Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 60, Issue 5
Displaying 1-50 of 50 articles from this issue
  • Hiroyasu Toyoki
    1991 Volume 60 Issue 5 Pages 1433-1436
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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    A three-dimensional cell-dynamical-system with planar symmetry is used to study the ordering process following a quench. The configuration of vortex strings is investigated and their total length is found to decrease with time as t−0.91. It is shown that the form factor obeys dynamical scaling with a characteristic length increasing as t0.45. The results are consistent with the previous theoretical result.
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  • Setsuo Ichimaru
    1991 Volume 60 Issue 5 Pages 1437-1440
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    Liquid metals pressurized to a few megabars and consisting of light nuclear species such as D–H and Li–H can sustain considerable reaction rates due to electron screening and by the strong internuclear screening potentials when the temperature is raised above the onset of fluidity in hydrogen. The nuclear fusion rates may reach a power production level on the order of kW/cm3 at a temperature and a mass density of 600 K (550 K) and 3.9 g/cm3 (6.8 g/cm3) for D–H (Li–H). The detection of such a nuclear reaction at a density near 2–4 g/cm3 will make a first laboratory demonstration for the reaction processes in supernova.
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  • Takashi Doi, Kokichi Oshima, Hitoshi Yamazaki, Hiroshi Maruyama, Hiron ...
    1991 Volume 60 Issue 5 Pages 1441-1444
    Published: May 15, 1991
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    Polarized Cu K X-ray absorption fine structure (XAFS) has been measured on a single crystal of the organic superconductor κ-(BEDT–TTF)2Cu(NCS)2. From the temperature dependence of extended X-ray absorption fine structure (EXAFS) signal, anomalies of the local structure around 100 K and 60 K have been confirmed. This is the first report on the local structure consistent with the anomalies reported in other physical properties.
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  • Hideki Ushio, Tatsuo Schimizu, Hiroshi Kamimura
    1991 Volume 60 Issue 5 Pages 1445-1447
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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    The anomalous temperature dependence of the Hall effect in the normal state of La2−xSrxCuO4 is investigated theoretically, based on the electronic structure recently derived by Kamimura and Eto, in which holes are accommodated in the Cu dz2 upper Hubbard band in the normal state. The calculated temperature and concentration dependences of the Hall coefficient are in good agreement with the experimental results by Takagi et al. We also show that the cotangent of the Hall angle is proportional to T2. The temperature dependence of the Hall effect is due to the warped shape of the Fermi surface of the Cu dz2 upper Hubbard band.
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  • Ken-ichi Kumagai, Hirozumi Matoba, Nobuo Wada, Masahiro Okaji, Koichi ...
    1991 Volume 60 Issue 5 Pages 1448-1451
    Published: May 15, 1991
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    Anomalies of heat capacity and thermal expansion have been observed near x=0.12 in La2−xBaxCuO4. The anomalies are ascribed to the low-temperature structural transition. We determine accurately the phase baundary as a function of x. Widely broadened Cu-NQR spectra for x<0.14 show that the local charged states of the CuO2 plane are largely distributed in the low-temperature phase. The phase diagram and its relation with the suppression of superconductivity around x=0.12 are briefly discussed.
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  • Masa-aki Ozaki, Kazushige Machida
    1991 Volume 60 Issue 5 Pages 1452-1455
    Published: May 15, 1991
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    By enumerating group-theoretically the antiferromagnetic (AF) states allowed under the known crystalline symmetry in a representative heavy Fermion superconductor (SC), CeCu2Si2, the conditions are examined under which a double transition of either SC (TC) or AF (TN) states occurs. It is predicted that for almost all simple AF states a splitting of the transition temperature TC or TN can be induced by a nontrivial coupling of the two order parameters, provided that the existing SC state belongs to a degenerate Eg representation.
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  • Hiroshi Maruyama, Toshiaki Iwazumi, Hiroshi Kawata, Akihisa Koizumi, M ...
    1991 Volume 60 Issue 5 Pages 1456-1459
    Published: May 15, 1991
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    Magnetic effects in the X-ray absorption process have been measured using circularly polarized X-rays emitted from an elliptical multipole wiggler. Magnetic XANES spectra on the K-edge of Fe and Ni taken by the transmission method show positive and negative spin polarizations, respectively, near the Fermi level which are consistent with the results in literature. A large positive magnetic XANES spectrum on the Nd L2-edge of Nd2Fe14B compound measured by the fluorescent method indicates that the unoccupied 5d-bands are polarized due to a significant hybridization between 4f- and 5d-states. The magnetic XANES spectrum on the Nd L3-edge has a structure below the Fermi level, suggesting a quadrupole transition contribution of the partially vacant majority band of 4f-states.
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  • Hirokazu Tsunetsugu
    1991 Volume 60 Issue 5 Pages 1460-1463
    Published: May 15, 1991
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    We have calculated the spin correlation length of the half-filled one-dimensional Hubbard model down to the temperature of T=0.01×(transfer integral) by the Bethe-Ansatz method for the quantum transfer matrix. Its temperature dependence shows the crossover from (2 log πT)−1 at high temperatures to aT−1 with the log corrections at low temperatures, the low-T behavior being consistent with the prediction by the conformal field theory. When the Coulomb repulsion U is small, we have found at low temperatures another crossover in the proportional constant a from the value for the free electron system to that for the antiferromagnetic Heisenberg model. This crossover is due to the disappearance of charge fluctuation. A similar crossover has been observed for the linear coefficient of specific heat, CT.
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  • Izuru Umehara, Nobuyuki Nagai, Yoshichika \={O}nuki
    1991 Volume 60 Issue 5 Pages 1464-1467
    Published: May 15, 1991
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    We have measured the de Haas-van Alphen (dHvA) effect and magnetoresistance of the ferromagnetic substance CeGa2 with the hexagonal structure. The Fermi surface is found to consist of two kinds of ellipsoids of revolution and a multiply connected Fermi surface, which are well explained by the results of the LAPW band calculation performed by Harima and Yanase.
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  • Kenji Miyakawa, Kozue Kaibara
    1991 Volume 60 Issue 5 Pages 1468-1471
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    The intensity of the scattered light and the turbidity of aqueous solutions of the protein of the elastic fiber, α-elastin have been measured as a function of temperature and concentration. The coexistence curve and the spinodal curve were determined from the turbidity and the angular dependence of the scattered intensity, respectively. These two curves had minima which coincided near the concentration of 0.11 mg/ml and the temperature of 21.5°C. At this point, critical divergences of the forward scattering light intensity and the correlation length were observed.
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  • Benno Fuchssteiner
    1991 Volume 60 Issue 5 Pages 1473-1496
    Published: May 15, 1991
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    In this survey we show how to obtain from the analytic structure of one-soliton solutions, the complete action angle variable representation of arbitrary multi-solitons. Special attention is paid to the interacting solitons and their relation to singularity analysis.
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  • Kazuaki Narita
    1991 Volume 60 Issue 5 Pages 1497-1500
    Published: May 15, 1991
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    For the minus sign discrete Hirota equation, we present a dark 1-soliton solution, a dark 2-soliton solution and its particular state, and a dark N-soliton solution. For the plus sign equation, we present a superposed soliton-plane wave solution and its limiting forms.
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  • Kazuya Kobayashi
    1991 Volume 60 Issue 5 Pages 1501-1512
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    As a generalization of the Gamma function defined for a single complex variable, a new special function called a generalized Gamma function, defined for two complex variables and a positive integer, is introduced, and several important analytical properties are investigated in detail, which include regularity, asymptotic expansions and analytic continuations. Furthermore, as a function closely related to a generalized Gamma function, a generalized incomplete Gamma function, which is a generalization of the incomplete Gamma function, is also introduced, and some fundamental properties are investigated briefly.
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  • Tsuyoshi Horiguchi, Ojiro Nagai, Seiji Miyashita
    1991 Volume 60 Issue 5 Pages 1513-1522
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    We investigate theoretically the structure of the ground states of the antiferromagnetic Ising model of general-spin S on the triangular lattice. It is shown that a three-sublattice structure is stable as the ground state of the Ising model of infinite-spin. A phenomenological discussion is given for the structure of the ground states for the Ising model of finite-spin.
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  • Seiji Miyashita, Hidetsugu Kitatani, Yasumasa Kanada
    1991 Volume 60 Issue 5 Pages 1523-1532
    Published: May 15, 1991
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    Positions of critical temperatures of antiferromagnetic Ising model with ferromagnetic next nearest neighbour interactions on the triangular lattice are investigated by making use of their properties of the Kosterlitz-Thouless type of phase transition. In particular, finite-size scaling method and Monte Carlo Renormalization Group methods (MCRG) with flow diagrams of the anomalous dimension η show the fixed line structure where the correlation length diverges. Another MCRG with flow diagram of the stiffness constant also shows a critical property clearly. The temperature dependence of the long range order is also discussed in order to locate the lower critical point.
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  • Kazuhiro Satoh
    1991 Volume 60 Issue 5 Pages 1533-1540
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    A coupled logistic map is applied to population dynamics of three competing species. Interaction between three species (labeled by X, Y, and Z) is assumed to be intransitive, i.e., X beats Y, Y beats Z, and Z beats X. Phase diagrams are determined for a circumstance in which the species Z interacts weakly with the XY system. It is found that the intransitive interaction results in a variety of bifurcation diagrams of torus attractors and associated hysteresis phenomena.
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  • Yoshio Yamaguchi
    1991 Volume 60 Issue 5 Pages 1541-1552
    Published: May 15, 1991
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    We present the quantum mechanically honest description of unstable particles. We demonstrate it by taking the short-lived neutral K-meson KS as an example. KS can be described properly as a ππ resonance. This view will be explicitly shown based upon a toy model which allows exact stationary ππ scattering solutions at any fixed energy. All our results can easily be extended to cases of realistic unstable particles. Notably it will be shown that the weak interactions responsible to particle decays are dominating at resonances (decaying particles), where strong interactions play minor roles (and are regarded as small perturbation terms there). In other words, weak interactions exhibit non-perturbative effects at resonance regions.
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  • Toshiyuki Ishimatsu, Tutomu Tohei, Takemi Nakagawa, T\={o}ru Kawamura, ...
    1991 Volume 60 Issue 5 Pages 1553-1559
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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    Reaction particles from the (d, t) reactions on 110Cd and 116Cd at 33 MeV and the (3He, α) reaction on 116Sn at 65 MeV were measured to investigate the deeply-bound neutron hole states. Angular distributions of broad bumps in the reaction particle spectra with a width of 8 MeV on the scale of residual excitation are well reproduced with DWBA and coupled-channel analyses assuming that these structures are composed of the particles arising from the full-strength one-neutron pickup transitions to the 1g9⁄2, 2p1⁄2, 2p3⁄2 and 1f5⁄2 neutron hole states and those from the full-strength two-step transitions to the hole-vibration coupling states involving these neutron hole states and the first 2+ and 3 states in the target or core nucleus. Existing data for the (p, d) reactions on 116Cd and 124Sn at 52 MeV and for the (d, t) reaction on 116Sn at 50 MeV are also analyzed and the same conclusion as above is indicated.
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  • Shigeo Sasaki, Yukio Ikeda, Hiroyasu Shimizu
    1991 Volume 60 Issue 5 Pages 1560-1564
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    High-pressure Raman spectra of carbon tetrafluoride (CF4) have been measured up to 8 GPa at 300 K in a gasketed diamond anvil cell. The pressure dependence of four intramolecular vibrations has been investigated. The liquid-solid I, solid I–II and solid II–III phase transitions at respective pressures 1.86 GPa, 2.84 GPa and 3.5 GPa are presented by the splitting of vibrational modes and the drastic change in Raman band widths. The observed solid I and II phases correspond to plastic (non-cubic) and monoclinic phases, respectively, that also appear at low temperatures and atmospheric pressure. The solid III phase above 3.5 GPa is a new phase. These transition pressures are supported by the good agreement with those obtained by extrapolation (to 300 K) of phase boundaries previously determined at low temperatures.
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  • Shinobu Nakazaki, Masayuki Nakashima, Hisao Takebe, Kazuo Takayanagi
    1991 Volume 60 Issue 5 Pages 1565-1571
    Published: May 15, 1991
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    The energy distribution of secondary electrons in electron-impact ionization of ions is important in computer simulation of high temperature plasmas. Surprisingly enough, no one has published the required data. In this paper, the Coulomb-Born type calculations with and without electron-exchange effect are reported. The 1⁄Z4 scaling law holds fairly well down to smaller Z values, Z being the nuclear charge of the hydrogen-like target ion. The dependence on the incident electron energy is represented fairly accurately by an empirical factor in the approximation without electron exchange.
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  • Tomoyuki Nagaya, Hideki Hotta, Hiroshi Orihara, Yoshihiro Ishibashi
    1991 Volume 60 Issue 5 Pages 1572-1578
    Published: May 15, 1991
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    Dynamics of interacting disclinations is investigated by utilizing bubble domains. A pair of wedge disclinations with strength of +1 and −1 emerge from bubble domains when a suitable electric field is applied, and the density of disclinations can be controlled by adjusting the field. To investigate the interaction between the disclinations, the time evolution is analyzed on the basis of the equation of motion for the disclinations.
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  • Masahiro Nakagawa
    1991 Volume 60 Issue 5 Pages 1579-1590
    Published: May 15, 1991
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    In this work, a complete expression of the elastic free energy of the biaxial smectics is derived within a quadratic expansion in terms of the spatial derivatives of the biaxial tensor order parameter. It is found that there exist 25 non-chiral terms, 5 of which are found to eventually be reduced as surface contributions, and 5 chiral terms in bulk elastic energy. In a uniform helicoidal state with a flat layer structure, the helical pitch is expressed as a function of the molecular tilt angle and the microscopic order parameters related to the uniaxial and biaxial molecular orderings. According to the present result, the temperature dependence of the helical pitch in SmC* or SmCA* phase is found to result from an anisotropy of the elastic constants concerned with the molecular orientation and the biaxial molecular ordering.
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  • Yasuhide Mori, Kunihiko Kaneko, Miki Wadati
    1991 Volume 60 Issue 5 Pages 1591-1599
    Published: May 15, 1991
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    A dynamical lattice model is presented to simulate fracture of brittle materials caused by quenching. With this model, relations between fracture patterns and temperature difference in quenching are investigated. It is found that as the temperature difference increases, a tree-like (a few branched) pattern suddenly changes into a net-like (many branched) pattern.
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  • Masayoshi Tanaka, Ryuji Nishimoto, Seiichiro Higashi, Nobuhiro Harada, ...
    1991 Volume 60 Issue 5 Pages 1600-1607
    Published: May 15, 1991
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    The density limit in ECR plasma production is overcome using electron cyclotron waves. The plasma of 3×1013 cm−3 density is achieved by parallel injection of circularly polarized microwaves with a frequency 2.45 GHz, corresponding to a 400 times higher density than ordinary mode cutoff. It is found that the plasma is produced in the high field side region between the incident position and the ECR point, and this is due to the generation of high energy electrons and the Doppler-shifted cyclotron resonance.
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  • Takashi Sakuma, Tadahiro Kaneko, Takaaki Kurita, Haruyuki Takahashi
    1991 Volume 60 Issue 5 Pages 1608-1611
    Published: May 15, 1991
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    The crystal structure of CuBrSe3 at room temperature has been analyzed by the Rietveld method with X-ray powder diffraction data. It belongs to the orthorhombic system with the space group Pnc2, and has lattice constants of a=4.481(1) Å, b=7.672(1) Å, c=14.329(2) Å. The structure of CuBrSe3 includes the ordered arrangement of Cu+ ions. On the basis of the results of structure analysis, it is suggested that the nature of the bond between Cu and Br atoms is ionic, and that between Se atoms is covalent.
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  • Yasushi Kôzuki, Yoichi Hanayama, Masaki Kimura, Teruo Nishitake, ...
    1991 Volume 60 Issue 5 Pages 1612-1618
    Published: May 15, 1991
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    The effect of hydrostatic pressure on the elastic constants of the single crystal black phosphorus is studied by using a gas pressure apparatus. Neon gas is used as the pressure transmitting medium. A large single crystal of orthorhombic black phosphorus with the dimensions of 5×3×6 mm3, has been grown under the condition of 1 GPa and 900°C by using a large solid isotropic compression system. The ultrasound wave velocity is measured by a pulse transmission method up to 3.3 GPa. The longitudinal wave velocities along X and Y axes decreased, while that along Z axis increased. An anomaly was observed around 1.7 GPa, which may be attributed to the vanishing of the energy gap of black phosphorus.
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  • Masamichi Sakai, Masayumi Hayakawa, Noritaka Kuroda, Yuichiro Nishina, ...
    1991 Volume 60 Issue 5 Pages 1619-1627
    Published: May 15, 1991
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    We have studied the effect of the order-disorder transition of the orientation of perchlorate (ClO4) ions on the vibrational modes of ethylenediamine (NH2CH2CH2NH2) in [M(en)2][Pt(en)2Cl2](ClO4)4, where en is ethylenediamine and M=Pt or Pd ion, by means of Raman spectroscopy. Upon the transition into the ordered phase, the spectra due to the CH stretching modes split into two groups on account of the difference in the coordination sites of Pt(II)[Pd(II)] and Pt(IV). The spectral separation between the two groups is about 20 cm−1 at 270 K. On the other hand, the NH stretching and the NCCN skeleton modes exhibit no splitting. These results indicate that the protons of the methylene (CH2) group of the ethylenediamine have a strong interaction with the internal motion of the perchlorate ions which bind the CDW chains.
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  • Kêitsiro Aizu
    1991 Volume 60 Issue 5 Pages 1628-1633
    Published: May 15, 1991
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    The material constants that characterize simultaneously incommensurate and ferroelectric phases are linear electro-incommensurate constants, such as dh⁄dE, dq1⁄dE and dqn⁄dE, where E denotes an electric field applied in the direction of spontaneous polarization, h the wavenumber of the first harmonic (the fundamental wave) in Q (any one of the order parameters), q1 the amplitude of the first harmonic, and qn the amplitude of the nth harmonic (a high harmonic). One typical case is investigated, namely the P\bar4b2-(1/2, 0, 0) case. In this case, a ferroelectric incommensurate phase of the absolute type is possible. The transition between this phase and the prototypic phase can be second order. The expressions of the temperature dependences of almost all linear electro-incommensurate constants in the vicinity of the mentioned transition are presented.
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  • Yoshihiro Ishibashi, Yoshiki Hidaka
    1991 Volume 60 Issue 5 Pages 1634-1637
    Published: May 15, 1991
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    A phase diagram and several physical quantities related to an isomorphous transition are studied on the basis of a Landau-type free energy function. Relationship with a two-sublattice model including an asymmetric double minimum potential is discussed.
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  • Tôru Chônan, Atsushi Yamada, Kazuko Motizuki
    1991 Volume 60 Issue 5 Pages 1638-1646
    Published: May 15, 1991
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    Self-consistent APW band calculations are carried out for non-magnetic states of transition-metal intermetallic compounds having Cu2Sb-type crystal structure. The energy dispersions, densities of states and Fermi surfaces are shown. Differences and similarities of the electronic band structures of Cr, Mn, Fe-arsenides are clarified. To discuss the bonding nature, calculations of the bond order are also carried out.
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  • Noriyuki Takano, Satoshi Imai, Mitsuru Fukuchi
    1991 Volume 60 Issue 5 Pages 1647-1653
    Published: May 15, 1991
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    An expression for the density of states (DOS) is derived in the Korringa-Kohn-Rostoker cluster-coherent-potential approximation (KKR-CCPA) using the augmented space method. This expression is applied to the Cu–Pd and Cu–Ag disordered alloys in the 2-site cluster approximation. We present the DOS and the band structure energy for these alloys in the 2-site cluster approximation and discuss the effects of the cluster.
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  • Akira Hasegawa, Hiroshi Yamagami
    1991 Volume 60 Issue 5 Pages 1654-1665
    Published: May 15, 1991
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    Electronic structure is calculated for LaSn3 by a self-consistent relativistic APW method with the one-electron potential in the local-density approximation. LaSn3 is a reference for the mixed-valence compound CeSn3 in which the 4f electrons have recently been proven to be itinerant and contribute directly to the formation of the Fermi surface. Here, the relation between the Fermi surfaces of LaSn3 and CeSn3 is investigated. The main Fermi surface of LaSn3 consists of a distorted hole sphere and a network with slender arms, both of which are connected with small necks. These sheets can explain the de Haas-van Alphen effect and the high-field magnetoresistance reasonably well. The distorted hole sphere in LaSn3 and the hole sheet in CeSn3 originate from the eighth band, and look similar to each other. In CeSn3, the electron sheet exists as a result of compensation.
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  • Shin-ichi Furusawa, Satoshi Miyaoka, Yoshihiro Ishibashi
    1991 Volume 60 Issue 5 Pages 1666-1671
    Published: May 15, 1991
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    The conductivity of TiO2-dispersed AgI was measured as a function of mole ratio of TiO2 at 30°C and 180°C. An enhancement of the conductivity was observed at low temperature phase. A simple model is proposed, which will be useful in quantitative estimation of concentration dependence of the conductivity enhancement due to dispersed insulating particles.
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  • Kiyoshi Yonemitsu, Takaaki Takenobu, Hideyuki Sato, Yoshichika \={O}nu ...
    1991 Volume 60 Issue 5 Pages 1672-1678
    Published: May 15, 1991
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    Point-Contact-Spectra of f-electron compound NdCu6 were measured at 1.6 K∼10 K. We observed two types of structures, one is due to the inelastic conduction electron scattering by Nd ions accompanying the excitation between the crystal field splitted levels and another is due to a magnetic transition by way of Joule’s heating. From the careful analysis of simulation and the experiment, we got a method to discriminate the latter from the former. As a result, we succeeded to identify three peaks due to the crystal field excitation at 2 mV, 4.5 mV and 9 mV.
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  • Hideaki Kasai, Kunihiro Mitsutake, Ayao Okiji
    1991 Volume 60 Issue 5 Pages 1679-1688
    Published: May 15, 1991
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    The effects of confining geometry are investigated on ballistic transport in quasi-one-dimensional quantum wires. The coupled channel type method is used in order to calculate the conductance of the quantum wires as a function of the Fermi energy. It is shown that oscillations existing in the conductance of the wire with a confining potential of ‘step wise’ type geometry disappear as the variation of the confining geometry becomes smooth. In the wire with an extended part irrespective of its geometry, step wise or smooth, the conductance shows dip structures. In the wire with double constrictions, there appear oscillations in the conductance, which can be considered to reflect the existence of resonance and bound states between these two constrictions. The effects of the external magnetic field on ballistic transport are studied in the above-mentioned wires as well.
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  • Susamu Taketomi, Hiromasa Takahashi, Nobuyuki Inaba, Hideki Miyajima
    1991 Volume 60 Issue 5 Pages 1689-1707
    Published: May 15, 1991
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    Macro-clusters formation of the magnetic colloidal particles in magnetic fluids is investigated. Experiments of an optical microscope observation of the macro-clusters formation and of anomalous light scattering by the magnetic fluid are reported. Looking upon the anomalous light scattering of the magnetic fluid as a kind of critical opalescence and using Debye’s opalescence theory, we derive a thermodynamical instability theory of the colloidal particles’ dispersion. Relations among the instability theory of Cebers, that of Sano and Doi, and ours are discussed. An interaction energy among the colloidal particles is evaluated from the light scattering experiment. Similarities among the macro-cluster formation, spinodal decomposition of precipitation-type magnetic alloys, and flux-line lattice formation in type-II superconductors are discussed.
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  • Hiroaki Kadowaki, Toshiya Inami, Yoshitami Ajiro, Kenji Nakajima, Yasu ...
    1991 Volume 60 Issue 5 Pages 1708-1720
    Published: May 15, 1991
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    Universality classes of successive magnetic phase transitions in the triangular lattice antiferromagnet CsMnI3 are studied by measuring the critical exponents γ and ν using neutron scattering. The critical exponents of the successive transitions at TN1=11.2 K and TN2=8.2 K, which correspond to orderings of magnetic moments parallel and perpendicular to the c-axis, respectively, are determined to be γ⁄⁄=1.12±0.07, ν⁄⁄=0.59±0.03 (TN1) and γ=1.04±0.03, ν=0.56±0.02 (TN2). These values and the β exponents β⁄⁄=0.32±0.01, β=0.35±0.01 measured in our previous work do not agree with a theory which predicted the three dimensional XY universality for both the transitions. This is in contrast with the satisfactory agreement of critical exponents of CsMnBr3 with a theory of the novel three-dimensional Z2×S1 universality. A uniform magnetization parallel to the c-axis in terms of the three sublattices in the c-plane is found to increase slowly below TN1.
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  • Setsuo Mitsuda, Hideki Yoshizawa, Tsukasa Watanabe, Shinichi Itoh, Yas ...
    1991 Volume 60 Issue 5 Pages 1721-1729
    Published: May 15, 1991
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    Neutron depolarization measurements from reentrant spin glass (RSG) alloys of Au1−xFex (x=0.16 and 0.19) were performed to investigate magnetic properties of mesoscopic inhomogeneity. The wavelength dependence of the depolarization below RSG temperature, Tg, suggests that ferromagnetic long range order coexists in the RSG phase, which is consistent with the Gabay-Toulouse model. The present experiment also demonstrates that the averaged spontaneous magnetization over a mesoscopic scale shows unusual decrease with decreasing temperature, which appears well above Tg.
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  • Kazushige Machida, Yoshiki Hori, Masahiro Nakano
    1991 Volume 60 Issue 5 Pages 1730-1742
    Published: May 15, 1991
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    In order to explain recursive cascades of the field-induced spin density wave phase in organic conductors (TMTSF)2X discovered recently, a standard model or two-dimensional anisotropic Hubbard model under a perpendicular field is investigated theoretically: The field-induced SDW ground state is in general to be characterized by a set of countable many order parameters (OP) of the Fourier components of the SDW modulation or by a distribution of these OP’s. Due to interference between the lattice commensurability and magnetic length the OP distribution differs for every rational field, resulting in a phase diagram with devil’s staircase like infinite cascades. The band structure and spatial profile of the FISDW are analyzed and compared with ordinary density wave states.
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  • Mitsumasa Ishiwata, Yasushi Ishii
    1991 Volume 60 Issue 5 Pages 1743-1754
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    Longitudinal relaxation of 13C and 1H in chloroform dissolved in a nematic liquid crystal has been observed between 25 and 34°C at 89.6 and 400.1 MHz (for 1H) by the selective and nonselective inversion recovery method. The data can be satisfactorily explained by a combination of fast reorientation of the solute and slow fluctuations in the nematic phase, under consideration of the intramolecular dipole-dipole and external random field interactions together with cross correlations between the two. Local structure fluctuations in the nematic phase have played a substantial role in the spin relaxations. The external random field interaction on the proton and the cross correlation relating this interaction have considerably been dependent on the observing frequency.
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  • Hiroyuki Mashiyama, Mamoru Sakamoto, Hazime Nakamura, Hironobu Kasano, ...
    1991 Volume 60 Issue 5 Pages 1755-1762
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    X-ray scattering from thiourea is investigated by the use of an ordinary X-ray source and synchrotron orbital radiation. Discommensurations in the modulated phases are recognized in diffraction patterns which contain high-order satellites. In the ferroelectric phase, diffusive peaks are observed. This indicates the existence of residual discommensurations as ferroelectric domain walls. The peculiar dielectric anomaly at 161 K of thiourea is discussed in connection with the residual discommensurations.
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  • Takenari Goto, Yoshiro Goto
    1991 Volume 60 Issue 5 Pages 1763-1768
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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    We have measured luminescence spectra of a biaxial ZnP2 crystal under high density excitation at 2 K, and found two non-linear bands which are assigned as due to radiative annihilation of the excitonic molecule leaving an exciton. The lower energy band is concluded to be associated with the ground state of the excitonic molecule with symmetry Γ1+ and the higher energy band with the first excited rotational state with symmetry Γ1+2Γ2. From the time resolved spectra of these luminescences, it is assumed that a hot excitonic molecule with a large wave vector contributes to the higher energy luminescence. The binding energies of the excitonic molecules in the ground and the rotational states are estimated to be 5.0 meV and 3.6 meV, respectively.
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  • Masaaki Yamaguchi, Kazuo Morigaki, Shoji Nitta
    1991 Volume 60 Issue 5 Pages 1769-1791
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    Light-induced phenomena in a-Si1−xNx:H films with x of the range of 0<x≤0.28 were studied by photoluminescence (PL) and optically detected magnetic resonance (ODMR) measurements. The experimental results on the spectral dependences of PL and ODMR for various excitation intensities measured before and after prolonged illumination in a-Si1−xNx:H films are interpreted in terms of a newly introduced nonradiative center (E* center) as well as other radiative and nonradiative centers. The energy levels and nature of these centers are discussed. We obtained evidence for the creation of both radiative and nonradiative centers by prolonged illumination, whose creation rate depends on the substrate temperature for preparation, particularly the hydrogen content, as well as the nitrogen content.
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  • Masami Fujita, Hideyuki Nakagawa, Norio Kitagata, Hiroaki Matsumoto, T ...
    1991 Volume 60 Issue 5 Pages 1792-1798
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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    Reflection spectra of CdCl2-CdBr2 mixed crystals and pure CdI2 crystal were measured in detail in order to investigate Cd2+ 4d core exciton states. The second-energy-derivative reflectance spectra calculated from measured spectra reveal that the core exciton absorption consists of eight fine structures in CdCl2 and nine fine structures in CdBr2 and CdI2. The fine structures in mixed crystals shift continuously with the change in composition, and the correspondence between the fine structures in CdCl2 and CdBr2 has been clarified. Peak positions and relative intensities of the fine structures were obtained by a line shape analysis. Based on a one-electron excitation picture, the observed fine structures are explained in terms of spin-orbit splitting of the 4d core level and crystal field splittings of the 4d and 5p levels of the Cd2+ ion.
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  • Tetsuhiko Tomiki, Minoru Kaminao, Yoshikazu Tanahara, Tomoyoshi Futemm ...
    1991 Volume 60 Issue 5 Pages 1799-1813
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    Optical spectra of YAlO3 (YAP) single crystals are measured for ⟨a⟩, ⟨b⟩ and ⟨c⟩⁄⁄E in the region from 6.5 eV to 42 eV by use of a plane polarized synchrotron radiation, E being the electric field of light. Anisotropic spectral behaviour of the intrinsic absorption including the tail absorption is found, and a tentative interpretation of spectral features is given in terms of the energy levels of the constituent atoms of YAP. It is found that the principal factor determining the interband absorption onset position is the bond length of Y3+–O2− in the compounds of Y2O3, YAP and YAG. The steepness constants σs0 of these compounds are found to decrease in magnitude with increasing deviation from the mean value of the Y3+–O2− bond lengths participated in the tail absorptions.
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  • Koichi Terashima, Isamu Imai
    1991 Volume 60 Issue 5 Pages 1814-1823
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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    Piezotransmission spectra near the indirect absorption edge and piezoreflectance spectra in the visible region of group 4B transition metal disulfides ZrS2 and HfS2 have been studied by the stress modulation technique at 77 K. The uniaxial stress X was applied along the a axis and the spectra were measured using the polarized light, E⁄⁄X and EX, where E is the electric field of the incident light. The change of the energy levels by the strain is evaluated by comparing the piezo-modulated spectra with the wavelength-modulated spectra. The main peak and the broad structure at higher energy side in the spectra originate from the overlapping of the transitions at and near Γ point and the other structures at lower energy side are due to the transitions at L and M points.
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  • Atsunari Hiraya, Kazutoshi Fukui, Poh-Kun Tseng, Takatoshi Murata, Mak ...
    1991 Volume 60 Issue 5 Pages 1824-1828
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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    The absorption spectrum of solid Ne measured in the 800–1300 eV region is presented. Two sharp peaks near the K-edge around 865 eV which correspond to the 1s→3p and 1s→4p transitions in gaseous Ne are attributed to the excitonic transitions. Above the ionization energy of 1s electron in gaseous Ne, many structures are observed in solid Ne.
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  • Kazuaki Narita
    1991 Volume 60 Issue 5 Pages 1829-1830
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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  • Yoshikazu Suzumura
    1991 Volume 60 Issue 5 Pages 1831-1832
    Published: May 15, 1991
    Released on J-STAGE: June 01, 2007
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  • Susumu Hirakata, Midori Tanaka, Kay Kohn, Eijji Kita, Kiiti Siratory, ...
    1991 Volume 60 Issue 5 Pages 1833
    Published: May 15, 1991
    Released on J-STAGE: May 29, 2007
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