-
Jian–Zhong Ma
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 11 Pages
4059-4063
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The relationship between level statistics and the correlation hole inthe survival probability function in generic chaotic systems isinvestigated. It is shown that the depth and the area of the holemeasure the long- and short-range correlations of levels, respectively. Two models of level statistics, namely the Gaudin modeland an independent superposition of circular unitary ensembles, areanalyzed as examples for systems intermediate between chaos andintegrability.
View full abstract
-
Hideaki Ujino, Miki Wadati
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 11 Pages
4064-4068
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Following the definition of Haldane's exclusion statistics, we proposea new and simple representation of the spectrum and the state countingof the quantum Calogero model. We show that N non-interactingparticles with statistical interactions confined in an externalharmonic well give exactly the same energy spectrum and the samedegeneracy as those of the N-particle quantum Calogero model. We alsoshow that this picture exactly corresponds to the generalized idealgas, which was introduced by Bernard and Wu.
View full abstract
-
Alex Yu. Tretyakov, Norio Konno
Subject area: Statistical physics and thermodynamics.
1995 Volume 64 Issue 11 Pages
4069-4072
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Numerical estimates of critical value and critical exponents for thecontact process on the binary tree are given.
View full abstract
-
Hitoshi Hojo, Yasuaki Kishimoto, James W. Van Dam
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4073-4076
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The Kelvin-Helmholtz mode instability driven by an equilibrium radialelectric field in a cold plasma is studied analytically for flute-typeperturbation in cylindrical geometry. The growth rate and a thresholdin the radial gradient scale length of the E× B drift frequencyfor instability are obtained.
View full abstract
-
Mika Urano, Yasunori Ohkuma, Tsutomu Takahashi, Kiyomitsu Suzuki, Yasu ...
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4077-4080
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Near-infrared radiation from a field-reversed-configuration (FRC)plasma is observed during the stable phase using optical fibertubes. Internal structure of the FRC is estimated from an Abelinversion of the radiation intensities which are obtained from thevertical array of the fibers. It is confirmed that the structure has aconcaveform at the core region of the plasma column, as expected fromprevious FRC stud-ies. The axial array of the fibers shows that the separatrix boundaryis similar in shape to a racetrack when the FRC is long, extending tomirror regions of the confining field, and elliptical for a shortFRC. The equilibrium shape of the separatrix which is calculated usinga two-dimensional code also changes from elliptical to racetrack-likewith increase of the length in the mirror field, as observed in theexperiment.
View full abstract
-
Masayuki Kawakami, Shuji Nishizaki, Toshizo Fujita
Subject area: Structure of liquids and solids; crystallography.
1995 Volume 64 Issue 11 Pages
4081-4083
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
X-ray powder diffraction measurements were made of the intermetallicFe
2VSi compound. At 300 K, Fe
2VSi has the L2
1-type structurewith the lattice parameter a=5.674 Å, but it exhibits atetragonal deformation at low temperatures. The lattice parametersobtained at 10 K are c=5.623± 0.003 Å, a=5.688± 0.001 Åand c/a=0.989.
View full abstract
-
Tomotoshi Nishino, Kouichi Okunishi
Subject area: Thermal properties of condensed matter.
1995 Volume 64 Issue 11 Pages
4084-4087
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We propose a fast numerical renormalization group method-the productwave function renormalization group (PWFRG) method-for 1D quantumlattice models and 2D classical ones. A variational wave function, which is expressed as a matrix product, is improved through aself-consistent calculation. The new method has the same fixed pointas the density matrix renormalization group method.
View full abstract
-
Tomi Ohtsuki, Yoshiyuki Ono
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 11 Pages
4088-4091
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The level statistics in two dimensional disordered electron systems inmagnetic fields(unitary ensemble) or in the presence of strong spin-orbit scattering(symplectic ensemble) are investigated at the Anderson transitionpoints. The level spacing distribution functions P(s) are found to beindependent of the system size or of the type of the potentialdistribution, suggesting universality. They behave as s
2 in thesmall s region in the former case, while increase proportional tos
4 is seen in the latter.
View full abstract
-
Junichi Okada, Isao Sawada, Yoshihiro Kuroda
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 11 Pages
4092-4096
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Three decades ago, the quantum Langevin equation (Mori formula) wasused to reformulate the linear response theory (Kubo formula). Sincethen, the Mori formula has often been used to evaluate transportcoefficients, but only within the Born approximation. In the presentstudy, we obtain a rigorous expression for the transport coefficientsas a series expansion in terms of the projection operator. We thenevaluate the optical conductivity for a free electron system withimpurity scattering in order to discuss the mutual consistency betweenthe Mori formula and the Kubo formula.
View full abstract
-
Taro Nagao
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 11 Pages
4097-4100
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
It has been observed in experiments that the pronounced oscillationstructure in the magnetoresistance of a square antidot lattice isdrastically affected by an anisotropic deformation of the lattice. Weperform a numerical simulation on an anisotropic antidot lattice andobserve expected behavior in the magnetoresistivities. We discuss howthe classical theory of electron motion in an antidot lattice canexplain the observed anisotropy effect.
View full abstract
-
Kiiti Siratori, Yasuaki Nakagawa, Hiroaki Kato, Kay Kohn, Eiji Kita
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4101-4104
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Magnetization, M, of EuS and Eu
1-xSr
xS (x≤ 0.4) was measuredbelow 90 K in an external magnetic field up to 150 kOe. It is shownthat M in the paramagnetic region is well expressed by a Brillouinfunction for S=7/2, with an effective field H+λ M. Even attemperatures below asymptotic Curie temperature, magnetizationapproaches the Brillouin function with increasing fieldstrength. Moreover, it is found that magnetization scaled by(T-T
c)
b can be expressed as a universal function of magneticfield scaled by (T-T
c)
b+c. Here, T
c is the ferromagneticCurie point. Scaling exponents, b and c, are very different from thosein the critical region. The exponent c is about 1.15 and independentof x whereas b is 0.14 for EuS and decreases rapidly with increasingx, proportionally to T
c.
View full abstract
-
Nobuyuki Katoh, Masatoshi Imada
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4105-4108
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We investigate the mechanism of spin gap formation in atwo-dimensional model relevant to Mott insulators such asCaV
4O
9. From the perturbation expansion and quantum Monte Carlocalculations, the origin of the spin gap is ascribed to the four-siteplaquette singlet in contrast to the dimer gap established in thegeneralized dimerized Heisenberg model.
View full abstract
-
Kazutoshi Ogoh, Chihiro Yamanaka, Motoji Ikeya, Eiji Ito
Subject area: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1995 Volume 64 Issue 11 Pages
4109-4112
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
X- and Q-band electron spin resonance (ESR) studies were performed ona radiation-induced defect in stishovite synthesized under highpressure from high-purity SiO
2 glass, followed by γ-rayirradiation using a source of
60Co at room temperature. An oxygenvacancy center which traps an electron (E' center) has an anisotropicg-factor of orthorhombic symmetry, g
x=2.0055, g
y=2.0044 andg
z=2.0023, an axial hyperfine structure due to
29Si (I=1/2), A
x=A
y=1.2 mT and A
z=8.5 mT, and an almost isotropicsuperhyperfine structure due to the second-nearest
29Si, A
shf=1.2 mT.
View full abstract
-
Haruo Furuta, Yuhji Tsujimi, Yukihiro Shimada, Toshirou Yagi
Subject area: Dielectric properties and materials.
1995 Volume 64 Issue 11 Pages
4113-4116
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The quasi c
33 acoustic mode of ferroelectric TGS is observed byimpulsive stimulated Brillouin scattering. The mode is excited bypicosecond laser pulses at 500 MHz and 2.0 GHz and its vibrationalbehavior is probed in real time. The temperature dependence of thevelocity of the mode shows an anomaly through a piezoelectric couplingwith the fluctuating polarization below the transition temperatureT
c. The relaxation time τ
0 of the order of 10
-10 s·deg is obtained which is longer than these reported in the previousBrillouin scattering and the ultrasonic studies.
View full abstract
-
Yutaka Moritomo, Taka–hisa Arima, Yoshinori Tokura
Subject area: Optical properties and condensedmatter spectroscopy and other interactions of matter with particles and radiation.
1995 Volume 64 Issue 11 Pages
4117-4120
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Optical study of trivalent 3d transition metal oxide compoundsLaSrMO
4 (M=Cr, Mn, Fe and Co) with layered perovskite structure hasrevealed fundamental features of their electronicstructures. Systematic change of the charge-transfer gap (E
gap)with the 3d element (M) can be explained by a simple ionic model. Thespectrum below -- 7 eV is found to be strongly M-dependent, and isinterpreted in terms of multiplet splitting of the final 3d
N+1state.
View full abstract
-
Hideaki Ujino, Miki Wadati
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 11 Pages
4121-4128
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
It is shown that the quantum inverse scattering method(QISM) and the exchange operator formalism, which are independentlydeveloped to deal with the quantum Calogero-Moser-Sutherland models, give exactly the same operator algebra in the space of wave functionsof identical particles.
View full abstract
-
Masato Hisakado, Miki Wadati
Subject area: Mathematical methods in physics.
1995 Volume 64 Issue 11 Pages
4129-4134
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Motion of discrete surfaces (triangulate surfaces) in3-dimensional space is studied. The discrete surfaces are mapped tothe sphere S
2 and differential-difference equations are obtained torepresent the motion of the discrete surfaces on the S
2. Theseequations contain intrgrable dynamics. Relations between integrablesystems and the Gauss-Bonnet formula are discussed.
View full abstract
-
Ryutaro Kanno, Noriyoshi Nakajima
Subject area: Statistical physics and thermodynamics.
1995 Volume 64 Issue 11 Pages
4135-4141
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
To analyze the generalized Brownian motion, i.e. the{fractional} Brownian motion, we propose a path integral which isgoverned by the modified action along the principal path with fractalnatures, i.e. mainly observable path in a diffusive phenomena. Bymodified the definition of the action and summing over fractal paths, the path integral is derived. We investigate several properties ofthis integral. The principal path has a fractal structure and the pathintegral represents the transition probability of the fractionalBrownian motion. The transition probability itself has no dependenceon the structure of principal paths. The path integral is mainlycharacterized by two parameters, the Hausdorff dimension D
H ofprincipal paths representing a microscopic structure and the Hurstcoefficient H representing a macroscopic structure, which areindependent of each other.
View full abstract
-
Hiroaki Nakamura, Naomichi Hatano, Minoru Takahashi
Subject area: Statistical physics and thermodynamics.
1995 Volume 64 Issue 11 Pages
4142-4155
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The finite-size scaling function of the nonlinearsusceptibility of the ferromagnetic Heisenberg chain is givenexplicitly. It is conjectured that the scaling function is universalfor any values of S. The conjecture is based on the exact solution ofthe nonlinear susceptibility for S=∞, and numerical calculationsfor S=1/2 and S=1.
View full abstract
-
Ryo Sugihara, Kazumi Nishimura
Subject area: Electricity and magnetism: fields and charged particles.
1995 Volume 64 Issue 11 Pages
4156-4162
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A narrow electromagnetic beam propagating parallel to anexternal magnetic field in a plasma is considered theoretically. Thetheory assumes that the plasma pressure is larger than theelectromagnetic one. It is found that under the paraxial approximationthe beam having a Gaussian cross section can propagate. The Rayleighrange is enlarged or shortened depending on the dielectriccoefficients of the plasma. The beam is either right- or left-handpolarized and both modes have the longitudinal component of theelectric field as the Gaussian beam does in vacuum. The phasevelocities can become less than the light velocity c for some plasmaparameters for which those velocities of the plane R- and the L-wavesare always greater than c.
View full abstract
-
Nabil T. M. Eldabe, Salwa M. G. Elmohandis
Subject area: Kinetic and transport theory of fluids; physical properties of gases.
1995 Volume 64 Issue 11 Pages
4163-4174
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Velocity profiles for unsteady pulsatile laminar flows ofviscoelastic non-Newtonian conducting fluids through a channel havederived using the perturbation method. The induced magnetic field andwall shear have been obtained. The effects of pulsation, elasticityand the magnetic parameter on the velocity, induced magnetic field andwall shear are discussed. Results are illustrated numerically andgraphically. It is found that amplitude of the pulsation increases thevelocity distribution which would be obtained under steady flowconditions at the same mean pressure gradient. The effect of both themagnetic and elasticity parameters decrease the velocitydistribution. Also the properties of the fluid on the induced magneticfield and the skin-friction are discussed.
View full abstract
-
Taro Matumoto, Yuji Nakamura, Masahiro Wakatani
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4175-4184
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
MHD equilibrium and stability of LHD (Large HelicalDevice) are studied when circular plane magnetic axis is distortedinto spatial helical one by introducing unbalance between two helicalcoil currents. The helical axis effect increases rotational transformwith enhancing magnetic hill at zero beta, where beta is the ratio ofplasma pressure to magnetic pressure. The significant effect ofhelical magnetic axis is reduction of average radius of the outermostflux surface or elimination of edge region with large magnetichill. For finite beta plasmas this reduction of average plasma radiushas substantial stabilizing effect on pressure driven MHD modesthrough enhancement of magnetic well produced by both Shafranov shiftand helical shift of magnetic axis. However, by comparing the helicalaxis configuration of LHD to planer axis configuration with the sameradius produced by using limiter, the change of equilibrium andstability due to the helical axis is found weak in the LHD case. Themerit of the helical axis configuration is controllability of averageplasma radius without limiter.
View full abstract
-
Jian Du, Tetsuya Ohata, Katsuji Shimoda, Katsumi HIRANO
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4185-4190
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Soft X-rays generated with a gas-puff pinch device is characterizedusing a pinhole camera which enables a quantitative intensitymeasurement, a Bragg imaging spectrometer and an X-ray diode. Aneutral argon shell whose line density was 8.1× 10
17 atoms/cm(M=5.5× 10
-5 g/cm) was formed between the electrodes. Thesoft X-rays were emitted for about 10 ns in the early stage of theplasma column formation. Highly localized and intense soft X-raysources, so-called hot spots, were observed in the pinched plasma. Theemitted energy was estimated to be 50± 15 J into 4π sr, for ArK-lines. The reproducibility of the X-ray emission are discussed.
View full abstract
-
Hiroyuki Kitaoka, Atsushi Sakurai, Toshikazu Yamamoto, Katsuji Shimoda ...
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4191-4195
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A plasma focus device with a fast acting valve is designedfor additional high z gas puff and is successfully operated to produceintense soft X-rays. Using the fast acting valve, high z gas isinjected to the pinch region just before the discharge to decouple theinitial phase for the current sheath formation from the pinchformation phase. Quantitative measurement of soft X-ray intensity andthe observation of the plasma behavior were simultaneously carried outfor the additional gas puff discharge and the conventional gas-filleddischarge. Experimental results show the enhancement of the soft X-rayemission in two order of the intensity.
View full abstract
-
Naoyuki SATO, Rikizo Hatakeyama, Noriyoshi Sato
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4196-4208
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A plasma potential formation is investigated in acollisionless magnetized plasma flow in the presence of localizedradio-frequency electric fields. An extremely large-amplitude electronplasma wave is generated by applying an external rf potential to aring exciter surrounding the plasma column. Steep changes of electrondensity, temperature and potential along the plasma flow are observedin the region around the wave generation, where the waves arelocalized because of enhanced wave damping. The phenomena drasticallychange in accordance with the characteristics of electron-wavepropagation. The local potential hill and subsequent large potentialdrop observed are attributed to the ponderomotive force on electronsand the nonlinear electron acceleration due to enhanced wave damping, respectively. This claim is supported by calculations based onone-dimensional Poisson's equation including spatial variations of thecharged particles' velocity distribution functions which are stronglyaffected by the localized highly-nonlinear waves.
View full abstract
-
Hiroshi Shirai, Tomonori Takizuka, Osamu Naito, Masayasu Sato, Nobuaki ...
Subject area: The physics of plasmas and electric discharges.
1995 Volume 64 Issue 11 Pages
4209-4220
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Nondimensional local transport analysis of JT-60U plasmashas been carried out for NBI heated L-mode phase. Plasmas with thesame poloidal cross section and almost the same profiles ofnondimensional parameters such as ν
*, β
th, q, T
e/T
i except for ρ
* are compared. The ρ
*dependence of the one fluid thermal diffusivity, χ
eff, theelectron thermal diffusivity, χ
e, and the ion thermaldiffusivity, χ
i, has been examined. The property of χ
effis between the weak gyroBohm type diffusion and the Bohm typediffusion in the region a/3≤ r≤ 2a/3, which is consistent with theresults of the global confinement study done before. We have alsofound that χ
e is weak gyroBohm type diffusion while χ
itends to be Bohm like diffusion.
View full abstract
-
Teruo Ogihara
Subject area: Structure of liquids and solids; crystallography.
1995 Volume 64 Issue 11 Pages
4221-4241
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
A theory of the cooperative Jahn-Teller effect is developed toelucidate a structural phase transition observed in the CsCuCl
3crystal. This theory establishes the relationship between the localand the cooperative Jahn-Teller effect. We find that the helicalalignment of Cl
- ions along the c-axis agrees with experimentaldata when the two Δ
6 modes of the phonons executed bythe Cl
- ions contribute to the structutal phase transition.
View full abstract
-
Masayuki Hasegawa
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 11 Pages
4242-4247
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Freezing of the hard spheres is re-examined using the modifiedweighted-density approximation (MWDA) of Denton and Ashcroft and thegeneralized effective-liquid approximation (GELA) of Lutsko andBaus. It is found that one owes part of success of these theories tothe use of the Percus-Yevick (PY) direct correlation function and thecorresponding equation of state of uniform fluids as the input data inthese theories. In fact, if one uses virtually “ exact'' inputdata in place of the PY ones, the free energies of the solid phase aresomewhat lowered and predicted freezing properties worsen. It isargued that this unfavorable feature of the MWDA and the GELA becomesmuch more serious when these theories are applied to the referencehard spheres in the thermodynamic perturbation approach to freezing ofsystems with long-ranged potentials.
View full abstract
-
Masayuki Hasegawa
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 11 Pages
4248-4257
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Systematic investigations are made of the thermodynamic perturbationapproach to freezing, which has proved successful for systemsinteracting through soft-core or long-ranged potentials. The classicalone-component plasma (OCP) is taken as the extreme case of suchsystems and the investigations focus on the reference systems employedin this approach and on the approximation schemes used to treat thatsystem. It is confirmed that good results are obtained for thefreezing properties of the OCP if a system with repulsive, short-ranged potential is properly chosen as the reference system, andboth this system and the remaining part due to the long-rangeinteraction are separately treated by the modified weighted-densityapproximation (MWDA) using accurate input data. However, if we adoptthe hard spheres as the reference system in this approach and useeither the MWDA or the generalized effective-liquid approximation(GELA) for this system, we cannot get similar results unless we usethe input data in the Percus-Yevick (PY) approximation rather than thevirtually “ exact'' ones. This unfavorable result throwsserious doubt on the usefulness of the hard spheres as the referencesystem.
View full abstract
-
Hisashi Haga, Ryusuke Nozaki, Yoichi Shiozaki, Kenji Ema
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 11 Pages
4258-4264
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Heat capacity of K
2ZnCl
4 and K
2SeO
4 has beenmeasured using a high-resolution ac calorimeter. Critical behavior ofthe heat capacity anomalies associated with the normal-incommensurate(N-INC) phase transitions has been analyzed with the preasymptoticrenormalization-group expression which includes correction terms up tothe second order. It is revealed that the heat capacity anomalies ofK
2ZnCl
4 and K
2SeO
4 are described well with the threedimensional (3D) XY model; the critical exponent, the criticalamplitude ratio and the dimensionless ratio derived from thefirst-order correction terms agree well with the theoreticallyexpected values of 3D XY model. These results are consistent with ourprevious experimental result for Rb
2ZnCl
4 and the Cowley andBruce's prediction that the N-INC phase transition is classified intothe 3D XY system.
View full abstract
-
Kazuo Gesi
Subject area: Equations of state, phase equilibria, and phase transitions.
1995 Volume 64 Issue 11 Pages
4265-4269
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The low-temperature phase transition in N(CD
3)
4MnCl
3 (DTMMnC)has been studied by dielectric measurements. The transitiontemperature of DTMMnC is 126.4 K at zero pressure, which is almostunchanged from that of the normal compound N(CH
3)
4MnCl
3(TMMnC). The effect of deuteration on the pressure-temperature phasediagram is also insignificant: the deuteration lowers the criticalpressure at which the pressure-induced phase (Phase III) appears byabout 10 MPa. The isotope-effect is compared with that in[N(CH
3)
4]
2MnCl
4-type compounds and discussed.
View full abstract
-
Shigenori Tanaka
Subject area: Electron states in condensed matter.
1995 Volume 64 Issue 11 Pages
4270-4277
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The electronic structure of NiO solid with the fcc type-IIantiferromagnetic structure has been studied using a variationalquantum Monte Carlo approach. The Jastrow-Slater many-body wavefunction has been used for valence electrons, and the pseudopotentialshave been evaluated with the aid of a local approximation. Thecalculated results for the binding energy and the structuralproperties are in good agreement with experiment. Reasonableevaluations have also been made for the charge and spin densitydistributions and the electron-electron radial distributionfunctions. Although the results for the one-particle energydistribution and the charge-transfer excitation energy gap areencouraging, further increase in Monte Carlo steps and improvements incomputational methods would be required for the detailed comparisonwith experiments and the most dependable density-functional bandcalculations.
View full abstract
-
Shin–ichi Kimura, Yasuhiko Sato, Fumitaka Arai, Mikihiko Ikezawa ...
Subject area: Electron states in condensed matter.
1995 Volume 64 Issue 11 Pages
4278-4288
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The electronic structures of a magnetic semiconductorCe
3Au
3Sb
4 and the related materials, La
3Au
3Sb
4 andPr
3Au
3Sb
4, have been investigated by reflectivity andresonant photoemission spectra. From the resonant photoemissionspectra of Ce
3Au
3Sb
4, the hybridization between the Ce4fstate and the Sb5p valence band was found to be weak. This result isconsistent with the electronic structure which is derived from theanalysis of the optical data about the energy gap. The experimentallydetermined electronic structure is compared with a band calculation ofLa
3Au
3Sb
4. The unoccupied 4f state is concluded to be about3 eV above the Fermi level, which is higher by 2 eV than the resultof the band calculation. The exciton like absorption due to thetransition from 4f to 5d states was observed. The intra-atomic Coulombinteraction between 4f and 5d states is thought to play an importantrole.
View full abstract
-
Satoru Ohno, Tatsuya Okada
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 11 Pages
4289-4295
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The dependence of the electrical conductivity on concentration forliquid Sn
1-cSe
c alloys exhibited a sharp minimum and a broadmaximum at the composition c=0.5 and 2/3, respectively. The dependenceof the thermopower on concentration exhibited a typical { p-n} transitionat the stoichiometry SnSe. The electrical behaviour of liquidSn
1-cSe
c alloys with c ≤0.3 was explained by the decrease in theconduction electrons due to the formation of chemical bonds between Snand Se ions. The conductivity and thermopower near the stoichiometrySnSe were analyzed by using the equations derived from theKubo-Greenwood formula. The conductivity gap was about 0 eV forliquid Sn--Se alloys near the stoichiometry.
View full abstract
-
Tetsuo Kondo, Kazuya Suzuki, Toshiaki Enoki
Subject area: Electronic transport in condensed matter.
1995 Volume 64 Issue 11 Pages
4296-4307
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We investigated transport properties for incommensurate misfit layercompounds (CeS)
1.19(TiS
2)
n (n=1, 2) with stage-1 and stage-2structures. Both materials showed metallic conduction. The Hall effectshowed that the electrical conduction is dominated by the electroncarriers for both compounds, while thermoelectric power of stage-1(CeS)
1.19TiS
2 had a positive value of +5 μV/K at roomtemperature. This proved that the two different energy bands overlapat E
F of stage-1 (CeS)
1.19TiS
2. Detailed analysis of thethermoelectric power revealed the existence of short rangedomain-boundary phonon scattering process, where the mean free path isestimated to be of the order of 10 Å. This means that thelocal-lattice modulation induced by the incommensurate structure has aremarkable effect on the scattering process of the acoustic phonons aswell as the conduction electrons.
View full abstract
-
Hideaki Kasai, Naoya Okamoto, Ayao Okiji
Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
1995 Volume 64 Issue 11 Pages
4308-4316
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Effects of electronic excitations are investigated on thetranslational energy distribution of ions scattered by metalsurfaces. Coupling between the translational motion of ion and degreesof freedom of metal electron system is taken into account explicitly, in the framework of model consisting of the non-interactingNewns-Anderson Hamiltonian for the electron system and translationalenergy of the ion. It is shown by perturbational calculation thatwithin the Born-Oppenheimer approximation (BOA), a logarithmicsingularity comes out in the energy distribution of ions scattered bymetal surfaces as a Fermi surface effect. Further, it is shown thatbeyond BOA this singularity is weakened by interplay betweenelectronic state transitions and state changes of ion motion duringscattering process.
View full abstract
-
Akimasa Sakuma
Subject area: Electronic structure and electrical properties of surfaces, interfaces and thin films.
1995 Volume 64 Issue 11 Pages
4317-4321
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
To investigate the magnetic performance of a hybrid structure oftransition metals, we consider the Fe
3Pt/Fe system and examine theeffects both of the tetragonal distortion of L1
2 type Fe
3Pt andthe hybridization with bcc-Fe on the magnetic properties, usingLMTO-ASA method in the framework of LSD. The magnetic moment ofFe
3Pthas a maximum stationary value of 8.85 μ
B/cell atc/a=1/√2. The hypothetical struc-ture of Fe
20Pt
4 is supposed by combining Fe
3Pt of c/a=1/√2 and bcc-Fe lattice. It is predicted that the magnetizationreaches 2.27 T with the magnetic anisotropy constant of 11×10
5 J/m
3. With using the coherent rotation model formagnetization reversal process, we get maximum energy product(BH)
max=10.2 MJ/m
3.
View full abstract
-
Takeshi Narushima, Tota Nakamura, Satoshi Takada
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4322-4330
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The ground-state phase diagram of the S=1/2 XXZ laddermodel is investigated by using the density-matrixrenormalization-group method. This model is composed of two S=1/2 XXZchains with ferromagnetic rung couplings (λ ) and intra-chainanisotropy (Δ), and continuously changes from the twoindependent S=1/2 XXZ chains at λ =0 to the S=1 XXZ chain in thelimit of λ → ∞ . It is shown that there existedge states at Δ=1 and λ =1 in relation to thefour-fold degeneracy of the ground state and that an excitation gapopens nearly at λ =0 for 0.8≤ Δ≤ 1. In addition, it is clarified that the transition between the Haldane phase and theantiferromagnetic phase occurs at λ =1.15 ± 0.01 forΔ=1. A possible phase diagram in the λ -Δplane is proposed, which is consistent with the scaling analysis basedon the bosonization method.
View full abstract
-
Kenro Kawano, Minoru Takahashi
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4331-4344
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The logarithmic correction terms in the repulsive Hubbardchain is investigated by using the Bethe Ansatz. The magneticsusceptibility χ of this model has a field dependent logarithmiccorrection term in small magnetic field at zero-temperature. This termcauses ∂ χ /∂ h|_{h=0}=∞ . In arbitrary nand U the existence of the logarithmic correction term is shown forthe susceptibility. We consider how this term depends on n and U. Wealso discuss the logarithmic correction term of the super-symmetric t-J model.
View full abstract
-
Mikito Koga, Hiroyuki Shiba
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4345-4362
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The Kondo effect due to U-type impurities is studied in connectionwith the stability of the Fermi liquid and the non-Fermiliquid. First, an effective exchange Hamiltonian in terms ofirreducible tensor operators is derived for conduction electrons, which are coupled with plural 5f electrons. It is based on theassumption of strong spin-orbit and Hund couplings. Second, a modelfor f
2 configuration placed in a tetragonal or hexagonal crystalfield is studied by simplifying the internal structure as thenon-Kramers doublet ground state and the first singlet excitedstate. The numerical renormalization group analysis shows that thesinglet excited state plays an important role to stabilize the Fermiliquid over the non-Fermi liquid. Third, the difference of the Kondoeffect is examined between non-Kramers doublet for f
2 and Kramersdoublet for f
3 in the presence of the cubic crystal field. It isshown that for f
3 the Hund coupling reduces the channel number toone, while the situation is different for f
2.
View full abstract
-
Yasuaki Oohara, Yasushi Okayama, Hiroki Takahashi, Hideki Yoshizawa, N ...
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4363-4370
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Neutron diffraction measurements were performed on CeAs under highpressure. Above the critical pressure, P
c=1.1 GPa, twomagnetically ordered phases appear. The ferromagnetic ordering isestablished in the upper temperature phase. The type-I ordering isestablished in the lower temperature phase in addition to theferromagnetic ordering, which brings about the canted spinstructure. The temperature dependence of the Bragg intensity of thetype-I ordering has a long tail above the Néel temperature. Theferromagnetic moment increases with increasing pressure, while theantiferromagnetic moment decreases particularly above 2.0 GPa. Thetotal magnetic moment, which is the expected Γ
7 valuebelow P
c, decreases abruptly at P
c.
View full abstract
-
Naoshi Ikeda, Kay Kohn, Etsuko Himoto, Midori Tanaka
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4371-4377
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We observed a few magnetic relaxation phenomena in a LuFeMgO
4single crystal, that is, the difference in the magnetization betweenfield-cooled and zero-field-cooled specimens, the appearance ofthermoremanent magnetization, and the frequency dependence of the cusptemperature of AC susceptibility. The observed relaxation wasinterpreted in terms of thermal fluctuations and freezing of themagnetic clusters which are supposed to exist in this substance.
View full abstract
-
Seishi Takagi
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4378-4381
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The magnetic properties of honeybees have been investigated bymeasuring their susceptibility, magnetization andelectron-spin-resonance (ESR) absorption. The abdomen of adult workerhoneybees shows typical paramagnetism with small magnetic remanencedown to 4.2 K, while the other parts of the honeybees are apparentlydiamagnetic. The paramagnetism of the abdomen seems to develop not inthe pupal stage but after coming out of comb. Drones show noparamagnetism, but a queen bee seems to have some paramagnetic speciesin her abdomen.
View full abstract
-
Hiroshi Ajiki, Tsuneya Ando
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4382-4391
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Magnetic properties of carbon nanotubes (CN's) are studied in a k·p model. In a magnetic field perpendicular to the tube axis, themagnetization is essentially determined by that of a graphite sheet, while it is induced also by the Aharonov-Bohm (AB) effect in aparallel field. The AB effect manifests itself in the magnetic-fieldand temperature dependence of the differential susceptibility even forensembles of CN's having various circumferences and orientations. Themagnetic properties depend also on carrier doping.
View full abstract
-
Youichirou Iino, Masatoshi Imada
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4392-4401
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We investigate temperature dependence of spin correlations in the one-dimen-sional Hubbard model at or close to half filling by the quantum MonteCarlo method. The numerical data are analyzed by introducing acrossover generated from an interplay of the intrinsic correlationlength and the thermal correlation length. It provides a unifiedpicture of the spin correlation of the metallic phase near the Mottinsulator at finite temperatures. Our results show that the crossover, not taken account by the conventional renormalization group and theconformal field theory, becomes more and more important to understandthe spin correlation near the Mott transition point.
View full abstract
-
Masaki Mito, Masakazu Ito, Tatsuya Kawae, Masako Hitaka, Hiroyuki Degu ...
Subject area: Magnetic properties and materials.
1995 Volume 64 Issue 11 Pages
4402-4410
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
We measured the magnetic heat capacity, susceptibility andmagnetization of (CH
3)
4NCo(NO
2)
3 (TMCON) which is theiso-structural compound with the Haldane compound(CH
3)
4NNi(NO
2)
3 (TMNIN). From the analysis of thesethermodynamic properties, we found that TMCON is a one-dimensionalS=1/2 Ising system where the ferromagnetic nearest neighborinteraction J
1 and the antiferromagnetic next-nearest neighborinteraction J
2 are competing. The value of J
1 is estimated to beJ
1/k
B=28.0± 4.0 K. It is confirmed that the results can becomprehensively explained only when we take J
2<0, althoughJ
2=-0.22J
1 estimated from the thermal analysis differs fromJ
2=-0.46J
1 from the magnetic susceptibility for the powderedsample. Based on the results for TMCON, we discuss the stabilizationof the Haldane state in TMNIN, considering the frustration effectbetween J
1 and J
2.
View full abstract
-
Masayuki Kawakami, Susumu Uwanuyu, Tomohiro Nagano, Takeshi Shinohara
Subject area: Magnetics resonances and relaxations in condensed matter; MÖssbauer effect.
1995 Volume 64 Issue 11 Pages
4411-4417
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Hyperfine fields have been measured by the NMR spin-echo technique inzero external field at 4.2 K for intermetallic compoundsFe
2Mn
1-xV
xSi and Fe
2T
1-xCr
xSi (T=V, Mn). Theaverage Fe and Mn magnetic moments are derived using the relationsbetween the hyperfine fields and the atomic magnetic moments in theisomorphic compounds. These moments in Fe
2Mn
1-xV
xSi increasemonotonically with increasing x; for Fe from 0.35μ
B at x=0.2 to0.5μ
B at x=0.75; and for Mn from 2.4μ
B atx=0.2 to 3μ
B at x=0.8. The extrapolation to the V-rich side gives 0.5μ
B/Fe in Fe
2VSi, which is consistent with an extrapolatedsaturation moment of 1.1μ
B/f.u. The results inFe
2T
1-xCr
xSi (T=V, Mn) are also discussed. From thesetogether with saturation moments the transition from a ferromagneticto an antiferromagnetic ordering on the V-rich side inFe
2(Mn, V)Si and Fe
2(V, Cr)Si is suggested.
View full abstract
-
Tatsuo Komori, Koji Hukushima, Hajime Takayama
Subject area: Dielectric properties and materials.
1995 Volume 64 Issue 11 Pages
4418-4425
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Slow dynamics in the ± J Ising model on a square lattice is studiedby means of Monte Carlo simulation, in which the distribution functionof (logarithms of) relaxation times, P(x) with x=ln τ, isobtained by analyzing individual spin auto-correlation functions oneby one. At each temperature in the \lsquo Griffiths phase', namely inthe range above the spin-glass transition temperature T
c (=0) butbelow the Curie temperature of the corresponding pure ferromagnetTpurec, P(x) exhibits a characteristic crossover behavior at aroundx
c(=ln τ
c) which diverges toward T
c. Thecontributionsto the branch x ≤ x
c are interpreted due to the ordinary criticalslowing down process associated with T
c (critical dynamics). Thebehavior of P(x) at x≤ x
c, on the other hand, is quite consistentwith the picture of relaxation processes of large, rare clustersrelated to the expected Griffiths singularity at Tpurec (clusterdynamics).
View full abstract
-
Tomoyuki Nagaya, Yoshihiro Ishibashi
Subject area: Dielectric properties and materials.
1995 Volume 64 Issue 11 Pages
4426-4433
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
Domain structures formed by quench in the NaNO
2-type crystals, whose incommensurate phase transition can be reproduced by thethermodynamic potential with no Lifshitz invariant, have been studiedby solving the kinetic equation numerically, adopting atwo-dimensional model. The temporal evolution of domain structures, consisting of positive and negative domains, is shown and analyzed. Ithas turned out that in the early stage the amplitude of the modulationwave with a specific wavenumber grows up and then the phase approachesthe stable state.
View full abstract
-
Sayumi Hirose, Masao Kamada
Subject area: Optical properties and condensedmatter spectroscopy and other interactions of matter with particles and radiation.
1995 Volume 64 Issue 11 Pages
4434-4441
Published: November 01, 1995
Released on J-STAGE: October 01, 1999
JOURNAL
RESTRICTED ACCESS
The time response of photon-stimulated desorption (PSD) ofexcited-state alkali atoms from alkali halides has been investigatedwith synchrotron radiation pulses. It was found that the substancehaving a larger Rabin-Klick parameter shows a larger efficiency of thefast desorption. It was also found that there is a delay for the fastPSD, indicating the existence of the precursor state. It is proposedthat the fast desorption may be produced by electronic transition inthe surface layer, while the slow desorption may be due to the thermalinstability of surface defects.
View full abstract