-
Kazuhiro Hikami
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 4 Pages
1047-1050
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We consider the Yangian invariant eigenstates, “motifs”, of the Haldane-Shastry type spin systems. We relate the Rogers-Szegö polynomial to the representation of motifs through the partition function of the Haldane-Shastry type spin model. We further discuss the relationship between the generalized Rogers-Szegö polynomial and the Yangian Y(su(n)).
View full abstract
-
Hiroki Yamaguchi, Sanae–I. Itoh
Subject area: Kinetic and transport theory of fluids; physical properties of gases.
1995 Volume 64 Issue 4 Pages
1051-1054
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Heat pulse propagation is analyzed for different models of electron heat conduction coefficient χ
e. Cases in which initial temperature perturbation is induced by (1) electron cyclotron heating (ECH) or (2) sawtooth are studied. Five models are adopted which have various dependences on temperature or temperature gradient. A model in which χ
e has a temperature-gradient dependence explains the discrepancy that the values derived from heat pulse propagation deviate from those obtained from the stationary power balance in experiments. In this case the deviation is found to have appreciable radial dependence.
View full abstract
-
Hirotaka Yamaguchi, Masashi Yamaguchi, Toshirou Yagi
Subject area: Mechanical and acoustical properties of condesed matter.
1995 Volume 64 Issue 4 Pages
1055-1058
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Brillouin scattering of CuGeO
3 has been measured in the temperature range from room temperature to 20, K to investigate the relationship between spin-Peierls transition at T
SP=14, K and the elastic anomaly observed by neutron scattering. The excitation energy of the longitudinal acoustic phonon mode propagating along the b axis is as low as that of the transverse mode polarized along the c axis at room temperature. However, the low-lying longitudinal mode exhibits no anomalous temperature dependence in the observed temperature range. No critical behaviors for the phase transition at 14, K were observed in the acoustic phonon modes.
View full abstract
-
Takashi Uchihashi, Ryuta Yagi, Shun–ichi Kobayashi
Subject area: Electron states in condensed matter.
1995 Volume 64 Issue 4 Pages
1059-1062
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We have carried out spectroscopy of a single superconducting fine particle using a scanning tunneling microscope (STM). We observed the superconducting energy gap by making the tunnel resistance between the STM tip and the particle very low to avoid the Coulomb blockade. We measured the particle-size dependence of the spacing between the two peaks 2Δ
p-p in the tunneling spectrum. It is found that 2Δ
p-p increases with decreasing particle diameter from 250, Å to 50, Å. We discuss the result in connection with the fluctuation of the order parameter.
View full abstract
-
Kenichi Tenya, Masataka Ikeda, Takashi Tayama, Hiroyuki Mitamura, Hiro ...
Subject area: Superconductivity.
1995 Volume 64 Issue 4 Pages
1063-1066
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Magnetization curves of UPt
3 along the c-axis were measured at low temperatures down to 80, mK. Below 350, mK a peak of the irreversible magnetization was found just below the superconducting upper critical field H
c2. However, the peak disappeared above 390, mK, which is much lower than the superconducting critical temperature of 580, mK, suggesting an unconventional mechanism of the flux pinning near H
c2. No distinct anomaly was observed in the magnetization curves at the phase transition between B and C superconducting phases.
View full abstract
-
Kazushige Machida, Tetsuo Ohmi, Masa–aki Ozaki
Subject area: Superconductivity.
1995 Volume 64 Issue 4 Pages
1067-1071
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Motivated by a remarkable recent experiment of Keller et al. who find the basal plane anisotropy of H
⊥ c2, the superconducting pairing function in UPt
3 is identified. The identified odd-parity state belonging to E
1u in D
6h classified under strong spin-orbit coupling is characterized by not only broken time reversal symmetry, but also non-unitary. We demonstrate that this particular state can explain almost all the results of relevant experiments, concerning the phase diagram or gap topology, better than other proposals.
View full abstract
-
Naoki Shirakawa, Keizo Murata, Yoshikazu Nishihara, Shuji Nishizaki, Y ...
Subject area: Superconductivity.
1995 Volume 64 Issue 4 Pages
1072-1075
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We present the temperature dependence of the Hall coefficient (R
H) of Sr
2RuO
4, in which superconductivity with T
c=0.93, K has been discovered recently. The value of R
H shows strong temperature dependence, and sign reversal occurs at around 20, K, i.e., R
H is positive and small (≤ 2× 10
-11, m
3, C
-1) for T>20, K, while for T<20, K R
H is negative and \vert R
H\vert continuously increases at least down to 1.8, K, where R
H=-1.37× 10
-10, m
3, C
-1. A possible mechanism of the temperature dependence of R
H, involving the electron-correlation effect, is discussed.
View full abstract
-
Yasuhiro Kobayashi, Saburo Nasu, Teruya Shinjo
Subject area: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1995 Volume 64 Issue 4 Pages
1076-1080
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
197Au Mössbauer measurements have been performed for Au(1, nm)/Ni(1, nm) multilayer stacked on pure Au buffer layer (25, nm in thickness) at 75, 50, 25 and 11, K. Au atom ratio in multilayer and buffer layer has been prepared to be 2:1; however, the area ratio in
197Au Mössbauer spectrum, which is a superposition of multilayer and buffer-layer components, has been determined to be 3.2:1 in a thin-foil approximation at 11, K suggesting larger recoil-free fraction of
197Au in multilayer than that in Au buffer layer. Temperature dependence of the area ratio has been analyzed using a Debye model and the Debye temperature of
197Au in this multilayer has been determined to be 230± 20, K, which is much higher than 164, K of bulk Au metal, suggesting the existence of the supermodulus effect in this multilayer.
View full abstract
-
Osamu Moriyama, Mitsugu Matsushita
Subject area: Other areas of research of general interest to physicists.
1995 Volume 64 Issue 4 Pages
1081-1084
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We propose an extremely simple model for target patterns and spiral waves. Our model, based upon the moiré effect, is able to topologically reproduce these patterns. The velocity and frequency of the patterns are estimated. Only expanding target patterns or outwardly rotating spiral waves are allowed, if one physically reasonable restriction is taken into account in the model.
View full abstract
-
Wen–Xiu Ma
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 4 Pages
1085-1091
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Through taking a Bargmann symmetry constraint, the spectral problem and the adjoint spectral problem of KdV integrable hierarchy are transformed into a finite dimensional integrable Hamiltonian system in the Liouville sense. Meantime, under the control of this system (i.e. the spatial part), the time parts of the constrained Lax pairs and adjoint Lax pairs are reduced to a new hierarchy of commutative, finite dimensional integrable Hamiltonian systems in the Liouville sense, whose Hamiltonian functions constitute a series of integrals of motion for the spatial part of the constrained Lax pairs and adjoint Lax pairs.
View full abstract
-
Effat A. Saied
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 4 Pages
1092-1097
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Using Lie group methods, we analyse nonlinear diffusion equations in an inhomogeneous medium f(x)u
t=(g(x)D(u)u
x)
x with arbitrary diffusion coefficient D(u), and arbitrary thermal coefficients f(x) and g(x), which have a wide spectrum of applications in many areas of science. The Lie-group-based similarity method leads to a classification of the diffusion and thermal coefficients according to its symmetry properties. With the help of the adjoint representation, the optimal system of similarity reductions is calculated. Exact similarity solutions of the second-order ordinary differential equatiors resulting from the reductions are demonstrated by examples.
View full abstract
-
Masato Hisakado, Miki Wadati
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 4 Pages
1098-1103
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The Peyrard-Bishop model for DNA dynamics is generalized so as to include the differences among bases. The model reduces to a nonlinear Schrödinger type equation, which we name a stochastic nonlinear Schrödinger equation. Propagations of solitons are analysed under an assumption that masses and spring-constants obey Gaussian white noises.
View full abstract
-
Norio Ohtomo, Kazuo Tokiwano, Yukio Tanaka, Ayako Sumi, Saburou Terach ...
Subject area: Statistical physics and thermodynamics.
1995 Volume 64 Issue 4 Pages
1104-1113
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Power spectral densities (PSD's) were calculated by the maximum entropy method (MEM) for three types of chaotic time series numerically generated from the Lorenz, Rossler and Duffing models. Every PSD indicated exponential decay until it levels off at a limit determined by the accuracy of the present computation. This exponential chracteristics were universally found in all chaotic time series irrespective of the data length as well as the time range of data. The values of the coefficient of exponent were 3.26, 5.72 and 7.36 for 6000-point data of the Lorenz, Rossler and Duffing models, respectively, and they slightly increased as the data length shortened. The exponential form was also recognized in the MEM-PSD for the Lorentzian-type time series as in theory.
View full abstract
-
Tomoo Nakayama, Akio Nakahara, Mitsugu Matsushita
Subject area: Statistical physics and thermodynamics.
1995 Volume 64 Issue 4 Pages
1114-1119
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Fine particles of calcium carbonate (CaCO
3) have been found to aggregate and form clusters in two dimensions at the air/water interface. We experimentally studied the cluster-cluster aggregation of the CaCO
3 particles and found that the fractal dimension of these clusters is given by D=1.48± 0.06 and the time dependence of their mean radius can be described by the power-law relationship R-- t
ζ with ζ ≅ 0.78. We also found that the cluster-size distribution function with size s at time t, n
s(t), can be scaled by the form n
s-- s
-θ f(s/t
z) with θ ≅ 0.8 and z≅ 1.2.
View full abstract
-
U. Ochs, M. Sorg
Subject area: General theory of fields and particles.
1995 Volume 64 Issue 4 Pages
1120-1131
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The theory of the Relativistic Schrodinger Equations can be extended to many-particle systems and yields a local-realistic explanation of the well-known paradoxes of conventional quantum mechanics (i.e. Bohm-Aharonov effect and double-slit experiment). Within the new framework, it becomes obvious that the particle-wave duality does apply in the same way to both the elementary objects (e.g. electrons) and to arbitrarily complex material systems (e.g. nucleons, heavy atoms, molecules etc.).
View full abstract
-
Noboru Hashimoto
Subject area: Specific theories and interaction models; particle systematics.
1995 Volume 64 Issue 4 Pages
1132-1140
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We study the multiplicity distributions both in non-single diffractive and whole inelastic pp(\=pp) interactions in the framework of the geometric quark jet model. It is shown that the model reproduces successfully the approximate KNO scaling of multiplicity distributions at ISR and scaling violation at SPS collider energies, if the average internal multiplicity in the impact parameter space is suitably chosen. For multiplicity distributions in the rapidity interval \lceil 6 \
ceil <1.3, the model predicts validity of the KNO scaling throughout ISR-SPS collider energy range as experiments suggest.
View full abstract
-
Giovanni Fazio, Giorgio Giardina, Oleg Yu. Goryunov, Anatoly A. Shvedo ...
Subject area: Nuclear reactions and scattering: general.
1995 Volume 64 Issue 4 Pages
1141-1147
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The mechanism of the (α, ,
6Li)-reactions was studied by using
10B,
14, 15N, and
19F target nuclei and an α -particle beam of 27.2, MeV energy. The obtained contribution estimations of the statistical- and direct-process of two-nucleon cluster transfer to the reaction cross-sections were used in the attempt to describe the experimental data. The spectroscopic factors of the studied cluster configurations for the
10B,
14, 15N and
19F nuclei were obtained.
View full abstract
-
Nobuaki Ikuta, Sadanojo Nakajima
Subject area: Kinetic and transport theory of fluids; physical properties of gases.
1995 Volume 64 Issue 4 Pages
1148-1163
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The theory of flight time integral (FTI) method deduced from the path-integral solution of the Boltzmann equation is described with procedures to obtain the velocity ditribution and transport properties of charged particles in gases under static external fields. Here, the normalized starting rate distribution Ψ
Sn(v
0), determined by iterative applications of loop dispersion function, is used as the principal unknown function. FTI method is essentially a trajectory analysis that reproduces the flight behavior of charged particles in gases and is stable as far as those have a steady state.
View full abstract
-
Kiyohiko Nishimura, Masami Fujiwara
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 4 Pages
1164-1171
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Helical magnetic field produced by the continuous helical windings has many multi-helicity (higher or satellite harmonics of a fundamental helical field) components. Generally these multi-helicity components enhance the ripple trapping and, as a result, increase neoclassical transport. A new method of a coil width modulation (a modulation of a helical coil current distribution) is proposed to reduce multi-helicity and to satisfy the requirement for the magnetic configuration of confining a high temperature plasma in a low-aspect-ratio helical system.
View full abstract
-
J. M. Han, K. Y. Kim
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 4 Pages
1172-1185
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The theoretical and numerical investigation of the dynamical processes of non-monotonic double layers (NDL's) with potential depression (or hump) at the low (or high) potential side are presented. In order to obtain the NDL acceleration and growth rate from a momentum balance equation, a phase space hole concept in the negative effective mass term is used. In order to compare with the theory of the NDL dynamics and simulations, the evolution of NDL's in a one-dimensional Vlasov plasma with injection of current-carrying plasma from both ends is investigated by one-dimensional bounded particle-in-cell code XPDP1, which is the workstation version of the one-dimensional electrostatic bounded-plasma code PDW1 [J. Comput. Phys. 80 (1989) 253]. The theoretical acceleration and growth rate are in good agreement with the results of simulations.
View full abstract
-
Katsuji Chiyoda
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 4 Pages
1186-1192
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A magnetohydrodynamic (MHD) stability condition of the interchange mode in a reversed field pinch (RFP) plasma is obtained by using the Mercier criterion. The stability condition obtained here has, as in a tokamak, a factor (1-q2), where q is the safety factor and any ordering of the small parameter used is not imposed upon q. The stability condition is applied to equilibria which have been recently obtained and include effects of plasma pressure and toroidicity. It is found that the plasma is unstable near the magnetic axis and stable near the conducting shell. The latter indicates a wall stabilization.
View full abstract
-
Tsutomu Sato, Tomoyuki Asari
Subject area: Lattice dynamics and crystal statistics.
1995 Volume 64 Issue 4 Pages
1193-1199
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The first-order Raman spectrum of the A
1g mode in SnO
2 crystal was measured in the temperature range of 300--973, K and the linewidths at these temperatures were obtained. The temperature dependence of the linewidths was analyzed using the phonon dispersion curves based on the shell model, and the results showed that it may have been caused provably by the cubic anharmonic term in crystal potential energy.
View full abstract
-
Hitoshi Imaoka, Yasuhiro Kasai, Kohzaburo Ohnaka
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 4 Pages
1200-1210
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We simulate many kinds of fully-frustrated square Ising systems under the uniform magnetic field and observe various types of dependence of the magnetization on the field at low temperatures. For some systems, a critical dependence is observed; the response exhibits the scaling law belonging to the Villain-Stephenson universality class of δ =7. For other systems, a non-critical dependence (δ =1) and a marginal one are observed. Based on an idea of the partially disordered state, we propose a simplified method which can predict whether the response to the uniform field is critical or not. We examine possible changes in critical exponents through a mechanism of cancellation among the spin pair correlation functions.
View full abstract
-
Tohru Morita
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 4 Pages
1211-1216
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A Bose lattice gas of particles with spin 1/2, equivalent to the Heisenberg model, is presented. An approximate method of the cluster variation method, to be called as QCVM, is applied to this system, by which we can discuss the phase transition as well as spin waves at low temperatures. The study here is restricted to the ferromagnetic Heisenberg model on the s.c. lattice.
View full abstract
-
Kêiichiro Aizu
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 4 Pages
1217-1222
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Even a hard mode of lattice vibration belonging to a nonidentity irreducible representation is condensed in the prototypic phase, if an R-linear term such as ∂
zR or ∂
2xyR exists in the free energy function (R denotes the coordinate of the hard mode) and if the prototypic phase is suitably undulated. A detailed account of the above is given. If the soft mode only is taken into consideration and this mode is not condensed in the prototypic phase, the prototypic-to-ferroic transition temperature necessarily rises with increasing U (U denotes the amplitude of undulation of the prototypic phase). However, if the hard modes condensed in the prototypic phase are taken into consideration, the transition temperature does not necessarily rise but can fall with increasing U. A detailed account of the above is given.
View full abstract
-
Atsushi Goto, Hiroshi Yasuoka, Masahiko Isobe, Akihiko Hayashi, Yutaka ...
Subject area: Electron states in condensed matter.
1995 Volume 64 Issue 4 Pages
1223-1229
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The NMR method has been applied to investigate the electronic states of K
3Cu
8S
6, a copper sulfide with a layered structure. This compound has been known to show anomalous CDW behaviors such as the metal-CDW-metal transitions at T
c1 (153, K) and T
c2 (55, K), respectively. We measured the temperature dependences of the Knight shifts for the four Cu sites to investigate mainly the nature of the metallic state below T
c2. As a result, it has turned out that the CDW state remains even below T
c2 although the material shows a metallic character, and that the Knight shifts for all the Cu sites do not change at T
c2. For these results, we propose as one of the possible interpretations that the state below T
c2 is a metallic state with the CDW but no Fermi surface, i.e. the metallic state without the Pauli paramagnetism.
View full abstract
-
Shik Shin, Yasuhisa Tezuka, Toyohiko Kinoshita, Takehiko Ishii, Takayu ...
Subject area: Electron states in condensed matter.
1995 Volume 64 Issue 4 Pages
1230-1235
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Photoelectron energy distribution curves near the Fermi level have been measured on V
2O
3 above and below the critical temperature of the metal-insulator transition. In insulating phase, the band gap was found to be about 0.2, eV, which is consistent with the other experimental results. A clear Fermi edge, which becomes sharp at lower temperature, is found in the metallic phase. The 3d spectral feature is discussed in relation to the recent quantum-Monte-Carlo calculation. Resonant photoemission shows the hybridization effect is also important for the spectral feature.
View full abstract
-
Tatsuya Okada, Masaki Togashi, Satoru Ohno
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 4 Pages
1236-1244
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The conductivity of liquid Pb
1-cSe
c alloys decreases rapidly with increasing Se composition, and shows a broad minimum and a broad maximum at the composition c=0.55 and 0.75, respectively. The dependence of the thermopower on concentration exhibits a sharp minimum and a broad maximum at the composition c=0.5 and 0.7, respectively. The electronic behaviour of liquid Pb
1-cSe
c alloys with c\le0.35 was studied by the nearly free electron model. The conductivity and thermopower near the stoichiometry PbSe were analyzed by using the equations derived from the Kubo-Greenwood formula. The conductivity gap almost closed for liquid Pb--Se alloys near the stoichiometry.
View full abstract
-
Katsuki Amemiya, Kiyoshi Kawamura
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 4 Pages
1245-1250
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We study the Hall effect in a quantum dot to which four leads are attached by solving the Schrödinger equation for electrons in this system. We find that the Hall resistance shows wide dips in the quantized Hall resistance regime, which is in agreement with resonant suppression discovered by Ford et al. [Phys. Rev. B 43 (1991) 7343], and that it possibly takes negative values in some of these dips. We analyze results in terms of skipping orbits of classical electrons and relate it to the magneto-focusing of electrons on one of the leads attached to the dot. The interpretation of this phenomenon from the viewpoint of wave mechanics is also presented.
View full abstract
-
Nobuhisa Fujima, Tsuyoshi Yamaguchi
Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
1995 Volume 64 Issue 4 Pages
1251-1257
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Electronic states of the neutral and cationic Mn
N clusters for N=2--7 are calculated by the spin-polarized density functional method. For neutral clusters, the equilibrium interatomic distances are 20
View full abstract
-
Tsuyoshi Yamaguchi
Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
1995 Volume 64 Issue 4 Pages
1258-1274
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Electronic states are calculated by the DV-Xα-LCAO method for two model clusters C
60Si
101H
60 and C
70Si
101H
60 of the C
60/Si(111) and C
70/Si(111) surfaces where fullerene molecules reside on the center of the unfaulted half of the 7× 7 unit cell. Due to the electron transfer from the Si substrate, the molecules have ionicities, C
60-3.35 and C
70-2.63. For C
60 molecule, occupied (unoccupied) orbitals near the Fermi level have high charge density around double bonds between two hexagons (around single bonds on pentagons). For C
70 molecule, both occupied and unoccupied orbitals have high charge density around single bonds. The charge density of an individual occupied (unoccupied) orbital has a shape like a trigonal doughnut (clover leaves) over C
60 molecule, and it is high in three (four) regions over C
70 molecule which is nearly C
s (D
2) symmetry. These should be compared with the scanning tunneling microscopy images.
View full abstract
-
Yutaka Kishimoto, Takashi Ohno, Tatsuo Kanashiro
Subject area: Superconductivity.
1995 Volume 64 Issue 4 Pages
1275-1286
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The Knight shift K and the spin-lattice relaxation rate 1/T
1 of
51V nuclei, and the macroscopic magnetic susceptibility have been measured in an A15 superconductor V
3Si. From the K-χ plot, the hyperfine coupling constant and the temperature independent Van Vleck term have been estimated. In the normal state, 1/T
1T decreases drastically with increasing temperature. In the superconducting state, 1/T
1 shows no coherence peak just below T
c(=17.1, K), and obeys the T
3-law down to T
c/3, but deviates from it with decreasing temperature. It is shown that the temperature dependences of χ and 1/T
1T are well reproduced by the numerical calculation based on the narrow-band model at Fermi level, and that the band width should be much smaller than that given by the band calculation of Mattheiss and Weber. T
1TK
2d varies with temperature, which should also be explained with the narrow conduction band.
View full abstract
-
Hironaru Murakami, Ryozo Aoki
Subject area: Superconductivity.
1995 Volume 64 Issue 4 Pages
1287-1292
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Low temperature STM/STS observation for BSCCO single crystal was carried out to investigate an intrinsic superconducting gap state of CuO
2 layer. The STM observation revealed out a mid-level-layer between the top and bottom BiO surfaces of the half unit cell in the crystal c-axis direction. The STS study on this mid-level surface brought a reproducible definite superconducting gap structure which shows a finite gap region with a low conductance level of about 5
View full abstract
-
Sumiyoshi Fujiki, Tsuyoshi Horiguchi
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1293-1304
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A Monte Carlo study is carried out on the six-state clock model on the triangular lattice. Physical quantities which characterize the Kosterlitz-Thouless (KT) phase transition are calculated. The temperature dependence of the exponent of the spin-pair correlation function, η (T), in the KT phase is obtained precisely. The exponential divergence of the correlation length, ξ -- exp, (at
-b), with the theoretical value, b=0.5, gives a good fit to the data by the present MC simulations by choosing a=1.6-- 1.8, η =0.23-- 0.25 at the upper critical temperature T
U=1.46-- 1.49. However, the choice of critical parameters, a-- 3.1, b-- 0.3 and η -- 0.28 at T
U-- 1.53 gives the most consistent result by a finite-size scaling analysis on several physical quantities. The lower critical temperature, T
L, is estimated to be 1.1.
View full abstract
-
Teruo Bitoh, Kazuyuki Ohba, Masaki Takamatsu, Takashi Shirane, Susumu ...
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1305-1310
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The field-cooled (FCM) and zero-field-cooled (ZFCM) magnetization of ferromagnetic fine cobalt particles in a Cu
97Co
3 alloy has been studied. The spin-glass-like temperature dependence of the magnetization has been observed; ZFCM exhibits a spin-glass-like maximum (at T
p) and FCM is larger than ZFCM at low temperatures. However, the difference between FCM and ZFCM obviously exists far above T
p. Furthermore, FCM increases monotonically with decreasing temperature even below T
p while that of typical spin glasses is nearly independent of temperature. The analysis of the magnetization shows that the temperature dependence of FCM and ZFCM of Cu
97Co
3 is well described on the basis of the superparamagnetic blocking model with no interaction between the particles, whereas that of a typical spin-glass Au
96Fe
4 cannot be explained by the blocking model.
View full abstract
-
Teruo Bitoh, Kazuyuki Ohba, Masaki Takamatsu, Takashi Shirane, Susumu ...
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1311-1319
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The ac linear (χ
0) and nonlinear (χ
2) susceptibilities of ferromagnetic fine cobalt particles, which were precipitated in a Cu
97Co
3 alloy, have been studied. The χ
0 has a spin-glass-like maximum and χ
2 has a very broad negative peak at a low temperature. At high temperatures, the in-phase linear susceptibility χ
0' obeys the Curie law and the in-phase nonlinear susceptibility χ
2' is proportional to T
-3. A quantitative analysis of χ
0 and χ
2 based on a simplified superparamagnetic blocking model has been performed. The temperature dependence of the in-phase and out-of-phase susceptibilities is well described quantitatively by the superparamagnetic blocking model. It is concluded the behavior of χ
2 can be explained by the summation of the nonlinear term of the Langevin function over particle volume distribution. The analysis also yields information about the particle volume distribution and a value of anisotropy energy.
View full abstract
-
Kazuko Zenmyo, Hidenori Kubo
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1320-1325
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
With increasing temperature, the NMR line of nuclei in the spin glass region of random mixture Co
1-xMn
xCl
2· 2H
2O becomes gradually sharp and symmetric, and disappears at the transition temperature T
RSG from the reentrant spin glass to the antiferromagnetic phase. This phenomenon shows the change in the randomness of frozen spins and is analysed by considering the temperature dependence of the probabilities for ferro- or antiferromagnetic configurations. Based on the analysis of the observed spectra, we conclude that the randomness of the frozen spins decreases with increasing temperature.
View full abstract
-
Nobuhiko Nishimori, Kichizo Asai, Moriji Mizoguchi
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1326-1333
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Magnetic properties and the hyperfine magnetic fields at
55Mn in ferromagnetic oxides La(Co
2+1-xMg
x2+)
0.5Mn
0.54+O
3 (0≤ x≤ 0.4) are studied. The exchange integral, J, for the superexchange interaction between neighboring Mn
4+ and Co
2+ ions is found to be +15.3, K in magnitude.
55Mn NMR spectra, composed of several equidistantly separated peaks, are interpreted as each peak being the signal associated with Mn
4+ surrounded by a specific number of Co
2+ ions. The supertransferred hyperfine magnetic field, H
STHF, at
55Mn from each neighboring Co
2+ ion is found to be +5.0, kOe, which is considerably smaller than that (+6.3, kOe) from Ni
2+ in a similar oxide system La(Ni
1-xMg
x)
0.5Mn
0.5O
3. On the other hand, the hyperfine magnetic field (-296, kOe) originating from 3d magnetic moment of Mn
4+ is virtually the same in both systems. The values of J and H
STHF are discussed in relation with the spin density in 2p
σ orbitals of the oxygen ions.
View full abstract
-
Yoshio Shinoda, Keisuke Tajima
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1334-1338
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The spiral to ferromagnetic phase transition in Dy which is induced by magnetic field has been investigated using the X-ray diffraction and magnetization measurements. The appearance of the ferromagnetic phase has been detected by X-ray diffraction through the observation of the discontinuous change of the lattice parameter. The magnetization process near T
c has been well explained in terms of the coexistence of the spiral and ferromagnetic phases, while the volume fraction of the ferromagnetic phase is found to be not sufficient to reproduce the magnetization well above T
c.
View full abstract
-
Tetsuo Ohama, Hiroshi Yasuoka, E. V. Sampathkumaran
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 4 Pages
1339-1345
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The temperature dependence and the anisotropy of the magnetic susceptibility and the Knight shifts have been measured in PrCu
2Si
2 and GdCu
2Si
2 with magnetically aligned powder samples. For GdCu
2Si
2, the isotropic s-f exchange model provides a good description of its magnetic properties, but in PrCu
2Si
2 an anisotropic two-ion coupling has been found. It has been revealed that the hyperfine coupling at the Si sites is enhanced in PrCu
2Si
2, thereby suggesting preferential hybridization of the f-electrons with the Si valence electrons. This effect is responsible for the unusually high Neel temperature of PrCu
2Si
2.
View full abstract
-
Hiroshi Hatanaka, Tsuneo Hashi
Subject area: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1995 Volume 64 Issue 4 Pages
1346-1355
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We have clarified the origin of the irreversibility involved in adiabatic demagnetization in the rotating frame (ADRF). The irreversibility is very high (~= 50\permil)in single in single quantum ADRF for
19F in CaF
2.
7Li and
19f in LiF. Using an analysis based on the Provotorov's theory we conclude that the irreversibility is due to the thermal on the Provotorov's theory we conclude that the irreversibility is due to the thermal mixing between Zeeman and dipole systems in the demagnetization process.The conclusion is also supported by the experimental result that the reversibility becomes higher (or lower) when the dipole system is prepared at a positive (or negative) low temperature before ADRF. It is also shown that the characteristics of ADRF can be specified by a parameter T
2D, where T
2 is the free decay time and D the local Field in frequency units."
View full abstract
-
Masanori Arakawa, Hiroshi Ebisu, Hideo Takeuchi
Subject area: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1995 Volume 64 Issue 4 Pages
1356-1362
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
EPR measurements have been made on single crystals of CsCdF
3 and CsCaF
3 co-doped with Gd
3+ and Na
+ using X-band spectrometer. A new weak spectrum with monoclinic symmetry is observed. The principal z-axis is deviated about 8° for CsCdF
3 and 6° for CsCaF
3 from the crystalline axis in a ‹ 100› direction. The new centre is ascribed to a Gd
3+ ion associated with a Na
+ ion at the nearest divalent cation site. Its intervening F
- ion is considered to be displaced from the face centre point toward a ‹ 110› direction normal to the Gd
3+--Na
+ pair axis. The out-of-axis displacement shows that the intervening F
- ion on the pair axis becomes unstable by the existence of the associated Na
+ ion.
View full abstract
-
Shin–ichi Kuroda, Kazuhiro Murata, Takanobu Noguchi, Toshihiro O ...
Subject area: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1995 Volume 64 Issue 4 Pages
1363-1370
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Electron nuclear double resonance (ENDOR) measurements of paramagnetic species existing in the dark state of undoped poly (paraphenylene vinylene) have been performed using stretch-oriented samples. The spectra have shown a clear anisotropy ofa π -electron on the conjugated chain. The maximum value of the spin density reaches0.09, which corresponds to the half-width of the spatial extension of the spin over several phenyl rings. Three distinct spectral turning points have been resolved for the spectra of stretch direction, showing that the variation of the spin density is not monotonic. The resemblance between the ENDOR-induced ESR spectra and the photo-induced ESR spectra at low temperatures strongly suggests that the observed spins are trapped polarons.
View full abstract
-
Naoshi Ikeda, Kay Kohn, Hijiri Kito, Jun Akimitsu, Kiiti Siratori
Subject area: Dielectric properties and materials.
1995 Volume 64 Issue 4 Pages
1371-1377
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Dielectric dispersion was observed in a single crystal with the composition of ErFe
2O
3.95 below magnetic transition temperature. It is characterized by a large dielectric constant of the order of 10
4, and a Debye-type frequency dependence like in the polycrystalline samples of the same substance which we reported in a previous paper. Large anisotropy exists in the strength ε
s-ε
∞ and the characteristic relaxation frequency of the dispersion. The strength is higher within the c-plane than along the c-axis, while the characteristic frequency is much larger along the c-axis than within the c-plane. The dielectric dispersion in the polycrystalline sample cannot be explained by a simple average of the single crystal results. The observed dispersion is qualitatively discussed with a model of domain wall motion on an assumption that ErFe
2O
4 is a polar crystal.
View full abstract
-
Nobuyasu Adachi, Masahiro Inoue, Iwao Mogi, Giyuu Kido
Subject area: Optical properties and condensedmatter spectroscopy and other interactions of matter with particles and radiation.
1995 Volume 64 Issue 4 Pages
1378-1384
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Reflectance and luminescence spectra of a diluted magnetic semiconductor Cd
1-xCo
xSe (x≈ 0.01) have been studied in steady high magnetic fields up to 27, T. The bound and free exciton luminescence was clearly observed at 4.2, K. The magnetoreflectance spectra showed that the energy levels of A and B excitons split into two branches in magnetic fields parallel to the c-axis, respectively. The A exciton splitting energy increases proportionally to the magnetization, which results from the sp-d interaction. The linear Zeeman splitting and the diamagnetic shift of the exciton were observed in the magnetic fields higher than 12, T, where the magnetization saturated. We estimated s-d(p-d) exchange constant N
0α =0.27, eV (N
0β =-2.25, eV), the effective g values | 3g
h-g
e| =1.7, and the constant of diamagnetic shift σ =6.8× 10
-6, eV/T
2.
View full abstract
-
Jin Nakamura, Takayoshi Takeda, Kichizo Asai, Nobuyoshi Yamada, Yoshik ...
Subject area: Optical properties and condensedmatter spectroscopy and other interactions of matter with particles and radiation.
1995 Volume 64 Issue 4 Pages
1385-1393
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Directional magnetic Compton profiles (MCPs) of ferromagnetic intermetallic compound Mn
1.1Sb are measured using a circularly polarized synchrotron radiation light source. The overall shape of the derived momentum-density distribution of the magnetic electrons is reproduced well with the Hartree-Fock 3d wavefunction of free Mn atoms except in the low momentum region (| P| 2.0 atomic units). The anisotropy observed in the low momentum region is inexplicable only with the population, determined previously by a polarized neutron measurement, of unpaired electrons in Mn-3d orbitals in the trigonal crystalline field. The present result suggests an additional anisotropic negative polarization of Sb-5p electrons. The anisotropy is discussed using the hydrogen-like atomic Sb-5p wavefunctions.
View full abstract
-
Haruhiko Ogasawara, Akio Kotani
Subject area: Optical properties and condensedmatter spectroscopy and other interactions of matter with particles and radiation.
1995 Volume 64 Issue 4 Pages
1394-1401
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We present atomic calculations for the magnetic circular dichroism (MCD) in the 4d→ 4f excitation region of Eu, Gd, Tb, Dy, and Ho metal. The spectral shapes at T=0, K for non-polarized, right and left circularly polarized light, and their difference spectra are given. The interference effect between the 4d→ 4f excitation followed by 4d-4f4f super-Coster-Kronig decay process and the 4f→ ε g direct excitation process, which is known as the Fano effect, is considered in the calculations. The result reproduces the overall features of recently measured experiments. It is essential to consider the Fano effect for the understanding of the heavy rare-earth 4d→ 4f absorption and their MCD.
View full abstract
-
Xiaodong Zheng, Kazuo Minami, Md Ruhul Amin, Tsuguhiro Watanabe
Subject area: Electromagnetic technology.
1995 Volume 64 Issue 4 Pages
1402-1411
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A linear theory of electromagnetic radiation from a backward wave oscillator (BWO) with coaxial slow wave structure driven by an annular intense relativistic electron beam has been derived and analyzed numerically. The absolute instability of the mode (quasi-TEM) which is peculiar in the coaxial SWS is studied. It is shown that the quasi-TEM mode can be the fundamental mode of oscillation in the coaxial BWO with sufficiently large linear growth rates for moderately relativistic beam case.
View full abstract
-
Yuichi Masubuchi, Hidehiro Oana, Takako Akiyama, Mitsuhiro Matsumoto, ...
Subject area: Biophysics.
1995 Volume 64 Issue 4 Pages
1412-1420
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Direct observation of a DNA molecule in gel electrophoresis indicates that the DNA repeats a stretch-contraction cycle every time when it is hooked by a gel fiber. The dynamics of this process is analyzed for a simple situation that a DNA is hooked by a single obstacle. It is shown that in the weak field limit, the characteristic time of the stretch-contraction process is independent of the electric field, while in the strong field limit, it is proportional to L/v
0, where L is the contour length of DNA and v
0 is the migration velocity of DNA in free space. The experimental result of Oana et al. (submitted to Macromolecules) is interpreted by this result.
View full abstract
-
Takashi Nagatani
Subject area: Other areas of research of general interest to physicists.
1995 Volume 64 Issue 4 Pages
1421-1430
Published: April 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A stochastic cellular automaton (CA) model is presented to investigate the traffic jam by self-organization in the two-dimensional (2D) traffic flow. The CA model is the extended version of the 2D asymmetric exclusion model to take into account jam-avoiding drive. Each site contains either a car moving to the up, a car moving to the right, or is empty. A up car can shift right with probability p
ja if it is blocked ahead by other cars. It is shown that the three phases (the low-density phase, the intermediate-density phase and the high-density phase) appear in the traffic flow. The intermediate-density phase is characterized by the right moving of up cars. The jamming transition to the high-density jamming phase occurs with higher density of cars than that without jam-avoiding drive. The jamming transition point p
2c increases with the shifting probability p
ja. In the deterministic limit of p
ja=1, it is found that a new jamming transition occurs from the low-density synchronized-shifting phase to the high-density moving phase with increasing density of cars. In the synchronized-shifting phase, all up cars do not move to the up but shift to the right by synchronizing with the move of right cars. We show that the jam-avoiding drive has an important effect on the dynamical jamming transition.
View full abstract
