-
Yoshimasa Matsuno
1990 年 59 巻 5 号 p.
1523-1525
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
A new type of nonlinear integro-differential evolution equation, iφ
t+ρφH Re (φ
*Hφ)=0 (H: Hilbert transform), is investigated by using the bilinear transformation method. The equation is linearized if we seek solutions with a constant amplitude of the from φ=φ
0 exp [iθ(
x,
t)]. The resultant equation coincides with the linear equation which has already been obtained in the linearization of the sine-Hilbert equation, Hθ
t=−sin θ. Using this fact, we construct exact nonperiodic and periodic solutions of the equation.
抄録全体を表示
-
Takasi Endo, Kouichi Toyoshima
1990 年 59 巻 5 号 p.
1526-1528
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The noise of two incoherent lights was measured. The detected noise increased when one light source was set close to the other. This means that the two close light sources seem to tend to emit photons simultaneously in spite of their mutual incoherence and independence.
抄録全体を表示
-
Masatoshi Shiino, Tomoki Fukai
1990 年 59 巻 5 号 p.
1529-1532
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
We propose a simple asymmetric neural network which exhibits chaotic motions in retrieval dynamics with
a finite number of memory patterns. The characteristic feature of the model is that the synaptic couplings are designed in such a way that each neuron is given an exclusively excitatory or inhibitory function, i.e., a physiological constraint of the Dale hypothesis is taken into account. The updating rule of the neurons is assumed to be simple Markovian stochastic dynamics of the Little type (without time delay) in which the threshold for neuron firing is incorporated. Our analysis is based on the exact time evolution equations derived in the thermodynamic limit for the macroscopic pattern overlaps. It is shown that chaotic image retrieval can take place only when a finite amount of stochastic noise exists.
抄録全体を表示
-
Makio Uwaha, Susumu Seki, Yukio Saito
1990 年 59 巻 5 号 p.
1533-1536
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The multifractal analysis of the structure of an aggregation from a lattice gas of finite density
ng is performed. By using correlation integrals to avoid the effect of autocorrelation in lattice models, the generalized dimension
Dq is determined. In a scaling regime, the structure is found to be a simple fractal characterized by a single dimension
D=1.7 which corresponds to the fractal dimension of the diffusion-limited aggregation. The probability of finding
s atoms within a distance
b from an atom also fits the scaling form
Pb(
s)=
b−Df(
s⁄
bD) for different values of
ng.
抄録全体を表示
-
Mahito Kohmoto
1990 年 59 巻 5 号 p.
1537-1540
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
A tight-binding Hamiltonian is used to study integer quantization of Hall conductivity σ
xy in spin-density-wave (SDW) ordered phases of two-dimensional conductors. A fractional number of magnetic flux quanta per unit cell creates energy gaps within tight-binding bands; σ
xy values of both signs arise naturally, even in the presence of only one type of charge carrier. Although σ
xy is a topological invariant determined by zeros of electron wave function components in the Brillouin zone, it
changes under variation of the SDW amplitude in
fixed magnetic field, as pairs of zeros coalesce and annihilate.
抄録全体を表示
-
Mahito Kohmoto, Yasutami Takada
1990 年 59 巻 5 号 p.
1541-1544
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
We consider a new pairing Hamiltonian in which a filled valence band is separated from an empty conduction band by an energy gap. In the normal state, the system is insulating, but when a large enough attractive interaction acts between states in the two bands, it goes into a superconducting phase at
Tc of the order of the energy gap. Although we obtain the Meissner effect and infinite dc-conductivity similar to that in the BCS superconductors, there are many unusual properties due to an unconventional gap equation.
抄録全体を表示
-
Yoshiko Kurosawa, Izuru Umehara, Makoto Kikuchi, Nobuyuki Nagai, Kazuh ...
1990 年 59 巻 5 号 p.
1545-1548
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
We have measured the transverse magnetoresistance and de Haas-van Alphen (dHvA) effect in the antiferromagnetic Kondo substance CeIn
3. The magnetoresistance increases in all field directions, suggesting that this compound is a compensated metal. We have detected one dHvA branch which corresponds to the electron Fermi surface in the sixth band of LaIn
3, centered at the
Γ point. The dHvA frequencies (cyclotron masses) at the 〈100〉 and 〈111〉 directions are 3.20×10
7 Oe (2.02m
0) and 2.95×10
7 Oe (2.88m
0), respectively.
抄録全体を表示
-
Toshiyuki Oashi, Ken-ichi Kumagai, Kazuo Kadowaki
1990 年 59 巻 5 号 p.
1549-1552
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
Nuclear magnetic resonance of
63⁄65Cu in the antiferromagnetic Pb
2Sr
2RECu
3O
8+δ (RE=Y, Eu and Gd) was observed in zero external field. In the insulating state with antiferromagnetically ordered Cu moments, the other set of NQR signals was observed around 30 MHz, indicating that the transferred hyperfine field from Cu moments in the Cu–O pyramids is canceled out at the Cu nuclei in the oxygen-free Cu plane site. The results show that the magnetic Cu moments exist only at the Cu–O pyramidal site with the 3
d9 state and that the Cu ion at the oxygen-free plane site is nonmagnetic (
d10) in the insulating Pb
2Sr
2RECu
3O
8+δ.
抄録全体を表示
-
Akira Nakamura
1990 年 59 巻 5 号 p.
1553-1559
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
We consider the 2+1 dimensional Toda Molecule equation
Δ log
Vn−
Vn+1+2
Vn−
Vn−1=0 where
Δ≡(∂⁄∂
x)
2+(∂⁄∂
y)
2. The boundary condition is molecule type, which is
Vn=0 at finite
n corresponding to both ends of the molecule. By using the Hirota bilinear method, we derive the cylindrical multi-soliton solutions of this system which are written explicitly by the associated Legendre functions
PMn. In the large molecule limit, the present Toda Molecule cylindrical solitons precisely reproduce the (previously known) Toda Lattice cylindrical solitons. Brief study is also made for the cylindrical solitons of the semi-infinite Toda lattice.
抄録全体を表示
-
A. Kundu, B. Basu Mallick
1990 年 59 巻 5 号 p.
1560-1570
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Poisson bracket (PB) structures of the KdV equation, which caused recent controversies are analysed in details through an alternative
r and
s matrix approach exploiting their nonultralocal canonical property. A symmetry criterion is found behind the existence of three different PB’s. The required extensions of the PB are derived in a systematic way leading to the Faddeev-Takhtajan (FT) and the Arkadiev
et al. brackets. This allows us to construct explicitly the action angle variables and compare their PB relations for all the brackets. It is revealed that for the FT bracket, contrary to the earlier result, the singularity free sector of the scattering matrix elements yields canonical action-angles, which also resolves the controversy regarding the nonseparability of the soliton modes from the continuous spectrum.
抄録全体を表示
-
Shozo Takeno
1990 年 59 巻 5 号 p.
1571-1580
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The time evolution of pure anharmonic lattices with quartic, positive lattice anharmonicity is studied by transforming nonlinear differential-difference equations into nonlinear integro-difference equations with kernels given by lattice Green’s functions. Such a formulation enables us to treat one-, two-, and three-dimensional lattices on equal footing. By studying the asymptotic properties for
t→∞ of the equations, it is shown that a long-lived, spatially localized oscillatory mode can exist under certain conditions for each of these three cases. A quasi-nonergodic behavior of anharmonic lattices obtained here may be of different nature from that found by Fermi, Pasta, and Ulam.
抄録全体を表示
-
Norio Konno, Makoto Katori
1990 年 59 巻 5 号 p.
1581-1592
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The one-dimensional contact process (CP) is studied by a systematic series of approximations. A new decoupling procedure of correlation functions is proposed by combining the idea of Suzuki’s correlation-identity-decoupling (CID) with a concept of
window. Liggett’s approximations are also considered. Applying Suzuki’s coherent-anomaly method (CAM) to the mean-field-type solutions, the values of the critical point and the critical exponents are estimated as λ
c=1.6490(±0.0008), β=0.280(±0.013),
Δ(=β⁄δ)=1.734(±0.001), \hatβ=0.627(±0.005). Finally a comparison with other estimates is shown.
抄録全体を表示
-
Shosuke Sasaki, Tosaku Kunimasa
1990 年 59 巻 5 号 p.
1593-1599
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
We calculate thermodynamic functions of a system of many bosons which are interacting with each other through a repulsive δ-function interaction in one-dimensional space. The entropy and the total energy of the system are explicitly determined up to the second order in the inverse coupling constant.
抄録全体を表示
-
Hideo Tsuru
1990 年 59 巻 5 号 p.
1600-1616
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The stability of equilibrium configurations of nematics in two concentric cylinders is examined by considering the change of free energy. The analysis is carried out by comparing the exact form of the free energy and taking the second variation of the free energy. When the ratio of the outside radius to the inside one exceeds a certain value, the pure splay or the pure bend configuration becomes unstable to infinitesmal perturbations. This value depends on the elastic constants and an external magnetic field. Whole results are derived by analytic calculation.
抄録全体を表示
-
K. C. Sharma, Suneet Parmar
1990 年 59 巻 5 号 p.
1617-1622
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The present paper is an investigation to study the Rayleigh-Taylor instability of a partially ionized porous medium in the presence of a variable horizontal magnetic field. The criteria determining stability and instability are independent of the effects of viscosity and collisional effects. The magnetic field stabilizes the system which is otherwise unstable in the absence of the magnetic field. The viscosity of the medium has stabilizing effect on the growth rates. The permeability of the medium is found to have no effect on the stability or instability of the system. It is found that the growth rate increases with the increase in permeability of the medium. An important conclusion that we have derived is that while the growth rate decreases with the increase in the collisional frequency in the nonviscous case, the collisional frequency has no effect on the growth rate in the viscous case.
抄録全体を表示
-
Shigehiko Nonaka
1990 年 59 巻 5 号 p.
1623-1632
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Longitudinal quarter-wavelength resonances for surface waves were found in the partial length of a low-frequency (28 MHz) surface-wave-produced plasma column with an axial inhomogeneity of the plasma density. Input RF power for the resonance increases with the finite length of the plasma column. The resonances were determined to be of quarter-wavelength by axial measurement of surface wave electric fields. By means of our mode-coupling theory, such resonances were well identified as the longitudinally lowest and azimuthally symmetric surface mode modified by an axial inhomogeneity of the plasma that was simultaneously produced by the interaction of surface waves with plasmas.
抄録全体を表示
-
Hideki Akao
1990 年 59 巻 5 号 p.
1633-1646
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The behavior of periphery magnetic field lines in the standard Large Helical Device (
l=2 heliotron/torsatron type) configuration is studied numerically. Three different types of behavior are found, corresponding to three different regions: the stochastic region near the outermost magnetic surface, the whisker region, and the inter-whisker region outside the stochastic region. The behavior of whisker and inter-whisker field lines is specifically analyzed. It is found that whisker field lines exhibit both regular and irregular types of behavior, whereas inter-whisker field lines exhibit only regular behavior. The connection lengths for the whisker field lines are usually as long as several tens of toroidal pitches, whereas those for the inter-whisker field lines are usually less than ten toroidal pitch lengths. Whisker field lines are characterized by three fundamental processes: stretching, folding, and nesting associated with the motion of a residual X-point of the separatrix. Simple modeling is performed to reproduce these three fundamental processes.
抄録全体を表示
-
Hirofumi Kasatani
1990 年 59 巻 5 号 p.
1647-1659
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
Absolute crystal structures of Ca
2Pb(CH
3CH
2CO
2)
6 (DLP) were determined by X-ray diffraction from monodomain crystals at 70°C above
Tc and at 45°C and −80°C below
Tc. The space groups of dextrorotatory crystal are P4
32
12 and P4
3 above and below
Tc, respectively. Above
Tc, β-carbon atoms in three of the independent four propionate ions and α-carbon atom of one propionate ion are in the disordered state having two equilibrium positions with equal occupancy. At 45°C, these carbon atoms are in the partially disordered states. At −80°C, only one β-carbon remains in the partially disordered state, whereas all of the other α- and β-carbons are in the ordered state. The spontaneous polarization is well explained by displacements of Pb, Ca and O atoms along the
c-axis.
抄録全体を表示
-
Takashi Tonegawa, Makoto Kaburagi, Junjiro Kanamori
1990 年 59 巻 5 号 p.
1660-1675
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The ground state of the lattice gas model on the triangular lattice in which two kinds of particles,
A and
B, interact by pairwise interactions extending to the second neighbors is analyzed by using the method of geometrical inequalities. The relation
VkAA=
VkBB=2
VkAB is assumed for the
kth (
k=1, 2) neighbor interaction constants between the
A and
A (
VkAA),
B and
B (
VkBB), and
A and
B (
VkAB) particles. The ground state is determined rigorously except for certain regions of the interaction constants and the particle densities. In these regions, on the other hand, the ground state is determined by the energy comparison. It is found that various ordered structures of the
A and
B particles including an infinite series of those appear as the ground states at characteristic values of the particle densities.
抄録全体を表示
-
Isao Minagawa
1990 年 59 巻 5 号 p.
1676-1685
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Using a cell of four molecules, the order-disorder transition of ice Ih-XI is studied by mean field theory, where the expression of the internal energy due to the short range interaction in a previous paper is improved and long range interaction is added. The free energy is given as a function of two short range interaction parameters
EM and
EC, and temperature
T, and minimized with respect to 13 variables by simplex method. A phase diagram is obtained in the
EM-
EC-
T space.
EM and
EC determined from the paraelectric Curie temperatures of dielectric constants along the two axes are shown to result in the low temperature phase of ordered structure
Cmc2
1 up to the transition temperature.
抄録全体を表示
-
Akihiko Matsuyama
1990 年 59 巻 5 号 p.
1686-1694
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
A theory is presented for the thermoreversible aggregation of ends-functional polymer solutions in which rings and chains of various sizes are formed by intra or intermolecular reactions. Equilibrium solution properties of such mixture of chains and rings are examined based on the the lattice theory of Flory-Huggins type. We focus especially on the size distributions of chains and rings on the temperature-concentration plane. Various types of the phase separetion are predicted according to the size distributions of chains and rings.
抄録全体を表示
-
Hiroo Oya, Toshiaki Enoki, Nobuhiko Wada
1990 年 59 巻 5 号 p.
1695-1701
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The heat capacity of ultrafine particles of silver (21 nm) was measured by an adiabatic method between 1.6 K and 13 K. The capacity was smaller than that of bulk Ag at lower temperatures and larger at higher temperatures. A peak and a hump were observed at 1.8 K and 3.4 K in the curve of temperature dependance of heat capacity. A trough and sharp cutoff were found in the curve at 2.2 K and 1.6 K. By sintering the sample, periodical multiple peaks appeared in the curve at lower temperatures and heat capacity at higher temperatures decreased to the same value as that of bulk. These phenomena are interpreted in terms of resonance of lattice vibration in a particle.
抄録全体を表示
-
Seiji Mizuhashi
1990 年 59 巻 5 号 p.
1702-1710
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The dynamical Jahn-Teller effect in the case where electronic states
T1(
dN) and
T2(
dN) (
N=2∼5) couple with doubly degenerate vibrational mode ε in
Oh symmetry is discussed. The off-diagonal Racah parameters are partially quenched and diagonal ones are diminished by amount of energy gained by Jahn-Teller interaction. As the result, Tanabe-Sugano diagrams are much changed from those without vibronic interaction.
抄録全体を表示
-
Yoshikazu Suzumura
1990 年 59 巻 5 号 p.
1711-1722
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
We examine the property of the fluctuation which exists around the mean field of the spin density wave state in low dimensional conductors. The collective modes are calculated for the spin density fluctuation, the charge density fluctuation and the superconducting fluctuation. The effective Hamiltonian describing these modes are derived microscopically from the path integral method and from the perturbational method. The effect of the nonmagnetic impurity is also discussed.
抄録全体を表示
-
Hiroshi Matsukawa, Hidetoshi Fukuyama
1990 年 59 巻 5 号 p.
1723-1727
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The role of apical oxygens in high-
Tc Cu-oxides has been analyzed based on the effective Hamiltonian derived previously by the present authors. It turns out that these oxygens modulate notably the oxygen
p-hole band structure, which leads to the enhancement of the long-range hopping integrals of the Zhang-Rice singlet. This effect is further enhanced if the distance between apical O and in-plane Cu is reduced. This finding may relate to the remarkable experimental result by Murayama
et al. of the strong pressure dependence of
Tc in the T
* structure and its complete absence in the T′ structure.
抄録全体を表示
-
Masafumi Kyogaku, Yoshio Kitaoka, Hiroyuki Nakamura, Kunisuke Asayama, ...
1990 年 59 巻 5 号 p.
1728-1732
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
119Sn NMR study has been made in a gap-type valence fluctuating compound CeNiSn. From the measurements of Knight shift and the nuclear spin lattice relaxation time
T1 of
119Sn, it is proved that no magnetic ordering occurs down to 0.38 K. The relaxation rate, 1⁄
T1 markedly decreases below 30 K down to 0.40 K. This behavior can be well interpreted by a quasiparticle band model which possesses a band width of 140 K and a low energy excitation inside an energy gap of 14 K at the Fermi level. Then it is clarified from the microscopic point of view that the pseudo-gap formed at the Fermi level has a character that the quasiparticle density of state is linearly proportional to the energy near the Fermi level at low temperatures.
抄録全体を表示
-
Mihoko Yoshida, Kazuo Morigaki
1990 年 59 巻 5 号 p.
1733-1739
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The photoluminescence (PL) spectral change in a-Si:H induced by prolonged exposure to strong light was studied at 7 K and 300 K. The light-induced change in PL is twofold, a fatigue of the PL main peak and an enhancement in the low energy region. Careful analysis of the intensity changes for exposure temperature dependence and excitation intensity dependence suggests that at least two processes are involved. The PL-spectral change associated with light soaking is interpreted as the photocreation of radiative and nonradiative defects.
抄録全体を表示
-
Ryusuke Ikeda, Tetsuo Ohmi, Toshihiko Tsuneto
1990 年 59 巻 5 号 p.
1740-1752
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The massless mode of harmonic fluctuations of the Abrikosov flux lattice is studied in detail within the GL theory. Without relying on the usual approximation to neglect all but the lowest Landau level we prove exactly that no terms quadratic in
k0 appear in the spectrum of this mode where
k0 is the wave vector of fluctuations perpendicular to the flux lines. This mode is identified as the incompressible shear lattice mode even if the GL parameter is finite and all fluctuations of the gauge field are taken into account. Some problems concerning this mode are also discussed.
抄録全体を表示
-
Masafumi Tamura, Hiroyuki Tajima, Haruo Kuroda, Madoka Tokumoto
1990 年 59 巻 5 号 p.
1753-1759
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Temperature dependence of the shielding and Meissner effect and anisotropy of the magnetization curve are investigated. The superconductivity of θ-(BEDT–TTF)
2I
3 is found to be a bulk one, while in some samples the superconducting volume are significantly suppressed. Anisotropy of the lower critical field,
Hc1, is estimated;
Hc1,b is 40 G, while
Hc1,a and
Hc1,c are less than 2 G. The in-plane anisotropy of
Hc1 is compared with the result of an optical study.
抄録全体を表示
-
Takami Tohyama, Sadamichi Maekawa
1990 年 59 巻 5 号 p.
1760-1770
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Physical parameters in the so-called
t-
t′-
J-
J′ model are determined for the hole-doped copper oxide superconductor, (La, Sr)
2CuO
4, by using the cluster model approach. We find that in the superconductor both freedoms of spin and charge, which are represented by
J and
t, respectively, should be taken into account on an equal basis. The dependence of
J on two factors is examined in the cluster model; one is the magnitude of 2
p-3
d hybridization and the other is the charge transfer energy between Cu-3
d and O-2
pσ orbitals in the CuO
2 plane. The calculated values of
J for various compounds with T-, T
*- and T′-phases are compared with the experimental results. Finally, a role of apical oxygen in the Cu-oxides is examined by calculating the electronic state as a function of the energy level of the apical oxygen.
抄録全体を表示
-
Nobuo Furukawa, Masatoshi Imada
1990 年 59 巻 5 号 p.
1771-1791
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Two dimensional coupled spin-fermion model as a model for high-
Tc oxide is examined by using the perturbation method and the spin wave approximation in the weak Kondo coupling region. The logarithmic singularity appears in the fermion self energy. It is shown that one fermion doped into the Heisenberg spin system forms the self-trapped states of the fermion and spins. The doped many fermions remains localized as the self-trapped states below the critical fermion concentration. The relation to the Kondo effect is discussed. The relevance of our results to optical and photoemission experiments in high-
Tc oxides is also discussed.
抄録全体を表示
-
Masayuki Itoh, Isao Yamada, Mamoru Ishizuka, Kiichi Amaya, Tatsuo Koba ...
1990 年 59 巻 5 号 p.
1792-1800
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Temperature dependence of dc and ac susceptibilities of K
2Cu
xCo
1−xF
4, a random mixture having competing ferromagnetic and antiferromagnetic exchange interactions, has been measured to reveal magnetic properties, especially a temperature vs. concentration phase diagram. It has been found that there exist ferromagnetic (1≥
x>0.84), spin-glass (0.84>
x>0.5) and antiferromagnetic (0.5>
x≥0) regions. The ferromagnetic phase is composed of three distinct phases, i.e., planar, oblique and axial ones, due to competing XY and Ising anisotropies of Cu
2+ and Co
2+ ions, respectively. In the spin-glass region, freezing of longitudinal and transverse spin components successively occurs at different temperatures, indicating a two-dimensional Ising spin-glass character.
抄録全体を表示
-
Youiti Ootuka, Noriaki Matsunaga
1990 年 59 巻 5 号 p.
1801-1809
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The static magnetic susceptibility of phosphorus doped silicon is measured over the temperature range from 10 mK to 4.2 K at phosphorus concentrations from 5.3×10
17 to 2.8×10
19 cm
−3. The paramagnetic deviation of susceptibility is observed for samples
N≤4.5×10
18 cm
−3 at low temperatures and the donor susceptibility χ
D varies continuously across the metal-insulator transition. The temperature dependence of χ
D is roughly described by
T−a law for the lightly metallic samples as well as for the non-metallic ones. The results are discussed in connection with the theories and the experiments of ESR and specific heat.
抄録全体を表示
-
Kiichi Amaya, Hidenobu Hori, Iwane Shiozaki, Muneyuki Date, Mamoru Ish ...
1990 年 59 巻 5 号 p.
1810-1816
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Magnetization of quasi one dimensional Ising antiferromagnet CsCoCl
3 is measured at liquid
4He temperatures in pulsed high magnetic fields. In the case of an applied field
H parallel to the Ising
c-axis, the magnetization
M at liq.
4He temperatures shows a metamagnetic transition which is characterized by the sharp double peaks of the field derivative of the magnetization d
M⁄d
H at 33.0 T and 43.9 T, respectively. The results are qualitatively explained by the Ising-like linear chain model with small antiferromagnetic inter-chain exchange interaction. The role of the inter-chain interaction is discussed within the framework of molecular field approximation. The temperature dependence and the transverse case of the magnetization process are also studied.
抄録全体を表示
-
Nahonori Miyata, Hiromitu Asami, Toshio Mizushima, Kiyoo Sato
1990 年 59 巻 5 号 p.
1817-1824
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The uniaxial magnetic crystalline anisotropy of Pd
1−xFe
x in tetragonal L1
0-type ordered phase (0.38\lesssim
x\lesssim0.50) was obtained from magnetization curves of quasi-single crystal samples in a magnetic field up to 100 kOe. The first anisotropy constant
Ku1 at 4.2 K of stoichiometric composition (
x=0.5) was estimated to be 2.1×10
7 erg/cm
3. The constants of
x=0.42 and 0.38 were 1.5×10
7 and 0.8×10
7 erg/cm
3, respectively. From the present result the most evident magnetic field dependence of torque curve found in
x=0.42 (reported in Part II) was attributable to the difficulty to suppress the ordered atomic arrangement due to the highest order-disorder transition temperature of this sample.
Ku2 was much smaller than
Ku1 for all compositions.
抄録全体を表示
-
Shin-ichi Furusawa, Shoji Tange, Yoshihiro Ishibashi, Kazuo Miwa
1990 年 59 巻 5 号 p.
1825-1830
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The temperature dependence of Raman spectra of lithium diborate (Li
2B
4O
7) was measured at temperature range from 300 K to 900 K. At room temperature, 12
A1, 12
B1, 15
B2 and 22
E modes were observed by various scattering geometries. No soft mode was observed in the above temperature range, implying that no displacive-type phase transition takes place there.
抄録全体を表示
-
Masaya Nakamura, Hiroshi Orihara, Yoshihiro Ishibashi, Pan-chae Kim, S ...
1990 年 59 巻 5 号 p.
1831-1834
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
The Raman spectra of α-GaPO
4 single crystals have been investigated. In the polarization measurements at room temperature under atmospheric pressure we observed seven new Raman lines, not observed so far. In addition, the measurements of the temperature and pressure dependences of Raman spectra show the results which are well in accordance with those obtained for the single crystals of the same structure such as quarts and AlPO
4.
抄録全体を表示
-
Ping He, Kiyoshi Deguchi, Masaki Hirokane, Eiji Nakamura
1990 年 59 巻 5 号 p.
1835-1840
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Dielectric dispersions in mixed crystals Rb
1−x(NH
4)
xH
2PO
4 (RADP,
x=0.35) and Rb
1−x(ND
4)
xD
2PO
4 (D-RADP,
x=0.35) were studied around their glass-freezing temperatures. The complex dielectric constants along the
a- and
c-axes have consistently been described by the Vogel-Fulcher law of the relaxation time τ=τ
0 exp {
E⁄(
T−
T0)} with a Gaussian distribution of the energy parameter
E around the mean value
E0. The values of τ
0,
T0 and
E0 of D-RADP are several times as large as those of RADP. No appreciable anisotropic character was found between the dispersions along the
a- and
c-axes in both RADP and D-RADP.
抄録全体を表示
-
Kazuo Gesi
1990 年 59 巻 5 号 p.
1841-1847
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Effect of hydrostatic pressure has been studied for the normal-incommensurate-ferroelectric phase transitions in two isotropic ferroelectric crystals, Rb
2CoCl
4 and Rb
2CoBr
4. The pressure coefficients of the normal-incommensurate transition temperature, d
Ti⁄d
p, are −12 K/GPa for Rb
2CoCl
4 and +39 K/GPa for Rb
2CoBr
4. The initial pressure coefficients of the incommensurate-ferroelectric transition temperature, (d
Tc⁄d
p)
0, are −70 K/GPa and −52 K/GPa for Rb
2CoCl
4 and Rb
2CoBr
4, respectively. The results are compared with those of other K
2SeO
4-type ferroelectrics obtained so far, and discussed.
抄録全体を表示
-
S. K. Pandey, A. R. Chetal, P. R. Sarode
1990 年 59 巻 5 号 p.
1848-1852
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
Chemical shifts,
ΔE, of the X-ray K-absorption edge in several compounds, complexes of copper including its superconducting oxides possessing formal oxidation states +1 and +2 have been measured. It has been shown that the chemical shift is primarily governed by the effective ionic charge on the absorbing ion and the nature of the atoms in the first coordination shell around the absorbing ion. The relation between the chemical shift,
ΔE , and the effective charge
q on the absorbing ion is found to be
ΔE=
Aq+
Bq2+
Cq3+
Dq4 (
A,
B,
C and
D are constants). The effects of electronegativity, atomic number, oxidation state, crystal structure, the valence
d-orbital electrons, etc. on the X-ray absorption chemical shift have been discussed.
抄録全体を表示
-
Kikuo Cho, Andrea D’andrea, Rodolfo Del Sole, Hajime Ishihara
1990 年 59 巻 5 号 p.
1853-1867
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
In search for an accurate and convenient method to calculate optical properties of excitons in thin films as a non-local response, a comparison is made among the different frameworks available for different regions of film thickness (
d). A detailed discussion is given about the multi-mode nature of polariton interference in optical spectra. The exciton levels in GaAs films with
d>2.5
aB are shown to follow approximately the center-of-mass quantization. The measured reflectance spectra for GaAs films with
d≥4800 A are reasonably interpreted in terms of three-branch polaritons arising from light- and heavy-mass excitons.
抄録全体を表示
-
Jun-ichi Igarashi
1990 年 59 巻 5 号 p.
1868-1880
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり
Cu 3
p-resonant photoemission spectrum and Cu
M23M45M45 Auger spectrum are calculated in detail on a cluster of (CuO
6)
10− and (CuO
6)
9− as a model for the high-
Tc material La
2−xSr(Ba)
xCuO
4. Various transition matrix elements are evaluated by using the Herman-Skillman potential on Cu and O atoms. A weak resonant enhancement of the satellite intensity exhibiting two-peak structure is obtained near Cu 3
p-core level photothreshold, in addition to a large intensity of the main-band peak due to the direct transition from O atoms. It is shown that the
p-
d hybridization makes the satellite peaks broad, particularly the peak with lower binding energy. A strong hole doping is shown to give rise to little effect on the spectral shape with about 1 eV reduction of the Coulomb repulsion.
抄録全体を表示
-
Minoru Itoh, Satoshi Hashimoto, Nobuhito Ohno
1990 年 59 巻 5 号 p.
1881-1889
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
The effect of dilatational strain on the self-trapped exciton (STE) luminescence of alkali halides is investigated at 11 K by using thin crystals grown inside a narrow gap of the quartz cell. In strained NaBr, new luminescence is found to appear around 3.13 eV in addition to the well-known π emission. This luminescence has an excitation threshold at the absorption band associated with spin-triplet exciton states, and exhibits a long lifetime of 103 μs. The same emission band can be produced by causing electrons to recombine with
VK centers. It is pointed out that an expansion of the lattice parameter leads to an STE configuration of low symmetry, from which the 3.13 eV luminescence occurs. It is further proved that the dilatational strain has a considerable effect on the STE luminescence in RbI, but not in KBr. These results are discussed in terms of the off-center model for the STE.
抄録全体を表示
-
Shozo Takeno, Shigeo Homma
1990 年 59 巻 5 号 p.
1890-1901
発行日: 1990/05/15
公開日: 2007/06/01
ジャーナル
認証あり
Nonlinear dynamics of a DNA double helix is studied on the assumption that one of the most flexible and relevant modes leading eventually to a local denaturation is nonlinear collective modes of base twisting. The hydrogen-bonding energy, the dipole-dipole interaction energy, the local-field energy, and the stacking energy are incorporated in the Hamiltonian for a plane base-rotator model. Equations of motion satisfied by base pairs are of the form of a generalized version of a two-component double sine-Gordon equation in a quasi-one-dimensional “aperiodic” lattice. By introducting Green’s functions of the aperiodic lattice, a detailed analytical study is made to obtain stationary localized-mode solutions to the equations. A brief discussion is given on implications of such nonlinear-brcathing-type modes to a possible precursor to the local denaturation.
抄録全体を表示
-
Hiroshi Yoshie, Yoji Nakamura
1990 年 59 巻 5 号 p.
1902-1903
発行日: 1990/05/15
公開日: 2007/05/29
ジャーナル
認証あり