bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Tc Superconductivity of Y-Ba-Cu-O System
Authors: Akimitsu Jun , Ekino Toshikazu , Sawa Hiroshi , Tomimoto Koukichi , Nakamichi Toshimasa , Oshiro Masanori , Matsubara Yuji , Fujiki Hideo , Kitamura Norihisa
Published: November 2005

A high-T
c superconductivity has been observed in the Y-Ba-Cu-O system by both resistivity and magnetic susceptibility measurements. A superconducting transition with an onset temperature of 120 K has been achieved. About 8% Meissner effect has been confirmed indicating that superconductivity in this material is of the bulk nature. Preliminary X-ray diffraction experiments show that the crystal structure is a non-primitive perovskite structure.
Superconductivity and Electronic Structure of SrxLa2-xCuO4-y Prepared under Reducing Condition
Authors: Ihara Hideo , Hirabayashi Masayuki , Terada Norio , Kimura Yoichi , Senzaki Kiyoshi , Tokumoto Madoka
Published: November 2005

The compound Sr
x
La2-x
CuO4-y
(x∼0.7, y∼1.0) with a tetragonal K2NiF4 structure prepared under reducing conditions showed a high superconducting transition temperature (T
c) of 37.0 K and T
co (the onset of T

c
) of 54.0 K. Its photomission spectrum showed the existence of a large amount of monovalent Cu ions and a small amount of bivalent Cu ions. The valence band spectrum has a strong resemblance to the semimetallic DOS (the density of states) of ZrC and has a small DOS at the Fermi level. These facts suggest the T
c enhancement from a plasmon or exciton origin due to the Cu d-hole creation and anihilation resonating with vibration modes of the CuO6 and CuO5 clusters.
Far-Infrared Absorption to Test Anisotropy of Energy Gap in High Tc Superconducting Oxides
Authors: Maekawa Sadamichi , Ebisawa Hiromichi , Isawa Yoshimasa
Published: November 2005

The far-infrared absorption spectra are theoretically studied in poly-crystalline superconductors with anisotropic energy gap. The discrepancy between the recent far-infrared and tunneling experiments in the high T
c oxides, (La, Sr)2CuO4, are explained by the anisotropy of the energy gap.
Crystallochemical Studies on the High Temperature Superconductors La2-xMxCuO4-y (M=Ba and Sr)
Authors: Oh-ishi Katsuyoshi , Kikuchi Masae , Syono Yasuhiko , Hiraga Kenji , Morioka Yoshiyuki
Published: November 2005

High temperature superconductors La2-x
M
x
CuO4-y
(M=Ba and Sr) with the K2NiF4 structure were synthesized by solid state reaction and characterized by X-ray diffraction, electron microscopy, IR measurements and thermogravimetry. Anomalous behavior of unit cell parameters was confirmed. Electron diffraction study of the orthorhombic La2CuO4 revealed weak forbidden spots for Fmmm symmetry, suggesting a space group of lower symmetry. One of three IR bands observed in La2CuO4 rapidly disappeared around x=0.1. Highest superconducting transition temperature was found to be 38.0 K in La1.85Sr0.15CuO3.96.
Effect of Vacuum Annealing on the Superconducting Transition Temperature of La-Sr-Cu-O System
Authors: Shamoto Shin-ichi , Hosoya Syoichi , Onoda Masashige , Sato Masatoshi
Published: November 2005

Effect of vacuum annealing on the superconducting transition temperature T
c of the ceramic superconductor La-Sr-Cu-O system with K2NiF4 type structure has been studied. For a constant annealing time, the resistivity-increase and the T
c-decrease become larger for higher annealing temperatures. This may be qualitatively understood as the result of introduction of oxygen vacancies at their sites in the basal plane of CuO6 octahedra which are parallel to the (001) plane of the tetragonal cell.
A Study on the Superconductivity in Ba1-xYxCuO3-z
Authors: Takabatake Toshiro , Takeya Hiroyuki , Nakazawa Yasuhiro , Ishikawa Masayasu
Published: November 2005

The superconducting transition with an onset temperature of 96 K has been confirmed in the Ba1-x
Y
x
CuO3-z
system by resistivity and AC susceptibility measurements. By combining the X-ray diffraction and AC susceptibility data on both bulk and powdered samples, we conclude that the superconducting phase is a minority phase in the present system.
Compression and Shaping of a Short Light Pulse by a Monochromator
Authors: Shimizu Fujio
Published: November 2005

A simple technique to shape a short light pulse to an arbitrary temporal pattern using a monochromator is described. Operational conditions of the pulse shaping by Fourier transformation are discussed.
Tetragonal Lattice Distortion and Tensile Stress in GaAs Layers Grown on Si Substrates by MOCVD
Authors: Ishida Koichi , Akiyama Masahiro , Nishi Seiji
Published: November 2005

The lattice distortion and stress in GaAs layers grown on Si substrates by MOCVD have been studied. The lattice is tetragonally distorted under tensile stress at room temperature, contrary to the compressive stress expected from the fact that the lattice parameter of GaAs is greater than that of Si. The degree of lattice distortion and tensile stress is quantitatively explained by the purely elastic distortion due to the difference between the thermal expansion coefficients of GaAs and Si. This result demonstrates that the GaAs layer is stress-free at the higher growth temperature of the MOCVD two-step growth method and therefore thick GaAs layers can be grown on Si.
Stress and Strain of GaAs on Si Grown by MOCVD Using Strained Superlattice Intermediate Layers and a Two-Step Growth Method
Authors: Soga Tetsuo , Imori Toru , Umeno Masayoshi , Hattori Shuzo
Published: November 2005

The stress and strain of GaAs on Si grown by using strained superlattice intermediate layers and a two-step growth method are characterized by the photoluminescence, X-ray diffraction and the curvature radius. The strain of GaAs grown using strained superlattice intermediate layers is smaller than that grown by the two-step growth method.
Epitaxial Growth of High Quality ZnSe on GaAs Substrate by Atmospheric Pressure MOVPE Using Dimethylzinc and Hydrogen Selenide
Authors: Yodo Tokuo , Oka Hidetoshi , Koyama Tadashi , Yamashita Ken
Published: November 2005

Single crystalline layers of undoped ZnSe have been grown on GaAs substrates by atmospheric pressure MOVPE using dimethylzinc (DMZ) and hydrogen selenide (H2Se). Premature reactions typically encountered with this source combination can be eliminated completely, even at atmospheric pressure, by controlling the flow velocity of each source gas and the source gas mole ratio. For the first time, an excellent mirror surface morphology, as revealed by Nomarski interference microscopy, was obtained even for 8.2 µm thick epilayers grown at 300°C.
Initial Growth and Dislocation Accommodation of GaAs on Si(100) by Molecular Beam Epilaxy
Authors: Takasugi Hidetoshi , Kawabe Mitsuo , Bando Yoshio
Published: November 2005

The nucleation and growth process of GaAs on Si has been studied by auger electron spectroscopy and transmission electron microscopy. At growth temperatures above 120°C, epitaxial growth begins with island formation, the size of which depends on the growth temperature. At low growth temperature(∼120°C) the epitaxial islands grow preferentially on Si surface terraces rather than on steps, and misfit dislocations are introduced at steps where the leading edges of growing islands come into contact with each other.
Bulk Superconductivity of Y-Ba-Cu-O and Er-Ba-Cu-O
Authors: Takagi Hidenori , Uchida Shin-ichi , Sato Hisashi , Ishii Hideo , Kishio Kohji , Kitazawa Koichi , Fueki Kazuo , Tanaka Shoji
Published: November 2005

High T
c superconductivity in Y-Ba-Cu-O prepared with the improved conditions are investigated by both elctrical resistivity and magnetic susceptibility measurements. The results provide a clear evidence for the bulk superconductivity in this oxide material. A discovery of new supercoducting oxide Er-Ba-Cu-O with transition temperature as high as 90 K is also reported. It is found that these two compound shows very similar X-ray diffraction patterns and, thus, it is likely that the high T
c superconductivity is realized in the common crystal structure.
High Pressure Study and the Critical Current of High Tc Superconductor (La0.9Sr0.1)2CuO4-y
Authors: Yomo Shusuke , Murayama Chizuko , Takahashi Hiroki , Môri Nobuo , Kishio Kohji , Kitazawa Koichi , Fueki Kazuo
Published: November 2005

The superconductivity of the multi-phased sample of (La0.9Sr0.1)2CuO4-y
has been studied under hydrostatic pressure to 2.0 GPa and quasihydrostatic pressure to 4.2 GPa. The superconducting transition temperature (T
c) increases initially with increasing pressure. The results of the critical current and the diamagnetic susceptibility measurements, and the high sensitivity of T
c to the hydrostaticity of pressure suggest that the superconductivity of the high T
c phase in this multi-phased material is of bulk and highly anisotropic in nature, while that of the low T
c phase is of interfacial nature.
Oxygen-Defect Perovskite Structure with Superconducting Tc above 50 K in La-Ba-Cu-O Compound System
Authors: Hikita Makoto , Tsurumi Shigeyuki , Semba Kouichi , Iwata Tsunekazu , Kurihara Susumu
Published: November 2005

It is shown experimentally that the La-Ba-Cu-O system has a new high-T
c phase La2Ba4Cu6O14+y
with oxygen-defect perovskite structure, other than the well-known La2-x
Ba
x
CuO4 with K2NiF4 structure. The new phase shows a superconducting transition at much higher temperatures (T
c onset>55 K, T
c endpoint>42 K) as compared with the K2NiF4 type phase.
A Revised Structural Model for the Ba-Y-Cu-O Superconductor
Authors: Izumi Fujio , Asano Hajime , Ishigaki Tōru
Published: November 2005

A possible structure with a space group Pmmm is proposed for a superconducting oxide, Ba2YCu2O7, on the basis of Rietveld analysis of X-ray powder diffraction data. It has a metal-ordered, layered structure in which an oxygen atom at a 1c site is deficient completely, and 1b and 1e sites are partially occupied. Each layer consists of those pyramids and octahedra of oxygen atoms which are linked with each other by sharing corners.
Effect of Ge Addition on Ga-Se-Te System Reversible Optical Recording Media
Authors: Matsushita Tatsuhiko , Suzuki Akio , Nakau Tanehiro , Okuda Masahiro , Rhee Jung Chul , Naito Hiroyoshi
Published: November 2005

A reversible optical storage medium capable of more than 104 write/erase cycles has been realized using a Te0.8(Ga0.05Se0.95)0.2+5 wt% Ge film (∼1000 Å). For this composition, a peak temperature of an exothermic curve of 156°C and an activation energy from Kissinger's plot of 2.24 eV were obtained using a differential scanning calorimeter. In this film, a peak of GeTe crystal was identified by X-ray diffraction. To investigate changes of the film surface induced through an annealing (200°C + 100 mW/cm2Xe, ∼1 min), a high resolution SEM observation was carried out; while cracks preventing the high reversibility of write/erase cycles were generated for the GeTe film, the cracks were not recognized for the Te0.8(Ga0.05Se0.95)0.2+5 wt%Ge film.
Estimation of the Filling Factor of the High Tc Superconducting Phase in Y-Ba-Cu-O Mixed System
Authors: Onari Seinosuke , Ohshima Ken-ichi , Arai Toshihiro , Uwe Hiromoto , Sakudo Tunetaro
Published: November 2005

A method to estimate the filling factor f of the high T
c superconducting materials from the infrared reflection measurement is presented. It is shown that the Y-Ba-Cu-O mixed phase system can exhibit the characteristic superconductive resistance behaviours near 90 K in the samples with the filling factor less than 0.1.
Vibrating Sample Magnetometry of High-Tc Superconductor Y-Ba-Cu Oxide
Authors: Hioki Tatsumi , Ohkubo Masataka , Itoh Akio , Doi Haruo , Kawamoto Jun-ichi , Kamigaito Osami
Published: November 2005

Magnetic properties of a high-T
c superconductor Y-Ba-Cu oxide are studied by using a vibrating sample magnetometer. The specimen prepared shows a rapid resistivity drop at 95 K and zero-resistance state at 91 K. A diamagnetic susceptibility as large as 43% of the perfect diamagnetism is observed at a temperature as high as 84 K. At this temperature, the lower critical field is about 200 Oe and the upper critical field is suggested to be higher than 10 T.
Electrical Resistivity, Critical Current and Crystal Orientation of the Sintered Y-Ba-Cu-O Compounds
Authors: Watanabe Hirohito , Kasai Yuji , Mochiku Takashi , Sugishita Akimitsu , Iguchi Ienari , Yamaka Eiso
Published: November 2005

The electrical resistivity and critical current of the sintered Y-Ba-Cu-O compounds with the various molar ratio of (Y, Ba):Cu are reported. The sintered pellet with the 1:1 or 2:1 ratio has the zero-resistance transition temperature of 94-95 K with ΔT
c≤1 K. The temperature dependence of critical current is in good agreement with the Ginzburg-Landau theory near T=T
c. It is also shown, from the X-ray analysis, that the sintered pellet has the strong c-axis orientation perpendicular to the pressed surface.
Josephson Point Contact Using High-Critical-Temperature Oxide-Superconductors
Authors: Nishino Toshikazu , Hasegawa Haruhiro , Nakane Hideaki , Ito Yukio , Takagi Kazumasa , Kawabe Ushio
Published: November 2005

The current-voltage characteristics of Josephson point contacts, Nb/YBa2Cu3O7-δ and YBa2Cu3O7-δ/YBa2Cu3O7-δ, are studied. At temperatures up to 40 K, nonlinear characteristics due to dc Josephson effect are observed for the YBa2Cu3O7-δ/YBa2Cu3O7-δ point contacts. The effect of thermal fluctuation on dc Josephson effect is discussed in comparison with experimental results.
Superconducting Properties of Highly Oxidized Superconductor Ba2-xY1+xCu3O7-y
Authors: Ishizawa Yoshio , Fukunaga Osamu , Nozaki Hiroshi , Tanaka Takaho
Published: November 2005

Superconducting properties of Ba2-x
Y1+x
Cu3O7-y
(x=0.09) have been investigated by using samples prepared in different oxygen partial pressure. It is found that critical current density increases rapidly with the higher oxidation leading to the large Meissner signal while superconducting transition temperatures remain at about 90 K.
Study of Superconductors with High Transition Temperature by Positron Annihilation
Authors: Ishibashi Shoji , Yamaguchi Akira , Suzuki Yasuyuki , Doyama Masao , Kumakura Hiroaki , Togano Kazumasa
Published: November 2005

Positron annihilation Doppler-broadening measurements have been performed on La-Sr-Cu-O and Y-Ba-Cu-O systems, which are superconductors with high transition temperatures. The line shape parameter of Doppler-broadened spectra shows anomalous increases near the transition temperature.
Two Crystal Phases in the Superconducting Ba-Y-Cu-O System and Their Reactivity to Water
Authors: Nakada Ichiroh , Sato Shoichi , Oda Yasukage , Kohara Takao
Published: November 2005

Crystals with a stoichiometry either Ba2YCu3-x
O7-y
or Ba4YCu2O8-y
are a high t
c superconductor. The former is well known. With respect to the latter the crystal structure was determined to be tetragonal with lattice parameters a=5.78 Å and c=7.99 Å. It was found that both of them reacted with water. The former was slowly decomposed by warmed water at about 35°C, while the latter was destroyed at room temperature in an instant.
Metallugical Analysis of Mix-Phase Y-Ba-Cu Oxides
Authors: Takagi Kazumasa , Miyauchi Katsuki , Ito Yukio , Aida Toshiyuki , Hasegawa Haruhiro , Kawabe Ushio
Published: November 2005

Mix phase ceramics of Y0.4Ba0.6CuO3-y
is examined by an X-ray diffraction and an EPMA methods. When the sintering temperature is high (1050°C), ceramics show a mix phase consisting of CuO, Y2BaCuO6-y
and YBa2Cu3O8-y
. By lowering the sintering temperature, single phase is obtained. This single phase ceramics show a sharp superconducting transition at 93 K.
High-Tc Superconductivities of (Y1-xYbx)2Ba4Cu6O14+y(0<y<2.5)
Authors: Tsurumi Shigeyuki , Hikita Makoto , Iwata Tsunekazu , Semba Kouichi
Published: November 2005

High T
c superconducting phase of (Y1-x
Yb
x
)2Ba4Cu6O14+y
compounds is investigated by X-ray diffraction patterns and electrical resistivities. All compounds of this system show high T
c (end point > 90K) and extremely narrow transition width (ΔT
c<2K). The substitution Yb3+ ion for Y3+ ion is found to give no effect to CuO2 plane for providing superconductivity.
Preparation and Characterization of Superconducting Y-Ba-Cu-O Thin Films
Authors: Adachi Hideaki , Setsune Kentaro , Mitsuyu Tsuneo , Hirochi Kumiko , Ichikawa Yo , Kamada Takeshi , Wasa Kiyotaka
Published: November 2005

Thin films of Y-Ba-Cu-O system have been prepared by rf-magnetron sputtering technique. The films were crystallized through post annealing and superconductivity was appeared. The film on R-plane of sapphire showed superconducting transition with an onset temperature at 94 K and zero-ρ state was achieved below 70 K.
High-Tc Superconductor Ba0.5Y0.5CuOx –Upper Critical Field and Phases
Authors: Aoki Haruyoshi , Asada Yuji , Hatano Takeshi , Matsushita Akiyuki , Matsumoto Takehiko , Ogawa Keiichi
Published: November 2005

The critical field (H
c2) has been studied for the compound Ba0.5Y0.5CuO
x
. The behaviour of the lower temperature side T
cl of the resistive superconducting transition region is found to depend on the heat treatment given to the sample. The dependence is understood in terms of the coexisting phases i.e. tetragonal and orthorhombic, formed in the sample. The H
c2(0) for the orthorhombic phase is estimated to be as high as 197 T for the Ba0.5Y0.5CuO
x
compound.
Meissner Effect in High-Tc Superconductive Thin Films
Authors: Hatta Shin-ichiro , Higashino Hidetaka , Wasa Kiyotaka
Published: November 2005

The Meissner effect of the superconductive thin films was measured by the simple technique, which is the observation of the change in the sensing inductance faced to the superconductive plane. By using this method, slight and gradual exclusion of magnetic flux was found below the perfect conductivity temperature in the Y-Ba-Cu oxide films.
High Tc Yb-Ba-Cu-O Thin Films Deposited on Sintered YSZ Substrates by Sputtering
Authors: Kawasaki Masashi , Nagata Shunroh , Sato Yohsuke , Funabashi Makoto , Hasegawa Tetsuya , Kishio Kohji , Kitazawa Koichi , Fueki Kazuo , Koinuma Hideomi
Published: November 2005

Thin films of superconductors Yb-Ba-Cu-O were prepared by 50 Hz ac sputtering technique. The critical temperatures for onset and zero resistivity were 93 K and 66 K, respectively. The metal compositions and crystal structures of the films were controlled by varying such preparation conditions as sputtering gas, target composition, and substrate temperature and their relations with superconductivity were investigated.
An AlGaAs/InGaAs/GaAs Strained Channel MISFET
Authors: Maezawa Koichi , Ito Hiroshi , Mizutani Takashi
Published: November 2005

A new strained channel MISFET (SC-MISFET) with n+-implanted source/drain regions was fabricated using lamp annealing method on an undoped AlGaAs/undoped InGaAs/undoped GaAs hetero-structure. The threshold voltage of this FIT reasonably agreed with that expected from the band diagram. This suggests that the strained InGaAs channel is scarcely disordered during high temperature annealing, and the interface state density is very small. The SC-MISFET can be expected to have additional advantages as compared with AlGaAs/GaAs MISFETs, such as an increased barrier height, an increased electron velocity.
Model of the Two Dimensional Electron System in the Ceramic Superconductivity
Authors: Kinase Wataru , Zvyagin I. P. , Takahashi Kunio , Hirose Kenichi
Published: November 2005

The mechanism of the high-T
c ceramic superconductivity is discussed by using a model of the 2D electron lattice and also the percolation theory, where the 2D electron system in atom layers and also in the grain boundaries in the crystal plays an important role. The behavior between the onset temperature and the zero resistivity temperature can be explained by this model.
Specific Heat and Superconductivity of Ba2YCu3Oy
Authors: Kitazawa Koichi , Atake Tooru , Ishii Hideo , Sato Hisashi , Takagi Hidenori , Uchida Shin-ichi , Saito Yasutoshi , Fueki Kazuo , Tanaka Shoji
Published: November 2005

The specific heat measurement was performed on recently discovered oxide superconductor Ba2YCu3O
y
with T
c above liquid nitrogen temperature. A clear specific heat jump, at least 2 J/mol K, was observed at around 92 K, which provides electronic specific heat coefficient of 15 mJ/mol K2 in the weak coupling limit. The obtained γ is rather low in view of the high T
c of 90 K range. This leads us to postulate that the superconductivity in this oxide system is brought about by some mechanism other than conventional phonon mediated BCS theory.
Specific Heat and Superconductivity of (La0.925Sr0.075)2CuO4
Authors: Kitazawa Koichi , Atake Tooru , Sakai Masayuki , Uchida Shin-ichi , Takagi Hidenori , Kishio Kohji , Hasegawa Tetsuya , Fueki Kazuo , Saito Yasutoshi , Tanaka Shoji
Published: November 2005

The specific heat of (La0.925Sr0.075)2CuO4 was measured over the temperature range 14.5-87 K. A clear specific heat jump ΔC was observed at the critical temperature around 38 K. Subtraction of the lattice specific heat estimated by curve fitting yielded the electronic specific heat coefficient approximately 11 mJ/(mol·K2) according to the BCS relation. Comparison of this result with those of the other high T
c oxide superconductors seems to raise a difficulty in explaining the results simply by the ordinary BCS mechanism.
Critical Temperature and Critical Current Density of La-Sr-Cu Oxide Wires
Authors: Kohno Osamu , Ikeno Yoshimitsu , Sadakata Nobuyuki , Sugimoto Masaru , Nakagawa Mikio
Published: November 2005

Superconducting wires with La-Sr-Cu oxide were successfully produced. The resistivity became zero at 32 K. No difference was observed in the critical temperatures of wire and disk-shaped specimens. The critical current density of the wire was 50 A/cm2 at 4.2 K and zero external field.
Preparation of Single Crystals of the Superconductor Ba2YCu3O6.5+x
Authors: Ono Akira , Tanaka Takaho
Published: November 2005

Single crystals for X-ray structural analyses were prepared and characterized by thermogravimetric (TG) and X-ray powder diffraction methods. Superconductive compounds obtained are tetragonal or orthorhombic in crystal system at room temperature. The value x in the chemical formula Ba2YCu3O6.5+x
is in the range of 0.25 to -0.6 on the basis of TG curves of the stoichiometric compound measured in nitrogen or oxygen atmosphere. Oxygen contents of the compounds are mainly controlled by oxygen fugacity, permeability of oxygen into specimens, cooling rate and grain sizes of the crystals.
Short Range Order in High Tc Superconductors BaxY1-xCuO3-y and SrxLa2-xCuO4-y
Authors: Oyanagi Hiroyuki , Ihara Hideo , Matsushita Tadashi , Hirabayashi Masayuki , Terada Norio , Tokumoto Madoka , Senzaki Kiyoshi , Kimura Yoichi , Yao Takafumi
Published: November 2005

Short range order in high T
c superconductors Sr
x
La2-x
CuO4-y
and Ba
x
Y1-x
CuO3-y
have been analyzed by extended X-ray absorption fine structure (EXAFS) on the Cu K-edge. The radial distribution around Cu+ and Cu2+ ions in oxygen-deficient Sr
x
La2-x
CuO4-y
is interpreted in terms of a modified K2NiF4 structure which is characterized by i) vacancies in the axial oxygen sites of CuO6 octahedron and ii) the displacement of La(Sr) positions along the c-axis. In Ba
x
Y1-x
CuO3-y
, the radial distribution of oxygens around Cu2+ and Cu3+ ions indicates that average 4.8 oxygen atoms are present at 1.925 Å. A possible model is presented to describe the cooperative motions of oxygen atoms in the basal plane which are induced by the valence fluctuation of Cu ions.
Composition Dependence of Superconductivity in (Ba0.1La1.9)AgxCu1-xO4-y System
Authors: Saito Yoshitami , Noji Takashi , Endo Akihiko , Matsuzaki Nozomu , Katsumata Masao , Higuchi Naoaki
Published: November 2005

We report results of substitution effect of Ag for Cu as a function of x (0.0≦x≦1.0) in high T
c superconductors, (Ba0.1La1.9)Ag
x
Cu1-x
O4-y
compounds.
Transition temperatures increased with a small amount of Ag and are nearly constant in a wide composition range of x (0.05<x<0.6). No superconductivity above 4.2 K was observed for the sample of complete substitution of Ag;(Ba0.1La1.9)AgO4-y
compound.
Halogen and Mercury Lamp Annealing of Arsenic Implanted into Silicon
Authors: Yokota Katsuhiro , Muta Kenji , Kimura Masatoshi , Tamura Susumu , Ishihara Shinji , Kimura Itsuro
Published: November 2005

As implanted Si was annealed using halogen and mercury lamps whose lights primarily have, respectively, infrared and ultraviolet regions. Annealing time necessary for fully electrically activating the implanted As in the mercury lamp annealing was shorter than that in the halogen lamp annealing, when the light emitted from the two lamps was of the same intensity. This was due to the difference in intensity of the light absorbed into the implanted Si between the lamps used at the beginning of annealing.
Infrared Spectroscopy in High Tc Superconductors (La1-xSrx)2CuO4
Authors: Sugai Shunji , Uchida Shin-ichi , Takagi Hidenori , Kitazawa Koichi , Tanaka Shoji
Published: November 2005

Infrared active phonons in (La1-x
Sr
x
)2CuO4 are investigated by reflection spectroscopy. The main peaks of Im(ε) in La2CuO4 are 117, 148, 166, 347, 509 and 679 cm-1. On increasing the carrier density by replacing La with Sr a new peak appears at 246 cm-1 in place of the decrease of the above peaks except for the 509 cm-1 peak. The existence of structures in the far infrared spectra in metal with the carrier density as high as 5 × 1021 cm-3 is very abnormal. The possibility is pointed out that the 246 cm-1 mode is related to the electronic excitation.
Structure-Property Relations in High Tc Oxide Superconductors: Search for Systematics
Authors: Rao C.N.R. , Ganguly P.
Published: November 2005

Some interesting aspects of the structure and stoichiometry of YBa2Cu3O7+δ and other high-T
c oxide superconductors are discussed. The nature of Cu and the importance of the Cu3+/Cu2+ ratio in these copper oxides are pointed out. Marginal metallicity of the non-superconducting phase in these oxides as an important factor in the mechanism is indicated. Effect of Y substitution in YBa2Cu3O7+δ by other rare earths is commented upon.
Observation of Microdefects in Thin Silicon Crystals by Means of Plane-Wave Topography Using Synchrotron X-Radiation
Authors: Chikaura Yoshinori , Imai Masato , Ishikawa Tetsuya
Published: November 2005

In order to observe microdefects in silicon crystals, plane-wave topography using synchrotron X-radiation has been successfully applied to thin silicon crystals. We have aimed increasing a ratio of a diffraction signal from microdefects to diffracted intensity from the matrix crystal by taking advantage of an extinction effect of X-ray dynamical intensity. Our plane-wave topography revealed that microdefects for such thin crystals always show a distinct contrast, though we have not obtained zero intensity at the background because of a long-range elastic strain. It is proposed that when silicon wafers are thinned, stress relief at the specimen surface allows a strain field to apread around microdefects to an extent which is detectable using plane-wave topography.
Seeded Electron Beam Recrystallization of Large Area SOI Using Striped Tungsten Encapsulation Technique
Authors: Kakimoto Seizo , Kudo Jun , Koba Masayoshi , Awane Katunobu
Published: November 2005

Large area SOI (silicon on insulator) film with (001) orientation has been produced by applying a seeded electron beam recrystallization technique to the specimen with striped encapsulation. The encapsulation stripes consisted of tungsten and polysilicon. A pseudoline electron beam was scanned parallel to the stripes. A 400 µm×800 µm area had become a single crystal including subgrain boundaries in one sweep. These subgrain boundaries were confined to the region between the encapsulation stripes. The orientation of the crystal gradually rotates from (001)[110] to (103)[331̄] as recrystallization propagated away from the seed.
Low-Temperature Photoluminescence of Lightly Si-Doped AlxGa1-xAs on (511) GaAs Substrates Grown by Molecular Beam Epitaxy
Authors: Takamori Takeshi , Fukunaga Toshiaki , Nakashima Hisao
Published: November 2005

The low-temperature (1.8 K) photoluminescence of lightly Si-doped Al
x
Ga1-x
As on (100), (511)B and (511)A GaAs substrates grown by molecular beam epitaxy (MBE) has been studied. Strong orientation dependence of defect complex (d) emission has been observed in Si-doped (ND-NA=1017 cm-3) AlGaAs samples. This orientation dependence in AlGaAs samples strongly suggests that the (d) line is related to defect complexes induced by Si atoms and is highly sensitive to the surface configuration of atoms during MBE growth.
Sputter-Deposition of Fe Films in a High Pressure Atmosphere
Authors: Ishii Kiyoshi
Published: November 2005

A sputtering apparatus in which sputtered atoms were carried from the target to the substrate by Ar gas flowing between them was developed by the author. Using it, iron films were deposited at a considerably high rate in a very high pressure atmosphere, and sputtered atoms could be completely thermalized before arriving at the substrate.
Titanium Nitride Crystal Growth with Preferred Orientation by Dynamic Mixing Method
Authors: Kiuchi Masato , Tomita Masato , Fujii Kanenaga , Satou Mamoru , Shimizu Ryuichi
Published: November 2005

Titanium nitride films were produced by dynamic mixing method on four kinds of substrates whose crystal structures differed. By the X-ray diffraction it was observed that the four films had the same preferred orientation. Cross-sectional observation with a transmission electron microscope revealed that an amorphous intermixed layer had formed. The profile of crystal growth on the intermixed layer clearly indicated that the growth started from isotropically oriented small grains and progressed gradually to preferentially oriented columnar grains.
Epitaxial Growth of Silicon by Plasma Chemical Vapor Deposition at a Very Low Temperature of 250°C
Authors: Nagamine Kunihiro , Yamada Akira , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

A new technique for the epitaxial growth of silicon has been developed using plasma chemical vapor deposition. Epitaxial thin films were grown on (100) Si substrates at 250°C from a gas mixture of SiH4, SiH2F2, and H2 by glow discharge decomposition. Reflective high-energy electron diffraction (RHEED) measurements showed that the surface of the epitaxial film obtained was smooth. The epitaxial films have been characterized by high resolution transmission electron microscopy (HRTEM) and secondary ion mass spectroscopy (SIMS).
Selective Coordination Epilaxy of Transition Metal Coordination Compounds III. Evidence of Epitaxial Growth by Buerger Precession Method
Authors: Tanino Hiroshi , Takahashi Kazuhiro , Yao Takafumi
Published: November 2005

Epitaxially grown crystals of transition metal coordination compounds (TMCC's) by selective coordination epitaxy (SCE) are studied by Buerger precession method. Three-dimensional order between the epitaxially-grown crystal and the substrate is established. Thus, the epitaxial growth by SCE is proved in the same manner as the proof by electron diffraction pattern in the case of molecular beam epitaxy. The Buerger precession method is proposed as a powerful method to characterize tailored structures grown by SCE. The characteristics of SCE of TMCC's are discussed.
Frequency Shift of a Tunnel-Diode Microwave Oscillator
Authors: Arizumi Tetsuya , Wada Takao
Published: November 2005

The oscillation frequency in a tunnel-diode microwave oscillator varies depending upon both the ambient temperature and the bias voltage. This variation can be interpreted mainly by the change in the junction capacitance. At medium bias voltages the temperature dependence of the junction capacitance is in agreement with those estimated from Bernard's results at low frequencies. At higher bias voltages the variation in the frequency as a function of bias voltage are primarily caused by the non-linear I–V characteristic, while at lower bias voltages the anomaly of the junction capacitance as well as the non-linearity determines the variation in the oscillation frequency.
PEM Effect in Germanium
Authors: Ishigame Mareo
Published: November 2005

The PEM effect in germanium was observed by using two specimens G
1 and G
2, 7×1012 cm-3 and 8×1012 cm-3 in impurity concentration and nearly equal in their surface characteristics. The variation of the PEM voltage with magnetic field showed that the linearity held for the small magnetic field, but it saturated for the strong field. From the results of observation, it was found that the energy level of the recombination centers exists at E

t
-E

v
≈0.35 eV. The spectral dependence of the PEM effect together with that of the photoconductive effect indicated that the half value wavelength of the PEM effect was shorter than that of the photoconductive effect and that a peak was found at 1.9 micron in the latter case.
On “Lattice Image” in Electron Micrographs
Authors: Miyake Shizuo , Fujiwara Kunio , Tokonami Masayasu , Fujimoto Fuminori
Published: November 2005

Assuming a plate-shaped crystal in which a lattice plane with the spacing d is perpendicular to the crystal surfaces and the potential varies according to the harmonic form V(x)=2V
1cos
(2πx/d) in direction x perpendicular to the lattice plane, the lattice image of electrons on the exit surface was calculated by using the exact solution of Schrödinger equation for electron waves in the crystal. The values of d and V
1 were assumed to be 13.0 Å and 2.14 volts, respectively. These values are those approximately appropriate to (001) of Pt-Phthalocyanine. Calculation was made both for the case of normal incidence of primary electrons and the case in which Bragg condition is satisfied. Wavelength of electrons was assumed to be 0.0603 Å corresponding to the accelerating voltage 41.5 kV. A number of aspects of the lattice image which take place by the participation of higher order reflections were revealed. By the effect of higher order reflections, the peaks in the lattice image become much pronounced for the crystal thicker than about 300 Å, while, on the contrary, the intensity profile turns out to be rather flat for the crystal thinner than about 150 Å, in accordance with the trend expected from the phase grating theory.
Superparamagnetism in ZnFe2O4 Induced by High Pressure Squeezing
Authors: Goto Yasumasa
Published: November 2005

It was found that ZnFe2O4 exhibited a superparamagnetic behavior due to the formation of magnetic clusters inside the specimen when squeezed by an anvil under the pressure of (1∼3)×104 kg/cm2 at room temperature. From the analyses of the magnetization curves, the mean magnetic moment of a cluster was calculated to be of the order of 10-17 emu and its temperature dependence was also determined from the initial susceptibility. The number of the clusters involved in 1 gr of the squeezed ZnFe2O4 was about 1017 which varies almost proportionally with applied pressure. It is suggested that the magnetic cluster may be the stacking fault formed by squeezing in which some ferric ions are slipped into tetrahedral sites during the crystal slip. The superparamagnetism disappears gradually by annealing above 400°C and the activation energy for the recovery was about 1.7 eV.
Fast Neutron Time-of-Flight System for Use with 16'' Variable Energy Cyclotron
Authors: Kobayashi Shinsaku , Ohnuma Hajime , Uchida Akira , Imaizumi Minoru
Published: November 2005

The fast neutron time-of-flight system for use with ISSP 16'' variable energy cyclotron is described. Proton beam of peak current of about 400 µA is obtained with the duration of less than 2 ns (natural bunching) and reduced repetition frequency of 3 Mc at the neutron producing target. The overall time resolution obtained with the system is 4 ns for 1 MeV neutron.
Theory of Self-Pinching of an Electron-Hole Plasma
Authors: Glicksman Maurice
Published: November 2005

The dynamic behavior of an electron-hole plasma undergoing pinching is discussed under the assumption that the compression heats the plasma with little energy loss to the lattice. Calculated pinch-times are in good agreement with observations at low and intermediate currents.
Theory of the Diffraction of Light by Ultrasonic Waves of Finite Amplitude: A Parametric Expansion Method
Authors: Nomoto Otohiko
Published: November 2005

An initially sinusoidal ultrasonic wave of finite amplitude becomes sawtoothed as the distance from the sound source increases. A parametric expansion method is proposed for computing the intensity distribution amongst orders of the diffraction spectra of light produced by ultrasonic waves of finine amplitude. Exact analytical expressions in compact form are obtained for the light intensity in various orders.
A New Method of Measurement of Sedimentation Potential at High Centrifugal Field
Authors: Matsukura Yasuo
Published: November 2005

A new method of measuring sedimentation potential at high centrifugal field is described for the purpose of investigating the charge effects on sedimentation of macromolecules, and of determining the transference number of ions. At a high speed of rotation a large electromotive force of sedimentation potential is obtained, because the emf produced by the rotation should increase with the square of the number of rotation per second. In the present method, a condenser commutator was designed to avoid poor contact in the case of the common mercury contact at high speed of rotation, and to eliminate the production of thermo-electromotive force at the point of contact. For the calibration of the sedimentation potential, a combination of solar batteries and light sources was used as a standard cell. The potential can be measured with this apparatus with an accuracy higher than 0.1 mV at the speed of rotation from 1000 to 11100 r.p.m.
Energy Selecting Microscope
Authors: Watanabe Hiroshi
Published: November 2005

A new instrument called “Energy Selecting Microscope” has been completed, by means of which electron microscope images and diffraction patterns formed by mono-energetic electrons of any pre-selected energy can be obtained.
The energy of electrons forming an image or pattern is analysed by a Möllenstedt type analyser, and the electrons within a certain energy range are selected by a slit placed on the plane of the energy spectrum. To obtain the entire image of the specimen, the images on the entrance slit of the analyser and on the final screen are scanned perpendicularly to the slit by properly synchronized saw-tooth voltages. The energy resolution of the selected-energy image is approximately 1 eV at 50 kV acceleration.
In the case of amorphous specimens such as carbon particles, the characteristic-loss electron image looked similar to the ordinary dark field image, while Fresnel fringes did not appear in the loss electron images.
In the case of crystalline specimens the extinction contours and dislocations were clearly observed in the characteristic-loss electron images. This observation indicates that the characteristic-loss electrons produced a diffraction contrast similar to that of no-loss electrons.
Segregation of Copper from Supersaturated Solid Solution in Germanium
Authors: Mannami Michihiko , Izumi Kunihide , Hayashida Toshiaki , Nakagawa Masayuki
Published: November 2005

The segregation of copper from supersaturated solid solution in germanium has been studied by an electron microscope. The segregation takes place only along as-grown dislocations. The growth rate of the radius of the cylindrical segregate is approximately proportional to the square root of the growth time. The rate-limiting process of the segregation of copper is discussed.
Cavity Theory of Fabry Perot Resonator
Authors: Ogura Hisanao , Yoshida Yasuo
Published: November 2005

A theory of Fabry Perot resonator is developed on the basis of the cavity picture, in contrast to interferometer picture of the ordinary theory. The radiation leakage from the open surface is treated as a boundary value problem. This theory is applied to the circular Fabry Perot resonator and numerically calculated for the case of the laser resonator. A concise formula is derived for the diffraction loss, which also shows the explicit dependence on the mode of resonance: δ
d
=2.40×10-2\varLambda2

e
m

N
-3/2, where \varLambda
e
m
denotes the m-th root of J

l
, N≡a
2/Lµ, a the radius of the disc, L the axial length and µ the wave length.
Hall Effect in Manganese Antimonide
Authors: Nogami Minoru , Sekinobu Masaaki , Doi Hitoshi
Published: November 2005

The temperature dependence of normal and extraordinary Hall coefficients, and of specific resistivity in MnSb is measured by the application of alternative current and d.c. magnetic fleld. Contrary to ferromagnetic metals the observed materials have the large normal Hall coefficient above magnetic saturation, the values of which is positive and the order of 10-9m3/C., and the observed ones decrease with decreasing temperature. The rations R
0/ρ are almost constant at various temperatures below the Curie point and in the different samples. (R

s
/ρ) versus ρ curve seems to be linear. It may be thought to confirm the reliability of theory.
Plastic Yielding in Ice Single Crystals
Authors: Higashi Akira , Koinuma Shoichi , Mae Shinji
Published: November 2005

Stress-strain relations in single crystals were investigated using ice cylinders in tension. The cylinders were deformed at strain rates varying from 8×10-6 min-1 to 4×10-4 min-1 and at temperatures between -15 and -40°C. The stress-strain curves obtained showed large yield drops and the amount of the drop increased with an increase in the deformation rate or with decreasing temperature. The stress-strain curves of ice single crystals from those of materials such as LiF, Ge, InSb etc., which also show large yield drops in that the slope of initial, linear portion of the curves varies with the strain rate and with temperature. Another characteristic feature of the curves is that past the yield point the curves do not show minimums. This indicates that ice crystals do not work-harden. The maximum stress τ
max
, and the slope of the initial, linear portion M=(dτ/d
ε)
i
are taken as characteristic parameters of the curves. Their dependence on temperature and strain rate are given as follows:
M=(M
0+D\dotε exp
(E
1/R
T)

and

τ
max
∝\dotε
1/m
exp
(E
2/R
T)

where m=1.53 and E
1=8.4 Kcal/mole and E
2=10.4 Kcal/mole
Values for the activation energy E
2 and m indicate that the results are in good agreement with those expected from interpretations of creep experiments based on Johnston's theory of movement and multiplication of dislocations. Specific features of the stress-strain curves are also discussed in terms of a special characteristic of ice crystals.
The Orientation Relationships and Crystal Habits in the Martensite Transformation of a Cu-Al Alloy
Authors: Kajiwara Setsuo , Nishiyama Zenji
Published: November 2005

The orientation relationships in a Cu-11.9% Al alloy have been studied with thin foils containing β' martensite (orthorhombic lattice) and β1 phase (ordered B. C. C.) produced by heating in an electron microscope. The crystal habits and other related phenomena have also been observed.
On heating β' martensite plate, β1 crystals nucleate in the inner region of the martensite at about 400°C and they grow very straight and all parallel. The growth is not jerky but continuous. Stacking faults in the β' martensite are not annealed out even at such high temperatures.
It is found that the orientation relationships are (110)β1
//(128̄)β', [11̄1]β1
//[21̄0]β'. The boundary plane between two variants of martensite is (128̄)β', which is parallel to (110)β1
in the parent phase.
A Double Injection Negative Resistance in p-Type Indium Antimonide at 77°K
Authors: Ando Koji
Published: November 2005

A large current-controlled negative resistance was observed in p-InSb at 77°K. As a natural consequence of the negative resistance, oscillations at about 31 Mc were also observed without applied magnetic field. These are similar to the oscillations which have been previously observed in p-InSb by Ancker-Johnson1) but not explained. The experimental observations are explained as a double injection negative resistance induced by avalanche breakdown. Analysis shows that the experimental results are in good agreement with theory.
A Supplement to “Thermodynamics of Impurity Doping Reactions in Vapor Growth of Ge”
Authors: Arizumi Tetsuya , Akasaki Isamu
Published: November 2005

Reduction yields of germanium iodides by hydrogen are largely governed by free energies of iodination of Ge. The experimental results on hydrogen reduction of GeI4 suggest that Lever's free energy data are more plausible than postulated in our paper, and the disproportionation reaction of GeI2 is predominant at 700°K in OTP. Both free energies of reduction of impurity iodides by Ge and reduction yields of their triiodides are calculated again. The experimental transfer ratios of some important impurities are of the same order as the reduction yields of impurity triiodides calculated from Lever's data.
Effect of Uniaxial Stress on Germanium p-n Junctions
Authors: Imai Tetsuji , Uchida Masao , Sato Hidekichi , Kobayashi Akio
Published: November 2005

The stress effect on germanium Esaki- and ordinary diodes has been investigated when the stress is applied perpendicularly to the junction which is parallel to the (111) plane. No essential difference in the stress effect has been found between Esaki- and ordinary diodes so far as the ordinary diode current region is concerned.
Stress-induced increase in forward current with constant slope of ln I vs V plots is interpreted in terms of changes in both mobility and intrinsic carrier concentration due to piezo-effect of germanium bulk. A large increase in forward current with stress accompanied by the decrease in the apparent slope of ln I vs V plots is attributed to the stress-induced recombination-generation current due to large local stress at the junction.
A decrease in reverse current with uniaxial stress observed in heavily doped specimens is explained by the decrease in number of [111] light mass tunneling carriers due to piezo-effect.
Current Voltage Characteristics and Negative Resistance Phenomena in the Forward Direction of Si PIN-Diodes
Authors: Shohno Katsufusa
Published: November 2005

Negative resistance phenomena in forward biased Si wide pin-diodes with almost intrinsic region are observed at room temperature. Two different types of off-state VI-characteristics are observed. One type has four regions (ohmic, diffusion, ohmic, and avalanche breakdown) and the other has three regions (ohmic, “J∼V1/2”, and avalanche breakdown). The possible mechanism underlying negative resistance may be the conductivity modulation of i-regions due to the injection of minority carriers into bulk i-region from heavily doped layer or the ionization multiplication of carriers in the bulk i-region under the high electric field. The current on the on-state can be regarded as the usual diffusion current except for wide samples with Wi>500µ.
“Gonio-Microscope” and Its Metallurgical Applications
Authors: Taoka Tadami , Furubayashi Eiichi , Takeuchi Shin
Published: November 2005

A new instrument, Gonio-Microscope, has been developed which permits measurement of the direction of the normal to a plane surface with an area as small as 10×10µ2. The accuracy of the measurement is within ±0.5 deg. for a small component plane of an etch pit. A special feature of this instrument is that the measurement is made simultaneously with the observation of the position and shape of the plane being measured. This was successfully applied to the determination of grain orientation, structure of twin bands and slip bands, and the shapes of tapered cross sections of razor blades.