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Kazunari Hori, Shozo Takeno
1992 年 61 巻 12 号 p.
4263-4266
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
The existence of two branches of moving anharmonic localized modes is shown for a one-dimensional (1D) lattice with hard quartic anharmonicity. By the use of a pair of exactly solvable model nonlinear lattice equations as a reference system, approximate analytical expressions for envelope functions, the eigenfrequencies and the velocities of low- and high-frequency modes are obtained for each of envelope-kinklike modes and envelope-solitonlike modes. The approximate analytical results are tested by numerical experiments to show that these two branches of the modes are robust against generation at initial stages of ripples, eventually preserving their own profiles as time evolves.
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Sumio Kogoshi, Tetsuya Abe, Goh Fujikawa, Makoto Katsurai
1992 年 61 巻 12 号 p.
4267-4270
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
The idea of the higher harmonic modulation on helical coils may provide another possibility for improvement in a helical system’s magnetic properties such as the formation of a local magnetic well. The higher harmonic modulation on
L=1 Heliotron/Torsatron coil can approximately reproduce one of the optimized helical heliac coils and its vacuum magnetic properties such as a deep magnetic well.
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Lu Bang, Hiroshi Maeta, Norimasa Matsumoto, Fumihisa Ono
1992 年 61 巻 12 号 p.
4271-4274
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
Measurements of X-ray diffuse scattering have been made on a disordered Fe-34.2 at% Pd Invar alloy in a temperature range from 18 K to room temperature, where no abnormal change in lattice parameters other than the Invar effect has been observed and the fcc state has been reported to be preserved. Strong diffuse scatterings were observed at the lower temperatures in the plane perpendicular to the a axis around the 200 lattice point. This result indicates an increase in lattice strain induced by a shear stress with decreasing temperature, suggesting the existence of a very early stage of the premartensitic transformation.
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Yasutami Takada
1992 年 61 巻 12 号 p.
4275-4278
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
In order to study the interplay of the electron-electron repulsion with the periodic electron-ion interaction in determining charge and spin responses of solids, the compressibility and the spin susceptibility in units of free-electron values, κ⁄κ
F and χ⁄χ
F, are calculated at zero temperature for Na and K. At zero pressure, the spin response dominates over the charge response as indicated by the relation χ⁄χ
F>κ⁄κ
F. However, as the electronic density decreases, the relation reverses and κ diverges eventually. Implication of this result is discussed in relation to superconductivity and ferromagnetism.
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Hiroyuki Yamaguchi, Taizo Masumi
1992 年 61 巻 12 号 p.
4279-4282
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
We have studied pulsed photoconductivity
Q(
T, λ) of undoped solid C
60 at
T=4.2∼300 K and λ=355∼780 nm. An observation of the Dember effect at λ=355 nm indicates that dominant photocarriers are electrons. At 250 K, we observed a significant anomaly in
Q(
T, λ) at the structural phase transition (from sc to fcc) due to the orientational order-disorder transformation. This suggests that the mechanism of photoconductivity sensitively reflects the change of electronic structure due to rotational motion of C
60 molecules. We have also recognized the critical energy gap at 2.0 eV in pulsed photoconductivity of undoped C
60 via the temperature dependence of
Q(
T, λ) above 250 K excited at various photon energies.
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Manfred Sigrist, T. M. Rice
1992 年 61 巻 12 号 p.
4283-4286
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The paramagnetic effect found experimentally in some granular high temperature superconductors is explained by a model of a Josephson network of
d-wave superconductors. The unusual microwave absorption characteristics of these systems is also explained in a consistent way. Finally, a new experiment is proposed to give a decisive test for
d-wave superconductivity in high
Tc superconductors.
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Takeshi Hanawa, Masayasu Ishikawa, Kazuo Miyatani
1992 年 61 巻 12 号 p.
4287-4289
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
Specific heat, magnetic susceptibility, and
M-
H measurements of CoNb
2O
6 revealed that the compound exhibits two successive phase transitions at 2.9 K (=
T1) and 1.9 K (=
T2): at
T1, long-range ferromagnetic order sets in, but below
T2, the ferromagnetism vanishes and recovers in applied fields higher than about 500 Oe.
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Yukio Saito, Ryota Morikawa
1992 年 61 巻 12 号 p.
4290-4293
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
A hard-rod system with a shadowing interaction is proposed to model the hydrophobic interaction between amphiphilic molecules. Monte Carlo simulations in two dimensions show that these hard rods form a stable ring vesicle at low temperatures. From the mode analysis of the shape fluctuation of the vesicle, the bending rigidity is estimated microscopically.
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Yasuhiro Ohta, Akira Nakamura
1992 年 61 巻 12 号 p.
4295-4313
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
We consider the “similarity KP equation” written as (d⁄d
x)
3u(
x)+6
u(
x)(d⁄d
x)
u(
x)−4
x(d⁄d
x)
u(
x)−2
u(
x)=0 which can be obtained from the KP equation by assuming the similarity solution form. We have investigated the structures of the solutions of this equation and have shown that they can be expressed by four different forms (representations) which are (i) two-directional Wronskian type, (ii) Gramian type, (iii) pfaffian type, and (iv) Wronski-Gram mixing type. For each of these cases (i) to (iv), the analytic proofs of the solutions have been presented.
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Tsuyoshi Ueta
1992 年 61 巻 12 号 p.
4314-4324
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
It is shown that the Green function for a charged particle in a uniform magnetic field is resolved into the gauge dependent exponential factor which breaks the translational symmetry and the translationally symmetric gauge independent function even if the system contains periodic potential. In the absence of the periodic potential, several exact expression for the Green function is derived. The method for numerical calculation is presented as well as an example of application to a practical problem.
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Hiromu Ishio
1992 年 61 巻 12 号 p.
4325-4335
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
A soliton-gas model is proposed to describe the orderly energy-level structures in quantum chaos. By diagonalizing the model Hamilton matrix, we show that our model leads to the transition from Poisson to GOE-like level-spacing distribution in the small spacing regime and that this transition depends on both the soliton density and the fluctuation of acceleration induced by collisions of solitons. Fitting of
spectral rigidity(what is called
Δ-statistics) in the transition regime to a theoretically proposed one is also carried out. In this case, it does not come to fit to the Gaussian orthogonal ensemble prediction. This can be considered to reflect the coherent nature of solitons lying behind the irregular spectra. Reflecting the fact that the number of levels is large, saturation of the rigidity is not observed. In addition, we discuss a possibility of applying our model to the recent experiment on diamagnetic Rydberg atoms.
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Hiroaki Ono
1992 年 61 巻 12 号 p.
4336-4343
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Based upon the preyiously derived equation, which includes as special cases the inhomogeneous KdV and MKdV equations, the lattice soliton propagation under the finite but gentle inhomogeneity is re-examined. It is shown that such inhomogeneity does not generate the reflected waves in the lowest order approximation to the original continuum lattices. In addition to a gradual mass interface, for several kinds of mild inhomogeneities, explicit formulae giving the number and the amplitude of solitons appearing from fission are obtained.
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Takeshi Iizuka, Miki Wadati
1992 年 61 巻 12 号 p.
4344-4349
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Scatterings of nonlinear lattice waves by a mass impurity are studied. The waves are assumed to be nonlinear modulations of the monochromatic waves. Due to the impurity there appear the incident, reflected and transmitted waves. We show that the three waves are described by independent Nonlinear Schrödinger (NLS) equations respectively. Using the continuity conditions of the waves at the impurity site, we analytically construct the transmitted and reflected waves from the incident wave. As an application, scattering of an incident NLS envelope soliton is investigated. We find that at most one soliton is generated both in the reflected wave and in the transmitted wave.
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Katsuya Honda, Hidekazu Tangi, Mitsugu Matsushita
1992 年 61 巻 12 号 p.
4350-4355
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
We propose a multifractal formalism to analyze a self-similar fractal pattern consisting of fractal fragments which may have distributed dimensions. To characterize statistical and geometrical structure of the entire pattern, the function
f(
D) is introduced, which plays a similar role to the singularity spectrum of multifractal patterns. As the first application, we analyze a collection of contour lines generated by cutting a self-affine Brownian surface at an average level. We clarify with an aid of model consideration that the fractal dimension of every single line should be unique and
f(
D) consists of only two points corresponding to each contour and the entire pattern, respectively. On the other hand, the continuous
f(
D) is clearly found for each cluster in a kind of cluster-cluster aggregation model applied as another example. The maximum of
f(
D) is associated with the size distribution of the clusters.
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Adam Lipowski, Masuo Suzuki
1992 年 61 巻 12 号 p.
4356-4366
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
A transfer-matrix version of a mean-field approximation is proposed which leads to the exact critical temperatures for the
S=1⁄2 Ising model on the square, triangular, honeycomb, and centered square lattices. The estimations of critical temperatures for more complicated models are also shown to be very accurate.
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Toshio Fukuta, Masaru Sugiyama
1992 年 61 巻 12 号 p.
4367-4380
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Continued from the preceding paper of the present series, the linear-wave-analysis is made on the basis of the evolution equations for nonequilibrium phenomena in anharmonic lattices, which were proposed in the first paper of the series. Firstly a general method of describing the nonequilibrium phenomena is discussed, and then, by using the method, dynamical features of the phenomena are investigated in detail through the study of four examples with typical initial nonequilibrium states. Dispersiveness of wave propagations is taken into account in the first and the second examples, but is not in the third and the fourth ones in which continuum approximation to the lattices is adopted. The first and the third are examples with typical mechanical initial states, and the second and the fourth with typical thermal ones. The local equilibrium assumption is also discussed in connection with the latter two examples.
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Mitsugu Fujinohara, Cheol Ho Kim
1992 年 61 巻 12 号 p.
4381-4389
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The system considered is a one-dimensional growing model that exhibits the capturing process of particles with an attractive interaction potential between the lattice edge particle and the incident particles. The zero temperature-one particle capturing model hitherto well known is extended to a general case of an arbitrary temperature-many particle capturing model. The equations of motion of the system are derived and their exact solution is obtained. It is assumed that the relative displacements and momenta of the particles in the system are normally distributed as in a steady state. Obtaining the explicit expressions for the sticking probabilities and the growth rates at the edge of the lattice as the solid-surface, their numerical estimations vs various parameters are illustrated. The results are compared with experimental data.
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Masahiro Nakagawa
1992 年 61 巻 12 号 p.
4390-4399
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
In this work a set of dynamic equations to study the elastic properties of the smectic phases is formulated explicitly on the basis of the elastic continuum theory of compressible smectics previously formulated. In this framework, the polarization electric field is consistently taken into account through the Poisson’s equation with a polarization electric charge. Then a few numerical results are presented for the surface-stabilised geometry with a bent and a chevron layer structures. It is explored that a bistable switching can be achieved even in the chevron layer structure while it is accompanied with a certain distortion under an alternative high external field. In addition it is first presented in a theoretical aspect that the compressible smectic layer structure may be drastically deformed under such a relatively high electric field and with a sufficiently small molecular tilt angle.
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Shigeo Kida, Mitsuru Tanaka
1992 年 61 巻 12 号 p.
4400-4417
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The spatial structure of the Reynolds shear stress in a uniform shear turbulence is investigated by the direct numerical simulation of Navier-Stokes equations and by the rapid distortion analysis. It is observed that many thin vortex tubes of various shapes develop from a random initial velocity field. The Reynolds shear stress also has tube-like structure and takes especially large values between pairs of counter rotating vortices aligned in the spanwise direction as was revealed before by conditional averaging (Adrian & Moin 1988). The turbulent kinetic energy increases exponentially in time as has been observed in laboratory experiments. The rapid distortion analysis demonstrates that the tube-like structure can be created only through the linear interaction of the turbulent velocity with the mean strain, leaving the velocity field be Gaussian. The organized structure does not necessarily imply non-Gaussianity of the velocity field.
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Masaru Shinohara
1992 年 61 巻 12 号 p.
4418-4424
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
A theoretical study has been made of the lateral velocity of a small sphere sedimenting in the axial direction with a velocity
U in a viscous fluid inside a vertically oriented circular cylinder. The ratio ε of the particle diameter 2
a to the cylinder diameter 2
L, and the particle Reynolds number
Re(=
Ua⁄ν) are assumed small. The cylinder Reynolds number
RL(=
UL⁄ν=
Re⁄ε), however, is assumed finite. Lateral velocity of first-order in
Re are obtained taking into account of the first-order effects of boundaries. Method of matched asymptotic expansions is used, in which the wall is assumed to be in the outer region of expansion.
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Nobuaki Ikuta, Eiji Nishi, Sadanojo Nakajima
1992 年 61 巻 12 号 p.
4425-4442
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Transport properties and velocity distributions of atomic ions in model atomic gases have been analysed over a wide range of reduced electric field using the flight time integral (FTI) method. Isotropic scattering in the center of mass frame was assumed for the determination of ion speed after collision. The FTI analyses were carried out for two model cases of constant collision frequency (CCF) and constant collision cross section (CCS) with the assumption of isotropic scattereing in the laboratory frame. In both the CCF and CCS, the transport properties show regular changes from the low field thermal region to the high field
E⁄
N dependent region. Zero field mobilities, temperature and
E⁄
N dependences of transport properties for CCF and CCS conditions are discussed. The velocity distributions as functions of ion velocity components in the field direction for various temperatures and
E⁄
N values are compared.
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Masayoshi Taguchi
1992 年 61 巻 12 号 p.
4443-4448
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
The expression for the bootstrap current density due to fusion-produced alpha particles is derived in an axisymmetric plasma by solving a drift kinetic equation in the presence of both drag and pitch-angle scattering. From this expression the alpha-particle induced bootstrap current for a D–T plasma is explicitly evaluated in a tokamak with circular cross-section. The evaluated results show that the ratio of this bootstrap current to that due to bulk particles does not become a large value for burning plasmas presently considered. However, the use of this bootstrap current for current profile control and a seed current for a steady-state tokamak may be possible.
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Gopalraja Praburam, Masao Sugawa
1992 年 61 巻 12 号 p.
4449-4451
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Wong and Bellan have observed the enhancement of drift waves by externally launched lower hybrid waves in a Q-machine. We explained these results semi-quantitatively by deriving the dispersion relation of the drift waves, incorporating the ohmic heating of electrons.
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Yasuo Murai, Tohru Morita
1992 年 61 巻 12 号 p.
4452-4464
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
A two-dimensional ANNNI model is investigated by an approximation method by Morita, which will be called the Scanning Line Method. Numerical calculation is performed by using a set of recurrence equations for effective fields and interactions. The modulated phase obtained is a genuine incommensurate phase and is characterized by a single wave number and its higher harmonics. Our numerical results are compared with those in earlier papers.
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Fuyuki Shimojo, Hideo Okazaki
1992 年 61 巻 12 号 p.
4465-4473
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The fcc-bcc phase transition of the Te sublattice in superionic conductor Ag
2Te is investigated by means of a constant temperature and constant pressure molecular dynamics simulation with Coulomb and soft-core potentials. As the temperature increases, a gain of the Coulomb energy in the low temperature fcc phase decreases with increasing the residence time of Ag ions in the octahedra, and then the transformation into the bcc phase takes place so as to make the configurational entropy increase. The phase diagram of the Coulomb and soft-core system is studied by varying both the temperature and the pressure. It is shown, by using the scaling properties of the system, that the reversible fcc-bcc phase transition appears only in a delicate balance between the Coulomb potential and the soft-core potential.
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Masaru Aniya
1992 年 61 巻 12 号 p.
4474-4483
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
The bonding nature of the superionic material AgI is studied by using a pseudopotential theory. The result is compared with that for GaAs, which is a well-known semiconductor. It is found that the real space valence electron distribution between these compounds differs qualitatively, and that the bonding in AgI is determined mainly by the iodine. It is also suggested that the local electronic excitations from the bonding to the antibonding orbitals can trigger the migration of the mobile species, initiating in this way the superionic transport.
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Takuma Ishikawa, Tadao Ishii
1992 年 61 巻 12 号 p.
4484-4489
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The frequency dependence of ionic conductivity σ(ω) in a one-dimensional hopping-model system is investigated by means of the pair-approximation of the path probability method (PPM) and the Monte Carlo simulation (MCS), where the MCS-method in calculating σ(ω) is developed. Comparative study of the two methods elucidates that the PPM correctly reproduces σ(ω) obtained by the MCS in the case of non-interacting ions, but it deviates in the case of strongly interacting ions.
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Fusayoshi J. Ohkawa
1992 年 61 巻 12 号 p.
4490-4501
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The Hubbard model is studied for its paramagnetic phase. The leading-order effects in 1⁄
d are Kondo-effect-type local spin fluctuations, with
d being the spatial dimensionality. For
d→+∞, a “local” Kondo temperature is defined to show an energy scale of the local spin fluctuations or the strength of the Kondo effect to quench magnetic moments. Even for finite
d, the local Kondo temperature is still unambiguously defined through the mapping to the Anderson model. It is so renormalized as to increase by intersite and critical spin fluctuations, which are of higher order in 1⁄
d. The renormalization of the local Kondo temperature can play crucial roles in the suppression of magnetism, the occurrence of high-temperature superconductivity, and the occurrence of metamagnetism in the presence of magnetic fields. The above results generally apply to strongly correlated electron liquids.
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Nozomi Orita, Komajiro Niizeki, Koichi Shindo, Hiroshi Tanaka
1992 年 61 巻 12 号 p.
4502-4510
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The band structures of solid iodine under ambient pressure and 15.3 GPa were calculated with the
ab initio pseudopotential method. The apparently complicated band structures have been resolved by a detailed analysis, revealing the mechanism of the band overlap which causes the pressure-induced insulator-to-metal transition: The interlayer interaction as well as the interaction between the third-nearest neighbor atoms is responsible for the band overlap. The effect of the spin-orbit interaction on the band overlap is also discussed.
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Yasuzi Inada, Keiichiro Nasu
1992 年 61 巻 12 号 p.
4511-4520
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Superconducting transition temperatures of a many-electron system coupled strongly with anharmonic phonons have been studied, to clarify how drastically anharmonicity changes the isotope effect from the harmonic case. The diagonal self-energy of electron as well as the off-diagonal one is determined self-consistently within Migdal’s approximation. Typical two types of anharmonicities are studied. The first is a sextic anharmonicity induced by a hard-core repulsion. Isotope shifts become almost zero in this case. When this repulsion is stronger, the shifts are reversed. The second is a small negative quartic anharmonicity in addition to the sextic one, just in the case of a mixture of a hard-core and a soft one. In this case, on the contrary, the shifts are greatly enhanced. Discussion is also given in relation to the observed anomalous isotope effects of newly discovered superconductors.
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Fusayoshi J. Ohkawa
1992 年 61 巻 12 号 p.
4521-4535
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Anisotropic superconductivity of strongly correlated electrons is studied in the 1⁄
d expansion, with
d being the spatial dimensionality. Kondo-effect-type local spin fluctuations are of the leading order in 1⁄
d. They are responsible for the formation of Gutzwiller’s heavy electrons. Superconductivity is of higher order in 1⁄
d. The superexchange interaction causes superconductivity of
s or
dγ wave, while a three-site exchange interaction causes that of
s or
p wave. Within the mean-field approximation which is one of the simplest schemes of the 1⁄
d expansion, the highest critical temperature is obtained for
dγ wave, two dimensions, and almost half filling where the effective mass of heavy electrons is large and the three-site exchange interaction is relatively ineffective through the enhancement of vertex functions for spin channels. An argument is given in connection with high-
Tc superconductivity in the cuprate oxides.
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Chihiro Sekine, Toshiro Sakakibara, Hiroshi Amitsuka, Yoshihito Miyako ...
1992 年 61 巻 12 号 p.
4536-4546
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Magnetic susceptibility, magnetization and specific heat measurements have been performed on single crystalline Ce(Ru
1−xRh
x)
2Si
2 in the Ru rich region(0≤
x<0.5) with a special interest in the small Rh substitution effects on the Kondo temperature
TK, the antiferromagnetic (AF) correlation and the metamagnetic transition in CeRu
2Si
2. Phase diagrams are obtained in both
x-
T and
H-
T planes with fields applied parallel to the tetragonal
c-axis. At low Rh concentration,
TK decreases with
x and a weak AF ordering (
TN≤5.5 K) appears in the region 0.05<
x<0.30. The metamagnetic transition field
HM decreases with
x, leveling off and disappearing above
x=0.20. This metamagnetic transition clearly exists in the AF ordered samples, where two successive transitions are observed in fields at
HC(<4 T) and
HM(>5 T). The AF ordering is destroyed above
HC and the system further undergoes a metamagnetic transition at
HM.
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Shozo Takeno, Kazuko Kawasaki
1992 年 61 巻 12 号 p.
4547-4558
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
A path integral theory in the SU(2) coherent state representation of elementary excitations in Heisenberg antiferromagnets is developed, in which no assumption is made on the smallness of spin deviations from the Néel state. Use of the stationary phase approximation leads to the Lagrangian equations in which the nonlinearity intrinsic to the magnon system is fully included at the cost of neglecting quantum fluctuations in the coherent state basis. Full nonlinear equations so obtained are of a simple renormalized form in the boson coherent state path integral formulation using the Dyson-Maleev transformation. The formal theory is illustrated to show the existence under certain conditions of self-localized magnons below the linear magnon energy band and of vortex-like modes in two-dimensional cases.
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Toru Shigeoka, Hironobu Fujii, Masakazu Nishi, Yoshiya Uwatoko, Toshir ...
1992 年 61 巻 12 号 p.
4559-4565
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
We studied magnetic properties in the TbNi
2Si
2 single crystal compound by magnetic and neutron diffraction measurements. The magnetic moments born on only Tb are fixed to the
c-axis due to a strong crystalline electric effect. The compound undergoes a commensurate-incommensurate phase transition at
Tt=7.9 K; the commensurate phase with
k=[1⁄2, 1⁄2, 0] is stable below
Tt, and above
Tt, the incommensurate one with
k=[1⁄2+τ, 1⁄2−τ, 0] (τ=0.074) appears and persists up to
TN=14.6 K. A multi-step metamagnetic transition was found in the low temperature
c-axis magnetization process in which at least nine magnetic phases appear. This process is a typical example of “the devil’s staircase” in real compounds.
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Tetsutaro Inoue, Kiyohiro Sugiyama, Tetsuya Takeuchi, Manabu Nakahanad ...
1992 年 61 巻 12 号 p.
4566-4571
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
High field magnetizations of three Cr-dimer complex powders, [Cr
2(acac)
4(4-X-phO)
2] (X=H, Cl, CH
3), are investigated up to 60 T at 1.3 K, and successive multistep metamagnetizations are found. They are explained by the model that two Cr
3+ ions with spin
S of 3/2 form an antiferromagnetic dimer with the singlet ground state and that the successive crossovers with the excited
S=1, 2 and 3 states occur under increasing magnetic field. Biquadratic exchange interaction should also be taken into account. Additional fine structures are observed and attributed to two kinds of dimers. Main exchange parameters of μ-Cl-, H- and CH
3-phO complexes are determined as −12.0 K, −11.4 K and −14.7 K, respectively. These values are in good agreement with the magnetic susceptibility data.
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Naokazu Shibata, Ryousuke Shiina, Chikara Ishii
1992 年 61 巻 12 号 p.
4572-4576
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
The effective RKKY coupling constants are derived from the one dimensional 22-site Anderson lattice model with various band fillings in the fourth order perturbation with respect to
d-
f mixing element, assuming that the other parameters belong to the Kondo regime. The resulting RKKY lattice model has been exactly diagonalized in terms of Lanczos method. The ground state
f-spin correlation functions are studied in detail. It is shown that a long range correlation is stabilized in the case of general filling of conduction band compared to the nearest-neighbor antiferromagnetic Heisenberg model, reflecting the coherent nature of RKKY coupling based on the Anderson lattice model.
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Kohei Murao, Fumitaka Matsubara, Sakari Inawashiro
1992 年 61 巻 12 号 p.
4577-4582
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
The magnetization process of a quasi-one-dimensional antiferromagnet CsCoCl
3 is analyzed by the Monte Carlo simulation combined with the diagonalization technique. We explained the step and the hysteresis loop of the
M-
H curve observed experimentally together with the magnetization process characteristic to a one-dimensional Ising-like antiferromagnet at higher magnetic fields. Although the interchain interaction
J1 is about 1% of the intrachain interaction
J, it is essential for reproducing those features.
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Yutaka Nakai
1992 年 61 巻 12 号 p.
4583-4588
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
A new method to evaluate distribution functions of electric field gradients in solids from Mössbauer absorption spectra is proposed. The spectrum is expressed by a formula whose denominator and numerator are polynomials of Doppler velocity
v. The application to an amorphous substance shows that very few terms of the polynomials are required to reproduce the observed spectrum. The obtained distribution function was given by the sum of two Lorentz distributions.
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Yukikuni Akishige, Yoshio Kamishina
1992 年 61 巻 12 号 p.
4589-4595
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Electric field effects on the dielectric constants ε in the mixed crystals, (RS)
1−x(ARS)
x where
x is from 0 to 0.025, have been studied in the temperature range between 220 K and 320 K. The temperature region of the ferroelectric phase narrows as the NH
4 content increases, and at around
x=0.023 the two critical points merge into one. Interestingly, the ε diverges at the point
Tc as ε∝1⁄(
T−
Tc)
2 and the ε vs
T curve changes from a single peak to a twin peak under a dc electric field
E. As the field strength increases, the two peaks shift to opposite directions and the maximum value of the dielectric constant steeply decreases. On the other hand, electric field effects on the ε in the pure RS crystal are understood as those of typical ferroelectrics.
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Kenro Nakamura, Wataru Kinase
1992 年 61 巻 12 号 p.
4596-4614
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The successive cubic-tetragonal-orthorhombic-rhombohedral phase transitions in BaTiO
3 are discussed quantitatively from the microscopic free energy based upon the mean field approximation, where the Ti ions shift in the lattice having the spontaneous deformation. It is shown that the effect of the spontaneous lattice deformation is essential to the appearance of the ferroelectric three phases and the experimental values of the transition entropies are well explained by this model of the displacive-type concerning the Ti ions.
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Makoto Iwata, Yoshihiro Ishibashi
1992 年 61 巻 12 号 p.
4615-4618
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
Measurement of the dielectric constant and optical observation of domain structure in (CH
3NH
3)
5Bi
2Cl
11 have been carried out in the temperature range including 170 K, which has been regarded as a transition temperature. No indication of any phase transition was obtained near 170 K. Temperature dependence of the dielectric constant in this temperature range has been explained applying the Landau theory.
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Kozo Okada, Akio Kotani
1992 年 61 巻 12 号 p.
4619-4637
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
We theoretically investigate X-ray photoemission spectra (XPS) from transition metal 2
p and 3
s core levels in late transition metal compounds in terms of an MX
6 cluster model (M=Mn∼Ni; X=halogen or oxygen), paying particular attention to the interplay between the intra-atomic multiplet coupling and covalency mixing effects. In the analysis of 3
s-XPS, we also take into account the intra-atomic configuration interaction between 3
s13
p63
dn and 3
s23
p43
dn+1 electron configurations. The systematic change of 2
p-XPS and 3
s-XPS on going from Ni to Mn compounds or from fluorides to bromides is mainly ascribed to that of the charge transfer energy from X to M ion. In the analysis, we show that the final state effects are very important in the 3
s-XPS as well as in the 2
p-XPS.
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Tadahiko Harami
1992 年 61 巻 12 号 p.
4638-4642
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Optical absorption, luminescence and ESR of
V-type centers have been studied for KI crystals containing excess iodine. Colored crystals were irradiated previously with
V3 light at liquid nitrogen temperature (LNT) to convert the primary
V centers into other
V-type centers. Dichroism is induced in the absorption bands of the crystal at around 420 and 800 nm by irradiation with the [110]- or [100]-polarized light. ESR spectrum of 11 equally spaced lines is detected at LNT under a magnetic field along a [110] axis of the crystal. Absorption bands, luminescence and ESR lines due to these centers disappear at temperatures above 110 K and original
V centers recover in pure KI crystals. We conclude that
VK and
VL centers are generated simultaneously by the optical bleaching of the primary
V centers.
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Takao Tsuboi, Masaaki Kamei, Katsuhiko Kobayashi, Yoshitaka Ikuta
1992 年 61 巻 12 号 p.
4643-4649
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
The time-history of particle-diameter and number density of acetylene soot produced in gas phase in the reflected shock wave were obtained from light absorption signals of two He–Ne-lasers (λ=3.39 μm and 0.6328 μm). The observed diameter was between 0.1 and 0.4 μm. The phase change temperature of soot for various vapor pressure (initial pressure of acetylene) was obtained from the simplified model for soot formation. From this temperature the latent heat and the surface tension of acetylene soot were estimated from the simplified model for soot production. The values were 710 kJ/mol for the latent heat and 3300 dyne/cm for surface tension.
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Yoshihiro Ishibashi, Hiroshi Orihara
1992 年 61 巻 12 号 p.
4650-4656
発行日: 1992/12/15
公開日: 2007/06/01
ジャーナル
認証あり
Ferroelectric switching times are theoretically discussed and found to depend upon the sample size. If the switching time is measured using the switching current transient, it becomes shorter with decreasing sample size.
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Kazuyuki Itoh, Takaaki Ukeda, Eiji Nakamura
1992 年 61 巻 12 号 p.
4657-4658
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
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Takashi Sakuma, Tadahiro Kaneko, Haruyuki Takahashi, K\={o}ji Honma, R ...
1992 年 61 巻 12 号 p.
4659-4660
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
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Kazuhiro Sano, Ken’ichi Takano
1992 年 61 巻 12 号 p.
4661-4662
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
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Chikao Kawabata, Takamitsu Nakanishi
1992 年 61 巻 12 号 p.
4663-4664
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり
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Takashi Tonegawa, Isao Harada, Makoto Kaburagi
1992 年 61 巻 12 号 p.
4665-4666
発行日: 1992/12/15
公開日: 2007/05/29
ジャーナル
認証あり