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Takaaki Kajita, Katsushi Arisaka, Masatoshi Koshiba, Masayuki Nakahata ...
1985 年 54 巻 11 号 p.
4065-4068
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Search for nucleon decays induced by magnetic monopoles has been carried out with a 3000 ton water Cherenkov detector by two independent methods. Search for multiple nucleon decays in the detector gives the cross section and velocity dependent limits on the monopole flux,
FM<2.5×10
−15 cm
−2s
−sr
−1 for 5×10
−5<β
M<10
−3 and for σ=100 mb at 90% C.L. Search for low energy neutrinos (30<
Eν<52 MeV) from the Sun gives a limit,
FM(σ
0⁄1mb)<1.6×10
−21(β
M⁄10
−3)
2 cm
−2s
−1sr
−1 at 90% C.L.
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Yoshifumi Kimura, Hidenori Hasimoto
1985 年 54 巻 11 号 p.
4069-4072
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Motion of two identical point vortices in a simple shear flow is studied. According to the competition between the strength of the shear flow and that of the vortices, two vortices either separate being carried by the flow or rotate on a periodic orbit. The critical ratio of these strength is found, and computer simulations are made for various situations according to this criterion. The integrability of this system is also considered as a Hamiltonian system. Though the Hamiltonian is less symmetric than that of the case without a boundary or an external flow, the system is integrable according to the Liouville theorem.
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Yukiharu Ohsawa
1985 年 54 巻 11 号 p.
4073-4076
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Korteweg-de Vries equation that is applicable both to magnetosonic fast and slow waves is derived from a two-fluid model with finite ion and electron pressures. For all propagation angles with the external magnetic field, the slow wave has the positive soliton. The fast wave has the positive soliton in quasi-perpendicular propagation and the negaive soliton for the angle below the critical angle; finite β effects lead to the broardening of the region of the positive soliton. The theory is applied to the
vp×
B acceleration by the nonlinear fast and slow waves. It is found that the slow waves can strongly accelerate the ions in high β plasmas, and that the finite β effect enhances the acceleration in the fast wave.
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Kenji Hiraga, Makoto Hirabayashi, Akihisa Inoue, Tsuyosi Masumoto
1985 年 54 巻 11 号 p.
4077-4080
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
High-resolution electron microscopic images of a melt-quenched Al-14 at%Mn alloy displaying an icosahedral point-group symmetry were interpreted in terms of projections of a three-dimensional space filling of the Penrose type skeleton, which was recently completed by Ogawa (J. Phys. Soc. Jpn.
54 (1985) 3205). Fitting with the observed images, two types of basic golden rhombohedra, acute and obtuse ones, are estimated to have the edge-length of 0.48 nm, and two atomic structure models are proposed.
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Masamichi Sakai, Noritaka Kuroda, Yuichiro Nishina
1985 年 54 巻 11 号 p.
4081-4084
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Pressure dependences of the Raman scattering and X-ray diffraction have been measured in ZnCl
2 at room temperature. As-grown crystals of the a phase transform at 2.1 GPa into a new phase, designated δ, which has the CdCl
2 type layer structure. On releasing the pressure, the δ phase transforms at 1.2 GPa into the γ phase with the red-HgI
2 type layer structure. The γ phase is stable even if the pressure is completely released. With increasing pressure on the second run and thereafter, the γ-ZnCl
2 crystal reversibly transforms into the δ phase with hysteresis between 1.2 and 2.6 GPa. This polymorphism is discussed in relation with dimensionalities of bonding networks in respective phases.
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Kuniyuki Koyama, Motohiro Matsuura
1985 年 54 巻 11 号 p.
4085-4088
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Proton NMR of a layer structure antiferromagnet Cu(HCOO)
2·2CO(ND
2)
2·2D
2O is investigated in detail near the transition temperature
TN. The temperature dependence of spontaneous staggered magnetization
L0 is found to be expressed by a single exponential law with an index β=0.22±0.02 in the measured temperature range 4·10
−4\lesssimε\lesssim4·10
−1. The very weak Ising-type anisotropy is predicted to be essential to the novel critical index. The origin for such a phase transition is discussed, taking the possible canting interaction into account.
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Yoshio Sakai, Kazuhiro Kaneda, Nobuo Tsuda, Midori Tanaka, Kiiti Sirat ...
1985 年 54 巻 11 号 p.
4089-4091
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Seebeck coefficient of stoichiometric YFe
2O
4 was observed down below the lower transition temperature. The conduction was
n type at lower temperatures. The result was analyzed with two-level hopping model, following Kuipers and Brabers together with a magnetic ordering effect on a mobility. It was suggested that a mobility of holes was greatly reduced by a magnetic ordering effect.
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Koji Kajita
1985 年 54 巻 11 号 p.
4092-4095
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Conductivity of two dimensional electrons trapped on the surface of solid neon has been measured with the electron density up to 3×10
10/cm
2. From the anomaly in the temperature dependence of the conductivity we have determined the critical temperature where electrons undergo a transition to a Wigner crystal, and extended the phase diagram of the crystal to a density one order of magnitude higher than that obtained for electrons on liquid helium surface. The transition was found to be characterized by a relation
Γ=138±25. No quantum effect was observed in this density region.
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Hideki Yayama, Hidenori Kubo, Akihisa Tomokiyo
1985 年 54 巻 11 号 p.
4096-4098
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Specific heat measurements are carried out on the random mixture of two antiferromagnets with competing anisotropies, CsMn
1−xCo
xCl
3·2H
2O (
x=0.032 and 0.102). Two anomalies are observed. One is due to the transition between the paramagnetic and antiferromagnetic phases and the other the transition between the antiferromagnetic and intermediate phases. The preliminary phase diagram is obtained.
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Kazumichi Namikawa, Masami Ando, Tetsuo Nakajima, Hiroshi Kawata
1985 年 54 巻 11 号 p.
4099-4102
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
A resonance-type X-ray magnetic scattering at the
K-absorption edge was first observed in 220 Bragg reflection of ferromagnetic Ni single crystal. Further a theoretical discussion on the resonance magnetic scattering curve observed was carried out; A difference of the oscillator-strength density for each direction of the spins was also derived from this curve. The oscillator-strength density for minority spin excesses that for the majority spin between the Fermi level and 25 eV above the level. The difference of oscillator-strength density amounts to about 1×10
−4/Ry at the maximum.
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Manabu Mizota, Yutaka Maeda
1985 年 54 巻 11 号 p.
4103-4106
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Radular teeth of chitons were studied using Mössbauer spectroscopy. Their spectra gave clear evidence of the presence of magnetite and a small amount of paramagnetic substance. These are characteristic features in biogenic magnetite. Measurements on the teeth at different locations along the radular were also performed. The results show that the magnetite in the radular teeth of chitons changes considerably from its stoichiometry as the teeth mature.
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Yoshihiro Ishibashi
1985 年 54 巻 11 号 p.
4107-4109
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
A new analytical expression is presented for the poly-nuclear growth (PNG) model, which provides a better agreement with the Monte Carlo simulation result than those proposed previously.
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Akira Nakamura
1985 年 54 巻 11 号 p.
4111-4114
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
We consider the spherical Boussinesq equation. We have found the exact solitary wave solution to it. The solution is the explode-decay solitary waves.
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Yoko Hase, Shinsuke Watanabe, Hiroshi Tanaca
1985 年 54 巻 11 号 p.
4115-4125
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Cylindrical ion acoustic solitons are investigated theoretically and numerically in a plasma with negative ion. In a theoretical part, we derive a cylindrical Korteweg-de Vries equation for an ion acoustic wave. The sign of nonlinear coefficient depends on the negative ion density. At the critical density of the negative ion where the nonlinearity of the Korteweg-de Vries equation vanishes, the ion acoustic wave is described by a cylindrical modified Korteweg-de Vries equation, and in the vicinity of the critical density, it is described by a combined cylindrical equation of the Korteweg-de Vries and modified Korteweg-de Vries types. The change of a soliton amplitude due to the geometrical effect is analytically obtained in two limiting cases when the geometrical effect is much stronger or weaker than the nonlinear and dispersive effects. In the numerical calculation, the theoretical prediction for the change of the soliton amplitude is verified.
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P. J. Hansen, D. J. Kaup
1985 年 54 巻 11 号 p.
4126-4132
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The analytic properties of the Jost functions for the inverse scattering transform associated with the forced Toda lattice are shown to determine the time evolution of this particular boundary valve problem. We suggest that inverse scattering methods may be used generally to analyze forced integrable systems. Thus an extension of the applicability of the inverse scattering transform is indicated.
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Masahiro Nakagawa, Tadashi Akahane
1985 年 54 巻 11 号 p.
4133-4141
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
A simple cubic lattice model by DiMarzio is applied to the study of the nematic-isotropic phase transitions in liquid crystalline mixtures. The order parameters of rigid cores and of completely flexible tails of molecules, transition entropies, and density changes at the transitions are numerically calculated in some binary systems. In addition, the phase diagrams of them are evaluated. The present results show that in most cases the nematic-isotropic transition temperatures in the binary mixture of nematogens are lower than the linearly interpolated values. However, for the mixture of components with the same ratio of the flexible chain length to rigid core, such lowering of nematic-isotropic transition temperatures does not be found.
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Hachiro Niizeki
1985 年 54 巻 11 号 p.
4142-4150
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The level scheme of
191Os has been studied from β-decay of
191Re. Gamma-ray singles spectra, γ-γ and β-γ coincidence spectra were obtained by using high resolution detectors. A total of 82 γ-transitions observed were assigned in the level scheme of
191Os consisting of thirty-six excited states up to 1391.89 keV. The level and γ-ray transition properties are discussed in terms of the Nilsson model combining the information from (
d,
p), (
d,
t) reactions and (
n, γ) spectroscopies.
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Hideo Yamada, Osamu Mochizuki, Haruo Yamabe, Tatsuya Matsui
1985 年 54 巻 11 号 p.
4151-4160
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Variation of pressure was measured by using a condenser microphone, when a vortex ring was approaching a flat wall. Considerably large negative pressure was observed even at the stagnation point on the wall. This negative pressure was found to occur when the ring “rebounded” from the wall. Before the ring rebounding, the pressure variation could be predicted approximately by the potential flow theory. After the rebounding, it showed negative values, entirely different from the theory. However, this fact can be illustrated by the potential theory applied to a simple, modified model of trajectory of the ring during the rebounding, which takes account of the viscosity effect.
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Toshihiko Dote, Masatoshi Shimada
1985 年 54 巻 11 号 p.
4161-4171
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The transition from free to ambipolar diffusion of the electrons in a cylindrical positive column of glow discharge has been treated on the basis of the quasi-neutral theory. The two-component (electron and positive ion) fluid equations in the cylindrical coordinate are used, where the inertia terms are firstly omitted, this being valid in a range of particularly low electron temperature. We obtain an expression of the diffusion coefficient which includes the linear and square terms of a quantity directly related to the space charge density. A general picture of the transition characteristics can be shown by the solution where the square term of the above quantity is neglected. This square term has, however, to be included in a region of the smaller electron density or the higher electron temperature. Finally, the inertia effect is discussed. At high and low electron density limits, the ambipolar and free diffusion coefficients, respectively, are found to be smaller than the values without inertia effect, because the inertia motions retard the flows of charged particles.
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Takaya Hayashi, Tetsuya Sato, F. Wysocki, D. D. Meyerhofer, Masaaki Ya ...
1985 年 54 巻 11 号 p.
4172-4177
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
A comparison is made of the tilting instability and resulting nonlinear reconnection between a three-dimensional magnetohydrodynamic (3D MUD) simulation and the proto S-1/C spheromak experiment. A good agreement is obtained. The observed fast reconnection process is found to be explained by the driven reconnection theory.
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Toshiaki Oosuga, Hideaki Takabe, Kunioki Mima
1985 年 54 巻 11 号 p.
4178-4187
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The magnetic field effects on the resonance absorption are investigated by numerical analysis in laser produced plasmas. The numerical analysis includes the expanding plasma dynamics determining the density profile modification and the d.c. magnetic field induced by the resonance absorption. The numerical results show that the absorption rate is enhanced by both the density profile steepening and the d.c. magnetic fields. The maximum absorption rate is found to increase up to 70% for the laser intensity,
Iλ
2 of 10
17 Wμm
2/cm
2.
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Takashi Sakuma
1985 年 54 巻 11 号 p.
4188-4192
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
A treatment to get the thermal factor
Tj(
Q) at site j for a harmonic and anharmonic potential field was discussed. A transformation of the scattering vector
Qj=
Rj−1Q1 was introduced in the treatment where
Rj is the rotational part of a symmetry operation which transforms the atomic positions from
r1 to
rj. This method can be applied to a general potential form including the 1st, 2nd, 3rd and higher order components. An application of the treatment to solid electrolytes α-AgI, β-AgI
3SI and β-Ag
3SBr was studied.
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Akito Igarashi, Toyonori Munakata, Yutaka Kaneko
1985 年 54 巻 11 号 p.
4193-4204
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Displacement-displacement dynamical correlation functions of an anharmonic chain are calculated with the use of the formalism of the self-consistent-phonon theory given by Götze and Michel. The memory function in this formalism is calculated by two methods. One is a lowest order perturbation approximation. The other is a fully-self-consistent approximation for the memory function based on the mode-mode coupling approximation. The results of these approximations are compared with the simulation results of our molecular dynamics calculations, and the applicability and limitation of the SCP theory are examined.
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Kazuo Gesi, Masashi Iizumi
1985 年 54 巻 11 号 p.
4205-4212
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The phase transition in deuterated compound of {N(CD
3)
4}
2ZnBr
4 was studied by dielectric and neutron scattering measurements. The transition temperature and its pressure coefficient are 14.2°C and 0.183 K MPa
−1, respectively. They are practically unchanged by deuteration. Above the transition, streak-like quasielastic neutron diffuse scattering was found both along the
c*-and along the
b*-directions. The maxima of the diffuse scattering locate around (
h,
k,
l±0.4) and (
h,
k±0.5,
l). The inverse intensity at (3, 0, 1.6) depends approximately linearly on temperature, and by extrapolation it tends to zero at −4.7°C. On the other hand, the peak intensity at (3, 1.5, 0) is less temperature dependent. Transverse acoustic phonons along the
b*- and
c*-directions do not show appreciable softening.
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Kêitsiro Aizu
1985 年 54 巻 11 号 p.
4213-4220
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The order parameter,
Q(
x), for incommensurate transitions can, as is well known, be expressed as a sum of harmonics of the form
Qn e
inhx, where
n is an integer. Let θ
n=arg
Qn. For |
n|>1, let η
n=θ
n−
nθ
1. Two different types of incommensurate phases are conceivable. In one, the phase differences η
ns’s (subscript
s means spontaneous) are constant against variation of temperature
T. In the other, η
ns’s vary with
T. The constant phase difference type is usual, but the varying phase difference type is also possible. On cooling, it is possible that an incommensurate phase of the constant phase difference type, which succeeds the prototypic phase, is changed to an incommensurate phase of the varying phase difference type by second-order transition. A detailed account of this transformation is given.
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Isao Minagawa
1985 年 54 巻 11 号 p.
4221-4223
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The presence of Bjerrum defects is taken into account in the study of phase transition of ice Ic, where Slater-Takagi model of KH
2PO is modified to include interaction between neighbouring molecules and fourteen order parameters are used. The phase transition of ice Ic with Bjerrum defects is of the first order as with Ic without them. When the formation energy for a pair of Bjerrum defects is larger than sixty times the energy of interaction of neighbouring molecules
EC, the effect of defects on the transition is negligible.
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W. N. Lawless, C. F. Clark, S. L. Swartz
1985 年 54 巻 11 号 p.
4224-4231
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The changes in the dielectric constant (ε) of a single crystal of KTaO
3 and of a ceramic plate of SrTiO
3 were measured at 4.2 and 20.4 K in magnetic fields up to 15 T to examine recent vibronic-theory predictions. It is found that these changes are orders of magnitude smaller than predicted and are of
opposite sign in KTaO
3 and SrTiO
3. Measurements on KTaO
3 at 20.4 K were made with the magnetic field aligned along the [111], [110], and [100] directions and with an electric field (4.5 kV/cm) along [001] in the latter case, and these data are analyzed for the magnetoelectric tensor coefficients. It is found that the largest vibronic change is along [001], and the magnetic field splits and hardens the soft-mode frequency in KTaO
3, the parallel effect being about twice as large as the perpendicular effect.
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Tomozo Tomoyose
1985 年 54 巻 11 号 p.
4232-4235
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The ion hopping dressed by conduction electrons is investigated to describe the temperature dependence of the deviation from the Einstein relation in silver chalcogenides. The ratio of the averaged diffusion coefficient \bar
D to the tracer diffusion coefficient
D* has led to the deviation and shown the power-law dependence on temperature
T. The deviation numerically calculated is in good agreement with that of the experiments.
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Naoyuki Tajima, Masuo Fukui, Yoshihiro Shintani, Osamu Tada
1985 年 54 巻 11 号 p.
4236-4240
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Oxidation studies of copper films at room temperature have been carried out by measuring the ATR spectra involving information about surface plasmon polariton characteristics. Oxidation is initially rapid, but after 10 to 20 minutes, drops to a negligible value, a stable film being formed ∼2.7 nm thick. It has been furthermore confirmed that copper oxide films formed in 20 Torr of oxygen at room temperature are composed of a mixture of Cu and CuO
0.67 (gross defect structure of Cu
2O) in the first stage of oxidation, but the final composition becomes CuO
0.67.
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Setsuro Asano, Shoji Ishida
1985 年 54 巻 11 号 p.
4241-4245
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The bandstructures of LaCd were calculated by the KKR method and the local-spin-density approximation for both the CsCl and the tetragonal structures. From these bandstructures, we find that the band Jahn-Teller effect can cause the cubic-to-tetragonal lattice transformation, that the important factor in this effect is the atomic shifts from the atomic positions of the CsCl structure to the ones of the body-centered-tetragonal structure rather than the distortion along this
c-axis and that not only d electrons of La but also p electrons of Cd contribute to this effect.
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Masako Akai, Hisazumi Akai, Junjiro Kanamori
1985 年 54 巻 11 号 p.
4246-4256
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The electronic structure of impurity atoms (atomic number
Z=1–56) in ferromagnetic iron is calculated self-consistently by the Green function method in the local density approximation of the spin-density functional approach. The calculation corresponds to an improvement and the extension of the previous work by Yoshida, Terakura and Kanamori. The mechanism proposed by them for the observed systematic variation in the hyperfine field and the nuclear spin-lattice relaxation time of impurity nuclei for substitutional impurities with
Z≥10 is confirmed on the basis of the present self-consistent calculation which is carried out systematically for the first time.
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Hisazumi Akai, Masako Akai, Junjiro Kanamori
1985 年 54 巻 11 号 p.
4257-4264
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The local magnetic moment
Mloc, the hyperfine field
Hhf and the nuclear spin-lattice relaxation time
T1 of 3
d and 4
d transition metal impurities in Fe are calculated in the framework of the Green function method and in the local spin density approximation (LSD). The calculation reproduces the observed major trends of
Mloc,
Hhf and
T1 quite well, though the calculated
Hhf shows a systematic deviation from the experimental values in the case of impurities whose magnetic moment couples parallel to the bulk magnetization. The mechanisms of the variation of these quantities are elucidated in the light of the present
ab initio calculation.
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Hiroshi Bando, Madoka Tokumoto, Keizo Murata, Hiroshi Anzai, Gunzi Sai ...
1985 年 54 巻 11 号 p.
4265-4270
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Resistance data of organic metals β-(BEDT–TTF)
2X (X=IBr
2, I
2Br, I
3) measured under magnetic fields up to 50 kOe and temperature down to 0.5 K are presented. For X=IBr
2, and I
2Br the magnitude of the transverse magnetoresistance measured in the field of 50 kOe applied along the
c*-axis is 1–4% of the normal resistance, being consistent with the two-dimensional band structure. On the other hand, the resistance of β-(BEDT–TTF)
2I
3 crystals exhibits a
stepwise change when the field strength coincides with the value
Hstep∼(25 kOe)[1−
T/(7 K)]. This is ascribed to the recently found 8 K-superconducting phase under a soft pressure, which is partly contained in the crystals even without pressure. The angular dependence of
Hstep is consistent with the critical field anisotropy of this superconducting phase.
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Keizo Morimoto, Michiharu Kitagawa
1985 年 54 巻 11 号 p.
4271-4281
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The compensation dependences of the resistivity and Hall constant of CdS containing 3×10
15 cm
−3 donors have been studied at temperatures between 4 and 300 K. The compensation ratio was changed by thermal recovery of acceptor-type defects which were introduced into high-purity samples by 10 MeV electron irradiation. At various compensations, the temperature dependences of the resistivity and Hall constant show the features of impurity conduction. At low compensations the conduction similar to the D
− band conduction appears, although the ratio of the average distance of donors
rD to their effective Bohr radius
aB is
rD⁄
aB≈17. At high compensations it is difficult to observe the low-temperature conduction. It is suggested that the low-temperature conduction is the impurity conduction assisted by electron-phonon interaction via the piezoelectric field.
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Tohru Takahashi, Michisuke Kobayashi
1985 年 54 巻 11 号 p.
4282-4289
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
We consider a semi-infinite intercalated compound, which is made of alternating layers of conduction electrons and mobile ions, and examine collective excitations of the system. Collective excitations of an infinitely extended system are also discussed. These properties are derived by a classical analysis using Maxwell’s equations.
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Kenji Takanaka
1985 年 54 巻 11 号 p.
4290-4294
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
The critical field
Hc3 of dirty superconducting films is calculated in the presence of Pauli spin paramagnetism and spin-orbit impurity scattering. It is shown that the ratio
Hc3⁄
Hc2 for thin films near the transition temperature has larger values than 1.695 and it decreases with decreasing temperature by both temperature and spin paramagnetic effects.
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Moriji Mizoguchi
1985 年 54 巻 11 号 p.
4295-4299
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Temperature dependences of the NMR line shape were measured in the low temperature phase of magnetite. For the sample which was cooled to 4.2 K in an external magnetic field, we found an abrupt change of line shape at about 26 K. This phenomenon must be caused by the changing of an electron ordering structure in the magnetic domain walls and may be explained by use of a pinning plane model. That is, in the magnetically stabilized structure, a kind of plane in which the electron ordering structure is “abnormal” pins the major part of magnetic domain walls. The plane structure changes at 26 K and an ordinary structure of the magnetic domain is reconstructed drastically by the release of the magnetic domain walls from the plane.
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Akio Furukawa, Yoshihide Kimishima, Yasukage Oda, Hiroshi Nagano, Yosh ...
1985 年 54 巻 11 号 p.
4300-4305
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The magnetization and the ac magnetic susceptibility of the quasi-two dimensional layered material 1T-TaS
2 has been measured in the temperature region of a few Kelvin to 30 mK. The characteristic magnetically ordered state has been found in this substance; the remanent magnetization becomes dominant below 1 K and the ac susceptibility has a peak around 0.5 K. This magnetic behavior is discussed on the basis of Anderson localization of 1T-TaS
2.
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Masayuki Shiga, Yoshitoshi Muraoka, Nobuyuki Ishibashi, Yoji Nakamura
1985 年 54 巻 11 号 p.
4306-4311
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The temperature dependence of elastic constants of quenched Fe
1−xAl
x (
x=0.26, 0.30 and 0.32) single crystals was measured by a ultrasonic pulse-echo technique from 4.2 K to 300 K under applied magnetic fields. For the ferromagnetic alloy with
x=0.26, the
ΔE effect was observed in the
C44 mode. The reentrant spin glass alloy with
x=0.30 also shows the
ΔE effect in
C44 above 90 K, which corresponds to the reentrant spin glass freezing temperature,
Tf. Below
Tf the
ΔE effect completely disappears, indicating freezing of spins or magnetic clusters. In the spin glass alloy with
x=0.32 a slight softening of
C44 was observed around
Tf determined by magnetization measurements. These observations indicate that the elastic measurement provides an useful experimental method of determining the spin glass freezing temperature, in particular, for reentrant type spin glasses.
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Takashi Tonegawa, Koichi Takasaki, Makoto Kaburagi
1985 年 54 巻 11 号 p.
4312-4320
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
It is shown that the lattice gas model in which two kinds of particles interact by pair-wise interactions is mathematically equivalent to the three-state Potts model under external fields, if the
k-th neighbor interaction constants between the same kinds of particles are equal and if the
k-th neighbor interaction constant between different kinds of particles is half of those between the same kinds. By using this equivalence together with our recent result of the rigorous ground state analysis of the lattice gas model for the case of the one-dimensional lattice with first and second neighbor interactions, the ground state of the three-state Potts model for this case is determined rigorously.
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Yoshihiro Yamada, Akihiko Sakata
1985 年 54 巻 11 号 p.
4321-4324
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Pulsed NMR investigations of
93Nb have been performed in the hexagonal Laves phase intermetallic pseudobinary system (Nb
1−xMo
x)Fe
2 with
x≤0.2. From the measurements of the Knight shift and the nuclear spin-lattice relaxation time
T1, it has been found that the substitution of Mo for Nb changes the nearly ferromagnetic properties of NbFe
2 to be less magnetic in the concentration of
x≤0.2. This is in strong constant to the case of the Zr substitution where NbFe
2 changes to be more magnetic by the substitution and the ferromagnetism is stabilized at
x=0.05∼0.15 of (Nb
1−xZr
x)Fe
2.
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Kichizo Asai, Takuya Okada, Hisashi Sekizawa
1985 年 54 巻 11 号 p.
4325-4330
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The supertransferred hyperfine magnetic field,
HSTHF, at
111Cd(←
111In) on the tetrahedral site of Fe
3O
4 was measured by means of the time differential perturbed angular correlation (TDPAC) between 85 and 300 K. Each TDPAC spectrum has a well-defined hyperfine frequency component above the Verwey temperature,
TV(=120 K), whereas remarkably distributed one below this temperature. The value of
HSTHF at low temperatures is +121 kOe in average, which shows the covalence in Cd
2+–O
2− bonds is considerably smaller than that in In
3+–O
2− bonds in spinel type oxides. The apparent distribution of the hyperfine frequencies below
TV is qualitatively explained by a distribution of
HSTHF at
111Cd due to fluctuation of the relative populations of Fe
3+ and Fe
2+ ions in the neighboring octahedral sites, or a small amount of electric field gradient acting on
111Cd in addition to
HSTHF.
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Norihiro Sugimoto, Hide Yoshioka, Mitsuo Yamaga
1985 年 54 巻 11 号 p.
4331-4339
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The intensities of the ODMR spectra of the STE (AgCl
6)
5−, and (AgBrCl
5)
5− in AgCl crystals are studied as functions of the microwave modulation frequencies at 1.6 K. The STE shows a broad maximum near 50∼200 Hz, suggesting the existence of polarized STE’s. The intensity of the (AgBrCl
5)
5− becomes maximal at 300 Hz, a higher frequency than those for the STE. Though the intermediate Jahn-Teller effect of (AgBrCl
5)
5− is not conclusive from experiments using the circularly-polarized-light detection, analysis of the intensities of the ODMR lines indicates that the reorientation of the Jahn-Teller axis occurs frequently during the lifetime.
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Mitsuo Yamaga, Norihiro Sugimoto, Hide Yoshioka
1985 年 54 巻 11 号 p.
4340-4344
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
An isotropic ODMR line other than the ODMR spectra of the self-trapped exciton (STE) with the tetragonal symmetry in AgCl at 4.2 K was observed using X-band and K-band spectrometers. The
g value satisfied the relation of
g=(
g⁄⁄+2
g⊥)⁄3 where
g⁄⁄ and
g⊥ are the
g values of the parallel and perpendicular spectra of the STE. The isotropic line is ascribed to motional narrowing of the tetragonal spectra of the STE. This observation of thermal dynamic Jahn-Teller effect of the STE at 4.2 K indicates that the bound electron in the STE lowers the barrier height between three configurations of the static Jahn-Teller distortion of the self-trapped hole (STH).
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Hidekazu Tanaka, Katsunori Iio, Kazukiyo Nagata
1985 年 54 巻 11 号 p.
4345-4358
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
We report the results of the EPR measurements performed on the single crystals of CsCuCl
3 in the temperature range 120 K to 560 K at X- and K-band frequencies. Discontinuous changes in the linewidth and the shift of resonance field are observed at the structural phase transition point of 420 K. The EPR properties, i.e. the magnitude of the linewidth, its anisotropy, the anisotropy of resonance field, etc, observed in both the high- and low-temperature phases can be interpreted in terms of the exchange modulation of the Dzyaloshinsky-Moriya antisymmetric interaction. This fact indicates that the CuCl
6 octahedra in CsCuCl
3 are already distorted above the transition point and the relaxation time of the distortion is much longer than 10
−12 sec.
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Masaru Komukae, Yasuharu Makita
1985 年 54 巻 11 号 p.
4359-4369
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
The real and imaginary parts of the complex dielectric constant along the
b axis of monoclinic RbD
2PO
4 were measured in a frequency range between 10
6 Hz and 10
9 Hz. It was found that RbD
2PO
4 shows dielectric critical slowing-down near the ferrielectric phase transition point. In addition, the static dielectric constants (ε
0) of RbD
2PO
4 and the partially deuterated crystal Rb(D
0.3H
0.7)
2PO
4 were also measured at 10
4 Hz. A theoretical expression of ε
0 for a ferrielectric phase transition was obtained on the basis of the quasi-one-dimensional Ising model with assumed two sublattices. The remarkable deviations of ε
0 from the Curie-Weiss law observed in these crystals were analyzed successfully by the present theoretical result and the experimental results were discussed.
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Hitoshi Nishimura, Tomonori Yamaoka, Kei Hattori, Atsuo Matsui, Kenich ...
1985 年 54 巻 11 号 p.
4370-4381
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Decay curves and spectral shapes of the singlet-exciton luminescence in anthracene crystals have been studied at room temperature and found to depend on the experimental geometry and on the penetration depth of the exciting light. The well-known wavelength-dependent decay time and time-dependent spectrum occur only when the luminescence is excited in the process of the one-photon absorption and is observed in the backward-scattering geometry. In the forward-scattering geometry, the decay time is independent of the luminescence wavelength. When the excitons are uniformly generated in the crystal in the process of the two-photon absorption, the wavelength-dependent decay time and time-dependent spectrum do not occur even in the backward-scattering geometry. These results are interpreted in terms of diffusion of the singlet excitons and reabsorption of the short wavelength photons of the exciton luminescence.
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Toyokazu Tambo, Chiei Tatsuyama
1985 年 54 巻 11 号 p.
4382-4389
発行日: 1985/11/15
公開日: 2007/06/01
ジャーナル
認証あり
Core electron binding energies of GaS(β), GaSe(ε) and InSe(γ) with respect to the vacuum level have been obtained by measuring the onset of secondary electron emission in the X-ray photoelectron spectroscopy (XPS). The chemical shift for the least bound core level of cation is estimated to be 3.4 eV for GaS, 2.0 eV for GaSe and 1.7 eV for InSe with respect to the level of metal. The Madelung constant of each compound is calculated to be 1.44, 1.60 and 1.48, respectively. The ionicity is estimated to be about 0.46, 0.45 and 0.49, respectively. The magnitude of chemical shift is discussed on the basis of the electrostatic model which reflects two-dimensional crystal structure.
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Hitoshi Ohta, Katsuhisa Homma, Keigo Nagasaka
1985 年 54 巻 11 号 p.
4390-4394
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Far-infrared transmission spectra of a single crystal N-methyl-N-ethyl-morpholinium-ditetracyanoquinodimethanide, MEM(TCNQ)
2, was measured for the first time over the range from 15 to 200 cm
−1 at 1.5 K (below spin-Peierls transition temperature
Tsp=17.4 K) and 23 K (above
Tsp). We found that the absorption lines 130.5 and 150.5 cm
−1 at 23 K shift to 126 and 156 cm
−1 at 1.5 K. With an aid of calculations of phonons above and below
Tsp, it is concluded that the 126, 150.5 and 156 cm
−1 lines are phonons and the 150.5 cm
−1 line at 23 K changes to the 156 cm
−1 line at 1.5 K. The 126 cm
−1 line at 1.5 K is due to the lattice distortion caused by the spin-Peierls transition and can be interpreted by the folding mechanism. The assignment of the 130.5 cm
−1 line at 23 K is remained in the present stage.
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Shin-ichi Uchida, Setsuko Tajima, Atsushi Masaki, Shunji Sugai, Koichi ...
1985 年 54 巻 11 号 p.
4395-4409
発行日: 1985/11/15
公開日: 2007/05/29
ジャーナル
認証あり
Infrared reflectivity spectra of BaPb
1−xBi
xO
3 alloys in their semiconducting phase (
x≥0.4) are presented. Four optical phonon bands are clearly observed in the reflectivity spectrum of BaBiO
3. It is found that the oscillator strength of one phonon mode remarkably decreases with increase of the Pb composition. This provides a strong evidence for the charge disproportionation which leads to the formation of a superlattice of alternating inequivalent Bi sites in BaBiO
3. It is suggested that the macroscopic formation of such Bi superlattice is also responsible for the semiconducting properties of alloys. Based on the experimental observations the nature of the metal-semiconductor transition of this system is discussed.
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