
Published: March 2014

Magnetic Properties R2Fe17Be have been studied in order to detect the effect of interstitial beryllium atom for the magnetic properties of R2Fe17. Experimental results show that the lattice constants, magnetization and Curie temperature of R2Fe17 decrease by adding beryllium. The effect of beryllium for the magnetic properties was discussed.
High Pressure Synthesis and Magnetostrictive Measurement of Laves Phase Pr1-xRxFe2 (R=Ce, Nd)
Authors: Notsu Yukio , Endo S. , Ono Fumihisa , Kohmoto O. , Uchida T. , Mori T.
Published: March 2014

Laves phase rare-earth iron intermetallic compounds were synthesized under high pressure and high temperature by using a double stage multianvil high pressure equipment. The minimum pressure required to synthesize the Laves phase was determined. The maximum magnetostriction of 8×10-6 was attained at room temperature for PrFe1.8.
NMR Study of (Nd1-xRx)2Co14B Compounds
Authors: Ichinose Kazuyoshi , Nagai Hiroyuki
Published: March 2014

Nuclear magnetic resonances of 59Co nuclei in (Nd1-x
R
x
)2Co14B (R=Y, Pr, Sm, Gd and Tb) compounds have been observed at 4.2 K. The shapes of 59Co NMR spectra change drastically near x=0.95, 0.9 and 0.4 for R=Y, Gd and Sm, respectively, in which the spin reorientation (axis→plane) appears. The domain walls in the compounds with Pr seem to be very stiff and narrow. The hyperfine fied at 59Co nuclei depends on the strong anisotropy of R.
Magnetism and Electrical Properties in the Perovskite-type Y1-xCaxTiO3
Authors: Iga Fumitoshi , Fukuchi Hideo , Inoue Isao H. , Nishihara Yoshikazu
Published: March 2014

The perovskite-type alloy system Y1-x
Ca
x
TiO3 has the magnetic transition near x=0.1 and the metal to insulator (M-I) transition near x=0.3. This system is found to be classified into the following three categories by the measurements of magnetic and electrical properties, (i) In the Y-rich region (0<x<0.1), this alloy system shows ferromagnetic and semiconducting behaviour, (ii) In the middle region (0.1<x<0.3), the temperature dependence of magnetic susceptibility shows Curie-Weiss type paramagnetic behaviour but transport property shows semiconducting behaviour, (iii) In the Ca-rich region (0.3<x<1), the alloy shows metallic transport and Pauli-paramagnetic behaviours.
Heat Capacity of PrCo2Si2
Authors: Jin Bi , Iwata Nobuo , Shigeoka Toru , Takeda Kazuyoshi , Konishi Kensuke , Deguchi Hiroyuki
Published: March 2014

Heat capacity of PrCo2Si2 is reported. This compound exhibits complicated magnetic phase transitions with increasing temperature, first from the commensurate structure with a wavevector Q
1=(0, 0, 1) to a high-order commensurate structure with Q
2=(0, 0, 13/14) at T
1=9.6 K and to a structure with Q
3=(0, 0, 7/9) at T
2=16.4 K and then to a paramagnetic state at T
3=29.7 K (=T
N). Magnetic contribution to the heat capacity has been evaluated in terms of the molecular field calculations including the crystal-field interaction.
Magnetic Phase Diagram of TbRu2Si2
Authors: Shigeoka Toru , Kawano Shinji , Kishino Takeshi , Mitsuyoshi Shigeki , Mitani Shigeshi , Iwata Nobuo
Published: March 2014

Neutron diffraction experiments have been made on a single crystal sample of TbRu2Si2 under magnetic fields up to 40 kOe and in a temperature range from 4.2 to 60 K. The compound is a metamagnet with two-step magnetization process. For H=0 it has a high-order commensurate structure with a wavevectors k=(0.23, 0, 0). At an intermediate field the structure changes to a two-dimensional high-order commensurate one with wavevectors of k=(0.23, 0, 0), (0, 0.23, 0), (0.23, ±0.23, 0) and k=0, and at a high field the compound becomes ferromagnetic. Schematic representation of the magnetic structures and a field-temperature phase diagram are presented.
Magnetic Phase Transition in DyNi2Si2
Authors: Hashimoto Yuzo , Shigeoka Toru , Iwata Nobuo , Yoshizawa Hideki , Ohara Yasuaki , Nishi Masakazu , Murata Akifumi , Ohashi Masayoshi , Onodera Hideya , Yamaguchi Yasuo
Published: March 2014

Magnetic ordering and magnetic phase transition in DyNi2Si2 have been studied by neutron diffraction measurements on powder and single crystal specimens. This compound has an order-to-order phase transition at about 3.5 K, below under the Néel temperature. Experimental results indicated that the phase transition is a first-order transition from a commensurate square-wave type modulation in the c-plane with the two-dimensional propagation vectors k=(1/2±τ, 1/2\mpτ, 0) with τ=0.125=1/8 just below T
N to a sine-wave type structure with τ=0.132 which is incommensurate with the lattice periodicity.
Variety of Magnetism in Incommensurate Misfit Layer Compounds (RES)xTS2 (RE=Rare Earths, T=Ta, V, Ti, Cr)
Authors: Suzuki Kazuya , Kondo Tetsuo , Iwasaki Makoto , Enoki Toshiaki
Published: March 2014

Magnetic properties of incommensurate layered compounds (RES)
x

TS2 were investigated for RE=rare earth metals and T=Ta, V, Ti and Cr. The magnetic structures in the ordered states depend on the rare earth elements used; ferromagnetic layers with the moments normal to the layer are stacked antiferromagnetically for the Ce compounds, and antiferromagnetic layers with the moments parallel to the layer are stacked antiferromagnetically for the Gd compounds. (LaS)1.20CrS2 containing nonmagnetic La shows successive magnetic transitions at 70 and 40 K, while (CeS)1.20CrS2 shows magnetic transitions at 65 and 5 K. The 5 K transition is due to the magnetic ordering in the CeS layers, which occurs independently of the magnetic ordering in the CrS2 layers.
Effect of Impurity Doping on Tc of 123 Superconductors
Authors: Singh R. K. , Varshney Dinesh , Dubey V. , Gaur N. K.
Published: March 2014

We have investigated the effect of substitution of magnetic impurities for copper in YBa2Cu3-x
M
x
O7 (M=Fe, Co) superconductors by developing a Fourier transformed effective potential (FTEP), which involves the influence of two dimensional (2D) acoustic phonons and plasmons. We have demonstrated that 2D acoustic plasmons have introduced 20–25% enhancement over the phonon contribution to the transition temperature (T
C) at various compositions (x). Further, we have found that the increase in the values of the plasmon coupling parameter (λpl=0.0 to 0.5) enhances T
C from 70 to 300 K. These achievements clearly indicates that the inclusion of the effect of 2D acoustic plasmons is essential for proper description of the mechanism of high T
C superconductivity.
Reversible and Irreversible Relaxation of Magnetic Permeability in Photoexcited Yttrium Iron Garnet
Authors: Hisatake Keizo , Matsubara Ikuya , Maeda Keiichiro , Lyakhimets Sergey N.
Published: March 2014

Photoinduced variation of magnetic complex permeability µ=µ'-jµ'' at low frequency, e.g., 0.14 kHz is studied as a function of temperature in yttrium iron garnet (YIG). We have observed a new phenomenon in YIG occurring solely after illuminated at low temperature; photoinduced disaccommodation. We discussed an origin of the observation, taking account of the charge state of oxygen vacancy and an interaction between lattice relaxation and domain wall.
High Magnetic Field Effect on Exciton Energies in CdTe/Cd1-xMnxTe Quantum Wells Grown by MBE
Authors: Kuroda Shinji , Shirai Yutaka , Kojima Kazutoshi , Uchida Kazuhito , Miura Noboru , Takita Kôki
Published: March 2014

The magneto-optical studies were performed through the transmission measurement on a series of CdTe/Cd1-x
Mn
x
Te multiple quantum wells with Mn contents of about 14% under pulsed magnetic fields up to 45 T. Observed absorption peaks of the heavy-hole and light-hole excitons show large Zeeman splitting due to the exchange interaction with Mn2+ spins in the barrier layer. Further, the observation of a series of Landau level transitions between the conduction and heavy-hole bands gives an estimate of the excitonic binding energy at 11–22 meV depending on the well width. The calculation based on the effective-mass approximation reveals that the hole states under magnetic fields exhibit complicated features due to the valence-band mixture and the strong s
p-d exchange interaction. Calculated results of the interband transition energies and intensities were compared with the observations and help for their understanding.
Growth and Magneto-Optic Properties of CdTe/Cd1-xMnxTe Multiple Quantum Wells
Authors: Abe Takashi , Ando Koji , Akinaga Hiroyuki , Takeuchi Yutaka , Yamamoto Hiroshi
Published: March 2014

Pronounced differences of magneto-optic properties are observed between (100) and (111) multiple quantum wells (MQW) of CdTe//Cd0.6Mn0.4Te on GaAs(100) and sapphire(111) substrates. The (100) MQW's on GaAs(100) well show resolved multiple magneto-optic spectral structures which arise fiom the transition between the quantum confined energy states. The X-ray diffraction and the reflection high energy electron diffraction (RHEED) also confirmed the best crystalline quality of the (100) MQW. The effective g-value increases with decreasing CdTe well thickness, but its value is too large to be explained by the wave function penetration into the Cd0.6Mn0.4Te barrier layers.
Zn1-xMnxSe Epitaxial Layers and ZnSe/MnSe Heterostructures Grown by Pulsed-Laser Deposition
Authors: Misiewicz J. , Huber C. , Heiman D.
Published: March 2014

Zn1-x
Mn
x
Se epitaxial layers for 0<x<0.60 as well as heterostructures ZnSe/MnSe were grown on GaAs(100) substrates by pulsed laser deposition technique. A Nd:YAG pulsed laser and high vacuum chamber were used. The highquality of the materials obtained was confirmed by X-ray diffraction patterns, Auger electron spectroscopy and Raman backscattering measurements. The low temperature magnetization was measured indicating a new magnetic ordering in the layers.
Phase Transition in Semi-Magnetic Semiconductors
Authors: Singh R. K. , Arora Anita
Published: March 2014

We have successfully described the high pressure phase transition pressure and associated phenomenon in the semimagnetic semiconductors (SMS) by means of a three body potential (TBP) model approach. This model has revealed the observed variation of the phase transition pressure with concentration (x) in Cd1-x
Mn
x
Te and Zn1-x
Mn
x
Te. It has been demonstrated that the TBP approach is an appropriate method to describe the phase transition in SMS material induced by pressure.
Some Properties of (Zn1-xMnx)3P2 –A New Semimagnetic Semiconductors–
Authors: Misiewicz J. , Bryja L. , Twardowski A.
Published: March 2014

(Zn1-x
Mn
x
)3P2 crystals were grown from the melt for the manganese concentration within a few percent range. Magnetic properties of this compounds were invistigated by using SQUID technique. For x<0.01 paramagnetic behaviour was observed. From the shift of the absorption edge value of exchange integrals were estimated.
Anisotropic Faraday Rotation of Cubic Semimagnetic Semiconductor Cd1-xFexTe
Authors: Savchuk A. I. , Klichuk O. R. , Nikitin P. I.
Published: March 2014

The anisotropic Faraday effect in cubic semimagnetic semiconductor Cd1-x
Fe
x
Te is observed. The effect is significant at low temperatures (T<40 K) in a strong magnetic field for photon energy corresponding to the absorption edge. The effect is due to the magnetization anisotropy in the cubic crystal under study.
Magneto-Optical Properties of Cd1-xMnxTe Multiple Quantum Wells Prepared by Ionized-Cluster Beam Technique
Authors: Anno Hiroaki , Hosoki Yugo , Miura Ken , Koyanagi Tsuyoshi , Matsubara Kakuei
Published: March 2014

The magneto-optical properties of Cd1-x
Mn
x
Te multiple quantum wells (MQWs) with different barriers are compared. The peaks of magneto-circular dichroism (MCD) are observed at the subband energies. The peak height is enhanced when the well width decreases less than the Bohr radius of an exciton, but the well width dependence of the peak height is slightly different between the MQWs with different barriers. The results are explained in terms of both the Zeeman splitting of subband levels and the oscillator strength of subband transitions.
New Results in Raman Scattering in Diluted Magnetic Semiconductors (DMS)
Authors: Rivera S. A. López
Published: March 2014

New results in Raman scattering in DMS are presented. The alloys M
x
A1-x

IIBIV are DMS in which a fraction of the cations of the II–VI compounds are randomly substituted transition metal ions. In this paper we study by Raman scattering ZnS ad the following DMS: Zn0.99Mn0.01S, Zn0.80Mn0.20S, Zn0.95Cr0.05S, Zn0.95Fe0.05S, Zn0.95Co0.05S, Zn0.97Ti0.03S, Zn0.90Ni0.10S. The measurements are compared with numeric calculations of the first order Raman intensities induced by the magnetic ion. The calculated results agree very closely with the experimental data. It was found that the incorporation of a magnetic ion greatly altered the central force constant and this modified considerably the vibration spectrum of the crystal.
Preparation of Chalcopyrite-type Semiconductor Films by Sulfuration of Oxide Films
Authors: Wada Takahiro , Negami Takayuki , Nishitani Mikihiko
Published: March 2014

Polycrystalline CuInS2 thin films on Mo coated glass substrates are prepared by sulfuration of Cu–In–O films. The Cu–In–O films are deposited from a Cu2In2O5 target by using a pulsed laser deposition method. The Cu–In–O films are converted into CuInS2 films by means of a subsequent annealing in an H2S gas atmosphere. The films are characterized by using an X-ray diffractometer (XRD), an energy dispersive X-ray spectrometer (EDX) and a scanning electron microscope (SEM). The crystallographic phases in the films and the microstructures of the films are discussed.
Time Dependent Effect of Magnetic and Magneto-Optical Properties in Cd1-xMnxTe
Authors: Irie Yuichiro , Jochi Kazuko , Sato Tetsuya , Ohta Eiji
Published: March 2014

Time growth features of the magnetization and Faraday rotation under zero field cooled condition were investigated for Cd1-x
Mn
x
Te, which are analyzed by using a stretched exponential time dependence. The best-fitted parameters τ and n are different between these experimental techniques, significantly in high Mn concentration region. Aspect of the spin freezing becomes more sensitive to a spatial scale relevant to the resolution inherent in these techniques with increasing Mn content.
Direct Observation of Exciton Magnetic Polaron in CdMnTe from Polarized Magneto-Photoluminescence
Authors: Takeyama Shojiro , Adachi Satoru , Takagi Yoshihiro , Aouekian Vadium F.
Published: March 2014

The photoluminescence in CdMnTe (with x=0.15 and 0.35) was carefully studied and clear evidence for the exciton localization due to magnetic polaron (EMP) formation was presented. It was revealed that the EMP localization induced striking features on the luminescence lines; peak positions, FWHM and intensities. The heavy hole and light hole exciton magnetic polaron stability under the magnetic field was demonstrated distinctly by the polarization measurements.
Laser Ablation Deposition of CuInSe2 Thin Films on Silicon and Fused Silica
Authors: Levoska J. , Hill A. E. , Leppävuori S. , Kusmartseva O. , Tomlinson R. D. , Pilkington R. D.
Published: March 2014

CuInSe2 thin films were deposited by an in situ process on fused silica and single crystal silicon substrates by pulsed laser ablation using a beam from an XeCl excimer laser focused on a polycrystalline target. The effect of deposition temperature and substrate material on the structure and orientation of the films was investigated. The structure and properties of the films were studied by X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy. The composition of the target material was largely maintained in the films deposited below 450°C. The films were highly oriented with the (112) planes of the chalcopyrite structure along the substrate surface, except for the films deposited above 350°C on to Si(100) which developed a {100} orientation.
Raman Scattering in Defective AIIB2
IIIX4
VI Compounds and Alloys
Authors: Razzetti C. , Lottici P. P.
Published: March 2014

We have synthesized and characterized a variety of defective AIIB2
IIIX4
VI compounds and alloys, many of which display a layered structure. Here we review and update Raman scattering results on both tetragonal and layered compounds. As to tetragonal compounds we check a simple bond stretching dynamical model, whereas for the layered structures we propose a phenomenological picture of the vibrational dynamics based on the intrinsic high degree of disorder.