bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Distribution of Trapped Magnetic Flux in the High Tc Superconductor Y1Ba2Cu3O7-δ
Authors: Kisu Takanobu , Enpuku Keiji , Yoshida Keiji , Takeo Masakatsu , Yamafuji Kaoru
Published: November 2005

Spatial distribution of the trapped magnetic flux density in Y1Ba2Cu3O7-δ is measured at T=4.2 K and 77 K with the GaAs Hall device as a magnetic sensor. Experimental results show that the magnetic flux density inside the sample is almost constant spatially, and suggest that superconducting grains are coupled with each other very weakly in the present sample.
Ab Initio MO Calculations of Effective Exchange Integrals between Transition-Metal Ions via Oxygen Dianions: Nature of the Copper-Oxygen Bonds and Superconductivity
Authors: Yamaguchi Kizashi , Takahara Yoichi , Fueno Takayuki , Nasu Keiichiro
Published: November 2005

The superexchange interaction between transition-metal ions via oxygen dianion was investigated by the ab initio molecular orbital (MO) method. It is found that the magnitude of the effective exchange integral (J
ab) for the CuOCu unit is far larger than those of the NiONi, CrOCr and FeOFe units. Implications of this result are discussed in relation to the high T
c superconductivity for Ba-La-Cu-O and R-Ba-Cu-O (R=Y, etc.).
Localized Electrons Around Cu Atoms of Superconductor, Tetragonal YBa2Cu3-xO7-y
Authors: Inoue Zenzaburo , Sasaki Satoshi , Iyi Nobuo , Takekawa Shunji
Published: November 2005

Crystal structure of tetragonal YBa2Cu2.93O6.38 has been determined by the single-crystal X-ray diffraction method. The space group is P4/mmm with lattice constants: a = 3.860(1) Å, c = 11.813(4) Å, and V = 176.05(7) Å3. The structure refinement has been successfully carried out with the final R value of 0.019(Rw=0.020). A difference-Fourier map reveals the existence of localized d-electrons around Cu2 atoms in the unit cell, although the electrons of Cul atoms have a spherical distribution.
Deposition of Diamond-like Carbon Films by Pulsed-Laser Evaporation
Authors: Sato Tetsuya , Furuno Shigeo , Iguchi Satoshi , Hanabusa Mitsugu
Published: November 2005

Diamond-like carbon thin films were deposited by pulsed-laser evaporation. A carbon target was irradiated by a Xe-Cl laser with a power density of 3×108 W/cm2. Ions were mixed with vaporized atoms. Deposition rates were typically 200 Å/ min. Film properties changed with substrate temperature. The films deposited at 50°C were diamond-like, as confirmed by refractive index (2.1 to 2.2), optical transparenty and chemical resistance. Hydrogen-free films were produced. Optical band gap was 1.4 eV and electrical resistivity was 108 Ω-cm. No crystallinity was observed.
Raman Scattering from High-Tc Superconductor YBa2Cu3O7-x and Its Analogs
Authors: Morioka Yoshiyuki , Kikuchi Masae , Syono Yasuhiko
Published: November 2005

Raman spectra of polycrystalline samples of orthorhombic YBa2Cu3O7-x
, HoBa2Cu3O7-x
, NdBa2Cu3O7-x
, metastable tetragonal YBa2Cu3O7-x
, and Y2BaCuO5 were measured at room temperature. Spectral differences among these materials were clarified and tentative assignments of the observed bands to the Raman active lattice vibrations were proposed.
Preparation of High-Tc Y-Ba-Cu-O Superconducting Filaments by Suspension Spinning Method
Authors: Gotō Tomoko , Kada Masahiro
Published: November 2005

The preparation of a high T
c Y-Ba-Cu-O system superconducting filament was studied using the method of suspension spinning. The reacted mixture of the Y-Ba-Cu-O powder was suspended in PVA aqueous solution containing dispersant. The viscous suspension was extruded as a filament into a precipitating medium and coiled on a winding drum. The long filament obtained was more than 80 µm in diameter and consisted of up to 93 wt % powder content. The filament was heated to remove volatile components and to generate oxide in the layered perovskite phase. The filament heated exhibited superconductivity at 84 K.
Effect of the Molecular Structure of the Chiral Part on Spontaneous Polarization and Dielectric Properties of Ferroelectric Liquid Crystals
Authors: Taniguchi Hiroki , Ozaki Masanori , Yoshino Katsumi , Yamasaki Noritsugu , Satoh Kazuo
Published: November 2005

The magnitude and direction of spontaneous polarization in ferroelectric liquid crystals with several bond moments in the chiral parts are found to be influenced strongly by the position and the orientation of those bond moments. By designing appropriate structures in the chiral parts, a spontaneous polarization and dielectric constant exceeding 200 nC/cm2 and 1000, respectively have been obtained.
Characteristics for a-Si:H Films Prepared by Mercury-Sensitized Photochemical Vapor Deposition
Authors: Kamimura Takaaki , Nozaki Hidetoshi
Published: November 2005

The density of states in a-Si:H, prepared by mercury-sensitized photo-CVD, was measured by the space-charge-limited current method. The density of Si dangling bonds (N
s) was measured by the electron spin resonance method. N
s and a minimum of the density-of-state near the Fermi level (N
min) indicated the same tendency versus substrate temperature, which showed a good correlation between N
s and N
min. Both N
s and N
min showed a minimum value near substrate temperature of 200°C. Photosensitivity reached more than 1×106 for the sample.
DC-SQUID Using High-Critical-Temperature Oxide Superconductors
Authors: Nakane Hideaki , Nishino Toshikazu , Hirano Mikio , Takagi Kazumasa , Kawabe Ushio
Published: November 2005

Voltage vs magnetic-flux characteristics of a DC-SQUID composed of YBa2Cu3O7-δ/YBa2Cu3O7-δ Josephson point contacts were studied. The DC-SQUID was operated up to 70 K.
Phase Diagram of the La2O3-CuO System and Crystal Growth of (LaBa)2CuO4
Authors: Oka Kunihiko , Unoki Hiromi
Published: November 2005

Single crystals of (LaBa)2CuO4 were grown by the top-seeded solution growth (TSSG) method. A crystallographic phase diagram of the La2O3-CuO system was derived by means of differential thermal analysis, quenching technique and X-ray diffraction.
High-Tc Superconductor Prepared by Oxidization of a Melt-Spun Eu1Ba2Cu3 Alloy Ribbon
Authors: Matsuzaki Kunio , Inoue Akihisa , Kimura Hisamichi , Masumoto Tsuyoshi
Published: November 2005

An Eu1Ba2Cu3 alloy ribbon with a nonequilibrium structure including an amorphous phase was prepared by melt-spinning. Heating of the alloy ribbon in air resulted in the structural change to a crystalline metallic phase at about 475 K, followed by the oxide formation of Eu1Ba2Cu3O6.5-6.7 at temperatures above about 555 K. The Eu1Ba2Cu3O6.7 prepared by oxidization of the melt-spun alloy ribbon was found to exhibit high-T
c superconductivity with onset at 93 K and zero resistance at 87 K, even though the J
c value at 4.2 K was as low as about 20 A/ cm2 in the absence of an applied field and 1.3 A/cm2 at H=7.5 T.
Crystal Structure of the Superconductor Ba1.8Nd1.2Cu3O7-y
Authors: Izumi Fujio , Takekawa Shunji , Matsui Yoshio , Iyi Nobuo , Asano Hajime , Ishigaki Tōru , Watanabe Noboru
Published: November 2005

The structure parameters of a superconductor with the nominal composition Ba1.8Nd1.2Cu3O7-y
were refined by the Rietveld analysis of TOF neutron powder diffraction data. This material is tetragonal with lattice constants a=3.8919 Å and c=11.6811 Å and isomorphous with Ba1.5La1.5Cu3O7±y
with an oxygen-deficient triperovskite structure. An oxygen site at (0, 1/2, 0) is 49% occupied, the Nd3+ ion at (1/2, 1/2, 1/2) is coordinated to eight oxide ions, and a metal site at (1/2, 1/2, 0.1842) is 90% and 10% occupied by Ba2+ and Nd3+ ions, respectively.
Changes in Soft Magnetic Properties of Fe and Ni-Fe Films Due to the Dispersion Angle of Sputtered Atoms
Authors: Nakatani Ryoichi , Kobayashi Toshio , Ootomo Shigekazu , Kumasaka Noriyuki
Published: November 2005

Fe and Ni-Fe films are formed by the ion beam sputtering method. Changes in magnetic properties due to the dispersion angle of sputtered atoms are examined. The lowest coercive force and the highest relative permeability are obtained at a dispersion angle of 60-90° . The Fe and Ni-Fe films show preferred orientations of <110> and <111> normal to the film plane, respectively. Good soft magnetic properties are found to be obtained at angles in which the films have strong preferred orientations.
Superconductivity and Magnetic Properties of DyBa2Cu3Oy
Authors: Waki Shinya , Yamaguchi Yuji , Oka Kunihiko , Unoki Hiromi , Mitsugi Kazuyoshi
Published: November 2005

The superconductivity and magnetic properties of DyBa2Cu3O
y
are reported. Superconducting properties are compared with those of YBa2Cu3O
y
. No significant effect is observed by replacing Y with Dy. Magnetic properties of a quenched DyBa2Cu3O
y
which is not metallic, are also reported. From the susceptibility and the magnetization at low temperatures, an antiferromagnetic transition is suggested at about 0.85 K and the magnetic moment in the ground state is estimated to be 6-7 µB. It is argued that the magnetic order is mainly due to dipolar interactions.
A Proposal for an Experiment to Compress and Amplify Ion Beam Pulse by Soft X-Ray Conversion
Authors: Yabe Takashi , Goel Balbir
Published: November 2005

A method for pulse compression and amplification of ion beam is proposed, in which the radiation wave acts as an energy reservoir. This intensity amplification can occur if the incident beam intensity exceeds 1 TW/cm2 and the amplification of 10 is possible above 10 TW/cm2 of ion beam intensity; soft X-ray more than 100 TW/cm2 can be produced. A proof-of-principle experiment is accessible with the present devices.
Magnetization Property of Annealed La1.85Sr0.15CuO4 from 300 K to 5 K
Authors: Yoshizaki Ryozo , Iwazumi Toshiaki , Sawada Hideaki , Matsuura Etsuyuki
Published: November 2005

Magnetization of sintered La1.85Sr0.15CuO4 was measured in magnetic field of about 0.0003, 1 and 3 T. As lowering the temperature from 300K, the paramagnetization decreases gradually from about 230 K, changing rapidly to large diamagnetization at 45 K and the diamagnetization increased abruptly at 14 K. The last two temperatures are indicated to the onset temperatures of the superconducting transitions. A tentative model is discussed about the two transitions.
Characterization of the High-Tc Superconductor Y-Ba-Cu Oxide –Critical Current and Crystal Structure–
Authors: Kagoshima Seiichi , Hikami Shinobu , Nogami Yoshio , Hirai Takashi , Kubo Koichi
Published: November 2005

Critical currents are measured in the title material. At 9.5 K, where an apparent resistance is zero, the critical-current density J
c is found to be about 1.7 A/cm2 in a sintered sample. For currents smaller than J
c the sample resistivity is less than 2.3 µΩ·cm. By X-ray diffraction the crystal structure is found to be essentially of a perovskite type. Its unit cell composed of eight units of the perovskite structure has a face-centered tetragonal symmetry with the lattice parameters a=b=7.83±0.02 Å and c=7.72±0.03 Å.
Preparation of Y-Ba-Cu Oxides with Superconducting Transition above Liquid-Nitrogen Temperature
Authors: Maeno Yoshiteru , Kato Masatsune , Fujita Toshizo
Published: November 2005

Details of sample preparation of Y-Ba-Cu oxides with superconducting transition temperatures well above the boiling point of liquid nitrogen are reported. The mid-point of the resistive transition is at 92.6 K , and the zero-resistance state is maintained up to 83.3 K. The ac susceptibility and the infrared spectra of superconductive Y-Ba-Cu oxides are also presented.
Ultraviolet Photoemission Study of High-Tc Superconductor (La1-xSrx)2CuO4-δ
Authors: Takahashi Takashi , Maeda Fumihiko , Hosoya Shoichi , Sato Masatoshi
Published: November 2005

Ultraviolet photoemission spectra of high-T
c superconductor (La1-x
Sr
x
)2CuO4-δ, (x=0.075 and δ≤0.04) are presented. The experimental result was compared with the band calculations of La2CuO4 by Mattheiss and Takegahara et al. It was found that as regards the valence-band width (about 7 eV) the experiment and the calculations are in good agreement with each other, but the position of the calculated valence bands contributed mainly by weakly bonding Cu(3d)-O(2p) states are shiftd toward the lower binding energy by about 1 eV with respect to the experiment. The possible origins for this discrepancy were discussed.
Upper Critical Fields on High Temperature Superconductivity in La-Sr-Cu-O System
Authors: Kobayashi Norio , Sasaoka Takaaki , Oh-ishi Katsuyoshi , Sasaki Takako , Kikuchi Masae , Endo Akihiko , Matsuzaki Kunio , Inoue Akihisa , Noto Koshichi , Syono Yasuhiko , Saito Yoshitami , Masumoto Tsuyoshi , Muto Yoshio
Published: November 2005

The electrical resistances of three La-Sr-Cu-O samples prepared by different methods have been measured undermagnetic fields up to 20.3 tesla between 4.2 and 50 K. The upper critical fields were determined by the midpoint of the resistive transition. The largest slope of the critical field was -2.7 T/K for a sintered sample La1.85Sr0.15CuO4. According to the Werthamer, Helfand and Hohenberg expression in the dirty limit, the upper critical field H
c2(0) was estimated to be 71 T. Various superconducting and normal states properties are derived.
139La Pure Quadrupole Resonance of High Tc Superconducting Materials (La1-xMx)2CuO4 (M=Ba, Sr)
Authors: Kitaoka Yoshio , Hiramatsu Shigeru , Kohara Takao , Asayama Kunisuke , Oh-ishi Katsuyoshi , Kikuchi Masae , Kobayashi Norio
Published: November 2005

Pure Quadrupole Resonance (PQR) of 139La in high T
c superconductor, (La1-x
M
x
)2CuO4 with M=Ba, Sr, has been observed at zero external field between 1.3 K and 4.2 K. In undoped La2CuO4, the PQR spectrum is very complicated, reflecting the orthorhombic structure, while in the superconducting compounds, the spectrum exhibits a drastic change and becomes more simple due to the tetragonal structure. The alloying is suggested to be responsible not only for the change of crystal structure but also for the change of microscopic electronic state.
Phonons in (La1-xSrx)2CuO4 and BaPb1-xBixO3
Authors: Masaki Atsushi , Sato Hisashi , Uchida Shin-ichi , Kitazawa Koichi , Tanaka Shoji , Inoue Kazuhiko
Published: November 2005

Inelastic neutron scattering measurement of (La1-x
Sr
x
)2CuO4 (x=0, 0.1) and BaPb1-x
Bi
x
O3 (x=0, 0.25) was carried out to get information about phonons. There is an obvious difference between non-superconducting BaPbO3 and superconducting BaPb0.75Bi0.25O3. On the other hand, little difference was observed between semiconducting La2CuO4 and superconducting (La0.9Sr0.1)2CuO4 with extraordinary high T
c.
Novel High-Tc Superconducting Phase of the Y-Ba-Cu-O Compound
Authors: Semba Kouichi , Tsurumi Shigeyuki , Hikita Makoto , Iwata Tsunekazu , Noda Juichi , Kurihara Susumu
Published: November 2005

A novel high-T
c superconducting phase is found in the oxide Y-Ba-Cu-O. A sample with nominal composition Ba0.5Y0.5CuO3-d
shows a sharp superconducting transition at 92.6 K with a width as narrow as 0.9 K. The Electron Probe Micro Analyzer (EPMA) data and the X-ray powder diffraction pattern show that the high T
c superconducting phase has the tetragonal oxygen-defect perovskite (ODP) structure with composition Y2Ba4Cu6O14+y
.
Transport Properties of (La1-xAx)2CuO4
Authors: Uchida Shin-ichi , Takagi Hidenori , Ishii Hideo , Eisaki Hiroshi , Yabe Tomoaki , Tajima Setsuko , Tanaka Shoji
Published: November 2005

Various transport properties are systematically investigated for the quasi-two-dimensional superconductors, (La1-x
A
x
)2CuO4 (A=Ba, Sr). They are compared with the calculations based on the two-dimensional tight-binding band. From this, it is inferred that the superconductivity is coexisting with Fermi surface instability, possibly a spin-density-wave which destroys a significant portion of the Fermi surface.
Superconducting Tunneling in Y-Ba-Cu-O System
Authors: Ekino Toshikazu , Akimitsu Jun
Published: November 2005

Electron tunneling study on high-T
c superconductor Y-Ba-Cu-O system with the onset transition temperature of about 95 K has been carried out. The observed energy gap is slightly larger than that expected from the BCS theory.
Properties of Superconducting ZrN Thin Films Deposited by dc Reactive Magnetron Sputtering
Authors: Tanabe Keiichi , Asano Hidefumi , Katoh Yujiro , Michikami Osamu
Published: November 2005

The structural, superconducting and optical properties of ZrN thin fims deposited on single-crystal sapphire substrates by dc reactive magnetron sputtering are investigated. Their properties, in particular superconducting T
cs, strongly depend on substrate temperatures. Films with a highly (100) textured B1 structure, which are deposited at substrate temperatures above 700°C, exhibit T
cs and residual resistivity ratios as high as 10.0 K and 15. Systematic changes in the wavelength of the optical reflectivity edge suggests that Zr vacancies suppress T
c for films deposited at lower substrate temperatures.
Meissner Effect and Resistivity of the Superconducting Y-Ba-Cu-O System
Authors: Oda Yasukage , Nakada Ichiroh , Kohara Takao , Asayama Kunisuke
Published: November 2005

The zero resistance and the complete Meissner effect of the Y-Ba-Cu-O system have been observed. It was found that the compound system includes three phases depending on the composition of the elements, and two of them are conductors responsible for the superconductivity. Crystallographically the two conducting phases belong to the body-centered-tetragonal symmetry. A tentative model is given for the origin of superconductivity.
Superconductivity in Ba-Ln(lanthanoid)-Cu-O Compounds
Authors: Yamada Tomoaki , Kinoshita Kyoichi , Matsuda Azusa , Watanabe Takao , Asano Yoshihiro
Published: November 2005

Superconductivity observed in the temperature dependence of the resistivity for Ba-Ln(lanthanoid)-Cu-O compounds with a nominal composition of Ba0.6Ln0.4CuO3-x
is reported. The compounds are classified into two groups according to the nature of the superconducting transitions and the structures. Those ones with a single perovskite-like phase, where Ln=Nd, Sm, Eu and Gd, showed smeared transitions with relatively low critical temperatures. The other compounds with mixed phases, where Ln=Dy, Ho, Er, Tm, Yb and Lu, have critical temperatures above 90 K with narrow transition widths.
High-Tc Superconductivity in New Oxide Systems and Their X-Ray Diffraction Study
Authors: Shamoto Shin-ichi , Onoda Masashige , Sato Masatoshi , Hosoya Syoichi
Published: November 2005

Resistivity measurements for Ln-Ba-Cu-O systems with Ln being lanthanide atoms have been carried out. In addition to the previously reported systems with Ln=Lu, Yb, Tm, Er, Ho, Dy and Eu, we have discovered the high-T
c superconductivity in the systems with Ln=Nd, Sm and Gd. Preliminary results of X-ray powder diffraction study are given and the superconductivity is discussed in relation to them.
Electron Probe Micro Analysis for Multi-Phase Superconducting Y-Ba-Cu-O Compound System
Authors: Iwata Tsunekazu , Hikita Makoto , Semba Kouichi , Tsurumi Shigeyuki
Published: November 2005

Electron probe micro analysis and resistance measurement were carried out for multi-phase compound Y
x
Ba1-x
CuO4-y
specimens with nominal composition of x=0.4 and 0.5. Two kind of crystal phases with apparently different chemical composition were found. The phase with chemical composition, [Y]:[Ba]:[Cu]=2:1:1, is green-colored and semiconducting. The other phase with chemical composition, [Y]:[Ba]:[Cu]=1:2:3, is black-colored and superconducting below 90 K.
Thermogravimetric and High-Temperature X-Ray Studies on the Orthorhombic-to-Tetragonal Transition of YBa2Cu3Oy
Authors: Takayama-Muromachi Eiji , Uchida Yoshishige , Yukino Ken , Tanaka Takaho , Kato Katsuo
Published: November 2005

Thermogravimetric experiment was performed to determine oxygen content in the high T
c superconductor YBa2Cu3O
y
. The y varies from 5.8 to 6.5 depending on temperature and oxygen fugacity, indicating that the average valence of copper ions is between 2 and 1. The oxygen content is strongly affected by quenching process of a sample. High-temperature X-ray diffraction study showed orthorhombic-to-tetragonal transition (second or possibly higher order) at around 900 K. Combining this fact with the thermogravimetric data, we concluded that the compound having y less than ∼6.0 has a tetragonal symmetry.
Superconductivity Achieved at Over Liquid Nitrogen Temperature by (Mixed Rare Earths)-Ba-Cu Oxides
Authors: Kishio Kohji , Nakamura Osamu , Kuwahara Kazuyuki , Kitazawa Koichi , Fueki Kazuo
Published: November 2005

Superconducting oxides were fabricated by reaction of powders of BaCO3, CuO and mixed rare earth (RE) carbonates at compositions expressed as (RE)1Ba2Cu3O9-y
. Two types of incompletely separated raw materials of mixed rare earths, namely, heavy rare earths (HRE) and medium rare earths (MRE) were examined. The zero-resistivity critical temperatures were observed at 92.5 K for the (HRE)-Ba-Cu-O and 85.0 K for the (MRE)-Ba-Cu-O systems, respectively, both of which being well above the boiling point of liquid nitrogen.
All-Ceramics Josephson Junctions Operative up to 90 K
Authors: Tsai Jaw-Shen , Kubo Yoshimi , Tabuchi Junji
Published: November 2005

Ba-Y-Cu-O/Ba-Y-Cu-O Josephson junctions are made by creasing fissures in the bulk Ba-Y-Cu-O ceramic superconductors. The critical current of the junction fissured at room temperature decreases exponentially with the increase in the operating temperature, similar to that of an S/N/S junction. However, with the junction fissured at cryogenic temperature, critical current persists all the way up to about 90 K (T
c of Ba-Y-Cu-O compound). The a.c. Josephson effectis observed for these junctions in all temperature range up till 90 K. The onset of the formation of the macroscopic quantum state just below 90 K is implied.
Substitution Effect of Sr for Ba of High-Tc Superconducting YBa2Cu3O7-y Ceramics
Authors: Wada Takahiro , Adachi Seiji , Mihara Toshihiro , Inaba Ritsuo
Published: November 2005

Single phase Y(Ba1-xSrx)2Cu3O7-y [x=0, 0.1, 0.2, 0.3, 0.4] ceramics were fabricated. In the fracture surface of the ceramics, many prism crystals were observed. Superconducting transition temperature measured by the magnetic susceptibility was linearly lowered from 94 to 84 K with increasing x from 0 to 0.4 and all the lattice constants of orthorhombic unit cell became short.
Crystal Structure of the HoBa2Cu3Ox Superconductor Determined by X-Ray Powder Diffraction
Authors: Asano Hajime , Ishigaki Tōru , Takita Kôki
Published: November 2005

The crystal structure of HoBa2Cu3O7 has been determined by Rietveld analysis of X-ray powder diffraction data. The structure is orthorhombic (space group Pmmm) with lattice parameters a=3.8850(1) Å, b=3.8192(1) Å and c=11.6770(2) Å, and isomorphic with YBa2Cu3O7-y
. Ordering of Ho and Ba, oxygen deficiency in the z=1/2 plane and selective occupancy of oxygen on the basal plane are the common structural feature of the high T
c superconductors.
On the Coprecipitation Method for the Preparation of High Tc M-X-Cu-O (M=Ba, Sr, X=La, Y) System
Authors: Kaneko Keiji , Ihara Hideo , Hirabayashi Masayuki , Terada Norio , Senzaki Kiyoshi
Published: November 2005

The maximum yield for each solute is obtained at different pH values. The pH values of 2.3 and 4 are optimum for the preparation of Ba-La-Cu-O, Sr-La-Cu-O and Ba-Y-Cu-O, respectively. The composition ratio of the high T
c superconducting materials was 0.54:0.33:1 (Ba:Y:Cu).
Self-Annihilation of Antiphase Boundary in GaAs on Si(100) Grown by Molecular Beam Epitaxy
Authors: Kawabe Mitsuo , Ueda Toshio
Published: November 2005

It has been shown that single domain GaAs can be grown on Si(100) which consists of two domains. A mechanism for self-annihilation of the antiphase boundary in the process of GaAs growth has been proposed to explain the experimental result.
Low-Energy Electron Energy Loss Spectroseopy on CaF2(111) Surfaces
Authors: Saiki Koichiro , Tokoro Takehiko , Koma Atsushi
Published: November 2005

CaF2(111) surfaces were studied by Auger electron spectroscopy and electron energy loss spectroscopy (EELS). A clean stoichiometric surface was achieved by heating samples under an ultrahigh vacuum at 600°C. A new peak in the EELS spectrum was observed in the band gap region, which may be ascribed to surface excitation. Peaks whose intensity strongly depends on the incident electron energy were observed in the region of core-electron excitation. These peaks seem to come from the optically forbidden transitions.
Far-Infrared Absorption and Tunneling Conductance of Anisotropic Singlet Superconductors at Finite Temperatures
Authors: Ebisawa Hiromichi , Isawa Yoshimasa , Maekawa Sadamichi
Published: November 2005

The far-infrared absorption spectra and the quasi-particle tunneling conductance are calculated at finite temperatures in poly-crystalline samples of superconductors with anisotropic singlet pairing. Currently observed small 2Δ/k
B
T
c ratio in far-infrared measurements and the large ratio in tunneling measurements for high-T
c oxides are shown to be consistent with the anisotropic pairing.
Effect of Uniaxial Stress on Germanium p-n Junctions (II)
Authors: Imai Tetsuji , Uchida Masao
Published: November 2005

Uniaxial stress effect on germanium backward diodes has been studied. Stress-induced increase in forward current (I

f
) with constant slope of ln
I

f
vs V plots are explained by the model of Wortman et al. Band gap change with stress σ, d
E

g
/dσ, is evaluated as 7.5×10-12 eV cm2/dyn. Stress-induced decrease in tunneling reverse current is interpreted on the basis of model that the effect of stress-induced decrease in tunneling carrier concentration exceeds that of increase in tunneling probability.
Instability Associated with the Gradient of Carrier Density in Germanium Slice
Authors: Miyazaki Kazuhiko , Yamaguchi Jiro
Published: November 2005

The onset of current oscillation in a germanium slice in a transverse magnetic field was studied by taking into consideration the existence of gradient of carrier density along the direction of thickness. The gradient was estimated from the observations of 9.3 Gc microwave reflection and the threshold gradient experimentally determined for the onset of the density wave instability was compared with the theoretically estimated one. The results show that this threshold gradient is nearly equal to that of the instability of fundamental mode. However, the oscillation was quenched in a high transverse magnetic field.
The Retarded Diffusion of Gallium in Silicon. I
Authors: Okamura Masahiro
Published: November 2005

The anomalous diffusion of gallium in silicon n
+-p-n structure resulting from the simultaneous diffusion of gallium and group V impurity (arsenic or phosphorus) is investigated.
Diffusion is carried out in a closed tube using gallium and gallium arsenide or gallium phosphide as impurity sources.
Gallium diffusion is retarded in the region where gallium is diffused together with donors. The retardation seems to be caused by the presence of donors of high concentration. Gallium-arsenic diffusion brings about a larger retardation than gallium-phosphorus diffusion. The retardation increases with diffusion time. Gallium-phosphorus diffusion causes push-out of the p layer in case of short time diffusion. From a study of impurity concentration profile, it is found that the diffusion of gallium is retarded in the n
+ layer.
Some possible explanations to account for the retarded diffusion are examined.
The Effects of Oxygen on Evaporated PbSe Films
Authors: Yasuoka Yoshizumi , Seki Torao , Wada Masanobu
Published: November 2005

Evaporated PbSe films were oxidized at the temperature range of liquid-air temperature to 300°C. These films were converted from n-type to p-type through the quasi-intrinsic state with the lapse of oxidation time. The photoresponse of these films at the quasi-intrinsic state were observed. The film oxidized at 200°C gave the maximum photosensitivity. Furthermore, the temperature dependence of the electric current in the quasi-intrinsic film was measured at room temperature down to liquid-air temperature, and the desorption process of oxygen was studied. In this film oxygen is chemi-adsorbed onto the particle surface, produces the acceptor level by diffusing into the bulk of the particle, or forms the oxide layer by reacting with the particle. But oxygen contributing directly to photosensitization is the one which forms acceptor level in the bulk of the film by diffusing into the particle.
Field-Evaporation of Tungsten in Field Ion Microscope
Authors: Tamaki Shozo , Kuroda Tsukasa
Published: November 2005

The enhancement factors β1and β2of electric field applied on surface atoms are obtained by means of electrobath and resistance network analogue computer. The results are in good agreement with experimental results by field ion microscope. Field-evaporation end patterns of tungsten at wide temperature range are investigated in connection with cohesion of surface atoms. The step heights are calculated for various planes of tungsten, molybdenum and tantalum, which are necessary to the calculation of local radii of curvature.
Epitaxial Growth with Light Irradiation
Authors: Kumagawa Masashi , Sunami Hideo , Terasaki Takeshi , Nishizawa Jun-ichi
Published: November 2005

The effects of light irradiation on crystal growth were investigated in the vapor epitaxial growth of silicon.
It was observed that the activation energy of crystal growth decreased with light irradiation. The magnitude of the decrease was 2.1 kcal/mole under the typical experimental condition in an r
f heating reactor.
Crystal growth was carried out at a temperature lower than that used in the conventional epitaxial method, and the crystal quality of the grown layers was found to be better in the case with light irradiation than that without irradiation.
The above results suggest that light irradiation techniques can be used for reducing the degradation of impurity distribution by decreasing the growth temperature.
At present, selective crystal growth according to an irradiation pattern can be realized. It is expected that epitaxial growth with light irradiation can be applied to a selective growth process.
Calculation and Correction of Field Inhomogeneities of a Betatron
Authors: Hattori Hiroyuki
Published: November 2005

The most important point to avoid the bumps or field inhomogeneities of a betatron is a precise air gap length between a pole and a yoke. Where the air gap is longer, the phase lag of magnetic flux on the electronic orbit increases.
However, the basic component of the bumps is caused by both flux distribution in the yoke and difference in length of the magnetic path in the yoke.
Each magnet component has its own figure of bumps. Measured bumps are the sum of the bumps of the upper pole, lower pole and the yoke. The bumps can be regulated by turning the poles within a certain limit.
Bumps of a yoke having two legs have some amount of the 2nd harmonic component. This 2nd harmonic component can be compensated with adjustable cores inserted in the yoke by pushing them toward the poles.
Observations of Dislocations in Phosphorus-Diffused Silicon by X-Ray and Etching Techniques
Authors: Yoshida Masayuki , Arata Hikaru , Terunuma Yukio
Published: November 2005

Dislocations induced by diffusion of phosphorus into (111) surface of silicon specimen are studied by X-ray and etching techniques. For X-ray observation, Cu target is employed to obtain sharp contrast of images. In order to observe individual dislocations separately by X-ray diffraction micrography, a specimen with low density of dislocation networks is used. The Burgers vectors of the dislocations are determined. The dislocations with the Burgers vectors parallel and inclined to the surface are observed. It is concluded that the dislocations are generated by climb as well as by slip. In the case of high dislocation density, a replica of etch-patterns is observed with an electron microscope. It is found by etching technique that some parts of the networks bow deep inside the specimen.
Dislocations passing through a specimen are also found.
Thermoluminescence of Natural Quartz Irradiated by Gamma Rays
Authors: Ichikawa Yoneta
Published: November 2005

The Present investigation was undertaken to explore gamma irradiation effect of natural quartz by thermoluminescence. Glow curves of the samples irradiated by γ-rays were observed for various doses at the temperature 50°C∼500°C and were resolved into four component peaks, B1, B2, C and D. The nature of defects responsible for each peak was determined by comparison with glow peaks resulting from the samples to which Li+, Na+ and Al3+ were added by the diffusion at 1000°C. As the results, the defects responsible for the B2 and the C peaks were due to the disturbed-network in the vicinity of the Li+ and the Na+ respectively, and the B1 peak was associated with the aluminium center, and the defect for the D peak was due to oxygen vacancy. Increase and decrease of the B1 peak height for the doses were related to the enhancement of the B2 peak and the D peak respectively.
Energy Loss of Electrons of 0.6 to 1.2 MeV in Relatively Thick Al Foils
Authors: Hara Eiichi
Published: November 2005

Energy distributions of electrons passing through A1 foils of 100 µ to 800 µ thickness in their normal direction from a Van de Graaff type electron accelerator were examined with a 60° deflecting analysing magnet for initial electron energies from 0.6 to 1.2 MeV. The most probable energy loss and the average energy loss were compared with the theoretical values deduced by Landau for heavy particles and those obtained by Bethe for electrons scattered in all directions, respectively. Although the experimental values and the theoretical one have not completely same physical meanings, they seem to be in agreement, but the Blunck-Leisegang theory which is based on the Landau formulation fails to explain the energy distribution curves obtained experimentally.
Diffusion of Zinc into GaAs
Authors: Maruyama Mitsuhiro
Published: November 2005

Experimental studies have been made of the zinc diffusion into GaAs Crystals containing dislocations of 0 to 108 cm-2 at various arsenic vapor pressures. The diffused layers were observed by means of chemical etching and an infrared microscope.
For the diffusion without arsenic, (1) the fast diffusion takes place in the presence of dislocations, and (2) a large number of dislocations, proportional to the square of the zinc concentration, are induced in the diffused layers. For the diffusion under high arsenic vapor pressure, (3) generation of new dislocations is suppressed in the shallow diffusion layers, while in layer deeper than 40∼60 µ the dislocation density is suddenly increased, accompanied by fast diffusion, thereby resulting doubly stepped diffusion front, (4) the rate of the ordinary substitutional diffusion is comparatively lowered, and (5) the existence of ZnAs2 is detected in the diffused layer.
The observed fast diffusion along the dislocations is qualitatively interpreted in terms of an induced dislocation model.
Some Observations of Large Imperfections in Highly Te-Doped GaAs Crystals
Authors: Iizuka Takashi
Published: November 2005

Large imperfections in highly Te-doped, boat-grown GaAs crystals were studied by the combination of etching technique, X-ray anomalous transmission and X-ray microanalysis. Impurity inclusions were observed. X-ray microanalyses showed the presence of tellurium and gallium, and the absence of arsenic in the inclusion. X-ray topographs revealed extended and corrugated contrasts of an unknown defect in the bulk. These defect structures were correlated with the high doping level of tellurium.
An Apparatus for Studying NMR in Gases
Authors: Ogawa Kanji , Senda Kantaro , Matsuoka Shin-ichi
Published: November 2005

A unit for holding gaseous samples for nuclear magnetic resonance (NMR) experiments was constructed. This unit allows pressure and temperature of a sample gas to be variable almost independently over the ranges of pressures from 0.03 kg/cm2 to 70 kg/cm2, and of temperatures from -50°C to 150°C.
A bellows pressure transducer was employed for the purpose of separating the gaseous sample from hydraulic oil which drives diaphragm pressure gauges.
Extraction of Characteristic Features from a Visual Pattern by Fraunhofer Diffraction
Authors: Fujimura Sadao
Published: November 2005

Two methods to extract characteristic features from a visual pattern are proposed by making use of Fraunhofer diffraction produced by a laser beam. One is to find the presence and the disposition of straight line elements in a pattern from a sequence of straight lines appearing in the diffraction image by illuminating a part of the pattern by the beam and moving the pattern across it. The other utilizes a double diffraction optical system which performs low-pass or band-pass spatial frequency filtering to modify the visual pattern. It is experimentally found that cross points, corner points and edges of the pattern are emphasized. An analogy between this system and the human visual nervous system is also pointed out.
Photoelectronic Properties of CdSe Evaporated Films
Authors: Okimura Hiroshi , Sakai Yoshio
Published: November 2005

Pure CdSe films deposited on 100°–400°C substrates show high photosensitivity after a treatment of subsequent baking in a temperature range of 500°–700°C in argon gas. The maximum value of light-to-dark current ratio at 1000 lx is of the order of magnitude of 106. The maximum peak of spectral sensitivity is in a range of 700–710 mµ. Spectral distribution of absorption coefficient of baked films is almost equal to that of single crystals. Effect of baking on deposited films was studied by measuring thermally stimulated current (TSC) and superlinearity. Trap denisty of deposited films estimated by TSC method is 1018–1019cm-3. Whereas, the decrease of trap density is observed in highly photosensitive films after baking, particularly for deep traps (trap density is smaller than 1014cm-3). Properties of sensitizing centers in baked films are observed to be similar to those of single crystals.
Electrical and Photoconducting Properties of Chemically Deposited CdS Thin Layers
Authors: Pavaskar Neela , Menezes Cornelius
Published: November 2005

The electrical and photoconducting properties of chemically deposited CdS thin layers have been studied. The contact characteristics of these layers show that ohmic contacts are obtained using indium contacts. The space charge limited currents have been measured using both D. C. and pulse techniques for field strengths upto 104 volts/cm. The similarity in behaviour between crystals and chemically deposited layers is demonstrated. New transient current effects associated with traps have been recorded and a mechanism has been proposed. The response time to light pulses has been found to be faster than that of sintered layers.
Thermoluminescent Spectra and Transition Kinetics of γ-Ray Colored Synthetic CaF2 Single Crystal
Authors: Nakajima Toshiyuki
Published: November 2005

The thermoluminescent spectra of synthetic CaF2 single crystals irradiated with γ-rays were investigated. Emission peaks were observed at 382, 416, 438, 481, 549, 577, 647 and 838 mµ. Wavelengths of these peaks did not vary with the increase of the temperatures from room temperature up to 700°K.
Glow curves for spectral emission peaks were recorded throughout the temperature range between 300°K and 700°K. The thermal activation energies in the spectral glow were not constant.
The shapes of the glow curves indicated that thermoluminescence of the emissions at 382, 416, 438, 481, 549 and 577 mµ occurred with bimolecular process.
Photographic Realization of an Image-Deconvolution Filter for Holographic Fourier-Transform Division
Authors: Stroke George W. , Zech Richard G.
Published: November 2005

The theory of the photographic realization of the Fourier-transform filter required for the authors' method (Phys. Letters, 25A, (1967) 89) of a posteriori image-correcting `deconvolution' by holographic Fourier-transform division is given. Subsequent to the first presentation of this work, the author's method of Phys. Letters 25A, (1967) 89 has now been experimentally verified by A. W. Lohmann and H. W. Werlich [Phys. Letters 25A (1967) 570] for two-dimensional “black-on-white” objects (point and letter), and for the deblurring of the photograph of a three-dimensional object by G. W. Stroke, G. Indebetouw and C. Puech [Phys. Letters, 26A (1968) 443].
Silicon N-Channel Normally-Off Insulated-Gate Field-Effect Transistors
Authors: Ohwada Atsushi
Published: November 2005

Characteristics of n-channel normally-off insulated-gate field-effect transistors (IGFETs) are studied theoretically and experimentally. The obtained theoretical drain current is as follows:-
I

D
=-I

D
O

e

q(V

G
S
-V

T
O
)/m
k
T
·(1-e
-q
V

D
S
/k
T
)

where I

D
O
is a constant, V

G
S
and V

T
O
are gate potential and the threshold voltage to make the onset of inversion, V

D
S
is drain to source bias and m is reciprocal slope which is numerical constant determined by the parameters of the given FET. As predicted by the theory, experimental log I

D

vs
V

G
S
relation exhibits excellent linearity in the low level. The reciprocal slope and the thereshold voltage for the intrinsic drain current are influenced by the surface states as much as by the fixed charges located at the interface. P-type (100) oriented substrate wafer of u

p
more than 14 is needed to make n-channel normally-off IGFET in the present technique, where u

p
is a normalized Fermi potential of the substrate.
Etch Pits in Manganese Ferrite Single Crystals
Authors: Mizushima Masahiro
Published: November 2005

An etching procedure for revealing dislocations intersecting the three crystallographic surface in manganese ferrites is developed. Different etchants were used for different crystallographic surface. Etch-patterns are observed on {100} and {110} surfaces etched in 10% H2SO4 with zinc powder and on {111} surfaces etched in hydrochloric acid. Etch-patterns of manganese ferrites best plastically at 1350°C are investigated by this etching technique. It is concluded that the slip planes of manganese ferrites are {110} with <110> Burgers vectors.
Low Temperature Melting of Elements under High Pressure and Its Progression in the Periodic Table
Authors: Kawai Naoto , Inokuti Yukio
Published: November 2005

Data Obtained and gathered to data regarding melting phenomena in elements and compounds have been both reviewed and summarized in this paper. The result has yielded information concerning a new melting relation for materials, the characteristics of which are described in the following three items.
1) Any solid possesses a maximum melting point at a characteristic applied hydrostatic pressure.
2) At any temperature below the maximum melting point the solid melts at two characteristic pressures.
3) The pressure corresponding to the maximum melting point is lower in a solid composed of elements having a larger mass number; the progression of pressure for the maximum melting point is evident in each group elements in the periodic table.
Effect of Heat Treatment on Gallium Arsenide Crystals. I. Thermal Conversion in Excess Arsenic Vapor
Authors: Toyama Masaharu
Published: November 2005

Undoped n-GaAs crystals grown from the melt have been heat-treated in a quartz ampoule under 3.4 Torr of arsenic vapor pressure at 650 to 800°C. The crystals were converted to p-type crystals by this heat treatment. Acceptor concentration in the crystals, which were in equilibrium with the ambient factors at temperature T, is expressed as 10-2.8exp
(-0.6 eV/k
T) per lattice site. The acceptors are initially formed at the crystal surface and then diffuse into the interior. Rate of junction migration has been measured, and analyzed, on an assumption that the formation rate of the acceptors (in flux) is proportional to the difference of the surface concentration from the equilibrium concentration. Results are: the formation rate constant k

f
(cm/sec)=10-0.6exp
(-1.1 eV/k
T) and the diffusion coefficient D(cm2/sec)=104.8exp
(-2.5 eV/k
T). These results cannot be explained in terms of copper contamination alone and are suggestive of an influence of Ga vacancies.
Pattern Washout Effect in Epitaxial Process of Integrated Circuit Fabrication
Authors: Enomoto Tatsuya , Yukawa Katsuhiko , Iwata Yasumasa , Ohkubo Toshimi
Published: November 2005

In fabrication of silicon integrated circuits, epitaxial layers are usually grown by hydrogen reduction of SiCl4, and the washout of buried layer patterns is occasionally observed after the epitaxial process. This paper describes a mechanism for pattern washout, based on experimental results of patterns depressed roughly 5,000Å in depth. In the case of etching, the slanting face develops from a step to a depression, while in the case of deposition, it proceeds to a raise. The degree of pattern washout is nearly inversely proportional to orientational deviation of substrate surfaces from (111). Pattern washout is extremely slight in the case of epitaxial deposition by SiH4. The model proposed for the mechanism of pattern washout is as follows; i) the (111) plane has an abrupt minimum rate in etching and deposition compared with surrounding planes and ii) occurrence of subsequent new (111) planes at steps results in the pattern washout.
Turbulence Dependence of Vaporous Cavitation in Oxygen Jet
Authors: Nishigaki Kazu , Kato Eiji , Saji Yoshiro
Published: November 2005

For the purpose of clarifying the cavitation characteristics and the effect of turbulence on the inception of hydraulic cavitation, liquid oxygen and oxygen-argon solution were cavitated in an immersed jet in the temperature range from 70°K to the normal boiling point under various hydrostatic pressures between vapor pressure and ordinary pressure. A good reproducibility in the inception of cavitation was obtained under the same hydrodynamic conditions. A simple relation was found among the critical velocity, the static pressure around the jet and the temperature of specimens. The result was discussed and the conclusion has been reached that the cavitation inception may be caused spontaneously in a flowing liquid by the turbulence with sufficient intensity.
Slope failure repair using tyre bales at Interstate Highway 30, Tarrant County, Texas, USA
Authors: Prikryl W. , Williammee R. , Winter M.G.
Published: November 2005

The remediation of soil cut slope instability in Texas has traditionally been achieved using conventional methods. However, in early 2002 an alternative approach was taken to achieve the remediation of a failed slope using tyre bales, which are blocks of compressed whole post-consumer tyres. This paper describes the construction of the repair, the comparative retrospective analysis that was carried out to determine the likely performance of such slope repairs, and visual observations made around two years after construction. Specific lessons are drawn from the experience gained from this work.
Impact of aquitard storage on leaky aquifer pumping test analysis
Authors: Rushton K.R.
Published: November 2005

Estimates of the effective vertical hydraulic conductivity of low permeability strata (aquitards) which overlie an aquifer are required when assessing groundwater resources. One approach to estimation is to conduct pumping tests and analyse the drawdowns using classical leaky aquifer theory. However, unreliable parameter values may be deduced since aquitard storage is ignored in classical leaky aquifer pumping test analysis. Analytical solutions which take account of aquitard storage are available, but there are few published examples of their successful application in practical situations. As an alternative, a numerical model based on the same mathematical formulation as the analytical solutions is developed. The numerical model is used to illustrate the flow processes within the aquifer–aquitard system; an important finding is that vertical velocities at the base of an aquitard initially increase rapidly and subsequently decrease to final steady state values. A field pumping test is analysed in detail. Errors in parameter values, which are likely to occur when aquitard storage is ignored, are illustrated.