bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Transfer of Polarization: A New Method of Polarization of Liquid 3He
Authors: Schuhl A. , Maegawa S. , Meisel M. W. , Chapellier M.
Published: March 2014

We have performed a new method of production of enhanced liquid 3He nuclear magnetization. Liquid is confined by fluorocarbon microspheres. Magnetization of nuclear spins in the substrate(19F,S=½) is enhanced by Dynamic Nuclear Polarization. At the surface of the substrate magnetization interaction between 19F and 3He spins transmits 19F polarization to 3He solid-like surface layer. Since magnetization transfer between solid 3He and liquid 3He is much faster than all relaxation processes, the magnetization enhancement is transmitted to liquid 3He. Peculiar consequence of fast magnetization transfer between the two 3He phases will be also discussed: a sudden lattice warming produces an increase of liquid magnetization.
Helium Fluid in Na–Y Zeolite–Pulsed NMR Study of 3He–
Authors: Kanada Toshinobu , Wada Nobuo , Kumagai Ken-ichi , Ito Taro , Watanabe Takashi
Published: March 2014

Motional state of 3He in Na–Y zeolite, that has a three-dimensional (3D) network of the channels only about 10 A in diameter, has been studied by pulsed NMR. At the adsorbed amount 60% of full channel, we measured a self-diffusion coefficient of the a atom at 25>T>2 K. The magnitude and the temperature dependence of the coefficient quite resemble those of bulk liquid 3He. The resonance frequency dependence of T1, suggests a 3D fluid at T>5 K and a 2D fluid at the lower temperatures.
Van der Waals Potentials of 4He Derived from Adsorption Isotherms
Authors: Brocken M. G. M. , Andel I. van , Geleijns J. , Beelen H. van
Published: March 2014

Van der Waals potentials for thin 4He films on glass and on diamond are deduced from helium adsorption measurements. Significant deviations from the expected cubic dependence on the areal mass density are found. The commonly used values for glass appear to be much too small.
Capacitance Measurements of Adsorption Isotherms and Capillary Condensation of 4He in Nuclepore: Calculation of Pore Size Distributions
Authors: Godshalk K. M. , Hallock R. B.
Published: March 2014

Adsorption isotherms have been directly measured for 4He adsorbed in Nuclepore filters of four different pore sizes using a capacitive technique. Here we report the adsorption and desorption isotherms for the nominal 2000 Å pore diameter. The isotherms show hysteresis as a function of pressure, which is predicted by Saam and Cole. We use these isotherms and the theory of Saam and Cole to obtain a distribution in pore sizes for the Nuclepore.
Raman Polarization Study of Quantum and Classical Liquids; 3He, 4He, Ne, and Ar
Authors: Udagawa Masayuki , Utsunomiya Yoshiharu , Fukumoto Akira , Watabe Mitsuo , Ohbayashi Kohji
Published: March 2014

Polarization property of Raman spectra of simple fluids 3He, 4He, Ne, and Ar has been measured. We have clearly found the polarized spectra in the large energy shift region for 3He and 4He. For 4He, we have estimated the s-wave contribution and have found that the ratio of the s-wave to the d-wave increases with an increase of pressure for both super fluid and normal fluid phases. We have also observed the polarized spectra in the large energy shift region for liquid Ne, but the amount of this contribution to the total scattering intensity is small. For liquid Ar, the polarized part is very weak but feasible. The observation of the polarized part suggests that the repulsive interaction due to the electron overlap effect is important in the Raman process of the simple fluids and we also found that the polarized part decreases with a decrease of a quantum nature of these fluids.
The Commensurate-Incommensurate Transition of Deuterium Monolayers on Graphite
Authors: Wiechert H. , Freimuth H. , Schildberg H. P. , Lauter H. J.
Published: March 2014

Specific heat and neutron diffraction measurements have been made to study in detail the commensurate-incommensurate (C-IC) transition of ortho-deuterium monolayers physisorbed on graphite. Several novel intermediate phases between the commensurate and the incommensurate phase have been observed, which we denote as α, β, γ, δ and ε phases. The neutron diffraction results reveal that these phases can be described by domain wall lattices of different types (striped or hexagonal), and thus provide an experimental verification of recent C-IC transition theories.
Anomalous Surface Tension of Liquid 3He at Low Temperatures
Authors: Suzuki Masaru , Iino Masaaki , Okuda Yuichi , Ikushima Akira J.
Published: March 2014

Surface tension of liquid 3He has been measured by using a capillary-rise method between 0.4 K and 15 mK. Data as a function of temperature T do not exhibit the T
2 dependence as expected from the behavior above 0.3 K. They deviate downwards below about 150 mK and become almost constant below 100 mK. The difference at 0 K between this data and the T2-curve is about 0.5 mdyn/cm, or 3×10-3 as fraction of the surface tension. The deviation does not depend on 4He impurity content, and would be partly related to the decrease of the zero-point energy of surface caused by the density decrease.
Investigation of the Kapitza Anomaly by Frequency-Resolved Phonon Transport in Silicon Wafers
Authors: Klar Wolfgang , Laßmann Kurt
Published: March 2014

The threshold at 85 GHz for anomalously large transmission of phonons into LHe has been investigated with Si-wafers for various surface treatments and coverages by phonon spectroscopy. With this multiple boundary scattering geometry we observe an increased sensitivity to spectral features. Connected with the threshold there is a phase shift of the signal compatible with a loss of the slower diffuse portion of the phonon signal to the covering liquid helium. This phase shift depends nonlinearly on modulation frequency between 5 kHz and 200 kHz (modulation of the generator to sort out the monochromatic phonons) and in a characteristic manner on the surface treatment. The finite phase shift at 5 kHz is indicative of very long lived 85 GHz phonons up into the 100 µs is range inspite of the multiple Si-LHe-interface scattering involved. Minor differences in polishing quality show up clearly in the phase shift at low modulation frequencies.
The Liquid and Solid 3He–4He Phase Diagram Revisited
Authors: Edwards D. O. , Balibar S.
Published: March 2014

The phase diagram of 3He-4He mixtures is calculated from -0.02K to 0.6K using well-known models to describe the liquid and solid phases. For the solids the regular solution model agrees well with data on the isotopic phase-separation and the bcc-hcp transformation. The theory can be applied in equilibrium or when the bcc-hcp transformation is slow on the experimental time-scale For the liquids the Zharkov-Silin or Landau-Pomeranchuk theories are used. Good agreement with experiment is obtained, including the univariants and the two quadruple points.
Thermal Conductivity and Kapitza Boundary Resistance of 4He near Tλ
Authors: Chui T. C. P. , Li Q. , Lipa J. A.
Published: March 2014

We report the preliminary results of high resolution measurements of the thermal conductivity of 4He in a cell with a nominal 1mm gap, and compare them with previous results obtained with a 2mm gap. The temperature dependence of the conductivity was found to be similar for both cells, indicating that size and boundary effects are well controlled. We also report the detailed behavior of the Kapitza resistance just below Tλ.
Influence of Electron Spins for the Magnetic Behavior of Surface 3He
Authors: Saito Shin-hachiro
Published: March 2014

The magnetic susceptibilities, χg, of small silver particles with averaged diameters of 400Å and 700 Å have been measured in zero applied field at temperatures below 4.2 K. The sample were prepared under several conditions of desorption. Electron spin densities on the surface of particles are estimated from the observed values of χg. The desorption to 10-4 Pa at 60 °C can reduce the density of surface electron spin to 1018 spins per gram. It is pointed out that the magnetic behavior of surface 3He must be under an influence of the surface electron spins.
The Effective Masses of Ions Trapped below the Surface of Superfluid 4He
Authors: Mellor C. J. , Muirhead C. M. , Traverse J. , Vinen W. F.
Published: March 2014

Experiments on magnetoplasma waves in two-dimensional pools of ions trapped below the surface of superfluid 4He have been used to obtain values of the cyclotron effective masses of these ions down to a temperature of about 20 mK. The cyclotron masses are found not to depend on the depth at which the ions are trapped below the surface, in contrast to the apparent behaviour of the effective mass obtained from the plasma resonant frequency in zero magnetic field. For reasons that are discussed, the latter masses are thought now to be unreliable. No evidence has been found for either crystallization of the ion pools or the formation of ripplonic polarons.
The Dynamic Broadening of the Roughening Transition
Authors: Gallet F. , Balibar S. , Rolley E. , Nozières P.
Published: March 2014

Precise measurements of the growth kinetics of helium 4 crystals near their first roughening transition at 1.28 K show a dynamic broadening of this transition. This broadening is an increasing
function of the departure from equilibrium. It is well interpreted as a finite size effect in the frame of the critical theory of roughening, which also accounts for all other experimental results (curvature and step energy measurements).
Triplet Correlation Effects in the Maxon-Roton Spectrum of Superfluid 4He
Authors: Kilić Srećko
Published: March 2014

Using Brillouin-Wigner perturbation theory up to the second order, it was shown that triplet correlations play an important role in the spectrum of elementary excitations of liquid 4He as well as in the ground state. Their influence is increased with the increase in density. These effects for Lennard-Jones potential, with respect to Jastrow's correlations, are from 16 to 20% in maxon and 15 to 26% in roton part of the spectrum. It was also found that at the particle densities (in 1028 m-3) beyond 2.46 for MDD-2 and 2.8 for Lennard-Jones the energy of a maxon is greater than the double roton energy. The effects of different potentials were also studied. It was shown that Bruch-McGee's MDD-2 potential leads to the smallest value of the roton gap.
Direct Observation of Dislocations in Solid Helium by SR X-Ray Topography
Authors: Suzuki Hideji , Iwasa Izumi , Nakajima Tetsuo
Published: March 2014

Dislocations in solid 4He were observed by SR X-ray topography. A helium crystal as grown from liquid in a sample chamber cannot be free from internal stress on account of the inevitable decrease of pressure in liquid at the last stage of crystal growth. Dislocations are multiplied and cause glide and climb motions to decrease the internal stress. Dislocations are also multiplied in the course of the martensitic transformation from hcp to bcc and in the reverse transformation.
Vacancies in bcc 3He
Authors: Iwasa Izumi
Published: March 2014

The vacancy formation energy φ and the vacancy formation entropy s in bcc 3He crystals at high molar volumes between 24.356 and 24.922 cm3/mole were obtained from the temperature dependence of pressure. The value of φ decreased between 4.84 K and 2.17 K while the value of s changed between -1.07 k and -4.32 k with increasing molar volume. These resutls were compared with other experiments.
Spin Structure of the Hyperfine Enhanced Nuclear Antiferromagnet Cs2NaHoCl6
Authors: Suzuki Haruhiko , Masuda Yumiko , Arthur John
Published: March 2014

The hyperfine enhanced nuclear spin of 165Ho in Cs2NaHoCl6 shows antiferromagnetic ordering below about 4.8mK. A neutron diffraction experiment has been carried out following adiabatic demagnetization cooling. We did not observe any antiferromagnetic diffraction peaks in the (11̄0) reciprocal lattice plane. The anisotropy of the magnetic susceptibility above and below TN was also measured. The magnetic structure is discussed.
NMR Behavior of Tl Metal at Very Low Temperatures
Authors: Eska G. , Schuberth E.
Published: March 2014

Bulk samples of polycrystalline Tl were cooled in a two stage nuclear demagnetization cryostat to temperatures below 70 µK to 150 µK in fields ranging from 33 mT to 0.17 T. A change in the NMR signal was observed for spin polarisations above 40% where the single line split into two lines with a nearly field and temperature independent splitting of 17±3 kHz. This is attributed to the onset of nuclear spin ordering. The intensity of the NMR line above the transition temperature Tc[µK]=103(B[T]+0.03) exceeded the intensity expected from the Curie susceptibility by roughly a factor of 2.5. Towards higher temperatures (∼1 mK ) this factor decreased monotonically to 1. Heat pulse experiments indicated irregularities in the specific heat in the temperature range 0.1 to 1 mK. Nuclear ordering and a possible change in the low temperature behavior of the conduction electrons are considered as the origin of these effects.
Self-Consistent Dynamical Approach to Heavy-Fermion Systems
Authors: Kuramoto Y. , Kim C.-I. , Kasuya T.
Published: March 2014

This paper studies the Anderson-lattice model using an extention of the non-crossing approximation (XNCA). The XNCA has already shown that the Kondo resonance in the f-electron density of states is enhanced by intersite interactions at temperature T higher than the Kondo temperature TK. This paper shows that at T>TK the static susceptibility χ Per f-electron site is correspondingly smaller than that of the dilute system. However, there Is a temperature (<TK) below which χ of the lattice system becomes the larger. The single-particle spectrum derived at T<TK shows that the quasi-particle renormalization factor is almost the same as that in the dilute system. Hence the Increase of χ is due to a large intersite contribution to the relevant Landau parameter.
All-Electron Coulomb Interaction Effects in MV and HF Systems
Authors: Yin Daole , Lu Guo
Published: March 2014

In addition to the usual U term in conventional Anderson lattice (AL) Hamiltonian, the intra-atomic Coulomb interaction between f-and itinerant electrons G as well as the Coulomb interaction between opposite-spin itinerante electrons I were introduced to form a new Hamiltonian HAEC. The latter can be transformed to a Kondo-like Hamiltonian by a canonical transfomation to coincide with the up-to-date theoretical methods. However, the usually constant parameter U now has to be replaced by an effctive parameter Ueff which varies with anti-spin occupation. This new effect may be conductive to solving some puzzles remained so far in MV and HE problems.
A Fermi Liquid Description for the Kondo Lattice System
Authors: Misawa Setsuo
Published: March 2014

It is shown that most anomalies of the thermodynamic and transport properties in the Kondo lattice system can be universally explained by the logarithmic temperature dependence arising from the Fermi liquid effect; the appearance of a pseudogap associated with the coherent state is not required. Negative thermal expansion is shown to be attributed to a decrease of the effective mass with volume.
The Mechanism of the Large Residual Resistivity in CePd3
Authors: Yanase Akira , Hasegawa Akira
Published: March 2014

To investigate an origin of the large residual resistivity in CePd3, we calculate the energy band structure by a full-potential LAPW method and a local-density approximation to the density-functional theory. We suggest that small Fermi surfaces in the 4f bands may play an essential role in the electrical conduction and the observed sharp rise of the resistivity by the replacement of Pd with Ag or Cu may be due to the Anderson localisation in the 4f bands.
Ferromagnetic and Antiferromagnetic Polarization in the Extended Hubbard Model
Authors: Wei Guo-Zhu , Nie Hui-Quan , Zhang Kai-Yi
Published: March 2014

The series expansion of the local appraoch to investigate the intraatomic electron correlation and the interatomic electron and spin correlation has been extended to the Extended Hubbard Model. We found that the interatomic electron and spin correlation can not be neslected for calculating the correlation energy, the local moments and the local polarization. There exists the antiferromagnetic local polarization for large n, while there exists the ferromagnetic local polarization for small n.
de Haas-van Alphen Effect Studies in CeCu6
Authors: Reinders P. H. P. , Springford M. , Boulet R. , Coleridge P. T.
Published: March 2014

We have investigated the dHvA effect in the “Kondo lattice” heavy-fermion compound, CeCu6, in magnetic fields of 4 to 13.6T and at temperatures between 20 and 500 mK. The results reveal a highly anisotropic Fermi surface with quasiparticle effective masses of 6–80mo. A differential scattering between up and down spin quasiparticles is detected. At low magnetic fields, < 4T, a structure is observed in the magnetic susceptibility which is not attributable to quantum oscillations. We believe this reflects changes in the density of states induced by the action of the magnetic field on the Abrikosov-Suhl resonance.
4f Hybridization in the Cyclotron Mass of PrB6 and PrCu6
Authors: Ōnuki Yoshlchlka , Umezawa Ado , Kwok Wai K. , Crabtree George W. , Nishihara Munekazu , Komatsubara Takemi , Maezawa Kunihiko , Wakabayashi Shigeru
Published: March 2014

Hybldlzatlon effects of the 4f electrons with the conduction electrons in PrB5 and PrCu6 are reflected in the Fermi surface and the cyclotron mass determined from the de Haas-van Alphen effect. The masses of PrB6 and PrCu6 are three times and twice larger than those of LaB6 and LaCu6, respectively.
Sound Attenuation and Dispersion near Tλ of 4He
Authors: Pankert J. , Dohm V.
Published: March 2014

The critical behaviour of first sound is investigated by renormalization-group (RG) methods on the basis of a new model describing the critical dynamics of all slow modes. A maximum is predicted for the attenuation at Tλ as a function of the frequency. Recent data on the dispersion at 1 GHz are explained.
Magnetostriction of Heavy-Fermion UPt3 in Magnetic Fields up to 24 Tesla
Authors: Visser A. de , Puech L. , Joss W. , Menovsky A. A. , Franse J. J. M.
Published: March 2014

The high-magnetic-field anomaly at 20 T in heavy-fermion UPt3 has been studied by means of magnetostriction measurements on a single-crystalline sample at liquid helium temperatures. The data for a field direction in the basal plane reveal an orthorhombic distortion of the hexagonal crystal structure. An explanation for this distortion is offered in terms of a (antiferromagnetic) spin-fluctuation model.
Anomalous Kondo Effect in CeCu6-xAgx Alloys
Authors: Ramakrishnan S. , Chandra Girish
Published: March 2014

CeCu6 is an established heavy Fermion system which does not exhibit either magnetism or superconductivity down to 20mK. The electrical resistivity shows a logarithimic temperature dependence at high temperature and resistivity maximum at 13K. We have shown that this resistivity maximum is a sensitive function of the Copper conduction band. In this paper we show that the coherent Kondo effect observed in CeCu6 is much more sensitive Copper susbtitution by Silver rather than the rare earth substitution for Ce in CeCu6.
Pressure Effects on NMR and PQR Properties of CeCu6 and CeCu2Si2
Authors: Kumagai K. , Aoki H. , Nakajima H. , Onuki Y. , Komatsubara T.
Published: March 2014

NMR and PQR techlques under high pressure are used to study the pressure effects of the nuclear relaxation and quadruple interaction in the Kondo lattice compounds down to 0.6K. The temperature independent T1 of 63Cu of the PQR spectra are reduced by pressure in their magnetic regime. The Korringa relation, which is expected in the Fermi liquid state, appears below 1K at 5.4kbar in CeCu6, indicating that the coherency becomes stable at higher temperature by pressure. The quadruple interactions at each Cu site increase differently with pressure in CeCu6, reflecting the anisotropic compressibility for each axis.
NMR and PQR Studies on Magnetic Properties of RCu6 (R=Ce, Nd and Sm)
Authors: Kumagai K. , Watanabe I. , Nakajima H. , Onuki Y. , Komatsubara T.
Published: March 2014

Pulsed NMR and PQR techniques are used to investigate magnetic relaxation and internal fields due to electric quadruple and hyperfine interactions of RCu6 (R=Ce, Nd and Sm) in the magnetically ordered and paramagnetic states. We found 5 PQR spectra Cu between 3 and 20MHz and one unshifted NMR spectrum, corresponding to the 6 crystallographlcally inequivalent sites of Cu in RCu6. Longitudinal relaxation rates of 63Cu of PQR in SmCu6 and NdCu6 are enhanced by fluctuations of the magnetic moments and seems to be diverge at TN whereas T1 of the unshifted NMR spectrum is comparable to that in the non-magnetic LaCu6.
Temperature and Magnetic Field Dependence of Elastic Constants in (La, Ce)B6 Single Crystals
Authors: Ewert Siegfried , Guo Simon , Lemmens Peter , Lenz Dieter , Sander Wilhelm , Thalmeier Peter , Winzer Klaus
Published: March 2014

Measurements of the sound velocity in dilute (La1-xCex)B6 (x=0.01,0.03,0.1) crystals were used to determine the temperature and magnetic field dependence of elastic constants c44 and (c11-c12)/2. Their softening below 4.2 K is explained on the basis of a single ion magnetoelastic interaction. From this we conclude that the majority of Ce-ions has static splitting (2.2 K) of the Γ8 ground state into two doublets. From the observed magnetoacoustic quantum oscillations in very dilute (La,Ce)B6 Fermi surface cross sections, effective Dingle temperatures and their T-dependence were determined.
Reduction of the Electronic Density of States of CePb3 at High Magnetic Fields and Low Temperatures
Authors: Fortune N. A. , Schmiedeshoff G. M. , Brooks J. S. , Lin C. L. , Crow J. E. , Mihalisin T. W. , Stewart G. R.
Published: March 2014

The specific heat of CePb3 has been measured for temperatures between .4 and 2 kelvin in magnetic fields ranging from 0 to 20 tesla. At zero magnetic field, we observe an antiferromagnetic transition at lower temperatures. For magnetic fields greater than 10 tesla, we observe a large reduction in the low temperature limit of C/T, which is suppressed from 1.5 J/mole-K2 in a 18.7 tesla magnetic field.
Magnetic-Field Studies of Heavy-Fermion Antiferromagnetic U(Pt0.95Pd0.05)3
Authors: Sprang M. van , Boer R. A. , Menovsky A. A. , Franse J. J. M.
Published: March 2014

The antiferromagnetic compound U(Pt0.95Pd0.5)3 is known to exhibit strongly anisotropic properties. Resistivity and susceptibility can differ with a factor of two along different crystallographic directions. The antiferromagnetic order at 5.8 K is related with spin density waves. Below the ordening temperature large anisotropies are observed within the basal plane. The anisotropy is studied by resistivity and specific heat experiments with magnetic fields up to 8 T. The results suggest that the magnetic moments involved in the spin density wave are parallel to the b-axis. Neutron diffractions data support this conclusion.
Point Contact Measurements on U2Zn17
Authors: Samuely Peter , Kupka Martin , Flachbart Karol , Diko Pavol
Published: March 2014

We report on point contact measurement on the heavy fermion system U2Zn17. It is shown that the first derivative of the current-voltage characteristics of low resistance contacts is very sensitive to the magnetic phase transition. The results are discussed in the frame of the heating model, which includes electrical and thermal resistivity as well as thermopower effects.
High-Field Behavior of (TMTSF)2ClO4: Generalized Quantum Hall Effect and Wigner Crystallization
Authors: Chamberlin R. V. , Naughton M. J. , Yan X. , Chaikin P. M. , Hsu S. Y. , Chiang L. , Brooks J. S.
Published: March 2014

We report measurements of the magnetization, Hall resistance, and magnetoresistance of (TMTSF)2ClO4 in fields up to 30T. In addition to the previously reported spin-density wave transitions, these measurements show a novel phase transition at a field, HX\cong25T. This phase transition is, at most, weakly first-order. Above Hx (TMTSF)2ClO4 is a compensated semi-insulator with an activation energy ΔX\cong1.4K. The behavior at Hx is consistent with the formation of a pinned Wigner crystal.
Pressure Dependence of the SDW Properties in the Organic Conductor (TMTSF)2PF6
Authors: Kawamura Hiroki , Ohyama Teruo , Maniwa Yutaka , Takahashi Toshihiro , Murata Keizo , Saito Gunzi
Published: March 2014

The pressure dependence of the SDW properties in the titled material has been examined by using 1H-NMR technique. (1) The wave number which is incommensurate and very near the optimal nesting vector was found constant in the whole range of measured temperature and pressure. The SDW amplitude extrapolated to the absolute zero is pressure independent while the transition temperature is decreased under pressure. This is a feature peculiar to the nesting model proposed by Yamaji, and the first direct support of this model. (2) A clear anomaly in 1H-NMR relaxation rate suggesting a magnetic transition, well below the SDW transition temperature has been observed. The `new' transition temperature is 3.5 K at ambient pressure and remarkably pressure dependent, with the coefficient of -0.2 K/kbar.
Collective Behavior of Field Induced Spin Density Waves in Bechgaard Salts
Authors: Virosztek Attila , Maki Kazumi
Published: March 2014

Within a model of quasi-two dimensional electron system interacting via on site Coulomb potential we study theoretically the collective behavior of the field induced spin density waves (FISDW) in Bechgaard salts. In a FISDW there are two gapless modes associated with the spin rotation around the external magnetic field and the sliding of the FISDW. These gapless modes cancel exactly the anomaly due to the modification of the quasi-particle spectrum below T

c
in the correlation functions like <[S
3, S
3]>, <[n, n]> and <[j

x
, j

x
]> where S
3, n and j

x
are the spin parallel to the external field, the electron density and the electron current parallel to the chain direction. The low frequency behavior of these correlation functions are unchanged at the FISDW transition when the quasi-particle damping is ignored. However, the rotational symmetry of the spin is broken by the dipole energy which gives rise to a small energy gap in the longitudinal spin wave spectrum below T

c
, which is accessible to the electron spin resonance. Furthermore the translational invariance of the SDW is in general broken by impurities and/or crystalline defects, which gives rise to the SDW pinning. Then the resulting expression of <[n, n]> and <[j

x
, j

x
]> resembles to those in a CDW in quasi-one dimensional conductors. Therefore we predict similar nonlinear conductivity in the presence of electric field and electromechanical effects as found in the CDW systems.
Impurity Pinning in One-Dimensional Spin Density Wave Systems
Authors: Suzumura Y. , Saso T. , Fukuyama H.
Published: March 2014

The effect of weak Impurities on the spin density wave (SDW) system Is studied by use of the one-dimensional discretized model of the phase Hamiltonian. It is shown that the impurity pinning always occurs even in the SDW systems by allowing the spatial variation of both the charge and the spin density fluctuations.
Thermal Convection in 3He–4He Mixtures near the λ-line
Authors: Bloodworth T. J. , Ardron M. R. , Lucas P. G. J. , Bhattacharjee J. K.
Published: March 2014

The critical Rayleigh number for a 3.24 molar percent normal mixture of 3He in 4He heated from below is measured as a function of temperature near the λ-transition. Agreement with the linear theory of Gutkowicz-Krusin et al is good in the separation parameter range S>-1.1 but convection sets in at lower than predicted Rayleigh numbers for S<-1.1. Frequencies an order of magnitude lower than those predicted by the linear theory are present in power spectra obtained just above onset. Modulation of the heat current at a comparable frequency produces a depression of the convection onset which is proportional to the modulation amplitude.
Numerical Study on Nonlinear Dynamics of Charge-Density-Waves
Authors: Matsukawa Hiroshi , Takayama Hajime
Published: March 2014

Mode locking phenomena in quasi 1D charge-density-wave (CDW) under a dc+ac electric field are studied numerically based on the Fukuyama-Lee-Rice (FLR) model. We observe both the harmonic and subharmonic mode lockings even under a large dc field (or an ac field with high frequency) as observed experimentally. This indicates, contrary to the recent criticism by Throne et al (Phys. Rev.Lett.58(1987) 828), that the CDW nonlinear dynamics can be well described by the FLR model.
Density of States for Quasi-One-Dimensional Conductors
Authors: Suzumura Y.
Published: March 2014

By applying the phase Hamiltonian method to quasi-one-dimensional electron systems, we study the electronic density of states for several kinds of ordered states at the absolute zero temperature. It Is shown that the density of states just avove the true gap Increases continuously from zero when the one-dimensional fluctuation Is large. Further we discuss the effect of finite temperatures and the ratio of the true gap to the second order phase transition temperature.
Theoretical Modeling of the He I–He II Interface
Authors: Giordano N. , Muzikar Paul
Published: March 2014

When liquid 4He is at a temperature sufficiently close to Tλ in the presence of a gravitational field, a two phase state exists. The upper portion of the liquid is superfluid, while the lower portion is normal, with an interface separating the two phases. We have studied the analog of this interface in simple spin models, using Monte Carlo simulations and scaling arguments.
Evidence for the Existence of the Inherent Periodicity of the Charge-Density Wave in the Switching State in K0.3MoO3
Authors: Maeda Atsutaka , Notomi Masaya , Uchinokura Kunimitsu , Tanaka Shoji
Published: March 2014

The current response in the highly conducting state after the switching at low temperatures in K0.3MoO3 Was measured both in time domain and in frequency domain. We found the inherent oscillation due to the sliding of charge-density wave (CDW). The relaxation-type oscillation which is sensitive to the external circuit is considered to be the extremely coherent response of the CDW condensate by one wavelength. Furthermore, the dynamical behavior of the CDW's very near the threshold voltage is analyzed quantitatively, which is unique to the low-temperature switching in K0.3MoO3.
Observation of Nonlinear Conduction in (NbSe4)3I
Authors: Taguchi Isao , Lévy F. , Berger H.
Published: March 2014

Switching is observed from a state with high resistance to a state with lower resistance in the current-voltage characteristics of some (NbSe4)3I crystals of type II. As temperature is lowered from 140 to 110 K, the threshold current decreases by about ten, while the threshold voltage does not change with temperature. These results are interpreted in terms of the depinning and the ánd the sliding motion of charge density waves in (NbSe4)10/3 I domains the inclusion of which is responsible for a much larger increase in the resistivity at low temperatures in type II crystals than in type I crystals.
Tunneling Spectroscopy of Quasi-One-Dimensional Material
Authors: Ikuta Hiroshi , Maeda Atsutaka , Uchinokura Kunimitsu , Tanaka Shoji
Published: March 2014

A tunneling spectroscopic measurement of the quasi-one-dimensional material blue bronze bronze K0.3MoO3 is performed from 40 K to room temperature in order to determine the Peierls gap. The junctions were prepared by the contact method. The temperature dependence of the Peierls gap showed a behavior quite different from the BCS-like one. The density of states and the temperature dependence of the Peierls gap of K0.3MoO3 are discussed in terms of the one-dimensional fluctuation and a two-band model, respectively.
Critical Velocities in 3He–4He Mixtures
Authors: Zeegers J. , Kuerten J. G. M. , Waele A. T. A. M. de , Gijsman H. M.
Published: March 2014

Mutual friction between 3He and 4He II plays an important role in the hydrodynamics of 3He–4He mixtures. A close analogy exists with mutual friction between the normal and the superfluid components in pure 4He II. In pure 4He II, the flow properties are characterised by the appearance of critical velocities below which no mutual friction occurs. In this paper we report on the first observation of non-zero critical velocities in 3He–4He mixtures in flow channels consisting of bundles of (about 100) parallel tubes. At the critical velocity the temperature rise at the exit of the channel was on the order of a few millikelvin. Both continuous and hysteretic transitions were observed. The experimental results show that the product of the critical velocities and the diameter is in good approximation constant.
Temperature Dependence of Shubnikov-de Haas Oscillations in Graphite Intercalation Compounds
Authors: Ibrahim A. K. , Powers R. , Zimmerman G. O. , Tahar M.
Published: March 2014

The Shubnikov-de Haas oscillations in the magnetoresistance are used to investigate the electronic properties of FeCl3-graphite intercalated compounds. From the field and the temperature dependence of the amplitudes of the dominant frequencies of these oscillations the effective masses, the Dingle temperatures, the relaxation times, and the carrier mobilities are determined for stages 2 and 5. Details of the stage dependence of these oscillations at several different temperatures will be presented and discussed.
Magnetic Breakdown Effect in KTaO3
Authors: Uwe Hiromoto , Okubo Noriyuki , Yoshizaki Ryozo , Sakudo Tunetaro
Published: March 2014

For Ca-doped single crystal of KTaO3 magnetoresistance oscillations have been observed at 1.4 K up to the field of 16 T. More than three frequency components can be assigned to interconnected trajectories caused by the magnetic breakdown effect, in addition to the normal ones of the heavy and light electrons. From the angular dependence of the frequencies, we have determined the band parameters, which are found to be consistent with the criterion for the magnetic breakdown effect.
New Evidence for Electron-Electron Scattering in Noble Metals from Radio-Frequency-Size-Effect Measurements
Authors: Stubi Rene , Probst Pierre-Alain , Huguenin Robert , Gasparov Vitali
Published: March 2014

High precision radio-frequency-size-effect measurements of the temperature dependent scattering rate have been performed in Cu and Ag down to 0.5K. The data can only be described by introducing a term αT2 from electroń-electron scattering with α\cong2·106 [s-1 K-2] in fair agreement with resistivity data and theoretical calculations.
Ballistic Temperature Point-Contact Spectroscopy of Cu
Authors: Reiffers Marián , Flachbart Karol
Published: March 2014

Non-symmetric generation of heat in metallic point-contacts dependent on the direction of the electrical current current through the contact (ballistic temperature point-contact spectroscopy) was investigated. The energy positions of the observed anomalies are in correlation with the characteristic energies of the electron-anomalies are in correlation with the characteristic energies of the electron-phonon scattering processes observed in Cu by the noise point-contact spectroscopy.
High-Field Magnetoresistance in Monocrystalline Aluminum with Vacancy Clusters
Authors: Ueda Yoshitake , Hosoda Hiroki , Kino Takao
Published: March 2014

The high-field magnetoresistance and Hall coefficient were measured on monocrystalline specimens of zone-refined aluminium that were annealed at 300°C, quenched from 300∼500°C and subsequently aged at room temperature, respectively. The latter was independent of the heat treatments. On the other hand, the former exhibited an anomalous decrease of 50% in the aged state. This anomaly is explained by a mechanism that conduction electrons go through the space between vacancy clusters grown during the aging when the cyclotron radius of the electrons becomes smaller than the mean distance between these clusters.
Point-Contact Spectroscopy of 3D Transition-Metal Intercalate FexTiS2
Authors: Inoue Masasi , Ueda Yoshifumi , Marushita Motoharu , Negishi Hiroshi , Koyano Mikio
Published: March 2014

The derivatives of the current-voltage characteristic of a homojunction point-contact of lT-CdI2 type TiS2 and its intercalation compound of magnetic Fe1/3 TiS2 have been measured at 1.4 K. A number of intra- and interlayer acoustic and optical phonon modes are identified, and the effect of Fe intercalation on the phonon dispersion curve is discussed based on the “extended-shell” model. The singularity at a characteristic bias voltage Vc in the d2I/dV2-V curve observed for Fe1/3TiS2 is attributed to a local heating of the contact up to the magnetic transition temperature Tc of this material.
Anomalous Quantum Diffusion in Quasiperiodic Potentials
Authors: Hiramoto Hisashi , Abe Shuji
Published: March 2014

The diffusion of electron wavepackets in quasiperiodic potentials is studied numerically. Calculations are performed in a one-dimensional tight-binding model with site-diagonal or site-off-diagonal Fibonacci modulation. The mean square width of the wavepacket put on a single site at the time t=0 shows such an overall time evolution as <Δx
2>∼t
2α (0<α<1). The exponent a decreases with increasing the modulation strength. This anomalous power law behavior is successfully explained by using renormalization group arguments.
Influence of Inelastic Scattering on the Relaxation Time at Low Temperature
Authors: Yonemitsu Kiyoshi , Onodera Ribun
Published: March 2014

Boltzmann equation was solved for two models. Model 1:electron-Einstein phonon scattering. Model 2: electron-two level system scattering. When inelastic scattering terms are taken into account structures appears in relaxation time vs.energy curve at low temperature. An oscilation in the model 1 and a stairway structure in the model 2. The origine of the structures is discussed.
Search for Superfluidity of 3He in 3He–4He Solution
Authors: Ishimoto H. , Fukuyama H. , Nishida N. , Miura Y. , Takano Y. , Fukuda T. , Tazaki T. , Ogawa S.
Published: March 2014

Cw NMR measurements have been done to detect superfluidity of 3He component in 3He–4He solutions with several 3He concentrations and pressures at Larmor frequencies of 1 and 2 MHz. With reduction of the sample temperature from the hydrodynamic to the collisionless region, the NMR absorption line narrows and several satellite peaks appear. The behaviors of these peaks were investigated with variation of an external magnetic field gradient. Numerical analyses of this phenomenon as the excitation of new standing spin wave mode lead to determination of the Fermi liquid interaction parameter λ=(1+F0
a)-1-(1+F1
a/3)-1.
Low Temperature Magnetoconductivity of n-InSb by Acoustic Measurements
Authors: Guillon F. , Fernandez B. , Cheeke J. D. N.
Published: March 2014

Results of the magnetic induced relaxation peak of n-InSb are presented and compared with the Hutson-White model of the piezoelectric interaction. It is suggested that apparent discrepancies with other recent results have their origin in a compensation effect.
Effects of Deformation-Potential Coupling on Acoustic Second-Harmonic Generation in n-Type InSb
Authors: Wu C. C. , Tsai J.
Published: March 2014

Acoustic second-harmonic generation has been studied in n-type InSb with a dc magnetic field \vecB directed along the acoustic waves propagating. We are interested in both high- and low-frequency regions, the electron relaxation time due to the scattering in solids is taken into account. The dominant electron-phonon interaction in solids is via deformation-potential coupling. It is shown that the ratio of the acoustic intensity in the second harmonic to the square of the acoustic intensity in the fundamental decreases rapidly and then increases slowly with the phonon frequency. A comparison between the deformation-potential coupling and piezoelectric coupling has been made. It is also found that the second-harmonic generation can be influenced by changing the dc magnetic field due to the nonlinear nature of energy bands in solids.
The Effect of Scattering Mechanisms on Transverse Magnetoresistance in Piezoelectric Semiconductors
Authors: Wu C. C. , Lin C. J.
Published: March 2014

The transverse magnetoresistance in nondegenerate piezoelectric semiconductors has been investigated according to the acoustic phonon scattering, the piezoelectric scattering, and the ionized-impurity scattering. The energy band of carriers in semiconductors is assumed to be nonparabolic. Results show that the transverse magnetoresistance for these three types of scattering depends strongly on the dc magnetic field and temperature. It is found that the effect of the piezoelectric and ionized-impurity scatterings on the transverse magnetoresistance is much smaller than that of the acoustic phonon scattering in the lower magnetic field region. However, in the high-magnetic field region, the effect of the piezoelectric scattering becomes comparable to the effect of the acoustic phonon scattering, while the effect of the ionized-impurity scattering is still insignificant.
Many Body Theory of the Formation and Dynamics of Excitons in an Electron-Hole Gas at Low Temperatures
Authors: Côté R. , Griffin A.
Published: March 2014

Using functional differentiation to obtain the two-particle Green's functions, we give a systemmatic discussion of the collective modes in an electron-hole gas at low temperatures. Our analysis is based on the well known pairing approximation for the single particle self-energies and corresponds to the generalized RPA. The excitons with finite momentum appear as fluctuations of the electron-hole condensate and have a linear dispersion relation (Keldysh and Kozlov).
Temperature Dependent Hall Constant Data in a 100 Å In2O3-x Film
Authors: Ben-Shlomo Moshe , Rosenbaum Ralph
Published: March 2014

We have observed a ln(1/T) temperature dependence in the Hall constant data of a 100 Å In2O3-x
film measured at liquid helium temperatures in a 1.95 Tesla magnetic field. The data was interpreted using the electron-electron interaction theory of Altshuler, et al. The only parameter in the theory was the electron screening constant F; the Hall constant data gave a value of 0.75 for F. Agreement was found between the resistance-temperature data and the theory composed of the interaction contribution and the weak localization contribution.
Conductance Fluctuations in Thin Metal Films
Authors: Meisenheimer T. L. , Beutler D. E. , Giordano N.
Published: March 2014

We have observed time dependent conductance fluctuations in thin films of Bi and Pt, at low temperatures. The magnitude of these fluctuations becomes larger as the temperature is reduced, and is in reasonable agreement with the theory of Feng, Lee, and Stone, which ascribes them to the motion of individual scattering centers. The time dependence of the fluctuations is in good agreement with this interpretation.
Specific Heat of the 2-D Electrons in a Strong Magnetic Field
Authors: Yoshioka Daijiro
Published: March 2014

Specific heat of the 2-d electrons is calculated both by exact diagonalization of the finite system Hamiltonian and by a simple model. The electron density around v=1/3 is considered, where v is filling factor of the Landau level. It is shown that the specific heat shows a peak around T=Δ/4, where Δ is the excitation energy at infinite momentum. Comparison of the model with the exact result indicates that the Δ is renormalized and increases as the temperature is raised.
Quantum Fluctuations in the Quantum Hall Effect
Authors: Aoki Hideo
Published: March 2014

Quantum fluctuations in the Hall conductivity, σxy, in two-dimensional systems of mesoscopic sizes in magnetic fields are studied. The fluctuation is shown to exhibit distinct features in the quantum Hall regime. Specifically, numerical results for finite lattice systems with disorder show that fluctuations in σxy, whose root-mean-square magnitude, δ σxy is of the order of e
2/h independent of sample size, has a definite relation with the averaged value, <σxy>, in which δ σxy decreases sharply as <σxy> approaches the quantised value. Temperature effects are also discussed.
The Propagation of High-Frequency Phonons in Liquid 4He
Authors: Wyatt A. F. G.
Published: March 2014

For the propagation of high energy phonons in liquid 4He it is often more important to know whether they remain at a high energy ie ≥ 9 K, rather than knowing they stay at exactly the same energy. It is shown that the energy mean free path is much longer than the scattering mean free path. The flux of high energy phonons that can travel through 4 mm of liquid 4He is calculated as a function of temperature.
Magnetotransport Studies of Weak Localization and Spin-Orbit Scattering in a HgCdTe Two-Dimensional Electron Gas
Authors: Palm Eric C. , Kobiela Pawel S. , Kirk Wiley P. , Schiebel Richard A. , Reed Mark A.
Published: March 2014

Transverse magnetoresistance and Hall effect measurements have been performed on' the two-dimensional electron gas formed in the inversion layer of H.78Cd.22Te MISFETS at low magnetic fields(<0.5 T) and at temperatures between 32 mK and 4 K. The sample fabrication included a gate structure allowing the carrier density of the 2-D system to be changed slightly more than an order of magnitude. At fixed temperatures the magnetoresistance smoothly transforms from a regime of pronounced weak localization to one of strong spin-orbit scattering with increasing carrier density. Also at low carrier densities an unusual asymmetry effect with respect to magnetic field is observed in the transverse magnetoresistance measurements. An analysis of these results is presented in view of the fact that HgCdTe system offers unique circumstances (eg. low effective mass, m*=0.006 m0, and large g-factor, g*=94) to investigate weak localization, spin orbit, and Coulomb interaction effects.
Electrical Resistance in Ion Beam Mixed Al/Si Thin Films
Authors: Xi Xiao-Xing , Ran Qi-Ze , Liu Jia-Rui , Guan Wei-Yan
Published: March 2014

Al/Si multilayer films were bombarded with energetic Ar ions at liquid helium temperature and the electrical resistances of the ion beam mixed samples were measured from 4.2K to 300K. In the sample with rather high Si concentration, a granular-like structure was formed during mixing and a logarithmical temperature-dependence was observed. It is proposed that the electron localization took place in this ion beam mixed Al/Si film.
Critical Behavior of the Low Temperature Dielectric Constant of Si:As
Authors: Brooks J. S. , Symko O. G. , Castner T. G.
Published: March 2014

Capacitance measurements on insulating uncompensated Si:As have been made to temperatures as low as 10mK from 10Hz to 1MHz. As T→0 C(ω,T) shows very little dispersion from hopping and one obtains the dielectric response ε'(N)-ε
h=4πχ'(N). As N→Nc-χ'(N)∝(Nc/N-1)-ζ and we obtain ζ=1.18±.08 for Nc=8.55±.05×1018/cm3, thus finding ζ=2µ where µ is the DC conductivity exponent. These agree with Si:P results and confirm universality of the exponents and the Mott criterion for n=type Si.
Effects of Nonlocality on Quantum Transport Phenomena in Microstructures
Authors: Isawa Yoshimasa , Ebisawa Hiromichi , Maekawa Sadamichi
Published: March 2014

Quantum transport phenomena in microstructures are the subject of much attention today. We show that the non-locality of the conductivity, which is a consequence of the electrons in the whole system being coherent, is a key concept in these phenomena. We also discuss how these phenomena will disappear as the temperature rises.