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Junji Suzuki, Takeo Izuyama
1987 年 56 巻 10 号 p.
3401-3404
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
An elastic model for the membrane is studied using the renormalization group approach of the momentum shell recursion method. It is shown that this model exhibits a phase transition between the flat surface phase and the rough one.
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Fujihiro Hamba
1987 年 56 巻 10 号 p.
3405-3408
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Constants in the
k−ε model are estimated using the statistics obtained from a large eddy simulation of a turbulent mixing layer. Estimated values are compared with those usually adopted in the
k−ε model and those derived by statistical analysis. It is shown that the estimate using large eddy simulation can give an important clue to the optimization of the constants and improvement of the model.
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Shunjiro Ikezawa, Keisuke Kida, Tomiya Yamazumi, Yoshinori Taki, Tatsu ...
1987 年 56 巻 10 号 p.
3409-3412
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
Circularizers in an endless mirror device with
l=2 and
l=3 helical windings were designed using computer calculations of the magnetic surfaces. The parameters determined were substituted into the approximate equations obtained by E. Friman
et al. to confirm their adequacy. It was found that the circularizer pitch is two and three times larger than that in a helical system of
l=2 and
l=3, respectively; that the circularizer may be mounted anywhere in the mirror part; and that the circularizer current
Ic needs about one third that required of helical systems.
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Hironobu Maeda, Naruhiko Bamba, Akihisa Koizumi, Yuzo Yoshikawa, Tadao ...
1987 年 56 巻 10 号 p.
3413-3416
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
The temperature dependence of the EXAFS (Extended X-ray Absorption Fine Structure) method has been carried out to study high-
Tc superconductors of composition Y
1−xBa
xCuO
3−δ with
x=0.6. The anomalous behavior of the Debye-Waller factor in the superconducting transition region is observed, which may result from the breathing-mode vibration of oxygen atoms around Cu atoms, as reported in the oxide superconductor La–Sr–Cu–O system.
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Takumi Kikegawa, Hiroshi Iwasaki
1987 年 56 巻 10 号 p.
3417-3420
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
In situ high-pressure X-ray and synchrotron radiation diffraction data for polycrystalline arsenic at ambient temperature show that it undergoes transition from the rhombohedral A7-type structure into the primitive simple cubic structure at a pressure of around 32 GPa and that this structure remains stable at least up to 45 GPa. The observation is in an agreement with the theoretical prediction by Mattheiss, Hamann and Weber (Phys. Rev. B
34 (1986) 2190), but the trautsition occurs at a more reduced volume (
V⁄
V0∼0.74) than that which was calculated.
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Toshio Soda
1987 年 56 巻 10 号 p.
3421-3424
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
A new estimate of the transition temperature
Tc of the superfluidity is made from the attractive interactions intermediated by the Bogoliubov phonon between two
3He particles in the background of the Bose condensed ground state of
4He, using the pseudopotential between helium particles and the magnitude of the correlation length of
4He. The precursors both in the proximity effect of superfluid
3He to the solution and the diffusion coefficient of the two-dimensional
3He–
4He film are shown to have the divergence of the type of the inverse of
T−
Tc as the temperature
T approaches
Tc from the above, as in the Curie-Weiss law of the magnetic susceptibility.
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Hiroshi Iwasaki, Shigehiko Hasegawa, Makoto Akizuki, Sung-Te Li, Shogo ...
1987 年 56 巻 10 号 p.
3425-3428
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
Diffuse spots slightly displaced from the (\sqrt3×\sqrt3) positions were observed in the high-temperature (1×1) state of Si (111) by low-energy electron diffraction. The spots showed threefold 3m symmetry and rotated around the \sqrt3 positions with changes in primary energy. These are reproduced by kinematic calculations for a surface configuration with adatoms distributed randomly over both the threefold-hollow and threefold atop sites of a (1×1) substrate with the exclusion of forming bonds with a common substrate atoms.
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Takehiko Mori, Kenichi Imaeda, Reizo Kato, Akiko Kobayashi, Hayao Koba ...
1987 年 56 巻 10 号 p.
3429-3431
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The electrical resistivity of an organic metal, (DMDCNQI)
2Cu (DMDCNQI: 2,5-dimethyl-N,N′-dicyanoquinonediimine) is measured under pressure. Though this compound retains a metallic state down to 1.5 K at ambient pressure, a metal semiconductor transition appears above 4.5 kbar, and the transition temperature increases with an increase in pressure. On the analogy of the related compounds, this transition is attributed to a kind of one-dimensional instability.
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Shozo Takeno
1987 年 56 巻 10 号 p.
3432-3435
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Superconductivity by electron pairing in real space is modelled by a reduced Hamiltonian in pseudo-spin form, which is similar to the Hamiltonian for a planar Heisenberg ferromagnet in an external field. By making correspondence of coherent states of the model pseudo-spin system to superconducting states, an effective, zero-temperature Ginzburg-Landau (GL) equation is derived. Pseudo-spin parameters are evaluated from the GL parameters obtained by Meissner effect measurement and other methods for Ba
2YCu
3O
6.9 with
Tc=91 K. The numerical value of
Tc is estimated by using the mean-field approximation. The result so obtained is shown to be in fairly good agreement with the experimental result.
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Koichi Kikuchi, Keizo Murata, Yoshiaki Honda, Takahisa Namiki, Kazuya ...
1987 年 56 巻 10 号 p.
3436-3439
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
We discovered superconductivity at ambient pressure in (DMET)
2I
3 at 0.47 K and in (DMET)
2IBr
2 at 0.59 K (midpoints), where DMET is (dimethyl(ethylenedithio)diselenadithiafulvalene), while in (DMET)
2I
2Br, superconductivity was not observed down to 0.5 K. In the DMET salts, those with smaller molar volume exhibit higher transition temperature, contrary to the BEDT–TTF salts. The effect of the disorder of the anion orientation on superconductivity is discussed.
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Katsurou Hanzawa, Kei Yosida
1987 年 56 巻 10 号 p.
3440-3443
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
A possible mechanism for superconductivity in heavy-fermion systems is presented on the basis of the infinite-
U periodic Anderson model. It is shown that the interaction between a strongly correlated electron (
f-electron) and a weakly correlated electron (conduction electron) resulting from a virtual exchange of density fluctuation of the strongly correlated electrons is attractive for singlet pairing. The expressions of the free energy and the self-consistent equations for the gap parameter and
TC are obtained in the Hartree-Fock approximation. Similar considerations can also be applied to high-
TC superconductors in which 3
d-electrons of Cu
2+ and
p-electrons of O
2− play roles of strongly correlated and weakly correlated electrons, respectively.
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Chiaki Uyeda, Akio Yamagishi, Muneyuki Date
1987 年 56 巻 10 号 p.
3444-3446
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
A large magneto-volume effect is found in liquid-phase oxygen. The volume expansion
ΔV⁄
V0 is 2.2×10
−4 under the field of 80 kOe, which is about ten times larger than that in ferromagnetic Fe, Co or Ni metals. The effect is understood by the exchange repulsion between O
2 spins polarized by an external magnetic field. The contribution of the magneto-volume effect to field-induced transparency is discussed.
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Takao Yoshinaga, Tsunehiko Kakutani
1987 年 56 巻 10 号 p.
3447-3463
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
By using a nonlinear coupled transmission line which consists of two
LC ladder lines connected by intermediary capacitors, characteristic properties of fast and slow mode solitons and their collisions (both overtaking and head-on collisions) are examined experimentally. The observed results show a good agreement with those predicted by the second order Korteweg-de Vries (K-dV) theory except for the phase shifts due to the collisions. A similarity of this line to a two-layer fluid in the long gravity wave region is also discussed.
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Yasuhiro Akutsu, Tetsuo Deguchi, Miki Wadati
1987 年 56 巻 10 号 p.
3464-3479
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Using a generalized Alexander-Conway relation derived from a three-state exactly solvable model in statistical mechanics, new invariant polynomials for knots and links are explicitly evaluated. It is shown that the invariant polynomials for closed 3-braids are obtained recursively. It is also shown that the invariant polynomials are more powerful than the Jones polynomials.
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Shigeo Homma, Shozo Takeno
1987 年 56 巻 10 号 p.
3480-3490
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
A sine-lattice equation sin (
un+1−
un)−sin (
un−
un−1)−\ddot
un=0 is shown both analytically and numerically to exhibit approximate, but well-defined, one- and multi-kink solutions of the form
un=
A tan
−1(α
n⁄β
n) for an arbitrary constant
A>0, where the quantities α
n and β
n are simply discrete versions of the corresponding ones in the conventional sine-Gordon equation. This is due to the kink dispersion relation 4 sinh
2(
k⁄2)−ω
2=0 entirely equal to the case of the Toda lattice solitons.
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Akira Nakamura
1987 年 56 巻 10 号 p.
3491-3498
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Exact solutions of the 3+1 dimensional Toda equation,
Δ log
Vn−
Vn+1+2
Vn−
Vn−1=0, where
Δ≡∂
2⁄∂
x2+∂
2⁄∂
y2+∂
2⁄∂
z2 have been obtained. The boundary condition is the “molecule” condition which is vanishing
Vn at both ends of the finite chain,
VN=
V−N=0 or
VN=
V−N−1=0. In the large molecule and small angle limit, the present solution reduces to the 2+1 dimensional cylindrical Toda soliton.
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Kunisuke Nisizima, Kazuyosi Ikeda
1987 年 56 巻 10 号 p.
3499-3511
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The exact expressions for the
volume-dependent cluster sums (composed of four or less molecules) for the three-dimensional simple cubic lattice gas (in a cube-shaped vessel) with nearest and second nearest neighbour interactions are obtained. The detailed behaviour of the cluster sums for the simple cubic lattice gas as functions of the volume of the vessel is investigated for the case when the nearest neighbour interaction is repulsive and the second nearest neighbour interaction is attractive. On the basis of their behaviour, the condensation phenomenon of such a lattice gas is discussed by applying Ikeda’s theory of condensation of systems satisfying the G-condition.
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Katsuhiko Nishimura, Susumu Ohya, Naoshi Mutsuro
1987 年 56 巻 10 号 p.
3512-3514
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
Nuclear magnetic resonance on oriented
73Se in an iron host has been observed at about 7 mK. From resonance-shift measurement, the magnetic hyperfine-splitting frequency ν
M,
g-factor and magnetic hyperfine field were derived as ν
M=102.61(3) MHz, |
g(9⁄2
+)|=0.188(16) and B
HF(
73Se
Fe)=716(81) kG. The experimental values of the
g-factors of the
g9⁄2 neutron states, in the neighborhood of the neutron number 40, are compared with the theoretical values based on the core-polarization model.
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N. Riahi
1987 年 56 巻 10 号 p.
3515-3524
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
Weakly nonlinear thermal convection in a horizontal fluid layer bounded above by a free surface is studied by taking effects of the surface tension gradient into account. It is found that the critical Rayleigh number, the horizontal size of convection cells and the instability of the convection can be affected by the surface tension gradient. The heat transported by the convection may have a maximum value at a certain value of the Marangoni number
M. For the particular range of
M, the hexagonal flow pattern may arise with either upward or downward motion at the cells’ centers.
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Takayuki Aoki, Keishiro Niu
1987 年 56 巻 10 号 p.
3525-3533
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The linear stabilities of a rotating and propagating light ion beam in a low-density plasma are studied numerically on the basis of the hydromagnetic equations. The centrifugal force acts on the beam and the self-magnetic fields are induced by the rotating and propagating charged particles. To clarify the physical mechanism, a simple model characterizing a rotating and propagating beam is utilized, and it is found that the centrifugal force and the magnetic field in the azimuthal direction play a role of stabilization. Under such beam parameters which are practically required for the energy driver for inertial confinement fusion, the numerical results indicate that the beam in the equilibrium state is stable if the ratio of the beam-rotating velocity to the propagating one is more than the value of 0.8.
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Shunjiro Ikezawa, Yoshiaki Ishizaki, Tomiya Yamazumi
1987 年 56 巻 10 号 p.
3534-3542
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
An ECR discharge plasma source obtained through the use of ferrite magnets was studied especially focusing on the threshold electric field at the breakdown and the energy distribution of charged particles in the plasma produced. The microwave frequency was a little smaller than the electron cyclotron frequency by about 0.5∼1%, which was explained clearly by the electron trapping condition. The energy distribution of electrons has the second harmonic and strongly depends on the localizing of the microwave field.
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Katsuhiko Hasebe, Hiroyuki Mashiyama, Naohiro Koshiji, Sigetosi Tanisa ...
1987 年 56 巻 10 号 p.
3543-3552
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
The crystal structure of [N(CH
3)
4]
2ZnCl
4 was studied at three temperatures, 30, 60 and 90°C, in the paraelectric phase and at 5.5°C in the ferroelectric phase by using the X-ray reflection data collected by an automatic four-circle diffractometer. The split-atom method and the significance test showed that the constituent ions are in disorder in the normal phase. In the ferroelectric phase, positional and thermal parameters and occupation probability of ions were calculated by the least-squares method. The density modulation of ZnCl
4 and that of one kind of N(CH
3)
4 ion were closely incorporated.
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Kazuyoshi Yamada, Ichiro Hirosawa, Yasuhisa Noda, Yasuo Endoh, Yoshich ...
1987 年 56 巻 10 号 p.
3553-3557
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Neutron scattering experiments using single crystals of LaCu
6 and CeCu
6 revealed the same type of the structural phase transition from orthorhombic to monoclinic structure in both compounds. The softening of [100] transverse acoustic phonons associated with the structural phase transition was observed in the high temperature phase. The temperature dependences of the distortion angle in the monoclinic phase and of the acoustic soft phonon can be unified for both compounds as a function of the reduced temperature
T⁄
Tm. The major contribution to this phase transition was concluded to be attributed not to 4f electrons of rare earth ions but to 3d electrons of Cu ions.
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Eiji Kato
1987 年 56 巻 10 号 p.
3558-3565
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
The mechanism of the glass transition of solvent quinoline in a polystyrene (quinoline) gel is studied by measurements of get length and depolarized Rayleigh scattering. It is found that the effect of intermolecular force between quinoline molecules and the polystyrene network is important in the glass transition of the solvent. Due to the force, fluctuations in orientations of solvent molecules are frozen and the molecules are bound to the network. With nearing the glass transition temperature, the intensity of a broad Rayleigh component decreases due to decrease of the number of solvent molecules fluctuating in the network and that of a narrow Rayleigh component increases due to increase of inhomogeneity of the gel density.
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Makoto Matsumoto, Shinya Wakoh
1987 年 56 巻 10 号 p.
3566-3569
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The electron-positron many-body enhancement effect on the two-dimensional angular correlation distribution of positron annihilation radiation (2D ACAR) inchromium is phenomelogically investigated. The enhancement parameters are determined so as to obtain the best fit of the theoretical 2D ACAR to the experimental one. Two kinds of enhancement are considered. The first is a state-dependent one. In this scheme two enhancement factors are used for
s–
p electrons and
d-electrons. For a hybridized state the value of enhancement is decided by a weighted mean of those two factors according to their partial populations in the state. The other is a character dependent one. In this scheme two enhancement factors are also used, but they are used to scale the partial wave functions in the electron wave coupled to the positron. The result using the character-dependent enhancement is very good, while that using the state-dependent one is not so good.
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Hisatoshi Yokoyama, Hiroyuki Shiba
1987 年 56 巻 10 号 p.
3570-3581
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The ground state of the Hubbard model on one-dimensional and two-dimensional square lattices is studied with the effective Hamiltonian derived for the strong correlation regime and Gutzwiller-type wave function. The non-half-filled band as well as the half-filled band is discussed. The variational Monte-Carlo method enables us to evaluate the energy for the singlet liquid (resonating-valence-bond state) and for Néel state. The result shows that the stability of the singlet liquid depends on the dimensionality of the system.
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Hisatoshi Yokoyama, Hiroyuki Shiba
1987 年 56 巻 10 号 p.
3582-3592
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
As a continuation of a previous paper [J. Phys. Soc. Jpn.
56 (1987) 1490], the variational Monte-Carlo method is extended to include the antiferromagnetic long-range order. The theory is based on the Gutzwiller-type correlation factor and its effect is exactly taken into account by the Monte-Carlo procedure. An application is made to the half-filled-band case of one-dimensional lattice (50 sites), two-dimensional square lattice (up to 20×20 sites) and three-dimensional simple cubic lattice (6×6×6 sites). The result is qualitatively different from previous studies relying on the random-phase-type “Gutzwiller approximation.” The variational energy for two and three dimensions is favorably compared with Hirsch’s quantum Monte-Carlo data.
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Haruyuki Takahashi, Shigeru Tamaki, Shoichi Sato
1987 年 56 巻 10 号 p.
3593-3597
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
The electron density distribution in AgBr was investigated on the basis of X-ray intensity data collected by single crystal diffractometry. It was verified from difference Fourier map that the charge tends to accumulate in the intermediate region between the neighbouring unlike atoms. The origin of the extra charge on the difference Fourier map is investigated in terms of the radial distribution of the valence electrons.It is pointed out that the estimated value of the diamagnetic susceptibility of AgBr based on the present result agrees consistently with the observed one.
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Atsutaka Maeda, Kunimitsu Uchinokura, Shoji Tanaka
1987 年 56 巻 10 号 p.
3598-3608
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The low-frequency broadband noise of K
0.3MoO
3 associated with the sliding motion of charge-density waves (CDW) was measured in the frequency range between 1 mHz and 1 MHz. The power spectrum of voltage fluctuation consists of several peaks and the 1⁄
fα background spectrum. As a result of an analysis, the former was found to be directly related to the energy distribution of the hopping among metastable states of the CDW’s, and the energy distribution was estimated from the experimental data. On the other hand, the latter is considered to come from the interaction among semi-macroscopic moving CDW domains, which are weakly coupled with each other.
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Masaki Togashi, Tatsuya Okada, Satoru Ohno
1987 年 56 巻 10 号 p.
3609-3615
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The enhancement of the susceptibilities χ
d of liquid In
2Te
3, InTe
4 and Te caused by addition of Cr, Mn and Fe solutes decreases gradually with increasing temperature. This suggests that Cr, Mn and Fe ions are in a magnetic state in these liquid solvents. Similarly, the d states of V, Co and Ni solutes become magnetic in liquid InTe
4 and In
2Te
3 alloys. The trend of χ
d versus transition metal solute exhibits a large peak at Mn. The low density of states of a solvent at the Fermi level is reflected on large values of χ
d in these liquid solvents, compared with the values of χ
d in liquid metals. It is found that χ
d(Fe)>χ
d(Cr) and χ
d(Co)>χ
d(V) in these liquid solvents. This relationship is attributed to a low density of conduction electrons of a solvent.
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Satoru Ohno, Tatsuya Okada, Masaki Togashi
1987 年 56 巻 10 号 p.
3616-3621
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
The electrical conductivity of the liquid InTe
4 alloy increases with addition of Fe, Co and Ni solutes, and decreases with addition of Ti, V, Cr and Mn solutes. For the liquid In
2Te
3 solvent, the trend of the increase in the conductivity in the series of transition metal solutes exhibits a large peak at Ni and a small peak at V. The increase in the conductivity for Fe, Co and Ni solutes is considerably larger than that for other transition metal solutes. The remarkable increase in the conductivity caused by addition of transition metal solutes is closely related to the increase in the total density of states at the Fermi level due to the sp-d admixture effect.
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Masahiro Inoue, Tadashi Takemori, Kazuo Ohtaka, Ryozo Yoshizaki, Tunet ...
1987 年 56 巻 10 号 p.
3622-3634
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
An inter-layer Cooper pairing mechanism is considered for layers of two-dimensional electrons which are coupled by the exchange of three-dimensional phonons. We propose that the high transition temperature of Ba–Y–Cu–O compound may originate from this mechanism because of the combined effects of the strong attraction due to phonon exchange and the substantially reduced Coulomb repulsion between paired electrons. Impurity effects and relative stability between the inter- and intra-layer Cooper pairings are discussed and a phase diagram is calculated.
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Mitsuo Kataoka
1987 年 56 巻 10 号 p.
3635-3647
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
In order to elucidate the different behaviours of the helical spin density waves (HSDW) due to the antisymmetric and symmetric exchange interactions, spin waves in the conical spin density wave (CSDW) states and the induced ferromagnetic states (IFMS) under external magnetic fields are calculated by use of phenomenological Hamiltonians with and without the antisymmetric exchange interaction. It is found that the spin wave spectra for the two types of HSDW are strongly different from each other, especially in the magnetic field dependences, enough to be able to distinguish them. The ESR frequencies are also investigated theoretically for both types. In the light of these results, the observed magnetic field dependencies of the ESR frequencies in MnSi and Fe
1−xCo
xSi are discussed to prove the HSDW due to the antisymmetric exchange interaction in these compounds.
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Tosizumi Aoki
1987 年 56 巻 10 号 p.
3648-3651
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Without assuming the classical ground state with a symmetry breaking, we derived spin wave excitation in the antiferromagnetic quantum spin systems on the triangular lattice. The motion of
z-component spin is investigated to second order in the time derivative within the effective-field approximation. The spectrum of excitation is calculated by the use of Miyashita’s trial function. The obtained spin wave excitation has a phonon-like spectrum, which is similar to the spin-wave one based upon the classical ground state, although its velocity is modified.
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Kazuyoshi Yoshimura, Kazuaki Fukamichi, Hiroshi Yasuoka, Mamoru Mekata
1987 年 56 巻 10 号 p.
3652-3660
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The Knight shift and the nuclear spin-lattice relaxation rate, 1⁄
T1, of
59Co in LuCo
2 have been measured. 1⁄
T1T due to the d-electron spins was found to be proportional to the d-spin susceptibility in good agreement with the SCR theory. From the quantitative analysis, the characteristic temperature,
T0, implying the energy width of the dynaical spin-fluctuation spectrum is estimated for LuCo
2 together with those for the typical nearly ferromagnetic metals. The value
T0 may be related to the degree of the ferromagnetic tendency as welll as the temperature of χ maximum in the nearly itinerant ferromagnet.
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Masatsune Kato, Kazuhiko Satoh, Yoshiteru Maeno, Yuji Aoki, Toshizo Fu ...
1987 年 56 巻 10 号 p.
3661-3666
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Specific heat of a dense-Kondo system, Ce
xLa
1−xCu
6, has been systematically measured between 2 and 80 K in order to clarify the transition from dilute-Kondo to dense-Kondo behavior as the cerium concentration,
x, increases. We have found that the magnetic specific heat per molar cerium,
Cm, is nearly independent of
x and is explained by a simple sum of the Kondo specific heat and the Schottky specific heat, with the
x-independent energy separation between the ground and the first excited states (65 K). However, due to the interaction between the cerium ions, the first excited state tends to be broadened as
x increases, and the width of the first excited state for the dense limit of CeCu
6 (
TK=3.9 K) is estimated to be about 20 K. At low temperatures,
Cm increases as
x is decreased. This tendency is qualitatively interpreted as due to the decrease in
TK caused by the increase of unit cell volume.
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Atsunobu Nakamura, Norio Kawakami, Ayao Okiji
1987 年 56 巻 10 号 p.
3667-3676
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
The low-frequency dynamical susceptibility for the Ce-Kondo system is investigated on the basis of the local Fermi liquid theory at zero temperature. The effects of the crystalline field are studied precisely by means of the Bethe-Ansatz solution of the Anderson model, for the cases of cubic, hexagonal and tetragonal fields. It is shown that the magnetic relaxation rate of the
f-electron is enhanced in general in the presence of the crystalline fields. The anisotropic properties of the relaxation are discussed for hexagonal and tetragonal fields as well.
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Hideo Takeuchi, Masanori Arakawa, Hiroshi Ebisu
1987 年 56 巻 10 号 p.
3677-3682
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
EPR measurements on Fe
3+ centres in RbCdF
3 and CsCdF
3 for crystals co-doped with Li
+ ions have been made in the cubic phase of host crystals. In both the crystals spectra from two kinds of Fe
3+ tetragonal centres associated with Cd
2+ vacancy (V
Cd) and Li
+ ion at the nearest-divalent-cation sites have been observed. From obtained fine structure parameters in the spin Hamiltonian the metal-ligand distances have been determined by the superposition model. The fine structure parameters have been explained well by the obtained metal-ligand distances, which show the contraction or distortion of fluorine octahedra surrounding Fe
3+ ions.
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Toshio Inase, Yoshiko Miyamoto
1987 年 56 巻 10 号 p.
3683-3688
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
An electric polarization which contains spontaneous electric polarization and magnetoelectric polarization of magnetite was measured over a temperature range from 4.2 K to 60 K. The observed electric polarization is divided into two parts: one is due to rotation of magnetization and the other is independent of it. An anomalous behavior in temperature dependence was observed in both of these two parts at the same temperature of 6 K. In earlier reports, anomalous behaviors in pyroelectric polarization and in magnetoelectric polarization were measured individually at this temperature. Another anomaly was observed at about 45 K, which was interpreted as an effect due to the switching of the
a axis to the
b axis by the magnetic field. A change caused by breaking of the mirror symmetry was not observed at about 10 K in the present measurements.
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Tsuneaki Miyahara, Atsushi Fujimori, Tsuneharu Koide, Shigeru Sato, Sh ...
1987 年 56 巻 10 号 p.
3689-3694
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
Near-noraml reflectance spectra of CeO
2 and Ce
xLa
1−xAl
2 alloy system were measured at photon energies from 90 to 140 eV. The results were compared with the photoyield data on Ce
xLa
1−xCu
6 alloy system paying attention to the chemical shifts of the 4
d-4
f multiplet components. It was found that the rigid wavefunction model is not consistent with the concentration dependence of the chemical shifts.
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Youichi Ohno
1987 年 56 巻 10 号 p.
3695-3702
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
Metal M
2,3 inner-shell electron-energy-loss spectra in layered transition-metal tri-thiophosphates MPS
3 (M=Mn, Fe, Ni) have been measured at low incident energies in reflection geometry. The spectra reveal the multiplet structures of the final states of localized divalent metal ions. The relative intensities of the peaks are varied systematically as incident energy decreases. Large deviation from the X-ray absorption spectra are found at low incident energies. The variations are interpreted in terms of the incident energy dependence of momentum transfer involved in the inelastic scattering process and exchange interaction between incident and target electrons. It is found that dipole selection rules are broken in 3p-3d transitions within the localized 3d transition-metal ions as incident energy approaches the excitation threshold.
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Keiichi Kaneto, Fumito Uesugi, Katsumi Yoshino
1987 年 56 巻 10 号 p.
3703-3709
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Absorption and luminescence induced by a photoexeitation are studied in polythiophene and poly(3-methylthiophene) films. The photoinduced absorption spectra which are nearly consistent with those of dopant-induced absorption at dilute doping levels indicate that the dominant photoinduced charged species are polarons. It is found that the magnitude of photoinduced absorption is rather independent on the condition of sample preparation, whereas the photoluminecence intensity is strongly influenced. The result suggests that the luminescent exciton does not play a primary role in the photogeneration of polaronic species.
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Takenari Goto, Jun Maeda
1987 年 56 巻 10 号 p.
3710-3714
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
We have measured the absorption and luminescence spectra of the ultra-thin PbI
2 film evaporated on a cleaved KCl crystal at 100 K. The energy of the exciton absorption band is analyzed by the one-dimensional quantum well, but the exciton energies in the platelet crystals consisting of the two and three layers deviate from the simple theoretical values because of the too thin crystals. From the appearance of the broad luminescence band in the ultra-thin film, it is concluded that the free exciton level may become higher than that of the self-trapped exciton by the quantum well effect.
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Hitoshi Nishimura, Yoshimitsu Saka, Shunji Nagata, Satoshi Hashimoto, ...
1987 年 56 巻 10 号 p.
3715-3725
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Absorption, luminescence and excitation spectra of LiI crystals have been observed in a wide temperature range. Being extremely hygroscopic, LiI crystals were cleaved in liquid helium inside a cryostat before optical measurements. With this method of crystal cleavage, the luminescence spectrum of LiI is drastically changed. Experimental results have led to following conclusions: (1) the steepness constant of the exciton absorption (Urbach) tail is 0.87, (2) at least one self-trapped exciton state stably exists, (3) from the state one luminescence band peaking at 3.4 eV occurs and (4) the potential barrier between the free and the self-trapped exciton states is 55 meV. A possibility of the self-trapped exciton state in LiI to be of three-center type is discussed.
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Shin’ichi Katayama, Ryoichi Fukasawa
1987 年 56 巻 10 号 p.
3726-3733
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
We present a theoretical description of the Raman spectra from longitudinal optical (LO) phonon modes confined in a heterostructure consisting of a thin surface layer on a semi-infinite substrate. The scattering cross section is derived by a dispersive continuum model for ionic displacement on the basis of classical response function theory. The spectra calculated for GaAs/AlGaAs reveal that phonon confinement in GaAs layer leads to asymmetric feature in line shape as well as peak shifts of the GaAs-type modes. The observability of the confined LO modes via Raman studies is discussed.
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Toshiaki Fujita, Koichi Kurita, Ken Takiyama, Toshiatsu Oda
1987 年 56 巻 10 号 p.
3734-3739
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
Absorption spectra near the fundamental absorption edge are studied in Sb
2S
3. Step-like structures characteristics to the indirect allowed exciton transition are found. The energy of the indirect exciton is determined to be 1.749 eV at 27 K. The band structure is calculated by the pseudopotential method and compared with the experimental results. It is shown that the top of the valence band and the bottom of the conduction band lie around
Γ and X points, respectively, and that the smallest direct gap is located at around the X point.
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Fukuko Yuasa, Éi Iti Takizawa
1987 年 56 巻 10 号 p.
3740-3741
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
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Takayuki Shirakura, Osamu Ono, Sakari Inawashiro
1987 年 56 巻 10 号 p.
3742-3743
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり
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Kenji Takanaka
1987 年 56 巻 10 号 p.
3744-3745
発行日: 1987/10/15
公開日: 2007/06/01
ジャーナル
認証あり
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Junji Iida, Yasuaki Nakagawa, Shunji Takekawa, Noboru Kimizuka
1987 年 56 巻 10 号 p.
3746-3747
発行日: 1987/10/15
公開日: 2007/05/29
ジャーナル
認証あり