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Volume 72, Issue 9
Displaying 1-50 of 51 articles from this issue
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Sachiko Kitajima, Mayumi Shingu-Yano, Fumiaki Shibata2003 Volume 72 Issue 9 Pages 2133-2136
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSNumber-phase uncertainty relation is examined on the basis of an orthogonal phase state and a quasi-probability function. The measure of number fluctuation is not the usual standard deviation but a kind of Fisher information. This is a direct generalization to a discrete system of the corresponding quantity used recently by Hall in a theory of uncertainty for a coordinate-momentum system. It is essential to separate the “classical” part of a phase operator with the aid of the orthogonal phase state.View full abstractDownload PDF (69K) -
Masanori Ichioka, Kazushige Machida2003 Volume 72 Issue 9 Pages 2137-2140
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe excitation spectra of Bose–Einstein condensates are investigated in a three-dimensional optical lattice by the Bogoliubov theory considering the original sinusoidal potential for the optical lattice. When the lattice potential becomes high, the excitations show softening at large wavelengths, suggesting the breakdown of superfluidity. We also study the filling and interaction dependences of the properties of the excitation spectra and one-dimensional lattice case.View full abstractDownload PDF (150K) -
Tatsuya Kawae, Tatsuharu Yamamoto, Kenji Yurue, Naoyuki Tateiwa, Kazuy ...2003 Volume 72 Issue 9 Pages 2141-2144
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe have studied the low-temperature properties of PrxLa1−xPb3 with non-Kramers Γ3 quadrupolar moments of the crystal-electric-field ground state, for a wide concentration range of Pr ions. For x≤0.05, the specific heat C⁄T increases monotonically below T=1.5 K, which can be scaled with a characteristic temperature T* defined at each concentration x. The electrical resistivity ρ(T) in the corresponding temperature region shows a marked decrease deviating from a Fermi-liquid behavior ρ(T)∝T2. The Kondo effect arising from the correlation between the dilute Γ3 moments and the conduction electrons may give rise to such anomalous behavior.View full abstractDownload PDF (424K) -
Hideo Yoshioka2003 Volume 72 Issue 9 Pages 2145-2148
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSSpin excitation in a nano-graphite ribbon with zigzag edges is investigated theoretically. Due to the strongly localized nature of the states near the Fermi energy, the effective Hamiltonian for the low-energy physics is given by the Heisenberg Hamiltonian with the nearest neighbor exchange coupling. The action corresponding to the effective Hamiltonian is mapped to that of the O(3) nonlinear sigma model. It is shown that the spin excitation has a gap when the number of the zigzag lines is even, whereas the excitation becomes gapless in the case of an odd number of zigzag lines.View full abstractDownload PDF (200K) -
Hiroshi Ito, Yasuhisa Hasegawa, Hisaaki Tanaka, Shin-ichi Kuroda, Mino ...2003 Volume 72 Issue 9 Pages 2149-2152
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSResistance measurements under uniaxial compression have been performed on the quasi-one-dimensional iodo-bridged diplatinum complex (MMX-chains) Pt2(n-butylCS2)4I between 100–355 K. The first-order phase transition between the low-temperature alternate-charge-polarization (ACP) state and room-temperature average-valence (AV) state (210 K at ambient pressure) shifted to a higher temperature under compression both parallel and perpendicular to the MMX chains. The stabilization of the ACP state by both compression directions indicates that the ligand molecules play a significant role in making the valence ordering state.View full abstractDownload PDF (166K) -
Ken Matsuba, Hideaki Sakata, Naoto Kosugi, Hitoshi Nishimori, Nobuhiko ...2003 Volume 72 Issue 9 Pages 2153-2156
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe ordered vortex lattice in Bi2Sr2CaCu2Ox (overdoped, Tc=83 K) has been observed for the first time at 4.2 K in 8 T by scanning tunneling spectroscopy (STS). The vortex lattice is short-range ordered in the length scale of 100 nm. The vortices form an almost square lattice with the sides parallel to the diagonal direction of the CuO2 square lattice, that is, the nodal direction of the dx2−y2 superconductor. In all of the vortex cores of the ordered lattice, the localized states are observed at ±9 meV symmetrically in the superconducting gap and are clearly determined to be intrinsic to the vortex in Bi2Sr2CaCu2Ox. The intensity is found to be electron–hole asymmetric.View full abstractDownload PDF (333K) -
Yukio Tanaka, Kazuhiko Kuroki, Yasunari Tanuma, Satoshi Kashiwaya2003 Volume 72 Issue 9 Pages 2157-2160
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe effect of Doppler shift is studied in a model for the α–β bands of Sr2RuO4 consisting of two hybridized one-dimensional (1D) bands. Assuming a superconducting gap with nodes in a diagonal direction, we examine the oscillation of surface density of states and thermal conductivity under a rotating magnetic field. Upon varying the strength of hybridization, the oscillation of these quantities is found to exhibit 2D to 1D crossover. In the crossover regime, which corresponds to the actual Sr2RuO4, the thermal conductivity exhibits a two-fold-symmetry oscillation, while a four-fold-symmetry component in the oscillation is barely detectable.View full abstractDownload PDF (118K) -
Yoshiaki Kobayashi, Mai Yokoi, Masatoshi Sato2003 Volume 72 Issue 9 Pages 2161-2164
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSLayered Co oxide NaxCoO2·yH2O with a superconducting transition temperature Tc=4.5 K has been studied by 59Co NQR. The nuclear spin relaxation rate 1⁄59T1 is nearly proportional to temperature T in the normal state. In the superconducting state, it exhibits the coherence peak and decreases with decreasing T below ∼0.8Tc. Detailed comparison of the 1⁄T1T values and the magnetic susceptibilities between NaxCoO2·yH2O and NaxCoO2 implies that the metallic state of the former system is closer to a ferromagnetic phase than that of the latter. These experimental results impose a restriction on the mechanism of the superconductivity.View full abstractDownload PDF (137K) -
Tadashi Shimizu, Takehiko Matsumoto, Atsushi Goto, Kazuyoshi Yoshimura ...2003 Volume 72 Issue 9 Pages 2165-2168
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe present evidence for the quasi one-dimensional (1D) antiferromagnetism of CuO in the framework of the Heisenberg model. Our result supports the speculations and conclusions made by earlier authors. We also present experimental evidence which explains the reason for CuO to be a quasi 1D antiferromagnet in spite of appearing to have a 3D structure.View full abstractDownload PDF (254K) -
Hisaaki Tanaka, Shin-ichi Kuroda, Takami Yamashita, Minoru Mitsumi, Ko ...2003 Volume 72 Issue 9 Pages 2169-2172
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSESR measurements have been performed on quasi-one-dimensional iodo-bridged diplatinum complexes (MMX-chains) Pt2(RCS2)4I (R = n-butyl (1) and n-pentyl (2)) in the temperature range between 4 K and room temperature. Both complexes show a steep drop in spin susceptibility at approximately 210 K, caused by the formation of a nonmagnetic alternate-charge-polarization (ACP) state at a low-temperature (LT) region for complex 1, and also presumably so for complex 2. Furthermore, thermal excitation of the soliton kink is discussed for complex 2, based on the enhancement of the spin concentration and the motional narrowing of ESR spectra.View full abstractDownload PDF (131K) -
Fumitaka Sakamoto, Kenji Miyakawa2003 Volume 72 Issue 9 Pages 2173-2176
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSDynamics of chemical waves is investigated in two coupled self-oscillating gels prepared by covalently bonding a catalyst of the Belousov–Zhabotinsky reaction. In this type of gel, chemical waves induce periodical swelling-shrinking oscillation in the gels. The spacing between the two gels varies with such a volume oscillation. Various entrainments of the chemical oscillation occur depending on the difference in the concentration of the catalyst immobilized in the two gels. When the difference in catalyst concentration between the two gels becomes larger, synchronization accompanying the apparent reflection of chemical waves occurs. This phenomenon is characterized by various types of entrainments.View full abstractDownload PDF (302K) -
Tatsunari Sakurai, Hidetoshi Miike, Koichi Okada, Stefan C. Mülle ...2003 Volume 72 Issue 9 Pages 2177-2180
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe excitable Belousov–Zhabotinsky (BZ) reaction coupled with diffusion can exhibit a large variety of spatial patterns. In this letter, we report on superimposed spiral structures, providing evidence of a hierarchical self-organized order that connects two complex phenomena involving the coupling of a reaction–diffusion pattern with convection. A macroscopic propagating spiral flow wave (wavelength about 50 mm) is induced spontaneously by the preexcited reaction–diffusion structure of chemical spiral waves (wavelength about 1 mm). The pattern dynamics links two different hierarchical levels of structure formation in a nonlinear system.View full abstractDownload PDF (249K) -
Atsushi Nagai2003 Volume 72 Issue 9 Pages 2181-2183
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSA new type of an integrable mapping is presented. This map is equipped with fractional difference and possesses an exact solution, which can be regarded as a discrete analogue of the Mittag-Leffler function.View full abstractDownload PDF (92K) -
Shu-fang Deng, Deng-yuan Chen, Da-jun Zhang2003 Volume 72 Issue 9 Pages 2184-2192
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe KP equation with self-consistent sources is derived through the linear problem of the KP system. The multisoliton solutions for the KP equation with self-consistent sources are obtained by using Hirota method and Wronskian technique. The coincidence of these solutions is shown by direct computation.View full abstractDownload PDF (127K) -
H. W. Tam, Dao Liu Wang2003 Volume 72 Issue 9 Pages 2193-2197
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe trapezoidal rule has often been referred to as being symmetric or time-reversible and is therefore good for Hamiltonian systems. However, it is well-known that the trapezoidal rule is not symplectic, but is related to the mid-point rule (which is symplectic) through a coordinate transformation. In this paper, we show that the trapezoidal rule preserves a symplectic structure different from the original one by O(h2). The ideas in this paper also motivate us to apply Richardson’s extrapolation to the trapezoidal rule. Numerical results show that the extrapolated trapezoidal rule preserves the Hamiltonian up to O(h4).View full abstractDownload PDF (92K) -
Norio Inui2003 Volume 72 Issue 9 Pages 2198-2202
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe Casimir forces between semi-infinite silicon slabs at 30 and 510 K are calculated by using analytical expressions of the complex dielectric functions of Si, ε(ω)=ε1(ω)+iε2(ω) described by Aoki and Adachi, which are in satisfactory agreement with the experimental information over the entire range of photon energies. The temperature dependence of the Casimir force on the transition of ε2 and that on the black body radiation at finite temperature are evaluated respectively. It is shown that the primary factor of the temperature dependence for separations smaller than 1 μm is the transition of ε2, and the contribution of the black radiation increases for larger separations. The strength relation between the Casimir force at 30 K and that at 510 K is reversed at a threshold near 45 nm along with the increment of the separation. This transition is discussed by examining the Casimir force between materials of which ε2 is characterized by a rectangle function.View full abstractDownload PDF (108K) -
L. Dobrzynski, J. Waliszewski2003 Volume 72 Issue 9 Pages 2203-2212
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe uncertainty of the electron charge and momentum densities reconstructed by the maximum entropy method is analyzed. The paper discusses various sources of uncertainties and errors that can appear in the reconstructions. In particular, it is shown that small features seen on the maps have to be treated with caution and analysis of their statistical significance must be particularly well done.View full abstractDownload PDF (2171K) -
Z. C. Wang, L. Tan2003 Volume 72 Issue 9 Pages 2213-2218
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSA theoretical study is made of the dissipative force and Doppler cooling of a ladder-type three-level atom coupled to a travelling coherent light beam. The dependence of the force on parameters such as detunings, Rabi frequencies, spontaneous decay and coherence transfer rates is calculated numerically and shown graphically. Analytical expressions for the force are obtained for special parameter values. It is shown that for suitable choices of parameter values, it is possible to cool three-level atoms to temperatures down below the Doppler limit.View full abstractDownload PDF (278K) -
Takashi Wakui, Wei-Guo Jin, Kenji Hasegawa, Haruko Uematsu, Tatsuya Mi ...2003 Volume 72 Issue 9 Pages 2219-2223
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSHigh-resolution laser spectroscopy has been performed for the rare-earth elements as well as Ba by using a tunable diode laser together with a well collimated atomic beam. Hyperfine structures and isotope shifts have been measured for eight transitions in Ba I, Ce I, Sm I, Eu I, Gd I and Yb I. Hyperfine constants A and B have been determined for the 4f75d6s6p 11F5 level of 155,157Gd, and the 4f146s6p 3P2, 4f146s7s 3S1 levels of 171,173Yb. The field shifts and 6s-electron densities at the nucleus have been derived for the studied elements and compared with the Hartree–Fock calculation.View full abstractDownload PDF (89K) -
Chang Jun Ye, Bold Gombojav, Takehisa Yoshinari, Shin-ichiro Nagasaka, ...2003 Volume 72 Issue 9 Pages 2224-2228
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe dry powder vessels of cyclodextrin including tin tetrabromides, SnBr4 were prepared in vacuum to investigate the electronic states of the isolated molecule. From the reflection spectra of SnBr4 single crystal, the exciton absorption band has been observed at peak energies 3.64 eV (2 K) and 3.21 eV (room temperature). The reflection spectra of SnBr4 clusters inserted in α-, β- and γ-cyclodextrins were measured. The lowest energy absorption peak of the molecule shows broad absorption band in 3–6 eV. It is analyzed as the overlapped shape of two absorption bands which are separated about 0.5 eV. They come from the spin–orbit split of HOMO state which is made of bromines and 5sp3 mixed states of a tin.View full abstractDownload PDF (382K) -
Akira Tsushima, Motoshi Kobayashi, Takanori Hishida, Yoshimitsu Amagis ...2003 Volume 72 Issue 9 Pages 2229-2235
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSMagnetohydrodynamic (MHD) modes with m=±1 (m: azimuthal mode number) in a current-carrying inhomegeneous plasma are numerically investigated on the basis of wave equations derived from MHD equations, which include effects of finite ion-cyclotron frequency and ion-neutral collisions. In addition to MHD surface waves, kink instability, global Alfvén eigenmode (GAE) and shear Alfvén wave appear when plasma current flows in a plasma column with inhomogeneous density.View full abstractDownload PDF (201K) -
Hironobu Kasano, Hiroyuki Mashiyama2003 Volume 72 Issue 9 Pages 2236-2242
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe crystal structure of K2ZnI4 is refined at 24 temperatures above and below the paraelectric–ferroelectric phase transition temperature by means of X-ray diffraction to reinvestigate the mechanism of the phase transition in more detail. The temperature dependence of the translation of K(1) and K(2) along the b-axis and the rotational angle of the ZnI4 tetrahedron about the axis nearly parallel to the a-axis is obtained by the structural analyses. It is concluded that the mechanism of this phase transition is not the order–disorder type but the displacive one. The temperature variation of the anisotropic temperature parameter U22 of K(1), K(2), I(1) and I(2) is coincident with the theoretical prediction for the displacive type phase transition proposed by Fujii and Matsubara [Prog. Theor. Phys. 78 (1987) 177].View full abstractDownload PDF (155K) -
Hiromitsu Matsuda, Tomonori Koda, Susumu Ikeda, Hatsuo Kimura2003 Volume 72 Issue 9 Pages 2243-2249
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe nematic–isotropic (N–Iso) phase transitions in mixtures of hard rod-like and disc-like molecules are studied by the mean field theory. We use the symmetry breaking potential method for the mixtures examining stability of biaxial nematic phase. Denoting the volume of a rod-like molecule and a disc-like molecule as vR and vD, respectively. We consider symmetric case of vR⁄vD=1, and asymmetric cases of vR⁄vD<1 and vR⁄vD>1. In our present study, the two types of uniaxial nematic phases, optically positive (N+) and negative (N−) are appeared. Biaxial nematic phase (Nb) is always less stable than N+ and N− phases. When aspect ratio and volume of disc-like molecules are large enough, the re-entrance of Iso+N− co-existence region is indicated in a phase diagram.View full abstractDownload PDF (161K) -
Mitsuo Machida, Hirotaka Ikeda, Takaaki Kakiuchi, Toku Ishibashi, Kats ...2003 Volume 72 Issue 9 Pages 2250-2255
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe phase transitions in (CH3)3NCH2COOH·H2PO3 at TC1=355 K and at TC2=216 K were studied by nuclear magnetic resonance. Spin–lattice relaxation time T1 of the 13C nucleus in the CH3 group shows two-mode behavior without showing anomaly in the both phase transitions. Activation energies are determined to be 23.1(9) and 1.3(2) kJmol−1 for two modes. T1 of the 13C nucleus in the CH2 group exhibits a shallow dip around TC1, suggesting that the motion of the CH2 group slows down more or less at TC1. T1 of the 31P nucleus takes a minimum at 253 K and activation energy is obtained as 12.6(2) kJmol−1. In addition to the T1 minimum, this shows a sharp dip at TC1 due to the critical slowing-down of the HPO32− motion. The incomplete slow-down of the CH2 motion is considered to be induced by the coupling with the disorder of the HPO32− anion. The critical relaxation rate of the 31P nucleus is well reproduced by the quasi-one-dimensional Ising model. Interaction parameters for intrachain J|| and interchain J⊥ are determined to be 567(1) and 28.4(4) K (J⊥⁄J||=0.05), respectively.View full abstractDownload PDF (149K) -
J. X. Cao, X. H. Yan, Y. Xiao2003 Volume 72 Issue 9 Pages 2256-2259
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSIn terms of the symmetry of single-walled carbon nanotubes, we present a two-atom unit cell model to study the lattice dynamics and the thermal properties. Different behavior of size dependence of specific heat is found at different temperature. At low temperature, it is found that the specific heat is proportional to the tubule diameter. However, at high temperature the specific heat is inversely proportional to the square of the diameter. The fit for specific heat at 300 K is CV=686.69−9.0⁄d2 (J/Kg K).View full abstractDownload PDF (203K) -
Saeed Yeganegi2003 Volume 72 Issue 9 Pages 2260-2264
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe have studied the dependence of thermal diffusion factor to the temperature for supercritical dense equimolar isotopic binary mixtures of atoms by direct Nonequilibrium molecular dynamics simulation method. The results showed that for these systems the sign of thermal diffusion factor and slope of it with respect to the temperature is positive. For low mass ratio the variation of thermal diffusion factor with temperature is very slow, and for higher mass ratio thermal diffusion factor increases with temperature. Based on the ratios of components of energy flux, microscopic mechanisms of energy transfer across the system are also analyzed.View full abstractDownload PDF (107K) -
Takashi Fujikawa, Takehisa Konishi2003 Volume 72 Issue 9 Pages 2265-2276
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSIn this paper we discuss relativistic short-range-order XPD theory applicable to the XPD from heavy elements (Z>50), where relativistic effects play some important roles. The 4×4 Dirac Green’s function can be expanded in terms of full non-relativistic 2×2 Green’s functions using Gestzesy expansion, which enables us to use well-defined Debye–Waller factors and optical potentials developed within the framework of nonrelativistic theory. We separately discuss the K-edge and other nonspherical deep core excitation by linear and circular polarized X-rays. The relativistic effects play a minor role in the analyses of K-edge XPD excited by linear polarized X-rays, whereas they play an important role in the analyses of spin-resolved K-edge XPD spectra excited by circularly polarized X-rays. Some illustrative numerical calculations demonstrate the contribution to spin polarization in the XPD spectra caused by the relativistic effects.View full abstractDownload PDF (240K) -
Ji\\v{r}í Málek, Stefan-Ludwig Drechsler, Sergej Flach, ...2003 Volume 72 Issue 9 Pages 2277-2281
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe reexamine the dimerization, the charge and the spin gaps of a half-filled Peierls–Hubbard chain by means of the incremental expansion technique combined with density matrix renormalization group (DMRG) method. We compare our numerical findings with results recently obtained by a bosonization and a renormalization group method and found out that this approach seems to be accurate in the weakly correlated case, only. In the strongly correlated limit we found that the charge gap of the dimerized chain tends to the sum of the charge gap of the equidistant chain and the spin gap of the dimerized chain.View full abstractDownload PDF (206K) -
Naoyuki Miyashita, Makoto Kuwabara, Kenji Yonemitsu2003 Volume 72 Issue 9 Pages 2282-2290
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSReal-time dynamics of charge density and lattice displacements is studied during photoinduced ionic-to-neutral phase transitions by using a one-dimensional extended Peierls–Hubbard model with alternating potentials for the one-dimensional mixed-stack charge–transfer complex, TTF-CA. The time-dependent Schrödinger equation and the classical equation of motion are solved for the electronic and lattice parts, respectively. We show how neutral domains grow in the ionic background. As the photoexcitation becomes intense, more neutral domains are created. Above threshold intensity, the neutral phase is finally achieved. After the photoexcitation, ionic domains with wrong polarization also appear. They quickly reduce the averaged staggered lattice displacement, compared with the averaged ionicity. As the degree of initial lattice disorder increases, more solitons appear between these ionic domains with different polarizations, which obstruct the growth of neutral domains and slow down the transition.View full abstractDownload PDF (644K) -
N. Hanasaki, H. Tajima, T. Imakubo, R. Kato2003 Volume 72 Issue 9 Pages 2291-2298
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe measured optical reflectance, Raman spectra, magnetic susceptibility, and electron paramagnetic resonance for the molecular conductor (IEDT)[Pd(dmit)2]. The excitation from the bonding molecular orbital to the antibonding orbital in the Pd(dmit)2 dimer causes a striking peak in the optical spectra around 11000 cm−1. By analyzing the spectral intensity for this peak, we determined the degree of the charge transfer from the IEDT molecule to the Pd(dmit)2 molecule. A gap structure appears below 2000 cm−1 in the reflectance spectra below 100 K. The magnetic susceptibility decreases around 100 K. These phenomena suggest a reduction in the density of states. The electron paramagnetic resonance measurement reveals that the gb*-value decreases around 80 K. This is due to a reduction in the paramagnetic contribution of the Pd(dmit)2 layer. The Ag modes of the Pd(dmit)2 molecule become infrared-active below 100 K as a result of the broken symmetry in the Pd(dmit)2 layer. We propose that the resistance anomaly around 80 K originates from the charge density wave formation within the Pd(dmit)2 layer.View full abstractDownload PDF (191K) -
Shota Shirai, Hiroki Tsuchiura, Yasuhiro Asano, Yukio Tanaka, Jun-ichi ...2003 Volume 72 Issue 9 Pages 2299-2307
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSJosephson current between two d-wave superconductors is calculated by using a lattice model. Here we consider two types of junctions, i.e., the parallel junction and the mirror-type junction. The maximum Josephson current (Jc) shows a wide variety of temperature (T) dependence depending on the misorientation angles and the types of junctions. When the misorientation angles are not zero, the Josephson current has anomalous temperature dependencies because of a zero energy state (ZES) at the interfaces. In the case of mirror-type junctions, Jc has a non monotonic temperature dependence. These results are consistent with previous results based on the quasiclassical theory [Y. Tanaka and S. Kashiwaya: Phys. Rev. B 56 (1997) 892]. On the other hand, we find that the ZES disappears in several junctions because of the Friedel oscillations of the wave function, which is peculiar to the lattice model. In such junctions, the temperature dependence of Jc is close to the Ambegaokar–Baratoff’s relation.View full abstractDownload PDF (449K) -
Yu Kawasaki, Shinji Kawasaki, Mitsuharu Yashima, Takeshi Mito, Guo-qin ...2003 Volume 72 Issue 9 Pages 2308-2311
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe report In-NQR and Co-NMR experiments of CeCoIn5 that undergoes a superconducting transition with a record high Tc=2.3 K to date among heavy-fermion superconductors. At zero magnetic field, an anomalous temperature (T) dependence of nuclear spin–lattice relaxation rate 1⁄T1 of 115In is explained by the relation 1⁄T1∝T·χQ(T)3⁄4 based on the anisotropic spin-fluctuations model in case of the proximity to an antiferromagnetic (AFM) quantum critical point (QCP). The novel behavior of 1⁄T1∼T1⁄4 over a wide T range of Tc<T<40 K arises because the staggered susceptibility almost follows the Curie law χQ(T)∝1⁄(T+θ) with θ=0.6 K and hence 1⁄T1∝T⁄(T+0.6)3⁄4∼T1⁄4 for θ<T. We highlight that the behavior 1⁄T1∼T1⁄4 is due to the proximity to the anisotropic AFM QCP relevant with its layered structure, and is not associated with the AFM QCP for isotropic 3D systems. We have also found that the AFM spin fluctuations in CeCoIn5 are suppressed by small magnetic field so that θ=0.6 K at H=0 increases to θ=2.5 K at H=1.1 T, reinforcing that CeCoIn5 is closely located at the QCP.View full abstractDownload PDF (94K) -
Kazuo Mukai, Masanobu Yanagimoyo, Shuichi Tanaka, Masaki Mito, Tatsuya ...2003 Volume 72 Issue 9 Pages 2312-2316
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe doping effect of paramagnetic organic radical impurities (p-CyDTV) on the organic spin–Peiels (SP) system of p-CyDOV (3-(4-cyanophenyl)-1,5-dimethyl-6-oxoverdazyl; the SP transition temperature TSP=15.0 K) was studied by the heat capacity measurement down to 0.1 K. At low temperatures below 1 K, quite a sharp heat capacity peak was detected for each system with small impurity concentration (x) at the temperature TN(x); TN(0)=0.135 K (±0.002 K), TN(0.01)=0.290 K and TN(0.07)=0.164 K. The appearance of the peak for the system with x=0 is considered to be due to minute and inevitable impurities in the pure p-CyDOV. From the dependence of TN(x), TN(0)<TN(0.01), and the heat capacity behavior on x, the peaks for x=0 and 0.01 are explained to be accompanied with the three-dimensional (3D) antiferromagnetic (AFM) transition in the SP phase. While the decrease of TN(x) for higher impurities x=0.07 than that for x=0.01 may be interpreted as merely a 3D AFM transition from the paramagnetic state in the quasi-1D systems with the interchain interaction |zJ′⁄J|=6×10−4. Although no anomaly of the heat capacity was found around TSP(x)=13–15 K in the present systems, where the characteristic decrease of the magnetic susceptibility is reported, we observed a distinct hump of the heat capacity at TSP′(0)=5.6 K and TSP′(0.01)=5.3 K with magnetic entropy consumption up to 3%, suggesting that this transition may relate to SP transition.View full abstractDownload PDF (117K) -
Yoshiyuki Fukumoto, Akihide Oguchi2003 Volume 72 Issue 9 Pages 2317-2325
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSAn antiferromagnetic Ising model on the Δ chain, with a macroscopic ground state degeneracy and exponentially decaying spin correlation functions, is studied. By introducing transverse magnetic fields Γ on spins at tips of the triangles and λΓ on spins on the bottom chain, we study the ground state as a function of λ and Γ. The λ=0 problem is exactly solved and the ground state has a staggered magnetization on the bottom chain for any Γ>0. Because the transverse field on the bottom chain with finite λ destroys the staggered order, the order–disorder transition occurs as λ is increased. We calculate the transition point λc(Γ⁄J) as a function of Γ⁄J, where J denotes the magnitude of the exchange interaction, by using the series expansion method around the λ=0 limit and conclude that λc(Γ⁄J=+0)\\simeq0.9459. It is shown that states in the degenerate ground state manifold at Γ=0 are crucial in getting a finite value of λc(+0).View full abstractDownload PDF (299K) -
Hiroyuki Shiba, Yoshifumi Ueda, Kouichi Okunishi, Shojiro Kimura, Koic ...2003 Volume 72 Issue 9 Pages 2326-2333
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe low-energy effective Hamiltonian is derived for a typical quasi-one-dimensional Ising-like antiferromagnet CsCoCl3. In contrast to previous treatments, in which only the processes within the crystal-field ground Kramers doublet are considered, second-order processes via crystal-field excited states are also taken into account in the present paper. They result in a new term, which is essentially a next-nearest neighbor ferromagnetic exchange whose anisotropy is different from the nearest-neighbor exchange. By including the new term the magnetization curve and ESR in CsCoCl3 are analyzed to show that those experiments can be explained in a way consistent with other experiments. Related theories on CsCoCl3 are discussed in this connection.View full abstractDownload PDF (170K) -
Chiaki Uyeda, Kenta Tanaka2003 Volume 72 Issue 9 Pages 2334-2337
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe diamagnetic anisotropies (Δχ)DIA of inorganic oxide composed of the octahedral [MO6] units showed a correlation to the degree of preferential orientation of M–O bond directions with respect to their crystal axes. The observed (Δχ)DIA values were explained quantitatively by assigning a constant amount of diamagnetic anisotropy to the individual M–O bond, as were explained previously for the (Δχ)DIA values of the materials composed of the hydrogen bonds and of the T–O bonds consisting the tetrahedral [TO4] units. Accordingly many of the diamagnetic oxides free from electron spins are expected to posses an efficiency of magnetic-alignment.View full abstractDownload PDF (95K) -
Shingo Kirita, Arumugam Thamizhavel, Tetsuya Takeuchi, Kanehito Tabata ...2003 Volume 72 Issue 9 Pages 2338-2343
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe have succeeded in growing a single crystal of CePtGe2 with the orthorhombic crystal structure by the Bi-flux method. In order to investigate the anisotropic properties, the magnetic susceptibility, magnetization and electrical resistivity measurements have been performed along the principal axes. From these measurements, it is found that CePtGe2 orders ferromagnetically below TC=5.1 K, and the magnetic easy-axis corresponds to the a-axis. The anisotropic properties have been analyzed on the basis of the crystalline electric field model. We have also studied the pressure effect on the ferromagnetic ordering, and TC is found to increase with increasing pressure. However, TC smears out around 3.5 GPa and a new phase appears at higher pressures, where the transition temperature of the new phase also increases with increasing pressure.View full abstractDownload PDF (1153K) -
Eiichi Matsuoka, Kazunori Umeo, Shigenari Tsuji, Masafumi Sera, Fumito ...2003 Volume 72 Issue 9 Pages 2344-2349
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSMagnetic susceptibility, electrical resistivity, thermopower, specific heat, and thermal conductivity measurements were made on Ce2NiB10−δ. The crystal structure is derived from that of CeB6 by replacing two B atoms in the B6–B6 network with one Ni atom. The sample prepared by arc melting is deficient in the boron composition, δ≅0.3. The magnetic susceptibility, electrical resistivity, and specific heat show no sign of magnetic ordering down to 0.5 K, but exhibit non-Fermi liquid (NFL) behavior, i.e., χ∝−T0.5, ρ∝T and C⁄T∝−lnT. This behavior of C(T) in zero field and its suppression by external magnetic fields are explained qualitatively by the Kondo disorder model with the average Kondo temperature of 26 K. Atomic disorder induced by boron defects is the most probable origin of the NFL behavior. The thermal conductivity of Ce2NiB9.7 is much reduced from that for CeB6, which is ascribed to the increase of phonon scattering by the lattice defect.View full abstractDownload PDF (645K) -
Seiji Miyashita, Akira Ogasahara2003 Volume 72 Issue 9 Pages 2350-2356
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe field- and frequency-dependence of Electron Spin Resonance (ESR) in the Shastry–Sutherland lattice with small Dzyaloshinsky–Moriya (DM) interaction is studied by the direct numerical estimation of the Kubo formula. Beside the strong paramagnetic resonance, we find the resonance due to the transitions between the triplet and singlet levels which are prohibited in the case without the DM interaction. Furthermore, we find the resonance which is distributed in a wide range of the field for a specific frequency, which corresponds to the transition between the states with the same magnetization.View full abstractDownload PDF (371K) -
Harukazu Kato, Hironori Sakai, Yo Tokunaga, Yoshihumi Tokiwa, Shugo Ik ...2003 Volume 72 Issue 9 Pages 2357-2363
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSGa and Pt NMR measurements have been carried out for two isomorphs compounds, UPtGa5 and UNiGa5, which exhibit different magnetic structures below TN. Knight shift K measurements in the paramagnetic region are reported here. The transferred hyperfine coupling constants at Ga and Pt sites are determined. The temperature independent part K0 of K, which probes the conduction electron polarization at the ligand site, has been successfully evaluated. A nearly identical conduction electron structure in the paramagnetic region is suggested for these two compounds. The origin of the different magnetic structures is discussed.View full abstractDownload PDF (282K) -
Khian-Hooi Chew, Yoshihiro Ishibashi, Franklin G. Shin, Helen L. W. Ch ...2003 Volume 72 Issue 9 Pages 2364-2368
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSInterface structures in double-layer ferroelectrics comprising two distinct layers of different polarization properties, with bilinear interface coupling across the interface, are examined analytically within the framework of Landau–Ginzburg phenomenological theory. The structures are investigated for coupled layers with: (i) one layer in paraelectric phase and the other in ferroelectric phase (ferroelectric–paraelectric), and (ii) both layers in ferroelectric phases (ferroelectric–ferroelectric). The effects of interfacial coupling on the total interface structure energies, interfacial coupling energies and mismatch in polarization across the interface are discussed.View full abstractDownload PDF (97K) -
Gra\\.{z}yna Bator, Ryszard Jakubas2003 Volume 72 Issue 9 Pages 2369-2371
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSDielectric dispersion is shown to occur at radio-frequencies in single crystals of [4-NH2C5H4NH][SbCl4] in the frequency range of 200 Hz–1 MHz. It is found that dielectric dispersion, measured in the incommensurate phase (270.5–304 K) along the [102] direction of the monoclinic symmetry, is monodispersive, except for the close vicinity of Tc=270.5 K, for T<Tc+1 K. In the incommensurate phase (for T>Tc) the apparent critical slowing down is found with τ≈1×10−4 s just above Tc.View full abstractDownload PDF (196K) -
Naoki Ishimatsu, Hiroshi Maruyama, Naomi Kawamura, Motohiro Suzuki, Ya ...2003 Volume 72 Issue 9 Pages 2372-2376
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSX-ray magnetic circular dichroism (XMCD) of γ′-iron nitride (Fe4N) was recorded at Fe K-edge under high pressue up to 27 GPa. The XMCD intensity decreased remarkably with pressure, and vanished at 24 GPa. Compressibility was measured by the X-ray diffraction method. These results indicate that Fe4N undergoes a second-order phase transition from the ferromagnetic state to a paramagnetic state without any structural change. The pressure-induced demagnetizing process is discussed in terms of the Fe magnetic states in the local environment.View full abstractDownload PDF (155K) -
Shin-ichi Kondo, Toshihiro Matsunaga, Tadaaki Saito, Hiroshi Asada2003 Volume 72 Issue 9 Pages 2377-2380
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSIt is possible to measure the fundamental optical absorption spectra of CsPbBr3 and Cs4PbBr6, whose stability is predicted by the study of phase diagram in the binary system CsBr–PbBr2, by means of in situ optical absorption and reflection spectroscopy of thermally induced solid-state chemical reaction in PbBr2-deposited CsBr crystals. On heavy annealing of the crystals, the Pb2+ ions are uniformly dispersed in the crystal matrix. The present experiment provides a novel method for measuring intrinsic optical absorption of ternary metal halides and also for in situ monitoring of doping metal halide crystal with impurities (metal ions or halogen ions).View full abstractDownload PDF (115K) -
Tatsuya Nagao, Jun-ichi Igarashi2003 Volume 72 Issue 9 Pages 2381-2384
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSWe reexamine the mechanism of the x-ray diffraction process by including the Thomson scattering (TS) term in addition to the resonant x-ray scattering (RXS) term previously evaluated by the present authors near the Ce LIII absorption edge in the antiferroquadrupole (AFQ) ordering phase of CeB6. Assuming the AFQ order in the 4f states but without any lattice distortion, we obtain the TS intensity comparable to the RXS intensity, owing to the anisotropic charge distribution of 4f states. The present calculation reproduces well the interference pattern between the TS and RXS terms for the (\\frac52\\frac32\\frac32) spot observed in the recent experiment. The results suggest that the TS signal as well as the main-peak of the RXS signal are a direct reflection of the AFQ order in CeB6. In addition, we add the analysis of the temperature and external field dependences of the TS intensity, which may be utilized in determining the possible type of the order parameter.View full abstractDownload PDF (112K) -
Atsushi Nomura, Makoto Ichikawa, Hidetoshi Miike, Mayumi Ebihara, Hito ...2003 Volume 72 Issue 9 Pages 2385-2395
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSThe present paper proposes a computational model for the realization of visual functions of edge and/or feature detection and segmentation. The model utilizes a reaction–diffusion model which is an extended version of the diffusion-based Difference of Gaussians (DOG) filter previously proposed by Marr and Hildreth as an edge detection model. The proposed model self-organizes spatial patterns having edges and/or features and segments. These patterns are sustained by the intrinsic mechanism of the proposed model under specific conditions. In addition, the model also helps to solve the stereo matching problem in random dot stereograms and the aperture problem in optical flow computation. These visual functions of the proposed model are demonstrated with both artificial and real images.View full abstractDownload PDF (404K) -
Masahiro Agu, Hideo Akabane2003 Volume 72 Issue 9 Pages 2396-2397
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
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Kyu Won Lee, Dong Keun Oh, Cheol Eui Lee2003 Volume 72 Issue 9 Pages 2398-2399
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
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Akimasa Ohnishi, Mamoru Kitaura, Takafumi Otomo, Minoru Sasaki2003 Volume 72 Issue 9 Pages 2400-2401
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
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2003 Volume 72 Issue 9 Pages 2402
Published: September 15, 2003
Released on J-STAGE: July 25, 2007
JOURNAL RESTRICTED ACCESSDownload PDF (21K)