Low Temperature Physics

Quasi-two-dimensional features in the phonon spectrum of graphite

I. A. Gospodarev, K. V. Kravchenko, E. S. Syrkin, and S. B. Feodos'ev
The phonon spectrum of graphite is analyzed in detail at the microscopic level and the partial contributions from the displacement of atoms in and perpendicular to the plane of the layers to the phonon density of states are calculated. The main distinctive features of the phonon spectrum of graphite ... [Low Temp. Phys. 35, 589 (2009)] published Fri Sep 11, 2009.

Structure and time-resolved phosphorescence spectra of crystalline and glassy 2-bromobenzophenone

O. S. Pyshkin, L. M. Buravtseva, R. V. Romashkin, M. A. Strzhemechny, D. I. Zloba et al.
Microsecond-level time-resolved photoluminescence spectra of 2-bromobenzophenone are measured on crystalline (at 1.6, 52, and 300 K) and glassy (at 1.6 and 95 K) samples. For each of these physical situations the characteristic decay times are determined for the 00 band of monomer emission from me ... [Low Temp. Phys. 35, 580 (2009)] published Fri Sep 11, 2009.

Isochoric thermal conductivity of solid n-alkanes: propane CH

V. A. Konstantinov, V. P. Revyakin, and V. V. Sagan
The isochoric thermal conductivity of solid propane CH is investigated on three samples of different densities in the temperature interval from 50 K to the onset of melting. In all cases the isochoric thermal conductivity exhibits dependences that are weaker than Lambda[proportional]1/T. The result ... [Low Temp. Phys. 35, 577 (2009)] published Fri Sep 11, 2009.

Nanoparticle size effect on the magnetic and transport properties of (LaSr)MnO manganites

V. Dyakonov, A. Slawska-Waniewska, J. Kazmierczak, K. Piotrowski, O. Iesenchuk et al.
Magnetic and transport thermal measurements of nanosize (LaSr)MnO manganite are reported. The nanoparticles are synthesized with use of the co-precipitation method at different (800, 900, and 950 degrees C) temperatures. Their crystal structure is determined to be perovskite-like with a rhombohedr ... [Low Temp. Phys. 35, 568 (2009)] published Fri Sep 11, 2009.

Hall effect and magnetic ordering in RB

A. E. Baranovskiy, G. E. Grechnev, N. Yu. Shitsevalova, D. N. Sluchanko, V. V. Glushkov et al.
The concentration of carriers in LuB is evaluated theoretically by applying ab initio FP-LMTO calculations. Theoretical results are found to be in agreement with high-precision measurements of the Hall coefficient R(T) carried out on single crystals of the rare-earth dodecaborides RB (R=Ho,Er,Tm,Lu) ... [Low Temp. Phys. 35, 565 (2009)] published Fri Sep 11, 2009.

Evolution and collapse of quasistationary states of an electron in planar symmetric three-barrier resonance-tunneling structures

N. V. Tkach and Yu. A. Seti
A theory of the evolution and collapse of pairs of resonances because of a change in the strength (thickness) of the inner barrier is developed in a model of effective masses and symmetric, square, potential barriers for an electron in a planar three-barrier structure. Analytical and numerical calcu ... [Low Temp. Phys. 35, 556 (2009)] published Fri Sep 11, 2009.

Hall-effect anomalies near the quantum critical point in CeCuAu

N. E. Sluchanko, D. N. Sluchanko, N. A. Samarin, V. V. Glushkov, S. V. Demishev et al.
The results of Hall-effect and resistance measurements on the substitutional solid solutions CeCuAu with concentrations 0<=x<=0.3, corresponding to a wide neighborhood of the quantum critical point (QCP) at x=0.1, are presented. The measurements are made by rotation of the sample in a constant magne ... [Low Temp. Phys. 35, 544 (2009)] published Fri Sep 11, 2009.

Electron-phonon interaction function in the layered dichalcogenide 2Ha-TaSe

G. V. Kamarchuk, A. V. Khotkevich, A. V. Savitskii, P. Molinie, A. Leblanc et al.
Point-contact spectroscopy is used to investigate experimentally the electron-phonon interaction spectrum in the layered quasi-two-dimensional dichalcogenide 2Ha-TaSe. The measurements are performed on 2Ha-TaSe/Cu heterocontacts. The point-contact spectra reflecting the effects of the electron-phono ... [Low Temp. Phys. 35, 539 (2009)] published Fri Sep 11, 2009.

Gruneisen's law and particularities of electronic excitations in quasicrystals

A. F. Prekul, N. I. Shchegolikhina, and S. M. Podgornykh
Gruneisen's law according to which the temperature dependence of the lattice specific heat at constant volume is similar to that of the thermal expansion coefficient is checked experimentally for the icosahedral phase of AlCuFe. The specific heat C(T) and linear thermal expansion coefficient alpha(T ... [Low Temp. Phys. 35, 536 (2009)] published Fri Sep 11, 2009.

Effect of pressure on the magnetic properties of CrB

G. E. Grechnev, A. S. Panfilov, A. V. Fedorchenko, V. B. Filippov, A. B. Lyashchenko et al.
The magnetic susceptibility chi of the itinerant antiferromagnet CrB with T~=87 K is studied as a function of the hydrostatic pressure up to 2 kbar at fixed temperatures 78 and 300 K. The pressure effect on chi is found to be negative in sign and weakly dependent on the magnetic state of the comp ... [Low Temp. Phys. 35, 531 (2009)] published Fri Sep 11, 2009.

Field dependences of the magnetization and exchange bias in ferro/antiferromagnetic systems. II. Continuum model of a ferromagnetic layer

A. G. Grechnev, A. S. Kovalev, and M. L. Pankratova
A model giving a qualitative explanation of the results of an experimental investigation of the field dependences of the magnetization in ferro- and antiferromagnetic media in contact with one another is proposed. In this model a thin ferromagnetic (FM) film with strong easy-plane anisotropy is desc ... [Low Temp. Phys. 35, 526 (2009)] published Fri Sep 11, 2009.

Monte Carlo investigation of the critical properties of a three-dimensional frustrated Heisenberg model on a triangular lattice

A. K. Murtazaev, M. K. Ramazanov, and M. K. Badiev
The Monte Carlo replica method is used to investigate the critical properties of a three-dimensional frustrated antiferromagnetic Heisenberg model on a triangular lattice. The static magnetic and chiral critical exponents are calculated within the theory of finite-dimensional scaling: specific heat ... [Low Temp. Phys. 35, 521 (2009)] published Fri Sep 11, 2009.

Superconducting and magnetic properties of a new superconductor: EuAsFeOF

V. M. Dmitriev, I. E. Kostyleva, E. P. Khlybov, A. J. Zaleski, A. V. Terekhov et al.
Polycrystalline samples of the new superconducting compound EuAsFeOF, with critical temperature T=11 K, are prepared by solid state synthesis. Its electric and magnetic properties are investigated in magnetic fields from 0.1 to 140000 Oe. The critical magnetic fields H and H are measured, and th ... [Low Temp. Phys. 35, 517 (2009)] published Fri Sep 11, 2009.

Dynamic dislocation effects in low-temperature creep stimulated in beta-tin single crystals by a superconducting transition

V. D. Natsik, V. P. Soldatov, G. I. Kirichenko, and L. G. Ivanchenko
Low-temperature creep of high-purity beta-tin single crystals oriented for plastic slip in the system (100)is studied. The experiments are performed in the temperature interval 0.5

IR Spectroscopy and ab initio calculations of imidazophenazine and its derivatives in a low-temperature argon matrix

E. S. Zarudnev, V. A. Karachevtsev, A. M. Plokhotnichenko, S. G. Stepan'yan, and L. Adamovich
IR Spectroscopy is used for the first time to study the absorption spectra (4001700 cm range) of imidazo-[4,5-d]-phenazine (F1) and its derivatives 2-methylamidazo-[4,5-d]-phenazine (F2), 2-fluorodimethylimidazo-[4,5-d]-phenazine (F3), and 1,2,3-triazolo-[4,5-d]-phenazine (F4) in a low-temperature ... [Low Temp. Phys. 35, 491 (2009)] published Wed Jul 15, 2009.

Radial thermal expansion of pure and Xe-saturated bundles of single-walled carbon nanotubes at low temperatures

A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, S. N. Popov et al.
The radial thermal expansion coefficient alpha of pure and Xe-saturated bundles of single-walled carbon nanotubes (CNTs) is measured in the interval 2.2120 K. The coefficient is positive above T=5.5 K and negative at lower temperatures. The experiment was done using a low-temperature capacitance d ... [Low Temp. Phys. 35, 484 (2009)] published Wed Jul 15, 2009.

Magnetization field-dependences and the exchange bias in ferro/antiferromagnetic systems. I. Model of a bilayer ferromagnetic

A. G. Grechnev, A. S. Kovalev, and M. L. Pankratova
A qualitative model explanation of the experimentally obtained field dependences of the magnetization in ferro- and antiferromagnetic media in contact with one another is proposed. In this model a thin ferromagnetic (FM) film on an antiferromagnetic (AFM) substrate consists of only two ferromagnetic ... [Low Temp. Phys. 35, 476 (2009)] published Wed Jul 15, 2009.

Magnetic ordering and charge transport in electrondoped LaCeMnO (0.1<=y<=0.3) films

V. G. Prokhorov, G. G. Kaminsky, V. S. Flis, Y. H. Hyun, S. Y. Park et al.
The microstructure and the magnetic and transport properties of as-deposited LaCeMnO (0.1<=y<=0.3) films prepared by pulsed laser deposition are investigated in a wide region of temperature and magnetic field. The microstructure analysis reveals that all films have a high c-oriented texture, an orth ... [Low Temp. Phys. 35, 468 (2009)] published Wed Jul 15, 2009.

Elementary excitations and thermodynamics of zig-zag spin ladders with alternating nearest-neighbor exchange interactions

A. A. Zvyagin and V. O. Cheranovskii
A one-dimensional spin-1/2 model in which the alternation of the exchange interactions between neighboring spins is accompanied by the next-nearest-neighbor (NNN) spin exchange (zig-zag spin ladder with alternation) is studied. The thermodynamic characteristics of the model quantum spin chain are ob ... [Low Temp. Phys. 35, 455 (2009)] published Wed Jul 15, 2009.

Low-temperature phase segregation in LaBaMnO: Manifestation of nonequilibrium thermodynamics

A. B. Beznosov, E. L. Fertman, V. A. Desnenko, A. Feher, M. Kajnakova et al.
Thermodynamic characteristics of the perovskite-like compound LaBaMnO, exhibiting a structural phase transformation of the martensitic type with a characteristic temperature T[approximate]200 K, are studied in the temperature range 2340 K. Step-like hysteretic temperature behavior of the effective ... [Low Temp. Phys. 35, 449 (2009)] published Wed Jul 15, 2009.

Flux pinning and vortex dynamics in MgB doped with TiO and SiC inclusions

V. G. Prokhorov, G. G. Kaminsky, V. L. Svetchnikov, J. S. Park, T. W. Eom et al.
The mixed-state superconducting properties of bulk MgB+2 at. %TiO and +8 at. %SiC, prepared by in situ solid state reaction, are investigated. Analysis of the mixed-state parameters, such as the upper critical field, the coherence length, and the Ginzburg-Landau parameter, proves that MgB+2 at. ... [Low Temp. Phys. 35, 439 (2009)] published Wed Jul 15, 2009.