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Miki Watabe, Fumiaki Shibata
1990 Volume 59 Issue 6 Pages
1905-1908
Published: June 15, 1990
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A simple formulation of the path integral theory of Brownian motion is given on the basis of a stochastic differential equation. Besides a formal manipulation, a practical method is proposed to calculate the path integrals explicitly. To demonstrate the usefulness of the method, linear and nonlinear diffusion processes are treated and compared with analytical solutions.
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Kousuke Yakubo, Kouichi Takasugi, Tsuneyoshi Nakayama
1990 Volume 59 Issue 6 Pages
1909-1912
Published: June 15, 1990
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Supercomputer simulations are performed in order to reveal characteristic features of vector fractons excited on very large two-dimensional percolating networks. It is found that the frequency region of the crossover from vector to scalar fractons in the density of states is rather broad. It is also confirmed that the vector fracton dimensionality \ ilde
D is close to 0.79, in accord with the scaling prediction.
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Shigeki Tomishima, Naoshi Suzuki, Kazuko Motizuki, Hisatomo Harima
1990 Volume 59 Issue 6 Pages
1913-1916
Published: June 15, 1990
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LAPW band calculations are carried out for the non-magnetic and ferromagnetic states of transition-metal intercalation compound Mn
1⁄4TaS
2. It is clarified that the Mn 3
d states hybridize strongly with the Ta 5
dz2 state which extends along the
c-axis, but the hybridization with the S 3
p states is rather small. These results suggest that the Mn–Mn interaction via Ta atoms is strong along the
c-axis. The calculated total magnetic moment per Mn (MnTa
4S
8) is 4.35 μ
B, which is in agreement with the observed value 3.9∼4.2 μ
B.
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Tadaharu Shibuya, Tatsuo Hashimoto, Shin Takeuchi
1990 Volume 59 Issue 6 Pages
1917-1920
Published: June 15, 1990
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Electrical resistivities have been measured from 4.2 K to 300 K for single-grained decagonal quasicrystals of Al
70Ni
15Co
15. The conductivity is quite anisotropic; the resistivity along the
c-axis (crystalline direction) is 50 μΩcm at 4.2 K and has a positive temperature coefficient, whereas that along a direction perpendicular to the
c-axis (quasicrystalline direction) is as high as ∼1200 μΩcm at 4.2 K and also has a positive temperature coefficient in spite of the high resistivity.
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Akira Yamazaki, Jun Akimitsu, Hideaki Miyatake, Satoshi Okuma, Nobuhik ...
1990 Volume 59 Issue 6 Pages
1921-1924
Published: June 15, 1990
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We have observed antiferromagnetic ordering in the insulating phase (
x≥0.50) of the single-CuO
2-layer (per unit cell) Bi
2(Sr
1−xLa
x)
2CuO
6+y system. The Néel temperature increases from 10 K to 140 K with increasing La concentration. In this respect the system behaves like other high-
Tc copper oxide superconductors. In both
x=0.55 and
x=0.60 specimens, two hyperfine magnetic fields (45 G and 300 G) were observed at different μ
+ sites in the crystal.
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Nobuyoshi Hosoito, Satoru Araki, Ko Mibu, Teruya Shinjo
1990 Volume 59 Issue 6 Pages
1925-1927
Published: June 15, 1990
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Small-angle neutron diffraction measurements have been made for a multilayer, [Fe(27 Å)/Cr(12 Å)]×30, at room temperature. It was found that the magnetizations of adjacent Fe layers are coupled in antiparallel. The decrease of antiferromagnetic peak intensity as a function of external field was observed. It is confirmed that the giant magnetoresistance in Fe/Cr multilayers is due to the antiferromagnetic ordering of Fe layers caused by the interlayer coupling across an intervening Cr layer.
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Susumu Katano, Nobuo Môri, Hiroki Takahashi, Tamaki Kobayashi, J ...
1990 Volume 59 Issue 6 Pages
1928-1931
Published: June 15, 1990
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Neutron diffraction experiments have been carried out to study the effects of pressure on the antiferromagnetism in Pr
2CuO
4−y. The intensity of magnetic scattering is sensitively affected by pressure. This result is interpreted as the changes in the spin orientations induced under high pressure. In contrast, the three-dimensional (3D) ordering temperature
TN is little dependent on pressure. The absence of the pressure effect on
TN indicates a marked contrast to the large effect on
TN in La
2CuO
4−y.
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Isao Watanabe, Ken-ichi Kumagai, Yuki Nakamura, Haruo Nakajima
1990 Volume 59 Issue 6 Pages
1932-1935
Published: June 15, 1990
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We observed the temperature and the
x-dependence of the
139La-NQR spectra in magnetically ordered La
2−xBa
xCuO
4. The internal field at La nuclei increases discontinuously at
Tc*, where the nuclear relaxation rate is enhanced and shows its peak. This indicates that a successive magnetic transition occurs at
Tc* for
x<0.02. An asymmetry parameter of the electric quadrupole interaction changes anomalously at the magnetic transition. The magnetic phase diagram of the La-system is discussed.
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Fuminao Shimizu, Toshihisa Yamaguchi, Haruhiko Suzuki, Masaaki Takashi ...
1990 Volume 59 Issue 6 Pages
1936-1939
Published: June 15, 1990
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The phase transition sequence of a K
2ZnBr
4 crystal was investigated by DTA and dielectric measurements. It was found that the crystal undergoes at least two phase transitions, at −118°C and around 200°C, on heating. Ferroelectricity was observed below the lower transition point.
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Daisuke Takahashi, Jeffrey R. Sachs, Junkichi Satsuma
1990 Volume 59 Issue 6 Pages
1941-1953
Published: June 15, 1990
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Solutions of the “magma equation”,
ft=[
fn{(
f−mft)
x−1}]
x, are investigated for compact support initial conditions. It is shown analytically that traveling wave solutions with compact support do not exist for this equation. Numerical integration demonstrates that although initial conditions with compact support produce solitary waves, these solitary waves do not interact like solitons. Moreover, a relationship between the magma equation and the KdV equation is established, and this relationship is used to explain previously observed soliton-like behavior. Both equations are shown to be related to the modified magma equation,
FT+[
F3(3
FXX+1)]
X=0, which is proven to have
N-soliton solutions with compact support and an infinite number of conserved densities.
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Masao Nomura
1990 Volume 59 Issue 6 Pages
1954-1961
Published: June 15, 1990
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Various recursion relations are exploited for the Clebsch-Gordan (CG) coefficient of the quantum group
SUq(2). These are associated with four kinds of explicit forms for the CG coefficient of
SUq(2).
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Seido Nagano, Ichiro Hirosawa
1990 Volume 59 Issue 6 Pages
1962-1969
Published: June 15, 1990
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The method to exactly calculate the total
T-matrix from the
T-matrices of the non-overlapping scatterers in the elastic process has been developed. A wide variety of applications are expected since this method does not require the interaction potential to have any specific form. The present method is applied to the problem of the focusing of the electron scattering.
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Masakazu Ichiyanagi
1990 Volume 59 Issue 6 Pages
1970-1980
Published: June 15, 1990
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We continue our investigation of nonequilibrium statistical mechanics in which irreversibility comes out from contractions of microscopic informations about a macroscopic system. The hypothesis advanced by Machlup and Onsager that an extended entropy depends upon the fluxes is examined by applying the time-smoothing procedure proposed by the present author. Starting from this hypothesis and by using the previous method, the expressions for these fluxes are given. It is necessary to assume that an initially time-smoothed density matrix depends upon a particular set of dynamical operators
Aj and \dot
Aj=[
iH,
Aj]. The fluctuation-dissipation theorem is also discussed.
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Hidetoshi Suemitsu, Shinji Imai, Eiji Yoshida, Hiroaki Imanishi, Ichir ...
1990 Volume 59 Issue 6 Pages
1981-1986
Published: June 15, 1990
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The relative cross sections of the production of Cs
+ and Cs
2+ ions through the two-photon ionization of Cs
2 were measured in the 5300–6200 Å wavelength range. A linear polarized dye laser was operated in the CW mode as a light source. The results showed that (1) the cross sections for Cs
+ ions have a broad peak at around 5570 Å and the threshold at around 6010 Å, and (2) those for Cs
2+ ions have the largest peak at around 5940 Å and many structures in the wavelength range longer than it. Through consideration of the above results, we suggested that Cs
+ ions are produced not only by two-photon ionization of Cs
2, but also by a participation of a third photon. The threshold for Cs
+ ions at around 6010 Å is concerned with the intermediate excited-state Cs
2(C
1Πu+(
v′)), which can be excited from the ground state X
1Σg+(
v″=0).
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Toshio Kusakabe, Yoshihiko Mizumoto, Kousuke Katsurayama, Hiroyuki Taw ...
1990 Volume 59 Issue 6 Pages
1987-1994
Published: June 15, 1990
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Electron capture cross sections for C
+, N
+ and O
+ ions produced by controlled electron impact have been measured in collisions with H
2 and He targets at low keV energy region. It is found that the metastable state ions, if present, change significantly the observed cross sections and, in particular, the previously determined cross sections for C
+ ions colliding with H
2 targets are found to be mostly due to the metastable state ions instead of the ground state ions. More significant effects of the metastable state ions are observed in He targets.
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Masahiro Nakagawa
1990 Volume 59 Issue 6 Pages
1995-2004
Published: June 15, 1990
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Some numerical solutions corresponding to the chevron layer structure in compressible SmC
* phases are obtained in terms of the torque balance equations on the basis of a phenomenological elastic free energy including the layer compression energy as well as the
c-director deformation energy. Similar to the previously derived analytical solution (M. Nakagawa: Mol. Cryst. & Liq. Cryst.
174 (1989) 65), a soliton-like solution is found to exist as an equilibrium state in SmC
* phase. In addition the electric field effect on the layer structure and the
c-director configuration in the chevrons is presented taking account of the polarization electric field induced by the polarization charge.
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Kiwamu Sugisaki
1990 Volume 59 Issue 6 Pages
2005-2013
Published: June 15, 1990
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The Magnetohydrodynamic (MHD) stability of a free boundary toroidal Z pinch plasma is investigated. Equilibrium field profiles are chosen so that μ is nearly uniform in the central region, μ and dμ⁄d
r vanish on the boundary and Suydam’s criterion is satisfied throughout the plasma. The stability of the equilibrium is examined for the ratio
b of the conducting wall radius to the plasma radius and plasma pressure. The stability of non-resonant ideal modes is determined mainly from the safty factor on the axis. Non-resonant modes are dominant for low plasma pressure, whereas resonant modes are dominant for high plasma pressure. Tearing modes are stable only for
b below 1.04. The width of the magnetic islands produced from the tearing modes is evaluated. As
b increases, overlap of the magnetic islands occurs over a wide area in the plasma.
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Ryuzo Koyama
1990 Volume 59 Issue 6 Pages
2014-2019
Published: June 15, 1990
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The persistence length of wormlike polyelectrolyte chains in the salt-free solutions is calculated on the following two assumptions: (i) the strong electrostatic repulsion of chain segments interrupts the mutual encounter of their monomers within a distance much larger than the monomer dimension, and (ii) the small-angle scattering intensity at zero scattering angle vanishes, or equivalently the osmotic compressibility of the solution is zero. The latter condition is expressed with the radial distribution function
g2(
R) of the monomers on different polymers as,
N−1n∫(1−
g2(
R)) d
R=1
where
N is the total number of monomers in one polymer and
n is the number concentration of monomers. The calculated persistence length is proportional to
n−1⁄2 in very high monomer concentration and to (
n⁄
N)
−1⁄3 in very low monomer concentration.
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Hideo Nitta
1990 Volume 59 Issue 6 Pages
2020-2026
Published: June 15, 1990
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Based on the optical potential method, a formal theory of electron and positron channeling is developed by taking account of spinor factors. Starting with the Lippmann-Schwinger equation, a Schrödinger like equation for channeling states is derived which includes relativistic corrections and a non-local optical potential. From an iterative formula of the optical potential, absorption coefficients for channeled electrons and positrons and the line width in chauneling radiation can be calculated in a systematic manner. Radiation from channeled electrons and positrons is clearly interpreted in terms of the optical potential.
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Kozo Hoshino, Naoshi Matsuda, Mitsuo Watabe
1990 Volume 59 Issue 6 Pages
2027-2035
Published: June 15, 1990
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The density dependence of the structure of expanded liquid caesium is studied theoretically from the melting point up to its critical point along the liquid-vapour coexistence curve. The structure factor and the pair distribution function are calculated in the modified hypernetted-chain (MHNC) approximation on the basis of the effective pair potentials obtained by the pseudopotential theory with two types of empty-core potentials. It is shown that the experimentally observed characteristic features of the structural change with decreasing density are well reproduced theoretically. In particular, the density dependences of the first peak and the low
q behaviour of the structure factor and the coordination number are in good agreement with experiment.
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Jean-Paul Pouget, Seiichi Kagoshima, Tsuyoshi Tamegai, Yoshio Nogami, ...
1990 Volume 59 Issue 6 Pages
2036-2053
Published: June 15, 1990
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The anions of (TMTSF)
2ClO
4 order below about 24 K. The speed at which this transition is passed has a drastic influence on the low temperature electronic properties of this salt. We determined as a function of the cooling rate the number of ordered ClO
4 as well as the average size of the ordered domains. A high resolution X-ray synchrotron radiation study showed that this transition exhibited very unusual features probably due to the coupling of the anions with angular deformations of the Bravais lattice during the ordering process. We investigated also the kinetics of the Ising order parameter describing the anion ordering by a study of the temporal evolution of a superlattice reflection during thermal annealing of quenched samples.
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Tohru Morita
1990 Volume 59 Issue 6 Pages
2054-2063
Published: June 15, 1990
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Diagrammatical method is applied to a quantity which is related with the interface free energy, for the Ising model on the two-dimensional lattice under zero external field. We obtain a simple method of evaluating the interface free energy and the critical temperature for the systems satisfying some ordinary symmetry properties. The present result justifies the method proposed by Müller-Hartmann and Zittartz in 1977, for some of the cases for which the present method gives the exact interface free energy.
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Tomonari Dotera, Ryuzo Abe
1990 Volume 59 Issue 6 Pages
2064-2077
Published: June 15, 1990
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High temperature expansion for ln
Z(
Z: the partition function in the absence of a magnetic field) of the Ising model on the dual Penrose lattice is discussed. The terms up to
w10 are derived by using projection method. The critical compressibility factor
Zc and the average correlation function \bar
C are calculated in terms of duality relation. The final results are
Zc=0.0846±0.007 and \bar
C=0.7403±0.0024, which are confirmed by the expansion. Lattice constants are shown in some tables.
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Haruhiko Kurita, Yoshiyuki Ono, Yasushi Wada
1990 Volume 59 Issue 6 Pages
2078-2097
Published: June 15, 1990
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Acoustic component of lattice displacement field is investigated for a soliton and a polaron in Su, Schrieffer and Heeger’s Model for
t–(
CH)
x, using a perturbation method. Since this component has a small magnitude of the first order with respect to the ratio between the lattice constant and the soliton and/or polaron width, we take account of the higher order corrections to Takayama, Lin-Liu, and Maki’s continuum model. The perturbation calculations determine corrections to electronic wave functions as well as the lattice displacement. Phase shifts of the wave functions are determined to give the correction of the soliton creation energy which turns out to be small. It is not straightforward to proceed to the second order calculations. The difficulty is associated with a new localized state below the valence band. Obtained results are in agreement with numerical simulation works.
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Katsuhiko Takegahara, Tadao Kasuya
1990 Volume 59 Issue 6 Pages
2098-2109
Published: June 15, 1990
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One-electron energy band structures for La
2CuO
4, Ce
2CuO
4 and Th
2CuO
4 with the Nd
2CuO
4 type crystal structure were calculated by the self-consistent APW method with the local density approximation. The bonding-antibonding splitting between the Cu 3
d(
x2−
y2) and O 2
p states on the CuO
2 plane makes a pair of sub-bands. In La
2CuO
4, the Fermi energy cuts the middle of antibonding band resulting in the half-filled band. By replacing La with tetravalent Th, the Cu 3
d states raise due to the increase in the number of Cu 3
d electron but the bonding band made from Th 6
d(3
z2−
r2) state falls down. In Ce
2CuO
4, the Fermi energy cuts the bottom of 4
f bands. To raise the 4f states, a correction is introduced to the Ce potential and then Ce becomes nearly tetravalent resulting in similar band structure to that of Th
2CuO
4. By considering the strong correlation in the Cu 3
d(
x2−
y2) state, the doped electrons in Nd
2−xM
xCuO
4 (M=Ce, Th) are thought to be injected into the M
d(3
z2−
r2) bonding band.
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Jun-ichiro Inoue, Sadamichi Maekawa
1990 Volume 59 Issue 6 Pages
2110-2123
Published: June 15, 1990
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Dynamics of holes in the antiferromagnetic state on the square lattice is studied. The dispersion curves, density of states and eigenfunctions of holes are calculated by using the
t-
J and
t-
t′-
J models. It is found that the hole moves in the antiferromagnetic state being accompanied by spin distortion around it. The dispersion curves consist of almost continuous band and the low energy band splitting from it. The low energy band is caused by a motion of holes mediated by the quantum spin fluctuations and is rather sensitive to the sign and magnitude of the second near-neighbor hopping integral
t′. The spectra of the optical conductivity and the Raman scattering due to two spin excitations around holes are calculated and compared with the experimental results. It is shown that spectra in the mid-infrared region appear in both the optical conductivity and Raman scattering.
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Yasuzi Inada, Chikara Ishii
1990 Volume 59 Issue 6 Pages
2124-2133
Published: June 15, 1990
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The electronic structure of BaPb
1−xBi
xO
3 (BPB) is calculated in the framework of mean field approximation and coherent potential approximation, describing the electronic motion in terms of the extended Hubbard model with two kinds of site-dependent parameters; difference in the on-site energies on Bi and Pb sites and effective on-site interaction due to the oxygen breathing modes. Three characteristic band-shapes are obtained as a function of Bi concentration
x; a single band and pseudo-gapped band for metallic phase and two separated bands for semiconducting phase, indicating that
x plays a role similar to that of the temperature in the case of the Peierls instability. These results are successfully applied to interpret the main features of metal-semiconductor transition of BPB obtained from optical spectra.
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Chikara Sugiura
1990 Volume 59 Issue 6 Pages
2134-2140
Published: June 15, 1990
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With a high-resolution two crystal spectrometer, the palladium
Lβ
2,15 emission and chlorine
Kβ emission spectra in fluorescence are measured for square-planar complex compounds K
2PdCl
4, (NH
4)
2PdCl
4,
trans-[Pd(NH
3)
2Cl
2], [Pd(NH
3)
4]Cl
2·H
2O, K
2PtCl
4,
cis- and
trans-[Pt(NH
3)
2Cl
2]. The result is presented along with the palladium
LIII absorption-edge and chlorine
K absorption-edge spectra of these compounds, reported previously. The effect of the ligand replacement (
Remark: Graphics omitted.) is found in the both emission spectra. The effect of geometrical isomerism is observed in the chlorine
Kβ emission spectra of
cis- and
trans-[Pt(NH
3)
2Cl
2]. The palladium
Lβ
2,15 emission and chlorine
Kβ emission spectra are interpreted in terms of the molecular orbitals of square-planar complexes.
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Hiromi Kobori, Tyuji Ohyama, Eizo Otsuka
1990 Volume 59 Issue 6 Pages
2141-2163
Published: June 15, 1990
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Studies of the Cyclotron Resonance Line-Width (CRLW) in the quantum limit have been made for phonon scatterings in basic semiconductors (Ge, Si, CdS and InSb). The acoustic deformation potential scattering has been examined for Ge and Si, while the acoustic piezo-electric scattering for CdS. The effect of the inelastic scattering is enhanced in the quantum limit. Furthermore, the spontaneous acoustic phonon emission is clearly affecting CRLW. Temperature dependences of CRLW for deformation potential and piezo-electric scatterings are similar to each other. Difference, however, arises in the magnetic field dependence. With regard to polar optical phonon scatterings, it has been confirmed for InSb that CRLW is dominated by the absorption part.
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Hiromi Kobori, Tyuji Ohyama, Eizo Otsuka
1990 Volume 59 Issue 6 Pages
2164-2178
Published: June 15, 1990
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Cyclotron Resonance Line-Width (CRLW) has been studied in the quantum limit for impurity and carrier-carrier scatterings in Ge, InSb and GaAs. Ionized impurity and neutral impurity (electron-neutral donor and electron-neutral acceptor) scatterings have been examined with impurity scatterings. The dependences on temperature and magnetic field of CRLW for these two scatterings are similar to each other. From our experimental results it becomes clear that CRLW is approximately (1) independent of temperature and (2) proportional to the inverse of the square root of magnetic field. Electron momentum cross section by neutral acceptor is noted to be some orders of magnitude less as compared with that by neutral donor even in the quantum limit.
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Masaki Asano, Ritsu Tanaka, Shoichi Endo, Shigemi Wada, Satoru Noguchi ...
1990 Volume 59 Issue 6 Pages
2179-2182
Published: June 15, 1990
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The electric resistance of Ga
0.5Mo
2S
4 containing tetrahedral Mo-clusters was measured at high pressure up to 42 GPa and low temperature down to 2 K. The temperature coefficient of the resistance changed from negative to positive at 38 GPa, which indicates that metallization was induced with vanishing of the energy gap.
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Kenji Yonemitsu
1990 Volume 59 Issue 6 Pages
2183-2204
Published: June 15, 1990
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The dp model of the two-dimensional CuO
2 system is investigated for its superconductivity and normal state properties. The normal and snomalous self-energy parts of electrons are determined self-consistently through the RPA for the exchange of spin fluctuations. We determine both parts without assuming their momentum dependences. The normal self-energy part is approximated by a linear function of the frequency variable. Quantities derived from one-body Green functions are presented in several ratios of the on-site repulsion
U at copper
d orbital to the energy difference
Δ between copper
d and oxygen
p orbitals. Neighboring to the antiferromagnetic state,
d-wave superconductivity takes place. Momentum dependences of the normal and anomalous self-energy parts on the copper site are similar to those in the single-band Hubbard model.
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Natsuki Mori, Takayuki Kobayashi, Teruhisa Shimizu, Hajime Ozaki
1990 Volume 59 Issue 6 Pages
2205-2210
Published: June 15, 1990
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The fluctuation conductivity above
Tc (paraconductivity) in niobium thin films with normal-state sheet resistances
Rnsq of 20 to 300 Ω/sq was measured as a function of temperature. Results were analyzed in terms of the Aslamazov-Larkin and Maki-Thompson theories to determine values of
Tc and the pair-breaking parameter δ. These theories account well for experimental data at temperatures not too close to
Tc. Just above
Tc, there is evidence that δ strongly depends on the temperature. Relations among
Tc, δ and
Rnsq are discussed in the light of theories of weak localization effects on superconductivity.
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Ikuo Nakai
1990 Volume 59 Issue 6 Pages
2211-2215
Published: June 15, 1990
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We have performed magnetization measurements on FCC Fe–Ni alloys in the Invar region in magnetic fields up to 5.27 T at temperatures between 4.2 K and 320 K. An explicit expression of the magnetization is presented as a function of magnetic field
B and temperature
T, consisting of the renormalized spin wave contribution and the Stoner-type contribution varying with
ST2. The coefficient
S decreases with
B, which can be written as
S=
S0(1−
S1B). Above about 25 K the observed magnetization is well represented by the expression, while it shows an unusual behavior below 25 K.
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Hiroumi Ishii, Shingo Aoyama
1990 Volume 59 Issue 6 Pages
2216-2222
Published: June 15, 1990
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Magnetic field induced phase transitions are studied in a simplified model to represent systems with a crystalline field singlet ground state such as some rare earth compounds by the mean field approximation. In the case where the magnetic field yields the level crossing of the ground and excited states in the absence of the exchange interaction, then its presence brings two types of the phase transition. One of them is a second order transition accompanied with a polarization perpendicular to the field. This is a transition found by Tsuneto and Murao, and Tachiki and Yamada. Another is a first order transition, which occurs for the ferromagnetic coupling when the perpendicular susceptibility can not be large enough to yield a spontanous polarization. The system skips over the level crossing from the lower to higher magnetization states without change of symmetry. The condition and the nature of these transitions are investigated.
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Toshiya Matsuda, Kazuo Hida
1990 Volume 59 Issue 6 Pages
2223-2229
Published: June 15, 1990
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The ground state properties of the double layer quantum Heisenberg antiferromagnet are studied by the spin wave approximation. It is shown that the spin fluctuation decreases with the increase of the antiferromagnetic interlayer coupling
JK for small
JK, while it turns to increase for large
JK within the linear spin wave approximation. It is expected that the long range order is destroyed for large enough
JK indicating the possibility of the quantum disordered state. This mechanism of the destruction of the antiferromagnetic order contains no frustration and is of purely quantum origin. This model is also related to the highly doped limit of the coupled spin-fermion model of the high
Tc superconductors if the intralayer magnetic coupling in one of the layers is absent.
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Kazuo Hida
1990 Volume 59 Issue 6 Pages
2230-2236
Published: June 15, 1990
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The low temperature properties of the double layer quantum Heisenberg antiferromgnet are studied by the modified spin wave method proposed by Takahashi. As expected from the lowest order spin wave analysis, the spin fluctuation decreases with the increase of the interlayer coupling
JK for small
JK, while it turns to increase for large
JK for the antiferromagnetic
JK. The long range order is destroyed for large enough
JK. The disordered phase is the singlet gas phase. The low temperature behaviors of the spin-spin correlation length are also calculated and characters of the low temperature phase are discussed.
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Yukito Furukawa, Yutaka Nakai, Nobuhiko Kunitomi
1990 Volume 59 Issue 6 Pages
2237-2240
Published: June 15, 1990
Released on J-STAGE: June 01, 2007
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The internal field distribution for a Au
0.97Fe
0.03 spin-glass system is obtained from the Mössbauer absorption experiment using a relation between a hyperfine field and an internal field, which holds in the case of RKKY interaction. The obtained distribution is well explained with the stable distribution with the characteristic index α of 0.86. It is shown that the internal field distribution is close to Lorentzian but far from Gaussian distribution.
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Yasushi Amako, Takashi Naka, Masashige Onoda, Hiroshi Nagasawa, Tomoki ...
1990 Volume 59 Issue 6 Pages
2241-2250
Published: June 15, 1990
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The mechanism of magnetic and transport properties of the spinel phase Li
xZn
1−xV
2O
4 system was studied by using NMR technique. On the basis of
51V NMR, it was found that metallic-magnetic state of LiV
2O
4 and nonmetallic-nonmagnetic state of ZnV
2O
4 coexist in Li
xZn
1−xV
2O
4 system. The
X-dependence of the ratio between metallic-magnetic state and nonmagnetic state was determined and its origin was discussed. The
7Li NMR shift measurement suggested that there existed the preference of valency of vanadium ions depending on the nearest neighbor configuration of Li
+ ions or Zn
2+ ions. The metal-insulator transition of this system was understood in terms of the percolation effect of the metallic-magnetic vanadium ions.
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T\={o}ru Ozaki, Kazuya Furuta, Masanobu Ninomiya, Yoshio Yamazaki, Tom ...
1990 Volume 59 Issue 6 Pages
2251-2253
Published: June 15, 1990
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For KH
2PO
4 (KDP) and NH
4H
2PO
4 (ADP), the orientation of the optical indicatrix for NaD light (589 nm) has been determined in the low temperature orthorhombic phase, through the optical and X-ray measurements. For both KDP and ADP, the principal refractive indices,
na,
nb and
nc have been found to satisfy
na>
nb>
nc for Fdd2 cell in KDP, and for P2
12
12
1 cell in ADP. Both crystals are optically negative and the
c axes are the acute bisectrices with the optical axial angle 2
Ω=61° in KDP at 90 K and 2
Ω=20° in ADP at 122 K. The {110} twin of ADP observed in the low temperature phase has been found to form the rotation twin with the two fold axis normal to the {110} twin boundary.
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Joo-Sin Lee, Noboru Miura, Tsuneya Ando
1990 Volume 59 Issue 6 Pages
2254-2273
Published: June 15, 1990
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Free carrier effects on the absorption and photoluminescence spectra were extensively investigated in
n-type modulation-doped GaAs–Al
xGa
1−xAs multi-quantum wells in pulsed high magnetic fields up to 40 T. The magneto-optical spectra were measured as a function of temperature. Near the absorption edge, we have observed anomalous sharp peaks which have different temperature and magnetic field dependence from the ordinary excitons. The nature of the anomalous peaks is discussed in terms of the Fermi edge singularity. The oscillatory magneto-optical spectra are analysed based on the Landau levels in the
n-type quantum well potential.
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Kaoru Ohya, Jun Kawata, Ichiro Mori
1990 Volume 59 Issue 6 Pages
2274-2282
Published: June 15, 1990
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The dependence of secondary electron emission from copper on the incident angle of the keV primary electron is investigated by using Monte Carlo techniques not only for the collision process of the primary electron in material, but also for that of the secondary electron, the ‘cascade’ process. The energy dependence of the secondary electron yield largely changes with the incident angle, while the energy and angular distributions of secondary electrons emitted in vacuum are rather insensitive to the angle, which is consistent with some experimental results. The cascade process reduces the dependence of secondary electron yield on the incident angle, which varies as an inverse cosine of the angle measured from the normal to the surface for high energy, although the effect of the cascade process is smaller than that of the collision process of the primary electron for keV energy.
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Akira Suzuki, Sakuo Matsui, Hikaru Inoue, Yasukazu Yoshizawa
1990 Volume 59 Issue 6 Pages
2283-2284
Published: June 15, 1990
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Takayuki Shirakura, Fumitaka Matsubara, Sakari Inawashiro
1990 Volume 59 Issue 6 Pages
2285-2286
Published: June 15, 1990
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Yasuzi Inada, Chikara Ishii
1990 Volume 59 Issue 6 Pages
2287-2288
Published: June 15, 1990
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Noriaki Okubo, Hajime Matsuura, Yoshihito Abe
1990 Volume 59 Issue 6 Pages
2289-2290
Published: June 15, 1990
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Masaaki Takashige, Fuminao Shimizu, Haruhiko Suzuki, Shozo Sawada
1990 Volume 59 Issue 6 Pages
2291-2292
Published: June 15, 1990
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Haruyasu Yamashita, Toshirou Yagi, Akira Onodera, Y\={o}ichi Shiozaki
1990 Volume 59 Issue 6 Pages
2293-2294
Published: June 15, 1990
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Yasuzi Inada
1990 Volume 59 Issue 6 Pages
2295-2296
Published: June 15, 1990
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Hideo Takeuchi, Masanori Arakawa, Hiroshi Ebisu
1990 Volume 59 Issue 6 Pages
2297
Published: June 15, 1990
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