巻号一覧
60 巻, 4 号
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Tetsuo Deguchi1991 年 60 巻 4 号 p. 1145-1149
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありWe present restricted IRF (Interaction Round a Face) models with discrete complex-valued crossing parameters. We discuss two types of restriction mechanisms of restricted IRF models and apply them to generalize the ABF models and An(1)-cyclic RSOS models.抄録全体を表示PDF形式でダウンロード (712K) -
Akira Imanishi, Koichi Maruyama, Shoichi Midorikawa, Teruhisa Morimoto1991 年 60 巻 4 号 p. 1150-1152
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありRecently, Hayasaka and Takeuchi (H-T) reported the anomalous weight reduction of spinning gyroscopes for right rotations around the vertical axis but no weight changes for left rotations. Although we examined the asymmetric weight changes using a gyroscope similar in mass and in equivalent radius to the lightest one of H-T, the observed weight changes, (−0.20±0.35) mg for left and (−0.02±0.33) mg for right rotations, are consistent with zero, and the data for right rotations are not compatible with those presented by H-T.抄録全体を表示PDF形式でダウンロード (364K) -
Hiroyasu Toyoki1991 年 60 巻 4 号 p. 1153-1156
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe ordering process of the quenched time-dependent Ginzburg-Landau model for the three-component nonconserved order-parameter in the three-dimensional system is numerically investigated. The form factor is found to obey a dynamical scaling law with a characteristic length growing as t1⁄2. The density of topological defects and the energy density exhibit a power decay that is consistent with the scaling of the form factor. The interaction of the defects is briefly discussed.抄録全体を表示PDF形式でダウンロード (512K) -
Masakazu Mizutani, Nobuo Kobayashi, Yozaburo Kaneko1991 年 60 巻 4 号 p. 1157-1160
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありIon energy-loss spectra were measured for He+–O2 collisions at the laboratory impact energy of 50 eV and scattering angles of 1≤θ≤8° by the use of a novel ion source which can produce a nearly monochromatic beam with high intensity. Peaks corresponding to vibrational excitation of the electronically ground state X3Σg− and vibronic excitation to the first excited state a1Δg of O2 are clearly resolved. The relative differential cross sections of vibronic excitation to a1Δg at the collision energy of 50 eV show humps at the scattering angles of θ>4°. This implies that a drastic change in the mechanism of the electronic excitation to the a state takes place around the scattering angle of 4°, and it induces highly vibrational excitation of the a state at larger scattering angles.抄録全体を表示PDF形式でダウンロード (384K) -
Hiroyuki Honji1991 年 60 巻 4 号 p. 1161-1164
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありIt has been found experimentally that in electrolyzed salt water, a wavy wake forms in the absence of submerged bodies downstream of a localized region influenced by the magnetic field of permanent magnets moving at a constant velocity. The lower and upper critical numbers of a dimensionless current density (Q) for the formation region of the wavy wakes decrease with Reynolds number. A straight wake and a meandering wake also form at smaller and larger values of Q, respectively. No wake formation of this type occurs in nonelectrolytic common fluids.抄録全体を表示PDF形式でダウンロード (924K) -
Mitsuyasu Yatsuzuka, Kikoh Satoh, Masataka Yamada, Hideki Kawarai, Tak ...1991 年 60 巻 4 号 p. 1165-1168
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありAn electron plasma wave driven by optical mixing of two oppositely propagating microwaves is experimentally studied. The wave amplitude is resonantly enhanced when the difference in frequency between two incident electomagnetic waves equals the electron plasma frequency. The absolute amplitude and the growth time of the excited waves are found to be 0.8% and 150 nsec (fpt=50, fp=340 MHz), respectively, at the incident microwave power of 40 kW. The wave amplitude obtained experimentally is in good agreement with that expected from the optical mixing theory with the damping term. The dominant damping term is ascribed to the Landau damping of high-energy electrons in the background plasma.抄録全体を表示PDF形式でダウンロード (512K) -
Hirofumi Kasatani, Takashi Umeki, Hikaru Terauchi, Yoshihiro Ishibashi1991 年 60 巻 4 号 p. 1169-1172
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありX-ray scattering experiments of Pb3(VO4)2 using a monodomain crystal were carried out above and below the ferroelectric transition temperature TC=273 K. The space groups were confirmed to be C2h5-P21⁄c and C23-A2 above and below TC, respectively. The ferroelastic and ferroelectric phase transitions with decreasing temperature are due to the instabilities at the F-point and the Γ-point, respectively, of the high-temperature trigonal phase.抄録全体を表示PDF形式でダウンロード (424K) -
Hirokazu Koizumi, Takayoshi Suzuki, Kaoru Kimura, Shin Takeuchi1991 年 60 巻 4 号 p. 1173-1175
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありUltrasonic measurements have been made between 2 K and 200 K for quasicrystalline Al6Li4Cu. The temperature dependence of the ultrasonic velocity shows an anomalous decrease below 50 K with decreasing temperature. This anomaly is explained well by the existence of two-level systems without distribution of energy splittings.抄録全体を表示PDF形式でダウンロード (376K) -
Akira Onuki1991 年 60 巻 4 号 p. 1176-1180
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありSecond-sound propagation is investigated in superfluid phases of 3He–4He mixtures in the presence of finely divided nonsuperfluid droplets. The attenuation is enhanced by diffusion of the entropy and the 3He component through the interface. At relatively high frequencies, it is proportional to the surface area density. At very low frequencies, we predict anomalous damping due to first-order phase transition periodically taking place at the interface. The second-sound speed is considerably decreased at low frequencies.抄録全体を表示PDF形式でダウンロード (596K) -
Takashi Nagatani1991 年 60 巻 4 号 p. 1181-1184
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe effect of thermal convection upon the diffusion-limited deposition (DLD) on a plate is investigated using a Monte Carlo model. The periodic flow of roll structure appearing in Be’nard convection is considered to be thermal convection. Morphological changes of diffusion-limited aggregation (DLA) under Be’nard convection are studied by computer simulation. The convective diffusion field is simulated by the biased-random walker resulting from a superimposed drift which represents the thermal convection. It is found that the deposit leads to the formation of a characteristic columnar morphology with increasing thermal convection. The columnar morphology is periodic in correspondence to the roll structure in Be’nard convection.抄録全体を表示PDF形式でダウンロード (520K) -
Yoshikazu Hidaka, Yukimichi Tajima, Kiyohiro Sugiyama, Futoshi Tomiyam ...1991 年 60 巻 4 号 p. 1185-1188
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありElectron high-Tc superconductor Nd2−xCexCuOy single crystals are studied under high magnetic field of up to 20 tesla. The superconducting state is completely destroyed by the field when the field is applied along the c-axis and the normal electrical resistivity is obtained at all temperatures. The temperature dependence of the normal resistivity is plotted down to 1.3 K and a clear resistance minimum is found. The result is understood in terms of the two-dimensional weak localization model and this means that the materials are regarded as the intrinsic two-dimensional conduction system.抄録全体を表示PDF形式でダウンロード (544K) -
Kazufumi Suenaga, Gendo Oomi1991 年 60 巻 4 号 p. 1189-1192
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe effect of pressure on the lattice constant and crystal structure of YBa2Cu3O7−δ (YBCO) has been studied up to about 120 kbar at room temperature in the wide range of δ, 0<δ<1. It is found that the lattice compression of all samples is anisotropic, and the volume compressibility of superconducting YBCO increases with δ, having a peak near the orthorhombic-tetragonal phase boundary δ\simeq0.8.抄録全体を表示PDF形式でダウンロード (488K) -
Shinpei Fujii, Shoji Ishida, Setsuro Asano1991 年 60 巻 4 号 p. 1193-1196
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありWe have carried out the total-energy band calculations of bcc Mn as a function of lattice constant for paramagnetic, ferromagnetic and antiferromagnetic states. We have found that bcc Mn undergoes a first-order transition from a low-spin state to a high-spin state, not only in the ferromagnetic state but also in the antiferromagnetic state. The obtained results of the total-energy calculations indicate that bcc Mn prefers a paramagnetic state under compression, a low-spin ferromagnetic state under zero pressure and a high-spin antiferromagnetic state under expansion.抄録全体を表示PDF形式でダウンロード (360K) -
Kazuyoshi Yamada, Masatoshi Arai, Yasuo Endoh, Syoichi Hosoya, Kenji N ...1991 年 60 巻 4 号 p. 1197-1200
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありInelastic neutron scattering measurements on the chopper spectrometer MARI installed in the pulsed neutron source ISIS observed a well-defined two-dimensional antiferromagnetic spin wave up to the zone-boundary of La2NiO4 at 124±3 meV.抄録全体を表示PDF形式でダウンロード (576K) -
Nobuhiko Sakai, Yoshikazu Tanaka, Fumitake Itoh, Hiroshi Sakurai, Hiro ...1991 年 60 巻 4 号 p. 1201-1203
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありThe spin polarization of conduction electrons in Gd is clearly observed in the magnetic Compton profile. The magnetic moment of the conduction electron is evaluated to be 0.53±0.08 μB/atom, consistent with the bulk magnetic moment. The measurement is performed with circularly polarized synchrotron-radiation X-rays emitted from an elliptical multipole wiggler. A segmented Ge solid-state detector having thirteen elements is successfully used for high count-rate accumulation.抄録全体を表示PDF形式でダウンロード (412K) -
Masashi Yoshida, Setsuko Tajima, Yuri Mizuo, Takahiro Wada, Yuji Yaega ...1991 年 60 巻 4 号 p. 1204-1207
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありPolarized Raman spectra of (Sm2⁄3Ce1⁄3)2(Ba2⁄3Sm1⁄3)2Cu3O9 with the Cu–O5 pyramid structure have been measured at room temperature using single crystals. Peaks have been observed at 450 and 525 cm−1 in the A1g symmetry configuration and at 200 cm−1 in the B1g configuration. A peak due to a Raman-forbidden mode has been observed at 560 cm−1. The B1g symmetry peak is assigned to the out-of-phase bending of oxygen in the Cu–O2 plane. The energy of this mode is much lower than that of YBa2Cu3O7 (330 cm−1). On the other hand, the energies of the A1g-symmetry peaks are nearly the same as those in YBa2Cu3O7 (440 and 500 cm−1), suggesting that these two peaks are associated with the vibrations of apical oxygen.抄録全体を表示PDF形式でダウンロード (504K) -
Hiraku Nishimori, Akira Onuki1991 年 60 巻 4 号 p. 1208-1211
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありWe simulate two-dimensional spinodal decomposition of binary alloys, taking into account both cubic elasticity and the difference of the shear modulus between two phases (elastic misfit). The cubic anisotropy leads to emergence of rectangular domains, while the elastic misfit produces a percolated network of softer regions wrapping harder domains and serves to dramatically slow down the coarsening. The resultant domain structures closely resemble real microstructures in cubic solids.抄録全体を表示PDF形式でダウンロード (584K) -
Katsuya Honda, Hatsuo Kimura1991 年 60 巻 4 号 p. 1212-1215
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありTo discuss the phase transition from the Lα or Lβ phase to the periodic ripple (Pβ) phase, we propose a model free energy, which is a functional of two kinds of fields. One denotes the displacement of the polar head groups of lipid molecules and the other the order parameter describing the configuration of hydrocarbon chains. The free energy is noted to include no intrinsic lengths to generate the periodic pattern spontaneously. The ripple phase can be found to occur intermediately between two flat phases due to large fluctuations of the order parameter. The temperature dependence of the period and a qualitative phase diagram are also given.抄録全体を表示PDF形式でダウンロード (536K) -
Takashi Nagatani, H. Eugene Stanley1991 年 60 巻 4 号 p. 1217-1225
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありViscous fingering in porous media is considered as the diffusion-limited aggregation (DLA) on the percolating cluster. The crossover between percolation and DLA is studied by using a three-parameter position-space renormalization-group approach. The global flow diagram in the two-parameter space is obtained. It is found that there are two nontrivial fixed points, the percolation point and the DLA point. Above the percolation threshold, the system crosses eventually over to the DLA fractal on the perfect lattice. The fractal nature and the multifractal structure of the growth probability distribution are derived from the position-space renormalization-group method. The multifractal structure at the percolation threshold is compared with that at the perfect lattice.抄録全体を表示PDF形式でダウンロード (1056K) -
Masakazu Ichiyanagi1991 年 60 巻 4 号 p. 1226-1232
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありWe address ourselves to the problem of treating Joule heat generated by applied fields. We go beyond the existing theories by developing a microscopic theory of cooling mechanism. This is done through a quantum mechanical reservoir model. Explicit expressions are given for the heat flux and the entropy production. It is shown that the cooling mechanism, which carries away the heat generated, can be realized by an electron-phonon interaction.抄録全体を表示PDF形式でダウンロード (912K) -
Samia S. Elazab1991 年 60 巻 4 号 p. 1233-1236
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe capillary instability of an incompressible inviscid, electrically conducting fluid cylinder immersed in another liquid, in the presence of axial currents is considered. The results with zero current show that the range of instability of the gas-core liquid jet is the same as that of full liquid cylinder. The case when the model is affected by the current is studied and it is found that the current has a destabilizing influence. With increasing the current intensity the domain of instability is increasing. In fact both the growing rate of instability and the critical wavenumber are extensively increasing. This showed that how much the domain of instability is extended and expanded with increasing the intensity of the current. Some reported works are recovered as limiting cases from the present result.抄録全体を表示PDF形式でダウンロード (420K) -
Takaaki Fujita, Yasutaka Fuke, Zensho Yoshida, Nobuyuki Inoue, Takeo T ...1991 年 60 巻 4 号 p. 1237-1246
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありAn equilibrium of toroidal plasma with a large electron-beam current has been realized using the runaway effect in a tokamak. Reproducible runaway-mode discharges are obtained with pure hydrogen gas by the help of intense titanium flashing which results in a low electron density. The beam current is estimated to be more than a half of the total toroidal current. The equilibrium of this discharge is maintained by a strong vertical field because the beam pressure gives rise to an additional increase in Shafranov Λ. The beam pressure is estimated to be more than 80% of the total pressure. The kinetic energy and the spatial distributions of beam electrons are studied by seeing X-ray emission from a tungsten wire inserted into the plasma. The increase of Shafranov Λ due to beam pressure is enhanced by puffing gas into the discharge.抄録全体を表示PDF形式でダウンロード (1168K) -
Yositaka Onodera, Nobuyuki Sawashima1991 年 60 巻 4 号 p. 1247-1256
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありA systematic correlation is discovered for a number of ferroelectrics between transition entropy ΔS and the Rhodes-Wohlfarth ratio pc⁄ps, where pc is the effective dipole moment determined from the Curie-Weiss constant assuming the existence of permanent dipoles, while ps is the saturation moment. The unified theoretical model of ferroelectrics, which is capable of describing essential features of both displacive-type and order-disorder-type ferroelectrics, is shown to reproduce the above correlation strikingly well.抄録全体を表示PDF形式でダウンロード (1156K) -
Fujio Kakinuma, Satoru Ohno, Kenji Suzuki1991 年 60 巻 4 号 p. 1257-1262
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありThe measurements of heat capacity were made for liquid Tl–Te alloys using an adiabatic scanning calorimeter over the whole concentration range. The excess heat capacity for liquid Te-rich Tl–Te alloys can be attributed to the change in the bonding configuration around Te. The concentration dependence of the heat capacity suggests that the bonding nature changes gradually with increasing Tl content and drastically changes around the composition of Tl2Te. The heat capacity for liquid Tl2Te alloys has a small temperature coefficient at temperature where a nonmetal-metal transition occurs. It means that the excess heat capacity for liquid Tl2Te alloy may not be due to the dissociation of the chemical complex.抄録全体を表示PDF形式でダウンロード (620K) -
Tomozo Tomoyose1991 年 60 巻 4 号 p. 1263-1271
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe jump diffusion of interacting mobile ions in superionic conductors (SIC) is studied by the phonon-assisted hopping theory. The interacting mobile ions are described by the lattice gas model. In order to study the correlated hopping of mobile ions, we calculate the average jump rate taking account of the average distribution of mobile ions at the nearest neighboring sites around the hopping ion after and before the hopping. We find that the average jump rate is thermally activated and that its activation energy is low at high concentration of mobile ions. This suggests that a low activation energy of SIC is due to the mutual interaction of mobile ions.抄録全体を表示PDF形式でダウンロード (1020K) -
Masao Iwamatsu1991 年 60 巻 4 号 p. 1272-1278
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありA simple phenomenological model for the liquid metal surface based on the density functional formalism is proposed to study the surface density profile. The model is based on the density functional formalism and takes care of the strong density dependence of the free energy as well as the electrostatic dipole barrier. It is shown that this dipole barrier due to the difference of the electronic and ionic density distributions in the liquid-vapor transition zone is responsible for the oscillation of the ionic density profile. The necessary condition for the appearance of this oscillation is also elucidated.抄録全体を表示PDF形式でダウンロード (708K) -
Nobuo Narita, Sumiaki Nagai, Shigeru Saito, Kenji Nakao1991 年 60 巻 4 号 p. 1279-1285
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありThe electronic band structure of layered semiconductor α-In2Se3 is calculated by using the KKR method. For the muffin-tin potential constructed from the ionized atoms In+1.30 and Se−0.86 the band gap is obtained to be about 1.45 eV which is consistent with the observed value. All of the bands corresponding to Se-4s, Se-4p, In-5s and In-5p states are separated completely one another and are comparatively flat reflecting the general characteristics of layered materials with complex structure. The calculated effective masses in conduction and valence bands are considerably large, whose values are mc=1.1m0 and mv=1.9m0, respectively. Further it is demonstrated that the calculation of structure constants is very serious for materials with complex crystal structure such as α-In2Se3.抄録全体を表示PDF形式でダウンロード (744K) -
Makoto Kuwabara, Yoshiyuki Ono, Akira Terai1991 年 60 巻 4 号 p. 1286-1293
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありBy numerical simulations treating the motion of a charged soliton in polyacetylene, we analyze the width of a moving soliton. The motion of the soliton is induced by applying an electric field as in the previous work. The soliton width is estimated by two methods; one is from the excess charge density profile and the other from the distortion in the lattice displacement. Both results indicate that the width decreases as the soliton velocity increases. Quantitatively, however, the amount of decrease is different in the two cases; the maximum change of the width is about 10% in the former case whereas it is 20% in the latter. Furthermore, the width obtained from the lattice distortion is found to oscillate as a function of time, consistently with the excitation of the amplitude mode around a soliton.抄録全体を表示PDF形式でダウンロード (892K) -
Izuru Umehara, Nobuyuki Nagai, Yoshichika \={O}nuki1991 年 60 巻 4 号 p. 1294-1299
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありWe have measured the magnetoresistance and the de Haas-van Alphen (dHvA) effect in LaSn3. From the results of magnetoresistance, this substance has been confirmed to be an uncompensated metal with open orbits. About fifteen dHvA branches have been observed, which are well explained by the results of the recent band calculation done by Hasegawa and Yamagami.抄録全体を表示PDF形式でダウンロード (572K) -
Takashi Uemura, Kazuyoshi Yoshimura, Koji Kosuge1991 年 60 巻 4 号 p. 1300-1305
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe ac susceptibility was measured for the powdered samples of La2−xBaxCuOy with various Ba and oxygen contents. Double maxima at x=0.08 and 0.16 and a large dip at x=0.12 were observed in both the Meissner volume fraction f and the superconducting transition temperature Tc′ where the Meissner signals start to show a large drop. We have newly found that for x=0.12 the decrease of the oxygen concentration y leads to a rise of Tc′ and an increase of f, suggesting that the decrease of y suppresses the low-temperature phase transition between orthorhombic and tetragonal structures which makes the superconductivity unstable around x=0.12. Furthermore, we observed that the onset temperature of the Meissner effect Tcos of about 30 K is almost independent of x and y, while the superconducting transition becomes broad and f decreases with lowering Tc. These results indicate that some optimum composition which shows the intrinsic superconductivity exists in the range of 0.08≤x≤0.16.抄録全体を表示PDF形式でダウンロード (700K) -
Akiharu Miyanaga, Yasumasa Hasegawa, Hidetoshi Fukuyama1991 年 60 巻 4 号 p. 1306-1320
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe possible symmetries of superconductivity is studied on a system near charge transfer instability in CuO2 layer structure for a case where the Cu sites do not have magnetic moment. This case corresponds either to ignore the existence of magnetic moments in actual high Tc Cu-oxides by focusing only on charge fluctuations or to consider the ground state configurations of d8 or d10 at the Cu-sites. By deriving effective interaction processes, which become important near the charge transfer instability, the critical temperatures have been estimated as a function of the doping rate, δ, based on weak-coupling approximation. It is seen that they have characteristic δ-dependence depending on symmetry.抄録全体を表示PDF形式でダウンロード (1212K) -
Hajime Shimizu, Isamu Oguro, Juichiro Arai1991 年 60 巻 4 号 p. 1321-1326
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありMagnetization measurements were carried out for the samples of superconducting and nonsuperconducting GdBa2(Cu1−xMx)3O7 (M=Fe, Co, Ni: x=0–0.19). From the magnetization curve at 1.3 K below Gd-ordering temperature TN, a Gd-spin flipping field, a molecular field and an anisotropy field were determined to be 1.5 T, 3.0 T and 0.4 T, respectively, and decrease of their saturation magnetizations due to increase of dopants was also observed. Furthermore, it was found that TN of metal doped samples decrease with increasing the concentrations of dopants. These results indicate that magnetic moments of doped metal atoms couple antiferromagnetically with Gd spins and this antiferromagnetic interaction reduces TN of Gd spins.抄録全体を表示PDF形式でダウンロード (788K) -
Yukio Tanaka, Masaru Tsukada1991 年 60 巻 4 号 p. 1327-1336
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe transition temperature of clean superconducting superlattice is shown to be raised above that of bulk superconductor, by choosing material parameters properly. This is due to the interference of the wave function which is reflected by the multilayered structure. However we can not expect this effect in the superconducting superlattice in the dirty limit, as the wave character of the Cooper pair is smeared out due to the impurity scattering.抄録全体を表示PDF形式でダウンロード (1140K) -
Ryusuke Ikeda, Toshihiko Tsuneto1991 年 60 巻 4 号 p. 1337-1346
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありUsing the renormalized fluctuation theory developed to explain the resistive transition in high temperature superconductors (HTSC) under an applied field, a formula for temperature derivative of magnetization is derived which enables one to study the reversible temperature region in HTSC with layer structure. It is pointed out that, because of strong fluctuation effects in HTSC, the reversible dc magnetization of HTSC below TcH has a nontrivial field dependent correction due to higher Landau level fluctuations to the usual mean field-like behavior, and that the linear temperature dependence should not be seen in BSCCO. A good agreement with YBCO data is obtained. A higher Landau level correction to the specific heat is also discussed.抄録全体を表示PDF形式でダウンロード (1028K) -
Kazuo Hida1991 年 60 巻 4 号 p. 1347-1354
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe properties of the spin-1/2 double chain Heisenberg antiferromagnet are studied by means of the numerical diagonalization and the projector Monte Carlo simulation. The model consists of the two spin 1/2 antiferromagnetic quantum Heisenberg chains coupled with each other via the ferromagnetic interchain coupling J′. It is shown that the first excited state has a gap for large enough J′. This gap continues to the Haldane gap in the limit J′→∞, where spins on the different chains form triplets on each site. On the other hand, the gap decreases rapidly between J′=1.0 and 0.6 and is undetectable for J′<0.6 within the present accuracy.抄録全体を表示PDF形式でダウンロード (772K) -
Mitsuhiro Motokawa, Hitoshi Dohnomae1991 年 60 巻 4 号 p. 1355-1360
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありMagnetization process of an antiferromagnetically coupled ferromagnetic layers is discussed. Magnetic phase transition occurs at a critical field from a ferrimagnetic structure to a twisted state. Angles between any magnetic moment and an applied field in the twisted state is analytically calculated by recursion formulae and the calculated magnetization curve is in good agreement with the experimental one.抄録全体を表示PDF形式でダウンロード (608K) -
Hitoshi Ohta, Ryuzo Tanaka, Mitsuhiro Motokawa, Satoru Kunii, Tadao Ka ...1991 年 60 巻 4 号 p. 1361-1364
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありFar-infrared transmission measurements of a single crystal of SmB6 have been performed over the range from 25 to 150 cm−1 at 1.5 K. The obtained spectrum shows a gradual increase of transmission below around 100 cm−1, which was first observed in this experiment, and a steep increase in transmission below 35 cm−1. From this result, we conclude that the absorption edge arising from the energy gap must be around 100 cm−1. The absorption between 35 and 100 cm−1 is attributed to impurities or defect sub-levels located in the energy gap. This gives a reasonable explanation to the two edges at 35 and 100 cm−1 which have been seen in many other types of measurements.抄録全体を表示PDF形式でダウンロード (540K) -
Manabu Takahashi, Tomotoshi Nishino, Junjiro Kanamori1991 年 60 巻 4 号 p. 1365-1371
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありA cluster model calculation in which a tight binding Hamiltonian including intraatomic electron electron interaction is exactly diagonalized is carried out to explain the observed values of the internal magnetic fields at the La site in La2CuO4 and La2NiO4 which are about 1 kOe and about 18 kOe, respectively. It is shown that the internal fields reflect the spin correlation between apical oxygen and Cu or Ni, and that the electron correlation is important to determine the magnitude of the field.抄録全体を表示PDF形式でダウンロード (760K) -
Victor M. Ratag, Hideki Miyajima, Nobuyoshi Wakabayashi, Shigeo Nakahi ...1991 年 60 巻 4 号 p. 1372-1378
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありMagnetic and electrical properties of amorphous and annealed Ni84Y8Kr8 samples have been investigated. A transition towards a state of higher magnetization is observed in a high field. This anomaly may be interpreted as a metamagnetic transition. The spontaneous magnetization, M(0, T), and the initial susceptibility, χ(0, T) exhibit maxima below 10 K. The resistivity measurements reveal that the amorphous sample has a resistivity minimum at about 15 K. The resistivity minimum is not observed in the annealed sample. The high magnetic field affects the resistivity at low temperatures.抄録全体を表示PDF形式でダウンロード (848K) -
Mitsumasa Ishiwata1991 年 60 巻 4 号 p. 1379-1387
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証あり13C and 1H relaxation times of a coupled 13C–1H spin system dissolved in a nematic phase have been measured at 400 MHz (for 1H) by the selective and nonselective inversion recovery method. The relaxation times of doublet lines of each spin are different from each other. Especially, when a 1H line is inverted selectively, the relaxation time of the 13C line connected progressively to the inverted one is fairly different depending on which line of the 1H is inverted. Master equations for longitudinal relaxation are derived under the assumption that in addition to two relaxation mechanisms of the intramolecular dipole-dipole and external random field interactions, interference effects between the two might be nonnegligible in the oriented phase. The differences in the relaxation times have been explained by this interference effect.抄録全体を表示PDF形式でダウンロード (1044K) -
Masato Nakamura, Kazuo Kitahara1991 年 60 巻 4 号 p. 1388-1397
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありThe spin depolarization of a quantum particle in random magnetic field is treated in terms of a path integral in the spin states as well as the translational motion. The path integral of the spin operator, represented in terms of Fermion operators, is performed in the Fermion coherent state representation. An expression for the spin depolarization is obtained for an arbitrary magnetic field distribution. A particular case, in which the magnetic field is oriented in the z-direction and the magnitude is Gaussianly distributed, is considered and the spin decays exponentially in time.抄録全体を表示PDF形式でダウンロード (772K) -
Xiao-lei Wang, Mikihiko Ikezawa1991 年 60 巻 4 号 p. 1398-1405
発行日: 1991/04/15
公開日: 2007/06/01
ジャーナル 認証ありLarge single crystals of Ag2F have been grown and anisotropic electrical conductivity and optical reflectivity have been measured. The dc conductivity along the c-axis is about one tenth of that in the c-plane and its temperature dependence is metallic. Reflectivity spectra have been observed from 0.05 to 30 eV with linearly polarized light whose electric vectors are perpendicular and parallel to the c-axis. Clear anisotropic reflectivity due to the conduction electrons has been found with the sharp Drude edges at 2.9 and 0.9 eV in the perpendicular and parallel directions, respectively. The analysis of the results does not give a quantitative support to the two Fermi surface model proposed by Hamada et al. Absorption spectra in the interband transition region above the Drude edges also show anisotropy.抄録全体を表示PDF形式でダウンロード (940K) -
Chikara Sugiura1991 年 60 巻 4 号 p. 1406-1414
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありThe fluorine-Kα and chlorine-Kβ emission spectra in fluorescence from a series of alkali halides MX (M=Li, Na, K, Rb and Cs; X=F and Cl) are measured with a high-resolution two-crystal spectrometer. Solid-state effects are observed on the intensities of the K1L1 and Kβx satellite peaks in the Kα and Kβ emission spectra, respectively. An anomalously low intensity of the K1L1 satellite peak is observed for KF. The measured emission spectra are presented along with the UPS spectra of the F− 2p and Cl− 3p valence bands obtained by Poole et al., the fluorine K absorption-edge spectra by Nakai et al. and the chlorine K absorption-edge spectra by the author. By using these spectra, the first shoulder at the K absorption edge is identified as being due to a core exciton, the energy level of which is formed below the bottom of the conduction band. The binding energy of the exciton is estimated.抄録全体を表示PDF形式でダウンロード (1152K) -
Takeo Ebisu, Naoki Nakagawa, Tadashi Watanabe1991 年 60 巻 4 号 p. 1415-1423
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありBy sampling spherical tin granules of diameter from 145 through 250 μm one by one, we studied responses of them in the superheated superconducting state to incident α particles of energies less than 4.7 MeV in a range of temperature from 2.25 to 3.00 K in magnetic fields. Line shapes of the signals obtained in the phase transition were found out to have a half-width of 4∼8 μs in time. The energy sensitivity of the specimens was ascertained to increase with decreasing temperature. The superheated state turns normal with an energy deposit two orders of magnitude less than that is required for the whole of a granule to be uniformly heated up. This means that heating ∼0.1% of the volume is enough to trigger the full penetration of an applied field into a hit granule. Our results offer elements indispensable for applying the breakdown of the Meissner effect to the detection of weakly-interacting particles.抄録全体を表示PDF形式でダウンロード (1012K) -
Takeshi Murakami, Yasuyuki Gono, Masumi Oshima, Hideshige Kusakari, Ko ...1991 年 60 巻 4 号 p. 1424-1425
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありPDF形式でダウンロード (280K) -
Madoka Tokumoto, Nobumori Kinoshita, Yasumoto Tanaka, Hiroyuki Anzai1991 年 60 巻 4 号 p. 1426-1427
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありPDF形式でダウンロード (296K) -
Setsuo Mitsuda, Hideki Yoshizawa, Nobuo Wada, Yoshichika \={O}nuki, Ta ...1991 年 60 巻 4 号 p. 1428-1429
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありPDF形式でダウンロード (176K) -
Minoru Sumita, Haruhisa Ishigami, Toshio Osaka, Yasuharu Makita1991 年 60 巻 4 号 p. 1430-1431
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありPDF形式でダウンロード (232K) -
Shigehiko Nonaka1991 年 60 巻 4 号 p. 1432A
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありPDF形式でダウンロード (40K) -
Koichi Shimoda1991 年 60 巻 4 号 p. 1432B
発行日: 1991/04/15
公開日: 2007/05/29
ジャーナル 認証ありPDF形式でダウンロード (24K)
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