Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 57, Issue 8
Displaying 1-50 of 54 articles from this issue
  • Hideki Takayasu
    1988 Volume 57 Issue 8 Pages 2585-2587
    Published: August 15, 1988
    Released on J-STAGE: May 29, 2007
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    Size distribution of fractal clusters is shown to follow a one-sided stable distribution. Its characteristic exponent α is determined by the fractal relation between the cluster’s surface (S) and volume (N) under the scale change: SaS, Na1⁄αN. This result means that an asymptotic power law size distribution p(N)∝N−α−1 is deduced from the above geometrical fractal relation.
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  • Kei-ichi Tainaka
    1988 Volume 57 Issue 8 Pages 2588-2590
    Published: August 15, 1988
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    The spatial pattern in the lattice system composed of three competing species is studied. An individual is assumed to react with a neighbour. It is found from the stochastic simulation that the dynamics of the system strongly depend on the lattice dimension (d). When d=2, the system approaches the stable state regardless of initial conditions.
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  • Ken Sekimoto, Kyozi Kawasaki
    1988 Volume 57 Issue 8 Pages 2591-2593
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    A diffusive phase boundary has been observed between a swollen phase and a shrunken phase of a get rod [S. Hirotsu; J. Chem. Phys. 88 (1988) 427]. We show that this is the consequence of the peculiarity of the elastic system; the order parameters (strain tensor) are of geometric nature and are dimensionless quantities.
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  • Ken Sekimoto, Kyozi Kawasaki
    1988 Volume 57 Issue 8 Pages 2594-2597
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    In this paper we present a nonlinear elastic network model of swelling gets that is numerically simulated. We show three qualitative results: selection of the length scale characterizing deformation on a free surface, generation of cusp singularity accompanied by a folded region on the free surface, and the occurrence of internal deformation patterns between fixed boundaries.
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  • Takashi Yabe, Eiji Takei
    1988 Volume 57 Issue 8 Pages 2598-2601
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    A new numerical method of the higher-order Godunov-type is proposed. The spatial profile within a grid is interpolated with the cubic spline. The time integration is represented by the time evolution of the value and the first spatial derivative of the quantity. This scheme is successfully applied to a linear wave propagation with less diffusion retaining monotonicity and to the nonlinear hydrodynamic equations. The extension to higher dimensions and to more general hyperbolic equations including coupled hyperbolic-parabolic equations is straightforward.
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  • Shinichiro Yanase, Nozomi Goto, Kyoji Yamamoto
    1988 Volume 57 Issue 8 Pages 2602-2604
    Published: August 15, 1988
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    Two-dimensional linear stability of dual solutions, two-vortex and four-vortex solutions, of the flow through a slightly curved tube is investigated numerically by the Fourier-Chebyshev spectral method in the range 96≤Dn≤10000, where Dn is the Dean number which characterizes laminar flow through a curved tube. It is found that a two-vortex solution is stable with respect to any small disturbances. A four-vortex solution, which appears when Dn≥956, is unstable to an asymmetric disturbance.
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  • Shunsuke Ide, Motomi Iida, Kazuo Ogura, Hitoshi Tanaka, Akira Yamazaki ...
    1988 Volume 57 Issue 8 Pages 2605-2608
    Published: August 15, 1988
    Released on J-STAGE: May 29, 2007
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    Electron cyclotron emission (ECE) from the lower hybrid current drive (LHCD) as well as the ohmic heating (OH) plasmas in WT-3 were measured along the horizontal chord in the equatorial plane and the vertical chord where the magnitude of the toroidal field is constant, respectively. Measurements show that the high energy tail electrons carrying the plasma current build up within 10 msec after the injection of the lower hybrid wave. The ECE spectrum from the LHCD plasma in a quasi-steady state can be fitted with a numerically calculated spectrum assuming that the electron velocity distribution function is Maxwellian with the temperature T=50 keV.
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  • Yukinori Ohta
    1988 Volume 57 Issue 8 Pages 2609-2611
    Published: August 15, 1988
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    Relative stability of the atomic configurations of a small cluster consisting of thirteen transition-metal atoms is examined as a function of the number of valence d-electrons by the simple tight-binding model accounting for their unsaturated covalency. The predicted structural trends are discussed in relation to the structural stability of bulk crystals and ultrafine particles observed experimentally.
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  • Terutaka Goto, Takashi Suzuki, Yohichi Ohe, Tadao Fujimura, Shinichi S ...
    1988 Volume 57 Issue 8 Pages 2612-2615
    Published: August 15, 1988
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    Low temperature properties of the elastic constants C11 and C33 in the heavy electron compound CeCu6 have been investigated. The remarkable amount of softening below the Kondo temperature down to 20 mK reflects the heavy electron state at the Fermi surface. The oscillations of the C33 mode under a magnetic field along the c axis have been found at low temperature ranges below 500 mK.
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  • Naoki Toyota, Takahiko Sasaki, Keizo Murata, Yoshiaki Honda, Madoka To ...
    1988 Volume 57 Issue 8 Pages 2616-2619
    Published: August 15, 1988
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    The cyclotron mass mc and the Dingle temperature TD in the layered planes of the organic superconductors are determined by the Shubnikov-de Haas effect at ambient pressure; mc=0.4 m0 and TD=7–8 K, for β-(BEDT–TTF)2IBr2 (Tc=2 K), and (0.4–0.5)m0 and 11 K for β-(BEDT–TTF)2I3 (Tc=1 K), and 3.5 m0 and (0.4±0.1) K for κ-(BEDT–TTF)2Cu(NCS)2 (Tc=11 K). A systematic difference is clarified in mc and TD between these salts, suggestive of the origin of different Tc’s among these salts.
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  • Seiichiro Suga, Hideaki Kasai, Ayao Okiji
    1988 Volume 57 Issue 8 Pages 2620-2623
    Published: August 15, 1988
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    The interplay between the Anderson localization and the Kondo effect in the low temperature region of the weakly localized regime is investigated on the basis of the Anderson Hamiltonian. By the perturbational expansion in terms of the Coulomb integral between d-electrons, it is shown that the quantum corrections to the conductivity have the ln T-dependence for the two-dimensional systems and \sqrtT-dependence for the three-dimensional systems, and that the magnetic susceptibility behaves anomalously even at low temperatures.
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  • Yoshinori Takahashi, Pascal Lederer
    1988 Volume 57 Issue 8 Pages 2624-2627
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    In this paper, we calculate the kinetic energy of a holon-defect bound state in an RVB wave function. We evaluate lower order moments of the holon density of states. From this calculation, we find that a lowering of the kinetic energy occurs compared to the undistorted RVB state.
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  • Hikomitsu Kikuchi, Yoshitami Ajiro
    1988 Volume 57 Issue 8 Pages 2628-2631
    Published: August 15, 1988
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    Unequivocal evidence that the superconducting and nonsuperconducting La2CuO4-based compounds show a markedly different behavior in their spin dynamics is given, for the first time, from the ESR study of the doped Mn2+ ions. The magnetic slowing down associated with a progressive freezing of the Cu spins is observed only in the nonsuperconducting compounds. The corresponding behavior is not found in the superconducting ones.
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  • Yoh Kohori, Yasukage Oda, Hirofumi Shibai, Naoya Okamoto, Takao Kohara ...
    1988 Volume 57 Issue 8 Pages 2632-2635
    Published: August 15, 1988
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    A NQR study of copper in YBa2Cu3O7−y with the doping of Co and Fe impurities has been performed. The nuclear spin lattice relaxation time, T1, of 63Cu was measured in both the CuO chain and CuO2 plane. The broad peak was observed in the temperature dependence of T1−1 in both systems. For the Co-doped system, T1−1 of Cu in the CuO chain is greatly enhanced compared to that in the CuO2 plane. From the analysis of the data, we conclude that Co ions occupy only Cu sites in the CuO chain, and Fe ions occupy Cu sites in both the CuO chain and CuO2 plane. The broad peak in the relaxation rate is considered to be due to the occurrence of a magnetic ordering.
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  • Hiroko Aruga, Atsuko Ito, Hidehiko Wakabayashi, Tsuneaki Goto
    1988 Volume 57 Issue 8 Pages 2636-2639
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    Field-dependent phenomena in the exchange competing Ising system undergoing the reentrant transition from the antiferromagnetic state, FexMn1−xTiO3 with x=0.60, 0.65 and 0.75, have been investigated by DC-magnetization measurements. It is observed that the temperature TM(H) giving the peak of magnetization decreases with the increase of magnetic field and it becomes ill-defined at high fields. On the other hand, the reentrant-spin-glass transition temperature TRSG(H) increases with magnetic field, and it begins to decrease after being coincident with TM(H). These kinds of field dependences of TM(H) and TRSG(H) are qualitatively consistent with the prediction given by the theoretical calculation using the mean-field approximation, and these are characteristic of systems undergoing the reentrant transition from the antiferromagnetic state.
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  • Hiroaki Kadowaki, S. M. Shapiro, Toshiya Inami, Yoshitami Ajiro
    1988 Volume 57 Issue 8 Pages 2640-2643
    Published: August 15, 1988
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    The critical exponents γ and ν of an XY antiferromagnet on a layered-triangular lattice, CsMnBr3, have been measured by neutron scattering. They are γ=1.10±0.05 and ν=0.57±0.03 in the reduced temperature range 0.015<ε<0.1 above the Néel temperature. These and the previously measured β show that this phase transition belongs to the universality class characterized by the O(2) symmetry order-parameter in three dimensions, as calculated by Kawamura.
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  • Hiroyuki Nakamura, Yoshio Kitaoka, Kunisuke Asayama, J. Flouquet
    1988 Volume 57 Issue 8 Pages 2644-2647
    Published: August 15, 1988
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    The ground state property of the heavy-fermion compound CeAl3 has been investigated by means of 27Al nuclear magnetic resonance (NMR). It has been found that the NMR linewidth increases markedly below 1.2 K and the nuclear spin-lattice relaxation rate 1⁄T1 exhibits a sharp maximum at 1.2 K. From these results, it is concluded that CeAl3 undergoes an antiferromagnetic transition with a Néel temperature of TN=1.2 K, in contrast to the finding by the μSR study of the development of the static antiferromagnetic correlation which occurs in a spatially inhomogeneous way below 2 K.
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  • Yoshitami Ajiro, Takeshi Nakashima, Yasuyuki Unno, Hiroaki Kadowaki, M ...
    1988 Volume 57 Issue 8 Pages 2648-2650
    Published: August 15, 1988
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    The phase transition of the XY antiferromagnet on a stacked triangular lattice, CsMnBr3 is studied by neutron diffraction. The critical exponent β is found to be β=0.25±0.01. The value is in excellent agreement with the predicted value by Kawamura for a new universality class, giving convincing experimental support to the phase transition characterized by the Z2×S1 or O(2) symmetry.
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  • Kazuyoshi Yoshimura, Yoshihiro Yoshimoto, Mamoru Mekata, Kazuaki Fukam ...
    1988 Volume 57 Issue 8 Pages 2651-2654
    Published: August 15, 1988
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    For the invar-type itinerant ferromagnet Lu(Co1−xAlx)2 (x=0.125, 0.15), the nuclear spin-lattice relaxation rate 1⁄T1 of 27Al has been measured. The observed temperature independent 1⁄T1 above TC was compared quantitatively with predictions based on two different theories: the hyperfine-broadened exchange-narrowed theory for the localized moment system and the self-consistent renormalization theory of spin fluctuations for the weakly itinerant ferromagnet. However, neither of the two dynamical theories furnish quantitative interpretation of the experimental results. This fact implies that the present system belongs to the intermediate regime ferromagnet.
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  • B. Madhu, B. A. Sastry, G. Ponticelli, G. Puggioni
    1988 Volume 57 Issue 8 Pages 2655-2658
    Published: August 15, 1988
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    ESR, IR and electronic srectral studies on [Cu(dpt)(enMe4)](B∅4)2 and [Cu(dpt)(enEt2)](B∅4)2 (dpt=3, 3′-diaminodipropylamine enMe4=tetramethylethylene-diamine, enEt2=diethylethylene-diamine, B∅4=tetraphenylborate) in powders and solutions revealed that the geometry of CuN5 entities in the former complex is square pyramidal with a fluxional nature, and in the latter complex is a square pyramidal with a distortion towards trigonal bipyramidal. It is concluded that the main reason for the difference in the above geometries is due to the difference in the steric impediments on the nitrogen atoms induced due to N-methylation and N-ethylations and the difference in packing forces.
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  • Hiroshi Yasuoka, Tadashi Shimizu, Yutaka Ueda, Koji Kosuge
    1988 Volume 57 Issue 8 Pages 2659-2662
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    The zero-field antiferromagnetic nuclear resonance (AFNR) of Cu in the high-Tc related oxide YBa2Cu3O6 has been observed at 89.89±0.05 MHz for 63Cu and 96.29±0.05 MHz for 65Cu with well articulated quadrupole splittings at 1.3 K. These frequencies correspond to a hyperfine field of 79.65±0.05 KOe. From the analysis of the AFNR spectrum and the observation of NQR at 30.11±0.2 MHz for 65Cu and 27.88±0.02 MHz for 63Cu, both of which have no Zeeman splitting, it is concluded that the antiferromagnetic moments reside only on the CuO2 plane sites and the direction of moments is perpendicular to the c-axis. This is consistent with the spin structure proposed by neutron diffraction studies. The nuclear relaxation behavior is also discussed briefly.
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  • Yoshihiro Yamada, Kenji Ishida, Yoshio Kitaoka, Kunisuke Asayama, Hide ...
    1988 Volume 57 Issue 8 Pages 2663-2665
    Published: August 15, 1988
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    New NMR signals in antiferromagnetic YBa2Cu3O6.1 with the Néel temperature of TN=410 K have been observed in the frequency range between 65 MHz and 125 MHz at the zero external field. In contrast to the nuclear quadrupole resonance (NQR) observed around 30 MHz, the newly observed signals are remarkably dominated by the appearance of the internal field generated by the antiferromagnetic ordering. According to neutron diffraction studies, there exists an antiferromagnetic moment of about 0.6 μB on the CuO2 plane site. Accordingly, NMR signals are unambiguously assigned to the CuO2 plane site and NQR signals around 30 MHz to the CuO chain site. This finding allows us to determine the magnetic phase diagram of YBa2Cu3O7−y from a microscopic point of view.
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  • Shuichi Emura, Masakazu Ishiguro
    1988 Volume 57 Issue 8 Pages 2666-2669
    Published: August 15, 1988
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    The second emission band (the ES band) which is observable only at low temperatures is found in NaBr:Cu+ at 4.11 eV (302 nm) through excitation at 5.06 eV (245 nm). The excitation spectrum at low temperatures shows a peak corresponding to the D2 absorption peak. The activation energies of thermal bleaching for the ES band and the known EL band are identified as 0.06 eV and 0.57 eV, respectively. The qualitative energy diagram for the emission process is shown.
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  • Taizo Masumi, Hiroshi Shimada, Hidetoshi Minami
    1988 Volume 57 Issue 8 Pages 2670-2673
    Published: August 15, 1988
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    Another echo-like “Novel Spectral Photoconductivity potentially correlative with Superconductivity” has been reasonably observed also in the Ba–Pb–Bi–O system, as expected naively from the results of the Y–Cu–O, Y–Ba–Cu–O and La–Cu–O systems by improving similar experimental procedures. A new novel spectral photoconductivity of the Ba–Pb–Bi–O freshly features the polarons and excitons in the Bi2O3-like part in the system. On the basis of these preliminary results on the Ba–Pb–Bi–O system together with those of Bi2O3, we can reconfirm substantial roles of “a coherent ensemble of united polarons and excitons” in the mechanisms of the high-Tc superconductivity in these series of compound superconductors.
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  • Taizo Masumi, Hidetoshi Minami, Hiroshi Shimada
    1988 Volume 57 Issue 8 Pages 2674-2677
    Published: August 15, 1988
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    Quite recently, we reported a preliminary part of the experimental results of “the Novel Spectral Photoconductivity of the Ba–Pb–Bi–O System potentially correlative with Superconductivity”. Here, we report an even further example of the preliminary part of the experimental data of the Ca–Sr–Bi–Cu–O system amazingly similar to those of the Ba–Pb–Bi–O system rather than those of the La–Cu–O, Y–Cu–O or Y–Ba–Cu–O systems. These results suggest the undisputed importance of “the exciton-mediated bipolaron mechanism” mainly in the Bi2O3-like part in the Ca–Sr–Bi–Cu–O system.
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  • Kazuaki Narita
    1988 Volume 57 Issue 8 Pages 2679-2684
    Published: August 15, 1988
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    We report the existence of the N-discontinuous soliton solution for the semidiscrete sine-Gordon equation under the vanishing boundary condition. First, we transform the equation for the discontinuous solitons into Hirota’s bilinear form. Next, we prove the N-soliton solution for the bilinear variables using the mathematical induction. We also discuss the complete classification of the 2-soliton solutions for the semidiscrete sine-Gordon equation.
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  • Michiaki Matsukawa, Shinsuke Watanabe
    1988 Volume 57 Issue 8 Pages 2685-2688
    Published: August 15, 1988
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    The two-dimensional Toda lattice equation is reduced to the K-dV equation by a transformation including arbitrary parameters. This transformation naturally contains Saitoh’s transformation connecting the Toda lattice and the K-dV equation. It is also studied how the discrete Zakharov-Shabat inverse scattering transformation formalism for 2D Toda lattice equation is represented by this transformation.
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  • Masatoshi Imada
    1988 Volume 57 Issue 8 Pages 2689-2698
    Published: August 15, 1988
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    A hybrid algorithm for lattice fermions is examined. The fermion determinant is evaluated by a replacement of a matrix inversion with a stochastic iteration procedure. An advantage is that the computation time increases linearly with the increase of spatial system size. Efficiency and convergence in Hubbard-type models are investigated in various cases and temperatures.
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  • Ichihiro Yamada, Atsunori Danjo, Takato Hirayama, Atsushi Matsumoto, S ...
    1988 Volume 57 Issue 8 Pages 2699-2704
    Published: August 15, 1988
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    Absolute cross sections for electron impact single ionization of O+, S+ and S2+ ions have been measured at an electron impact energy range from below threshold to 1000 eV, using the crossed beam technique. The measured cross sections for O+ ions are reproduced quite well with the semiempirical Lotz formula over the whole energy range investigated. The measured cross sections for S+ and S2+ ions show a more rapid rise from the threshold to their peak than those expected from the Lotz formula. For S2+ ions, another small bump beginning at 120 eV is observed, where no level exists that may contribute to any direct or indirect ionization processes.
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  • Fumihiro Koike
    1988 Volume 57 Issue 8 Pages 2705-2710
    Published: August 15, 1988
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    Post-collision interaction between an Auger electron and electrons created by photon- or electron-impact ionization of atoms is theoretically studied treating all the electronic coordinates as dynamical variables. Electronic wave packets are explicitly considered to properly include the wave-mechanical aspect of the process. Continuity and smoothness of the electronic wavefunction at the points where the Auger electron overtakes the ejected or scattered electrons leads an effect of the post-collision interaclion. A simple analytical formula is derived on the Auger line profile.
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  • Isamu Nakata
    1988 Volume 57 Issue 8 Pages 2711-2716
    Published: August 15, 1988
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    Nonlinear magneto-acoustic waves propagating perpendicularly to an external magnetic field in a cold collisionless plasma with random inhomogeneous density distribution are investigated. By means of a nonlinear perturbation method, a modified form of the nonlinear Schrödinger equation is derived from the basic system of equations for the magneto-acoustic waves and it is shown that the randomness of density distribution not only causes the amplitude damping and the wavenumber shift but also destroys the periodicity of a nonlinear wavetrain.
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  • Tetsu Mieno, Rikizo Hatakeyama, Noriyoshi Sato
    1988 Volume 57 Issue 8 Pages 2717-2724
    Published: August 15, 1988
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    A Spatial cyclotron resonance of ion beams passing through a multiple magnetic mirror field is investigated experimentally by varying parameters of the multiple mirror field. The optimum resonance condition is realized with a decrease in the cell length of the multiple mirror along the beams to satisfy the local condition of the spatial ion cyclotron resonance. The results show a remarkable increase of nonadiabatic transfer of the beam energy into the transverse direction to the magnetic field.
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  • Michiaki Matsukawa, Shinsuke Watanabe
    1988 Volume 57 Issue 8 Pages 2725-2729
    Published: August 15, 1988
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    The K–P and Modified K–P equations for ion acoustic wave are derived from the fluid equations for plasma with negative ion. At the critical density of the negative ion where the nonlinearity of the K–P equation vanishes, the ion acoustic soliton is described by the Modified K–P equation. The stability of Modified K-dV soliton against bending are investigated by using the Modified K–P equation. It is found that the soliton is stable, independent of the sign of amplitude.
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  • Tomejiro Yamagishi
    1988 Volume 57 Issue 8 Pages 2730-2738
    Published: August 15, 1988
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    By introducing global toroidal gyromotion of plasma particles into the Vlasov propagator in axisymmetric toroidal geometry, the eigenmode equation and dispersion relation for the universal drift wave are derived in the electrostatic approximation. At the mode rational surface, toroidal resonance of plasma is found to play an important role in the stability of the drift mode.
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  • Yasuhiro Shinnaka, Seishi Yamamoto
    1988 Volume 57 Issue 8 Pages 2739-2744
    Published: August 15, 1988
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    X-Ray diffuse scattering due to orientational disorder of NO3 ions in tetragonal NH4NO3 (phase II) is observed with the counter method. The intensity of the diffuse maximum at (1/2, 1/2, 2) critically increases with decreasing temperature and the critical temperature is estimated to be 43.5°C. It is clarified that the metastable transilions II–V*–V are structural phase transition induced by the instability of phase II. Diffuse intensity distribution is analyzed with the molecular field approximation in the Ising system. It is noticed that the first and the second neighbour interactions between NO3 ions are especially stronger than the calculated ones.
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  • Kunihiko Yamaji
    1988 Volume 57 Issue 8 Pages 2745-2750
    Published: August 15, 1988
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    By using a tight-binding-band method taking account of the spin-orbit interaction, the alternate tilt of CuO6 octahedra in the orthorhombic phase of La2−xMxCuO4 (M=Sr, Ba, …) is shown to bring in a small band splitting at the Brillouin zone boundary, which is absent without the above-mentioned interaction. The magnitude of the splitting in the highest bands mainly consisting of Cu dx2y2− and O p-orbitals is of the order of 10 meV, which is sufficiently large against magnetic breakthrough so that the Hall measurement results can be well interpreted in the framework of the band theory.
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  • Hiroshi Miyagi, Takuji Hatano, Hitose Nagara
    1988 Volume 57 Issue 8 Pages 2751-2762
    Published: August 15, 1988
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    On the basis of the local density approximation the structural expansion of the ground-state energy of simple metals is presented in the temperattare Green’s function formalism, where the terms are evaluated up to the fourth-order energy in power series of inhomogeneous density. For cubic structures, the ground-state energies of metallic hydrogen are calculated and critically compared with the recent band-theoretical calculation. Nature of the expansion in local density approximation is also discussed in comparison with results from many-body theoretical treatment.
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  • Toshiro Takabatake, Masayasu Ishikawa, Alain Junod
    1988 Volume 57 Issue 8 Pages 2763-2767
    Published: August 15, 1988
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    We have studied the transport and superconducting properties of the series of palladium-rich selenides, Pd9Se2, Pd4Se, Pd7Se2, Pd34Se11, Pd7Se4 and amorphous Pd0.7Se0.3. These compounds except Pd4Se, Pd7Se4 are superconductive above 0.38 K, whereas the rest of compounds in the whole Pd–Se system are not. The results of specific heat measurement revealed a relatively strong electron-phonon coupling inPd34Se11, which is responsible for both the enhanced Tc (2.66 K) and the anomalous temperature dependence of resistivity. The solid solutions of Pd(Se) and Pd(Te) exhibit no superconductivity above 0.38 K in spite of weakened spin fluctuations relative to those in pure Pd.
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  • Yoshikazu Suzumura, Yasumasa Hasegawa, Hidetoshi Fukuyama
    1988 Volume 57 Issue 8 Pages 2768-2778
    Published: August 15, 1988
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    The mean field theory for the coupled fermion (spinon)-boson (holon) system is developed by taking account self-consistently of coherent motions of both spinon and holon and singlet pair of spinon (RVB). The relative phase of RVB order parameters in x- and , y-directions, whose magnitudes are fixed to be the same, is treated as arbitrary. The phase, which minimizes the free energy, is found to be π for wide range of parameters. The bose condensation of holons is also examined in the case of weak interlayer electron transfer integrals. The specific heat, magnetic susceptibility and nuclear relaxation rate are calculated. It is found that their anomalies at the superconducting transition temperature depend markedly on the concentration of holons. The T-linear term in specific heat at low temperatures is shown to be vanishing, which is consistent with the recent experiments in Bi–Sr–Ca–Cu–O by Sera et al. and Kumagai et al.
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  • Isao Harada, Tetsuji Kimura, Takashi Tonegawa
    1988 Volume 57 Issue 8 Pages 2779-2790
    Published: August 15, 1988
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    Thermodynamic properties are studied for the one-dimensional spin-1/2 Heisenberg antiferromagnet with antiferromagnetic first- and second-neighbor exchange interactions. The internal energy, the specific heat, and the two-spin correlation function are calculated by means of the cluster transfer matrix method based on the Suzuki-Trotter equivalence theorem. Special attention is paid to the asymptotic behavior of the two-spin correlation function in the long-distarace limit. It is found that for a certain range of values of the interaction constants and of the temperature, the two-spin correlation function decays with an incommensurate or a higher-order commensurate oscillation as a function of the distance between two spins. We also find that there exists a quantum analog of the disorder line, on which the two-spin correlation function changes its character.
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  • Shinya Uji, Hiroshi Nagasawa
    1988 Volume 57 Issue 8 Pages 2791-2800
    Published: August 15, 1988
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    The NMR and EPR measurements of a quasi-one-dimensional conductor β-PbxV2O5 (x=0.18, 0.33, 0.37, 0.44) were carried out at temperatures between 12 K and 360 K. The evidence of a spin-singlet ground state was obtained from the temperature dependence of 51V Knight shift for x=0.18. The observed spin susceptibility is found to be those of both bipolarons having the spin singlet ground state and localized electrons showing Curie-Weiss susceptibility at the V3 sites. Bipolarons are formed only at ion pairs of the V1 site for x=0.18 with a binding energy 150 K. For x=0.44, bipolarons are expected to be formed at ion pairs of the V1 and V2 sites with a different binding energy of 350 K.
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  • Masanori Arakawa, Hiroshi Ebisu, Hideo Takeuchi
    1988 Volume 57 Issue 8 Pages 2801-2804
    Published: August 15, 1988
    Released on J-STAGE: May 29, 2007
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    EPR measurements on Cr3+ centres in K2MgF4 and Rb2MgF4 for crystals co-doped with Li+ have been made at room temperatures. In both crystals spectra for Cr3+ centres associated with a cation vacancy (VMg) and a Li+ ion at the nearest Mg2+ site in the c plane have been observed. The obtained fine structure parameters D and E are interpreted by two uniaxial spin-Hamiltonian parameters D1 and D2 using the separation method. The systematic relations among the tetragonal Cr3+–VM and Cr3+–Li+ centres in cubic perovskite fluorides are discussed by the separated parameters D2. The relation of the separation method to the Rudowicz’s net charge compensation model is also discussed.
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  • Shunji Bandow, Keisaku Kimura
    1988 Volume 57 Issue 8 Pages 2805-2811
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    A new method of observing the quantum size effect of ultrafine zinc particles is proposed. In the method proposed, an ESR-active ion as a spin probe is added to ultrafine particles (UFP’s). The electronic state of conduction electron of UFP’s is indirectly monitored via an observation of the ESR of this spin through the interaction between a spin probe and conduction electrons as in the case of d-electron spin resonance in metals. We measure the longitudinal electron spin relaxation time T1 as functions of temperature and particle size. The observed T1 is an exponential function of the inverse of temperature in the low temperature region (T<10 K). When the particle size becomes smaller, a phonon with a long wavelength no longer exists in a particle and the energy transfer from a spin system to a phonon system is prevented in a low temperature region. The quantum size effect on the phonon energy dispersion stated above is discussed in detail.
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  • P. C. Morais, G. M. Ribeiro, A. S. Chaves
    1988 Volume 57 Issue 8 Pages 2812-2818
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    Electron paramagnetic resonance of KAl(SO4)2·12H2O and NH4Al(SO4)2·12H2O doped with Tl2+ was investigated in the interval of temperature 65 K–160 K. The changes in the EPR spectra of the Tl2+ ion in both doped crystals are discussed based on the influence of a reorientational model for sulfate groups. A model to explain conflicting data reported in the literature and concerned with the presence of a phase transition in non-polarizable α-alums is suggested. Also, the changes of the EPR parameters near the phase transition in polarizable α- and β-alums are discussed here.
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  • Klaus W. Kehr, Kazuo Kitahara
    1988 Volume 57 Issue 8 Pages 2819-2825
    Published: August 15, 1988
    Released on J-STAGE: May 29, 2007
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    The spin depolarization of a particle on a linear chain with alternating Larmor frequencies is considered. The particle is initially prepared at one site with polarized spin. A crossover from initially classical behavior to an asymptotic polarization is found, as a consequence of quantum-mechanical tunneling. The influence of dynamic fluctuations on the spin depolarization is studied in the frame of the Haken-Strobl model.
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  • Kêitsiro Aizu
    1988 Volume 57 Issue 8 Pages 2826-2835
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    Phases that are incommensurate but yet also ferroelectric are possible. A ferroelectric incommensurate phase of the absolute type is defined as an incommensurate phase in which the relation P=f(|Qα|2, |Qβ|2, |Qγ|2,…) holds and which has P0≠0 through this relation. Here P denotes a polarization component; P0 is its spatial average; Qα, Qα*, Qβ etc. compose a degenerate set of order parameters; f is a function of only the absolute magnitudes (not depending on the arguments) of the order parameters. No possible specific forms of the above function have been known, except the simplest form P=J(|Qα|2−|Qβ|2), where J is a mere coefficient. The present paper shows a variety of specific forms and the cases where they occur. Some of these cases are particularly discussed.
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  • Kenji Komatsu, Kazuyuki Itoh, Eiji Nakamura
    1988 Volume 57 Issue 8 Pages 2836-2840
    Published: August 15, 1988
    Released on J-STAGE: May 29, 2007
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    The polarization reversal process is investigated on the basis of the crystal structure accurately determined by X-ray structure analysis at 170°C in the paraelectric phase. It is concluded from the anisotropic character of the atomic thermal vibrations that polarization reversal is achieved by rotation of the NO2 radical about the c-axis associated with the displacement of the Na atom along the b-axis. No significant residual electron density is found on a difference Fourier map to indicate that the atoms are on the way to another equilibrium position with a remarkably small probability.
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  • Riki Kawashima
    1988 Volume 57 Issue 8 Pages 2841-2851
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    The AC conductivities have been measured in the frequency range from 3 Hz to 100 KHz at temperatures in the three phases IV, III and II along the b-axis of RbNO3 crystal to study the dynamical properties near the successive phase transition points. The conductivities show anomalous behaviors at the transition points. The frequency dependence of the conductivities varies at the transition temperattures. The relaxation time τ(T) has been derived from the experimental results by the numerical analyses on the basis of the polydispersive model. The temperature dependence of τ(T) proposes that the relaxation processes, related to the response to the AC elecctric field, change at the transition points.
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  • Fukuo Yoshida
    1988 Volume 57 Issue 8 Pages 2852-2859
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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    Molecular reorientations are studied in the quasi-elastic region. A generalized formula of the incoherent scattering law is derived for a uniaxial motion, including the librational motion in the jump model. The indirect effects of librational excitations are explicitly shown for correlation functions. Based on this formula, discussions are given on neutron quasi-elastic scatterings for molecules in the glassy state.
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  • Takanao Asahi, Katsuhiko Hasebe, Kazuo Gesi
    1988 Volume 57 Issue 8 Pages 2860-2861
    Published: August 15, 1988
    Released on J-STAGE: June 01, 2007
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