bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Procedure for Superconducting Energy-Gap Determination from Tunneling Conductance
Authors: Hayashi S. , Aoki R.
Published: March 2014

The tunneling conductance spectrum dI/dV to V was numericelly computed for N/I/S and S/I/S' junction with parameter Δ/kBT. It turns out that the conventional method for determination of energy gap parameter Δ; (dI/dV)V=(dI/dV)∞ and Δ=eV. is valid only at temperatures of T< 0.7 Tc. When T goes up near Tc, the parameter Δ must be determined from eV with a correction here presented.
Characteristics of the Reciprocating Carnot Magnetic Refrigerator for He Liquefaction
Authors: Hashimoto T. , Yazawa T. , Li R. , Nakagome H. , Takahashi M. , Ogiwara H.
Published: March 2014

Recently, we developed the reciprocating Carnot magnetic refrigerator for He liquefaction in the temperature-range from ∼15 K to 4.2 K, using the Gd3Ga5O12(GGG) single crystal as the refrigerant. However, from the characteristics of the magneto-caloric effect of GGG, its refrigeration range was ristricted below ∼10 K as far as using the magnetic field of ∼4 T.
In the present paper we have developed the new single crystal, Dy3Al5O12(DAG), as the refrigerant and also improved the refrigeration system. As the results, we have succeeded to liquefy the He gas from ∼20 K. The apparatus, its operating cycle and refrigeration efficiency will be shown.
Operation of Eight-Loop Superconducting Magnetic Monopole Detector
Authors: Huber M. E. , Cabrera B. , Taber M. A. , Gardner R. D.
Published: March 2014

We have constructed a superconducting magnetic monopole detector with a sensing area greater than 1.25 m2 (averaged over 4π solid angle) for double coincident events. There is an independent planar gradiometer loop (16.9×521.1 cm) on each side of an octagonal cylinder. The conductors are 2 mm × 50 µm niobium-titanium (NbTi) ribbon. The detector is operating with a signal to noise ratio of about 30 for the passage of a single Dirac charge.
Proximity-Effect Induced Superconductivity at Millikelvin Temperatures
Authors: Bergmann Th. , Kuhl K. H. , Schröder B. , Jutzler M. , Pobell F.
Published: March 2014

We have studied the proximity induced superconductivity of thick Cu layers (up to 105 µm) clad on Nb or Nb-Ti cores by measurements of the ac susceptibility and of the thermal conductivity as a function of temperature (7 mK ≦ T ≦ 1 K), field (0.4 mG ≦ H ≦ loG), and electronic mean free path (0.2 µm ≦ℓ≦14 µm). The dependence of the Meissner screening length and of the hysteretic breakdown field on these parameters agree with numerical solutions of the de Gennes/Ginzburg-Landau theory. Evaporating a layer of Fe on Cu in our Nb/Cu sample results in a strong depression of the proximity effect. No measurable field screening was observed in the investigated temperature range in Pd in contact with Nb/Cu or with Nb. -Experiments to extend these measurements to lower temperatures and thicker Cu layers are in progress.
Microwave Detector for Galactic Halo Axions
Authors: Cho S. -I. , Hagmann C. , Sikivie P. , Sullivan N. S. , Tanner D. B.
Published: March 2014

We discuss the properties and design characteristics of a dielectric tuned high-Q low temperature microwave cavity and cryogenic receiver for the detection of cosmic axions in the laboratory. The total noise figure and bandwidth properties achieved by a pilot project are discussed in terms of the feasibility of detecting axions trapped in the halo of our galaxy.
A Cryopump-Operated Rotating Dilution Refrigerator
Authors: Berglund Peter , Kyynäräinen Jukka , Salmelin Riitta
Published: March 2014

A rotating cryostat reaching submillikelvin temperatures has been built. The design principles of the charcoal adsorption pumps are presented. The 3He circulates at liquid helium temperatures entirely. Some benefits of a cryopump-operated system are pointed out.
Low-Cost, Compact Dilution Refrigerator
Authors: Roach P. R. , Gray K. E. , Dunlap B. D.
Published: March 2014

We have developed a one-shot 3He-4He dilution refrigerator using charcoal pumps that will cool below 0.015 K and will run at this temperature for more than 10 hours. It is of a very compact and simple design and eliminates many of the problem areas of continuously operating refrigerators.
Saddle Point Model for the Quantum Hall Effect
Authors: Giura M. , Fastampa R. , Marcon R.
Published: March 2014

We present a model of the density of state for non parabolic electron dispersion law ε(\vecp) in 2D conductors with a weak random potential. In particular the model is developed assuming the existence of a critical point of saddle type in a narrow zone of the p-space. The application to the Quantum Hall Effect is given. The analysis of a series of experimental results concerning the measures of density of state and Hall resistivity in 2D conductors in an external magnetic field is presented. In particular the non gaussian tails of the Landau levels density of states as found by Klitzing's group (1985) are justified.
Superconducting and Normal State Properties of the L–B–Cu–O Systems
Authors: Przysłupski P. , Igalson J. , Dobrowolski W. D. , Raułuszkiewicz J.
Published: March 2014

L-B-Cu-O systems were prepared by solid state reaction. Basic parameters such as Tc, [dHc2/dT]Tc and Jc were measured. The best samples with YBa2Cu3O9-δ composition contain 75% of superconducting phase. The samples have zero resistance at 91K and 4K transition width. Estimated upper critical field is about 108 T.
Spin Waves in Spin Polarized Hydrogen
Authors: Lee D. M.
Published: March 2014

Observations of nuclear spin waves in doubly spin polarized atomic hydrogen below 0.6K are discussed. Spin wave spectra have been measured in a field of 8 tesla under various conditions of density, temperature and field gradient by means of both pulsed and cw magnetic resonance at a frequency of 1 GHz. The spectra are understood in terms of identical spin rotational scattering giving rise to a coherent wave, or alternatively, in terms of an approach based on many body theory. Recently observed non linear effects are also discussed. Spin wave phenomena in hydrogen will be compared with spin waves in other fluid systems including liquid 3He, spin polarized 3He gas and atomic deuterium.
Ferromagnetism in the Boundary Layer of 3He
Authors: Bozler H. M.
Published: March 2014

The boundary layer of 3He shows a ferromagnetic tendency on many substrates. Recent work at USC and Grenoble has shown both that this layer on graphite undergoes a ferromagnetic ordering and that this magnetism depends sensitively on the structure of the boundary layer. We use a dc SQUID based NMR spectrometer to perform very low field measurements. With T ∼ 1 mK and the applied field under a few gauss, we observe a multiple line spectrum with lines displaced from the Larmor frequency. We interpret these displaced lines as the collective modes of ferromagnetically ordered domains in the 3He surface layers. The data suggests that these domains reorient as the applied field is increased. We conclude that the 3He dipole field can only partially account for the anisotropy energy necessary for the observed line shifts.
Thermal Relaxation in Super fluid Helium-3
Authors: Neuhauser Barbara
Published: March 2014

The temperature at the top of a column of liquid helium-3 has been measured as a function of time following incremental step changes in the temperature of the CMN paramagnetic salt refrigerant to which the column is coupled. This thermal time constant data has been taken in the super fluid A, super fluid B, and normal phases at pressures between 11 and 29 bar. For pressures remote from the polycritical point (PCP) the abrupt increase in relaxation time at the normal-to-super fluid transition temperature Tc is consistent with the increase in heat capacity. However, data acquired near the PCP reveals a striking difference in the nature of hydrodynamic heat flow in the A and B phases. This disparity can be used to identify the polycritical point on the phase diagram. The abrupt change in response time at Tc for pressures above the polycritical point suggests that caution must be exercised when measuring temperatures near the normal-to-A phase transition if the thermometer is remote from the experimental region.
Theoretical Basis for the Correlations in Heavy Fermions
Authors: Jones B. A. , Varma C. M.
Published: March 2014

It has been fairly obvious on empirical grounds that the excitations in the mixed-valence and the closely related heavy Fermion problem are those of a Fermi-liquid with very strongly renormalized parameters due to the Kondo effect. This has led to a proliferation of pseudo one-electron theories most of which combine the qualitative aspects of the solution of the Kondo problem with the requirement that the solution for the lattice problem obey Bloch's theorem. This is a useful first stab at the problem. The recent solution of the two Kondo impurity problem has revealed however that renormalizations at the two sites are correlated with asymptotic properties not obtainable from the solutions to the single impurity problem. The low temperature solutions is expressible in terms of a fixed point Hamiltonian with corrections. The fixed point Hamiltonian corresponds to singlets in the even and odd parity states of the problem rather than those of individual moments. The corrections describe quasiparticle kinetic energies and interactions which depend both on the initial exchange interactions between the magnetic moment and the conduction electrons as well as the interaction between the magnetic moments. The magnetic interactions between the quasiparticles arise fundamentally due to a correlated Kondo effect.
A Fermi-liquid theory based on treating the lattice as a sum of pairwise effective Hamiltonian is discussed. The nature of magnetic correlations observed in the heavy Fermions, the observed anisotropic superconductivity and the remarkable effects of impurities in heavy Fermions are explained by the theory.
Magnetic Correlations and Heavy Fermion Systems
Authors: Goldman A. I.
Published: March 2014

Polarized and unpolarized neutron scattering measurements on both the Ce and U based heavy fermion systems have provided a great deal of evidence for the formation of a coherent state involving the f-electrons at low temperature. These experiments are reviewed, and common features of the low temperature magnetic correlations are discussed.
Metastability, Memory, and Dynamics of Charge Density Waves
Authors: Littlewood P. B.
Published: March 2014

Charge density waves pinned by disorder have many possible metastable configurations. The existence of metastable states give rise to generic glasslike behavior including hysteresis and power law time decays of the polarization. The characteristic behavior is controlled by high-energy metastable states which are marginally stable to perturbations. One consequence is a dynamic memory effect, whereby the system can be trained to remember the length of a voltage pulse.
Electronic Properties of Two Dimensional Electrons Formed on Liquid Helium and Solid Neon
Authors: Kajita Koji
Published: March 2014

Transport of the electrons on the surface of dielectric materials have been studied mainly referring to the electrons on solid neon. The interplay of random potential and the electron correlation is found to be important in this system. In all the regions of the electron correlation, it works to decrease the electron conductivity. In the region where electrons are in a liquid state, the effect of the correlation is understood in terms of the enhancement of electron scattering. While in the crystalline state, a drastic decrease in the conductivity should be interpreted as the pinning of the electron crystal. Nonlinear transport phenomena due to depinning of crystal are observed.
Macroscopic Quantum Tunnelling and Related Matters
Authors: Leggett Anthony J.
Published: March 2014

The last few years have seen a substantial amount of experimental and theoretical work on thequantum mechanics of macroscopic variables in low-temperature systems, and in particular on the phenomenon of “macroscopic quantum tunnelling.” This talk summarizes the present situation in this area of research with emphasis on a number of currently unresolved conceptual problems, and reviews its current and potential significance for the foundations of physics.
Pinning and Critical Currents in Type II Superconductors
Authors: Campbell A. M.
Published: March 2014

The factors affecting critical current densities in high Tc superconductors are discussed. The connection between pinning, weak links and granular superconductors are explored. The possibility of achieving high current densities seems to depend on processing.
Thermometry at Ultra-Low Temperatures
Authors: Greywall Dennis S.
Published: March 2014

A new millikelvin temperature scale is presented which is based in part on the constraint that the normal-phase specific heat of liquid 3He be linear in temperature with a proportionality constant taken from higher-temperature specific heat measurements. The new scale differs considerably from all of the commonly-used scales but provides an explanation for the long-standing 3He specific-heat controversy.
Multi-Electron Bubbles and Roton Scattering in Super fluid 4He
Authors: Ihas G. G. , Sanders T. M.
Published: March 2014

The scattering of rotons from multi-electron bubbles in liquid 4He is shown to account for the mobilities of the “fast” and “exotic” negative carriers that have been observed. The “fast carrier” is shown, by a detailed calculation of mobility, to be a two-electron bubble with a radius of approximately 30Å. A crucial role is played by the unusual kinematics of rotons, which have not previously been adequately treated. Some of the other “exotic” carriers are bubbles containing 3, 4, and 5 electrons.
Anisotropy of Negative Ion Mobility in Stationary and Rotating 3He–A
Authors: Salmelin Riitta H. , Salomaa Martti M.
Published: March 2014

The mobility tensor for negative ions in 3He is calculated for the axisymmetric A and polar phases. The superfluid energy gap Δ
A
(T) is extracted from the A-phase mobility. In rotating 3He-A, our calculation, based on the assumption that polar phase occupies the core of a singular vortex, explains the measured high mobility along vortices in rotating 3He-A.
Second Sound Measurements in 3He–4He Mixtures
Authors: Church R. J. , Owers-Bradley J. R. , Main P. C. , McHale G. , Bowley R. M.
Published: March 2014

We report measurements of the damping of second sound in a 0.1% 3He–4He mixture in the temperature range 100 mK to 1K and for frequencies from the fundamental cavity resonance of -700 Hz to 12 KHz. The measurements enable us to examine the phonon contribution to the damping over a much wider frequency range than hitherto. The data are compared to a theory based on ideas which are developed in detail elsewhere.
Heat Conduction Changes in Spin-Polarized Gaseous 3He
Authors: Leduc Michèle , Nacher Pierre-Jean , Betts David S. , Daniels James M. , Tastevin Geneviève , Laloe Franck
Published: March 2014

Although it is a dilute non-degenerate system, a gas of spin polarized 3He can exhibit interesting quantum properties due to particle indistinguishability. One of these effects is a variation of the heat conduction coefficient as a function of the nuclear polarization. We describe an experiment where this change has been observed and measured in the 1.5 - 4.2 K range. The experimental results, in reasonable agreement with theoretical predictions, are discussed.
The Melting Curve of Solid 3He in High Magnetic Fields
Authors: Kranenburg C. C. , Wiegers S. A. J. , Haar P. G. van der , Jochemsen R. , Frossati G.
Published: March 2014

The melting curve of solid 3He was measured using a small plastic Pomeranchuk cell and a vibrating wire viscometer as thermometer in fields up to 9.3 T and we plan to extend the measurements to B = 10.4 T. The depression of the melting curve with respect to the zero field melting curve is compared to the theoretical calculations using mean field theory.
New Developments in the Quest for Highly Polarized Superfluid 3He
Authors: Wiegers S. A. J. , Kranenburg C. C. , Jochemsen R. , Vermeulen G. A. , Bedell K. S. , Frossati G.
Published: March 2014

We present theoretical and experimental results concerning fast melting of highly polarized solid 3He with the aim of producing super fluid polarized liquid 3He at temperatures around 10 mK.
The technique is to make a fraction (10 to 20%) of highly polarized solid 3He which, upon melting and mixing with cold liquid 3He gives a liquid of moderate polarization at temperatures around 30 to 50 mK. The heat generated by irreversible entropy production during and after melting and the magnetic relaxation process is discussed and compared with our experiments. The necessary initial conditions for reaching super fluidity according to present theory are also discussed.
Measurement of the Longitudinal Spin Diffusion Coefficient in Spin Polarized Atomic Hydrogen
Authors: Bigelow N. P. , Denker J. S. , Statt B. W. , Lee D. M. , Freed J. H.
Published: March 2014

We report on the measurement of the longitudinal spin diffusion coefficient in doubly spin polarized atomic hydrogen. Measurements were made using pulsed nuclear magnetic resonance to probe the transport of magnetization between a sealed container and a large reservoir. Results are presented for densities between 1.4×1015 and 4.8×1016 cm-3 at temperatures between 246 and 470 mK in a magnetic field of 7.7 Tesla and are found to be in reasonable agreement with theoretical calculations by Lhuillier.
Theory of Bose-Einstein Condensation in Magnetic Traps
Authors: Lovelace R. V. E. , Tommila T. J. , Lee D. M.
Published: March 2014

We discuss the Bose-Einstein condensation of a weakly interacting gas confined in different types of three dimensional magnetic traps.
Evidence for the Role of Rotons in the Stimulated Emission of Phonons in Liquid 4He
Authors: Wyatt A. F. G. , Ashworth S. P.
Published: March 2014

When two high intensity pulses of excitations are injected into liquid 4He a strong non-linear interaction occurs which produces a large signal. We propose that rotons from the first pulse form relatively long lived surface rotons on the bolometer and these are stimulated to decay into phonons by rotons in the second pulse. The interaction signal is strongly dependent on the liquid 4He pressure and is αexp
(-Δr(P)/kTe) which is evidence that rotons are involved.
A Search for a Ferromagnetic Ordering in 3He Films
Authors: Okuda Yuichi , Fukushima Akio , Ikushima Akira J.
Published: March 2014

A search for a clear evidence of ferromagnetic ordering of 3He films adsorbed on the sintered silver powder was done down to 150 µK. Spontaneous nuclear magnetization was tried to detect by the field cooling procedure: adsorbed 3He films were first cooled down to the lowest temperature under external fields of 10 and 50 Gauss, the fields were reduced to zero, and then the static magnetization was measured as the temperature rose. No meaningful difference in the magnetization was detected from that of the background. Susceptibility was also measured under the field of 50 Gauss.
Flow of 3He through Vycor Glass at Very Low Temperatures
Authors: Spencer G. F. , Engel B. N. , Ihas G. G.
Published: March 2014

The flow of 3He through Vycor glass possessing very small pores has been studied using a differential manometer and a low temperature, constant volume pump system. NMR on the 3He in the Vycor shows that it's surface magnetic susceptibility is reduced by flow. This implies that this magnetism comes from 3He atoms localized at the walls, which are swept away by the flowing atoms, becoming part of a degenerate Fermi liquid. These atoms are eventually deposited “down-stream” in the tortuous Vycor pores, plugging the flow channels and stopping the flow.
Finite-Size Scaling near T
λ of 4He
Authors: Huhn W. , Dohm V.
Published: March 2014

We have calculated the specific heat of confined helium near Tλ using realistic boundary conditions On the basis of our one-loop results we argue that a new size-dependent scaling variable should be employed. We find good agreement between our prediction and the observed size dependence of the temperature shift of the specific heat maximum. This seems to solve a longstanding problem.
Frost Heaving Phenomena in Helium
Authors: Hiroi Masahiko , Mizusaki Takao , Hirai Akira , Tsuneto Toshihiko , Eguchi Kiyohisa
Published: March 2014

The frost heaving phenomena was studied by using a combination of 4He and porous glass. We were able to set up a perfect ice segregation condition such that the frost heave occurred at the boundary between bulk solid and supercooled liquid in the pores below the bulk freezing temperature. The frost heave was observed both in the super fluid and normal regions. The frost heaving pressure in the normal fluid region agreed well with the modified Clausius-Clapeyron equation.
Magnetism of 3He Contained in Vycor Glass at Low Temperature
Authors: Engel B. N. , Ihas G. G. , Spencer G. F.
Published: March 2014

NMR on 3He atoms in the very small pores of Vycor glass reveals magnetic states which are temperature, pressure, and magnetic field dependent. The susceptibility is Curie-Weiss-like with a Θ that increases with pressure. The longitudinal relaxation time τ1 is a weak, monotonically increasing function of temperature. The transverse relaxation time τ2 is a strong function of temperature at low temperature, with a positive slope at 286 gauss and a negative slope at 71.5 gauss.
Studies of T
1 and T
2 of Liquid 3He in Confined Geometry: Anomalous Exchange?
Authors: Maegawa S. , Schuhl A. , Meisel M. W. , Chapellier M.
Published: March 2014

The relaxation times T1 and T2, of liquid 3He confined by fluorocarbon microspheres have been measured over a wide spectrum of frequencies(125 kHz to 100 MHz). Below 100 mK, T1 and T2 have a linear temperature dependence. In the linear regime T1 varies linearly with Larmor frequency over the entire frequency range, whereas T2 is frequency independent. Spectral density of the solid-like adsorbed layer as deduced from the present experiment have a linear dependence in ω up to 100 MHz. Such peculiar behaviour is attributed to inhomogeneity of the substrate surface.
Striped Domain-Wall-Phase of D2 Adsorbed on ZYX-Graphite
Authors: Schildberg H. P. , Lauter H. J. , Freimuth H. , Wiecher H. , Haensel R.
Published: March 2014

Neutron diffraction data of the α-phase of deuterium adsorbed on ZYX-graphite prove this phase to be superheavy walls. The phase is stable up to an atomic density of 0.0734 Å-2, which corresponds to exactly three commensurate atomic rows between two superheavy walls. The distribution of the commensurate stripes and the effect on the spectra is discussed. Values of the atomic relaxations from the center of the graphite hexagons are derived.
Excitations in the Soliton Phases of D2 on Graphite
Authors: Frank V. L. P. , Lauter H. J. , Leiderer P.
Published: March 2014

The transverse phonon at the zone boundary has been studied in the commensurate(C)-phase of D2 adsorbed on graphite with inelastic neutron scattering. This excitation looses intensity and shows a measurable lifetime in the higher density striped domain wall phase adjacent to the C-phase. In addition an excitation at lower energy appears. These modes resist also above 7K in the reentrant liquid phase showing that this phase is in reality a solid phase with domain walls which possess however only short range order as can be concluded from elastic neutron scattering studies.
Resonant Phonon Scattering and Kapitza Conductance Induced by H2O Molecules on Clean Surfaces
Authors: Koester L. , Wurdack S. , Dietsche W. , Kinder H.
Published: March 2014

We have used phonon surface scattering spectroscopy to study adsorbed water layers in the mońolayer region on clean surfaces. We find a strong resonance at phonon energies of ≈ 1 meV. The position of the resonance decreases with increasing coverage. We suggest that a low lying mode of lateral vibration of the adlayer is excited.
Nonlinearity in the Kapitza Resistance between Gold and Superfluid 4He Near Tλ
Authors: Duncan R. , Ahlers G.
Published: March 2014

We report experimental results for the thermal boundary resistance RK between gold and superfluid 4He which were obtained by using thermometry with three-nanokelvin resolution. The data imply that RK is singular at the superfluid transition temperature Tλ. For t≡1-T/Tλ\lesssim10-4, RK becomes noticeably dependent on the heat flux Q used to make the measurement. The reduced temperature tc at which this nonlinear resistance is first observed is approximately proportional to Q. For t≤tc dRK/dQ is approximately proportional to 1/t.
Hydrodynamic Boundary Conditions in Superfluids
Authors: Grabinski Michael , Liu Mario
Published: March 2014

A complete set of boundary conditions is derived for superfluids and applied to He–II and superfluid 3He. A number of experiments are discussed. Three surface Onsager coefficients account for cooling set-ups in super fluid 3He instead of a single Kapitza resistance, as in 4He–II; while most sound experiments in 4He–II were found to be characterized by only one combination of surface Onsager coefficients.
Kapitza Resistance between Sintered Metal Particles and 3He–4He Mixture
Authors: Nakayama Tsuneyoshi , Yakubo Kousuke
Published: March 2014

The heat transfering mechanisms between sintered metal-particles and 3He–4He mixture are investigated theoretically in the millikelvin temperature region. It is suggested that a deformation coupling between 3He-quasiparticles and low-lying vibrational modes peculiar to sinters is relevant to the acoustic channel of heat transfer.
Transmission of Spin Waves through the Liquid 3He to 3He–4He Interface
Authors: Heff A. , Candela D. , Edwards D. O. , Kumar S.
Published: March 2014

We present a proposal for experiments to study the transmission of transverse spin waves across the interface between normal or superfluid 3He and saturated 3He-4He mixture. Our analysis is based on the general boundary condition for transverse magnetization formulated by Fredkin for ESR experiments on metal-to-metal junctions. Using a simple model, we find that the boundary coefficient for the liquid 3He-mixture interface is directly related to the quasiparticle transmission probability τ. The spin wave spectrum in a two-phase liquid sample between inert walls is calculated to show how τ might be measured.
Theory of the Growth Resistance of Atomically Rough Surfaces of 4He Crystals
Authors: Mukherjee S. , Edwards D. O.
Published: March 2014

Two puzzling features of the growth resistance of atomically rough 4He crystals are explained by a theory in which rotons collide with “kinks” on the surface. The two kinds of kinks on each step or terrace form one-dimensional gases of particles of finite mass. Good agreement with experiment is obtained if the kinks have roughly the atomic mass and Boltzmann statistics.
Growth and Melting of Dendritic Instabilities in Pure fcc 4He
Authors: Franck J. P. , Jung J.
Published: March 2014

During the growth of thermal dendrites of pure fcc 4He from the supercooled fluid two distinct instabilities are observed. At moderate supercooling four lateral wings growing in the <100> directions develop near the parabolic tip. The growth of these wings is determined by the anisotropy in attachment kinetics. At not too high supercooling these are the only instabilities that occur. At larger supercooling the wings develop a cellular Mullins-Sekerka instability, growing into the branched structure of a fully developed dendrite. Side-branching was never observed without the previous development of lateral wings. Subsequent melting of the fully developed dendrites proceeded as the exact time-reversal of their growth. The dendritic pattern formation appears to be a deterministic process.
Anomalous Properties of Pure Solid 4He under Fast Melting Conditions
Authors: Jung J. , Franck J. P.
Published: March 2014

Fast melting of pure solid hcp and fcc 4He at pressures between 240 and 1700 bar was studied. It was found that under these conditions solid helium exhibits properties which are quite different from those observed under near equilibrium conditions. For melting rates exceeding a certain value, and under constant volume conditions competition between surface and bulk melting was observed. Melting under these conditions starts as surface melting. During the last stage of melting a wetting transition takes place, during which the contact angle between the helium solid and the substrate (Vespel SP-1) changes from 0° to between 60 and 90°. The wetting transition is followed by continuous melting throughout the solid. The most likely mechanism of continuous melting is a disordering process i.e., the spontaneous generation of high concentrations of thermal vacancies.
Quantum Interaction of Steps and Crystallization Waves in a Stepped Surface
Authors: Uwaha Makio
Published: March 2014

A step in a singular crystal plane is viewed as an oscillating elastic string accompanied by superfluid flow, which carries the material from a melting part to a growing part. When there are many parallel steps with a distance d, the oscillation spectrum is modified by the interference of the flow, and as a result the zero-point energy increases, leading to a d-2 repulsive interaction of steps. The oscillation spectrum of a stepped surface at large wave number k is that of indivisual steps, and the spectrum at small k is that of a crystallization wave with a very anisotropic surface stress.
Spin Relaxation in Nuclear Ordered Solid Helium-3
Authors: Sasaki Yutaka , Sasayama Kohji , Mizusaki Takao , Hirai Akira
Published: March 2014

In order to clarify the intrinsic relaxation mechanisms in the low field phase of the Nuclear ordered solid 3He, we measured the linewidth of CW-NMR as a function of temperature and external magnetic field for various crystal orientations. We compared our results with three relaxation processes, i.e., the Leggett-Takagi type relaxation process, the three-magnon process and the energy transfer process across domain walls. Our results are affirmative to the Leggett-Takagi type relaxation mechanism among others.
Enhanced Nuclear Antiferromagnetic Resonance of Ho in Cs2NaHoCl6
Authors: Masuda Yumiko , Suzuki Haruhiko , Ohtsuka Taiichiro , Tamaki Akira
Published: March 2014

Hyperfine enhanced nuclear antiferromagnetic resonance of 165Ho(I=7/2) in Cs2NaHoCl6 was observed below about 4.8mK following demagnetization cooling. The measurements were made at several frequencies by CW NMR with a low field sweep. From the observed resonance fields the zero field resonance frequency ωo was deduced to be 272MHz, not far from the expected frequency from the calculation of the dipole interaction among the enhanced nuclear spins. This experiment is the first observation of the enhanced nuclear antiferromagnetic resonance.
Nuclear Adiabatic Demagnetization Cooling in Ground State Singlet Paramagnet
Authors: Ishizuka Mamoru , Deguchi Hiroyuki , Amaya Kiichi , Haseda Taiichiro
Published: March 2014

Cooling of the nuclear spin system in a singlet ground state paramagnet FeSiF66H2O is performed by the most simple way of single stage adiabatic demagnetization. Isothermal magnetization is tried at the crossing field(Hc) using powerful dilution refrigerator. The demagnetization cooling of the two proton system is confirmed by the steady NMR at 0.1T.
Calculation of Relaxation Times of k=0 Roton due to Orthohydrogen Impurities in Solid Parahydrogens
Authors: Igarashi Jun-ichi
Published: March 2014

Relaxation times of k=0 rotons are calculated in the low concentration of orthohydrogen in solid paprahydrogens by considering the electric quadrupole-quadrupole interaction between molecules and neglecting phonon contributions. The calculated results are in good agreements with the recent Rgman scattering experiment, although there is no adjustable parameter.
Spin-Orbit Coupling in Fermi Liquid Theory: Anisotropic g Factor and Spin Dynamics
Authors: Fujita Toshimitsu
Published: March 2014

The spin-orbit coupling is included in the quasiparticle interaction of the Landau Fermi liquid theory. As a result, the g factor is modified to become a tensor, which depends on the positions on the Fermi surface. Modifications of the spin dynamics are also considered. If the spin-orbit coupling exists, variables which describe the homogeneous spin waves with different spatial and spin quantum numbers are coupled with each other. The change of the eigenfrequencies of the homogeneous spin waves can be estimated by retaining only main terms in the eigenvalue equations. Possible applications are intended to include the heavy fermion compounds.
The Coherent Kondo Lattice State and the Linear Coefficient of the Specific Heat
Authors: Kaga Hiroyuki , Kubo Haruhiko
Published: March 2014

The low-temperature behaviors of the specific-heat coefficients of the Ce Kondo lattice compounds and alloys, i.e., the existence of a peak γmax in the former and a monotonous increase in the latter with decrease in temperature, are shown to arise from the different positions of the heavy quasiparticle density-of-states peaks below and just on the Fermi energy, respectively. The relation between the γmax-temperature Tmax and the coherence temperature T0 is also discussed.
Low-Frequency Susceptibility for Ce-Kondo System in Cubic Crystalline Field
Authors: Nakamura Atsunobu , Kawakami Norio , Okiji Ayao
Published: March 2014

The low-frequency susceptibility for the Ce-Kondo system is studied in case of the cubic crystalline field on the basis of the local Fermi-liquid theory at zero temperature. The magnetic relaxation rate of the localized f-electron is evaluated exactly with the aid of the Bethe-Ansatz solution of the Anderson model.
Suppression of the Mass Enhancement in CeB6 in High Magnetic Fields
Authors: Joss W. , Ruitenbeek J. M. van , Crabtree G. W. , Tholence J. L. , Deursen A. P. J. van , Fisk Z.
Published: March 2014

The effective mass of the itinerant electrons in the Kondo lattice system CeB6 is found to be strongly field dependent. Measurements of the de Haas-van Alphen effect at temperatures down to 60 mK in steady magnetic fields up to 22 T show a change of more than 100% in the cyclotron effective mass, decreasing with increasing field. The origin of the effect is not known but it is noted that a field of about 10 T corresponds to the energy scales in the system.
New Characteristic Kondo Energy by Point-Contact Spectroscopy
Authors: Kunii Satoru
Published: March 2014

Point-contact spectroscopy of La1-xCexB6 (x = 0, 0.03, 0.25, 0.5 and 1) has been investigated. The dV/dI vs. voltage characteristics is analized by the existing theory of dilute Kondo system. New characteristic Kondo energy is found for CeB6 which is one order higher than TK.
Static Magnetic Correlations in CeAI3 below 0.7 K
Authors: Barth S. , Ott H. R. , Gygax F. N. , Hitti B. , Lippelt E. , Schenck A. , Baines C.
Published: March 2014

We report the observation of a spontaneous muon-spin precession frequency in zero external magnetic field in CeAl3 below 0.7 K. At 35 mK the µ+ frequency reflects a local magnetic field of 220 G at the muon site. This is compatible with a static moment of about 0.05 µB per Ce ion. Specific heat measurements on the same sample reveal no anomaly in cp(T) at the temperature where the observation of the spontaneous precession frequency sets in.
Elastic Properties of CeCu6 at Low Temperatures
Authors: Goto T. , Suzuki T. , Ohe Y. , Tamaki A. , Sakatsume S. , Fujimura T. , Ōnuki Y. , Komatsubara T.
Published: March 2014

Elastic constant C33 of Kondo lattice compound CeCu6 has been measured down to 30 mK by ultrasonic method, where a remarkable softening below Kondo temperature has been found. A characteristic oscillation of C33 under magnetic field below 500 mK will be discussed.
Healing Lengths Near Tλ in Liquid Helium
Authors: Lea M. J. , Spencer D. S. , Fozooni P.
Published: March 2014

The λ-transition has been studied in bulk liquid 4He and in saturated films (thickness 14<d<23 nm) using viscous shear waves (penetration depth ≃20 nm) as a probe of the spatial variation of the super fluid density and viscosity near a solid/liquid interface and in superfluid films. The order parameter in Hell has a healing length a=0.1 ε
-2/3 nm, where ε=|1-T/T
λ|, for ε<10-2. Above T
λ the viscosity near a wall also exhibits a spatial variation on the same length scale.
Low-Temperature Specific Heats of RECu6-Type Compounds
Authors: Takayanagi S. , Onuki Y. , Komatsubara T. , Wada N. , Watanabe T.
Published: March 2014

We measured specific heats of RECu6-type magnetic compounds (RE=Nd, Sm and Pr) at 0.1<T<40 K. The results show successive magnetic phase transitions in zero magnetic field for NdCu6 at T=5.66, 5.78, 5.93 and 6.02 K and for SmCu6 at T=5.6 and 9.4 K. From the magnetic specific heat of PrCu6, we propose an energy scheme of 4f levels of the Pr ion under the influences of the crystalline electric field.
Magnetic Excitations of a Ferromagnetic Dense Kondo System CeSi1.8
Authors: Kohgi M. , Hippert F. , Regnault L. P. , Rossat-Mignod J. , Hennion B. , Satoh T. , Chui F. L. , Miura T. , Takei H.
Published: March 2014

We have studied the low energy magnetic excitations of the ferromagnetic dense Kondo system CeSix by neutron inelastic scattering measurements performed on a single crystal of CeSi1.8 (TC = 13.4 K). A spin-wave-like inelastic response was observed below TC over the Brillouin zone. The line widths of the excitations are, however, abnormally large. These features are substantially unchanged below TC. The present results suggest that the excited state of the ferromagnetic CeSi1.8 is unstable at low temperatures because of the Kondo effect.
Low Temperature Magnetoresistance of UPt3, U3Fe and U6Co
Authors: DElong L. E. , Crabtree G. W. , Hall L. N. , Hinks D. G. , Kwok W. K. , Mattingly R. B.
Published: March 2014

The transverse magnetoresistance Δρ(T,H)≡ρ(T,H)-ρ(T,0) has been measured at fixed temperatures in the range 0.5K \leqslant T \leqslant 40K as a function of magnetic field H \leqslant 15T for polycrystalline samples of U6Fe and U6Co, and a single crystal of UPt3 (\overrightarrowH||\overrightarrowa and \overrightarrowH||\overrightarrowc, \overrightarrowJ||\overrightarrowb). The sign of Δρ(T,H) changes from positive to negative as T increases through ∼25K for U6Fe and U6Co, and \i∼18K for UPt3. At low temperatures the data obey a novel universal form Δρ=AH2/B+H for all three materials, where A and B are T- and H-independent constants. Such behavior is postulated as typical of materials entering a heavy Fermi liquid state at low temperatures.
Tunneling Study of Heavy Electron System
Authors: Yasuda Takashi , Iguchi Ienari , Ōnuki Yoshichika , Komatsubara Takemi
Published: March 2014

We present the measurements of single particle tunneling between heavy fermion materials (CeCu2Si2,CeCu6) and a Pb film. The differential tunnel resistance under an applied magnetic field shows an asymmetric structure against junction voltage for both CeCu2Si2 and CeCu6, typical for valence fluctuation compounds. On the other hand, the tunnel resistance under no magnetic field for CeCu2Si2 below its transition temperature exhibits a series of gap structures around the Pb gap bump. The result suggests that CeCu2Si2 may be a singlet d-wave superconductor according to the tunnel calculation of Tachiki, Nakahara and Teshima. The estimated universal constant Δ0
*/kBTc is about 3.2, significantly greater than the BCS value of 1.76.
Antiferromagnetic Anisotropy in Organic Superconductors: A Probe for the Spin Density Wave (SDW) Amplitude and Nesting Vector
Authors: Roger M. , Delrieu J. M. , Mbougue E. Wope
Published: March 2014

The qualitative differences experimentally observed for the anisotropy axes in the SDW states of (TMTTF)2X and (TMTSF)2X salts are interpreted with pure dipolar anisotropy in Sulfur compounds and competing spin orbit and dipolar anisotropy in Selenium compounds. The anisotropy energies and axes are calculated as a function of the SDW amplitude δ and wave vector Q. The comparison with AFR data provides new estimates of Q and δ. The results are compared with those deduced from NMR on methyl protons.
Spin Correlation in the Spin-Peierls System
Authors: Okamoto Kiyomi
Published: March 2014

The spin correlation function <Si
zSj
z> in the Spin-Peierls system below its transition temperature is calculated on the basis of the dimerized spin-1/2 antiferromagnetic Heisenberg model with the XY-like anisotropy. The phase representation developed by Nakano and Fukuyama is employed. The correlation <S i
zSj
z> decays exponentially. At T=O, the correlation length ξ is proportional to the inverse of the energy gap between the ground state and the first excited state. It is conjectured that ξ as a function of T has a peak at some finite temperature.
Finite Temperature Effects on 1D CDW Dynamics
Authors: Miyashita Takashi , Takayama Hajime
Published: March 2014

Thermal fluctuation effects on the dynamics of charge-density-waves (CDW's) are examined numerically based on the 1D Fukuyama-Lee-Rice model. We observe that the threshold electric field ε
th (T) decreases linearly in T from T=0 with the slope which decreases gradually as T increases. We also report on the T induced broad band noise near above ε
th (T) and the soliton-antisoliton pair creation below ε
th (T) by the thermally activated process.
Charge-Density-Wave Behavior at Low Temperature in K0.3MoO3
Authors: Tsutsumi Kitomi , Shimoda Masahiko
Published: March 2014

Charge-Density-Wave (CDW) depinning behaviour in K0.3MoO3 was studied at low temperatures. The switching phenomenon and the electrical hysteresis were observed at 4.2 K. However these phenomena were not observed at 77.6 K. The origin of the difference in CDW depinning behaviours is discussed in terms of the temperature dependence of the pinning character in the Fukuyama-Lee-Rice (FLR) model on the CDW pinning by impurities and/or lattice defects.
Magnetic Field Effect on CDW in NbSe3 and Pristine Tetratellurides
Authors: Sambongi Takashi , Tadaki Sinji , Fukuda Kenji , Nomura Kazushige
Published: March 2014

Possible effect of magnetic field on the electronic structure of metallic CDW systems and on the dynamics of the CDW depinning were examined. In NbSe3 of a moderate purity, the magnetoresistance above 20K can be explained in terms of the conventional theory; no magnetic field induced decrease of normal carriers nor enhanced depinning ot the CDW was observed in the low magnetic field regime hωc<kT. Transport properties of novel materials, NbTe4 and TaTe4, are reported for the first time.
Effect of Interchain Interaction on the Charge-Density-Wave Phase Transition of Quasi-One-Dimensional Conductor Nb3Te4
Authors: Sekine Tomoyuki , Kiuchi Yoshinari , Matsuura Etsuyuki , Uchinokura Kunimitsu , Yoshizaki Ryozo
Published: March 2014

In the quasi-one-dimensional conductor Nb3Te4, a phase transition at about 110 K was studied by electrical-resistivity, magnetic-susceptibility and X-ray-diffraction measurements. It is a first-order phase transition accompanied by the appearance of satellite reflections which are characterized by commensurate wave vectors ±(a*/3+b*/3)+3c*/7, and it is due to charge-density-wave (CDW) formation. A possible crystal structure of the commensurate CDW state was discussed in terms of Landau theory; it has a √3|a|×√3|a|×7|c| superlattice structure with C\frac{1}{3} symmetry, which minimizes the interchain interaction energy between the CDW's on the individual zigzag Nb chains.
Charge-Density Wave Instabilities in Orthorhombic γ-Mo4O11
Authors: Inoue Masasi , Ōhara Shigeo , Marushita Motoharu , Koyano Mikio , Negishi Hiroshi , Sasaki Minoru
Published: March 2014

Pressure dependence of the electrical resistivity up to 10 kbar in the temperature range 1.7-300 K as well as the point-contact spectroscopy (PCS) at 1.4 K have been measured on quasi-two-dimensional γ-Mo4O11 crystals. We have found that the charge density wave instabilities are enhanced by hydrostatic pressure through increased electron-phonon interactions and the deformed Fermi surface. The PCS signals involve a number of phonon related peaks, together with a characteristic peak associated with the CDW instabilities.
Fermi Surface Study in SbCl5-Graphite Intercalation Compound
Authors: Yosida Yositaka
Published: March 2014

De Haas-van Alphen (dHvA) torque oscillations have been studied in stages 2,3 and 4 SbCl5-graphite intercalation compound (GIC) in magnetic fields up to 21 kOe. DHvA frequency branches for stage 2 are explained by the Fermi surface (FS) model which results from the commensurate (C) 14×14 in-plane superlattice trancations for the two-dimensional (2D) band structure of Blinowski et al. Effect of the liquid-to-incommensurate (IC) √39×√39 solid in-plane structural phase transition at Tc∼230 K on dHvA oscillations is also studied.
Experimental Study of the Electron-Phonon Interaction in LaB6
Authors: Samuely Peter , Reiffers Marián , Flachbart Karol , Akimenko Alexander I. , Yanson Igor K. , Ponomareno Nikolaj M. , Konovalova Elena S.
Published: March 2014

Very expressive point-contact spectra of LaB6 single crystals are obtained in the whole phonon energy range. A relatively strong anisotropy of the spectra is observed. The point-contact electron-phonon interaction function and the point-contact electron-phonon interaction parameter are lated data. The measured functions are employed to calculate the temperature dependence of LaB6 electrical resistivity and heat capacity.
Microwave Transparency of Thin Metal Plates in Parallel Magnetic Field
Authors: Cardenas V. , Lur'e M. A. , Peschansky V. G. , Yiasemides K.
Published: March 2014

It is a theoretical study of transparency oscillations in thin plates in magnetic field with the frequency widely ranging, including high frequencies where the “spikelike” mechanism changes to the “time-of-flight” mechanism of field penetration into the metal. The sensitivity of the oscillation amplitude to the surface state can be used to study the surface scattering of electrons.
Why the Resistivity of Dislocated Metals Is Almost Isotropic at Low Temperatures
Authors: Watts B. R.
Published: March 2014

By considering the structure factor of a crystal containing a long straight dislocation, it is shown that only if the underlying crystal structure is included in calculations of electron-dislocation scattering may one understand the experimentally observed rather isotropic resistivity of dislocated metal samples containing anisotropic dislocation arrays. This observation implies that most other treatments of the resistivity of dislocated metals are based on unphysical models. In support, a model calculation is described for <211> dislocations in a free-electron-like face-centred-cubic metal, based on a structure factor for the whole defected crystal, which does predict an anisotropy of electrical resistivity compatible with experiment.
Compensation Effect of Electrical Transport and Thermal Properties in Si:P
Authors: Nishio Y. , Kajita K. , Iwata T. , Sasaki W.
Published: March 2014

Electrical transport and thermal properties were studied on compensated Si:P with special interest in the critical behavior around the metal-nonmetal (MN) transition induced by Anderson localization in disordered system, measuring DC electrical resistivity and specific heat. Rigidity of the band structure and critical behavior of localization length were confirmed from the electronic specific heat and the Mott formula resistivity.
The Aharonov-Bohm Effect in Single Loops of Silver and Aluminum
Authors: Chandrasekhar V. , Prober D. E.
Published: March 2014

We have studied the effect of magnetic scattering on the Aharonov-Bohm effect in single loops of Ag. We find that adding magnetic impurities suppresses weak localization oscillations of period h/2e, but leaves the h/e oscillations unaffected. We also observe h/e oscillations in Al loops.
A Nonlinear Conduction in Disordered Surface of Si near the Metal-Nonmetal Transition
Authors: Ochiai Yuichi , Matsuura Etsuyuki
Published: March 2014

We report an experimantal study of an nonlinear conduction in disordered surface of doped Si near the metal-nonmetal transition. There exists two dimensional inhomogeneity of conductive domains in a insulating background because of the disordered surface layer near the transition. In order to clarify the physical origin of the nonlinear conduction, we have compared it with an electron tunneling model.