[en] To study effect of tin alloying on a value of I_c critical current density in bulky sintered specimens of PbMo₆S₈, a possibility for preparation of Pb_1-xSn_xMo₆S₈ solid solutions was studied in the temperature range from 500 to 1150 deg C, their temperatures of superconducting transition T_c were measured as well as temperature dependences of upper critical field H_c2 and conductivity, lattice parameters. Observed nonlinear, and, in some cases, nonmonotonous character of concentration dependences T_c and (dH_c2/dT)_Tc is connected with disorder influence due to alloying defects, and considerable increase of I_c (4.2 K) in solid solutions up to values ∼ 5x10⁹ A/m² in 1T field and ∼ 4x10⁸ A/m² in 13T field - with strengthening of vortex lattice pinning at grain boundaries

[en] Observation of galvanomagnetic waves in indium caused by carrier drift in a superposed electric field is reported. Experiments have shown the wave propagation to be of a unidirectional character. Characteristic ime of attenuation for the investigated sample (a approximately 4 cm, rho sub(300)/rho sub(T→0) approximately 4x10⁵) is about 5s. Increase in temperature from 1.4 K to 4.2 K resulted in a higher wave attenuation, which is associated with growth (25 fold) of resistance for both the life time of excitations and drift current induced in the sample decrease. Thus, the presence of direct current can essentially change the electrodynamic properties of specific metal

[en] Using simultaneous detection of Auger-electrons emitted from tungsten crystal and silicon atoms sputtered on its surface separation of contributions from primary electron direct incident flux and backscattering electron background variations to the observed orientation dependence on diffraction is carried out. A good quantitative agreemet beteen the obtained data and the results of multiwave calculations in dynamical diffraction theory permits to conclude on possibility of precise analysis of elementary composition crystals using the Auger electron spectroscopy

[en] Results of Moessbauer study of the EuBa₂Cu₃O_7-δ, YBa₂Cu_2.97Fe_0.03O_7-δ, YBa₂Cu_2.95Sn_0.05O_7-δ superconducting compounds in the 80-300 K temperature range on the ⁵⁷Fe, ¹¹⁹Sn, ¹⁵¹Eu isotope nuclei are presented. It is shown that iron ions are nonuniformly located in Cu1 ad Cu2 positions of initial compound and maintain valency 3⁺. Being synthesized, iron ions quickly occupy structural positions in crystal lattice of initial compound. A noticeable spectral line broadening in samples obtained after a short-term synthesis testifies to availability of quadrupole splitting distribution. For tin-substituted samples the isomer shift value points to relationship between tin and Sn⁴⁺ electron configuration. For ¹⁵¹Eu isotope the isomer shift value is close to Eu₂O₃ shift value

[en] X-ray diffraction methods are used to study diffusion scattering and to determine the lattice parameters in SiC, irradiated with the reactor neutron flux depending on the irradiation dose (Φ = 10¹⁷-10²¹ cm^-2) and the temperature of isochronous annealing (T_a = 200-2600 deg C). Change of electrical and optical properties of the samples in the annealing process is also investigated. It is states that radiation-induced defects cause increase of the lattice parameters and are partially annealed at T_a = 500-1000 deg C. The basic annealing stage resulting in almost complete reduction of initial concentration of charge carriers, optical absorption coefficient and the lattice parameters, takes place at T_a = 1500-1700 deg C and is characterized by 3.0 eV activation energy. Larger interstitial type clusters, which size grow with increase of T_a from 100-200 A at 1900 deg C to 2000-4000 A at 2500 deg C, are detected in samples at higher T_a ≥ 1900 deg C using method of diffusion scattering on three-crystal spectrometer

[en] The effect of the grain size D on the electric conductivity of polycrystalline PbTe films in the 4.2-700 K temperature range at D varying from 5x10^-3 to approximately 2x10^-7 cm is studied. Growth of film resistivity as D decreases depends on a growing contribution from scattering of charge carriers at the grain boundaries. Jump-like conductivity across the states at the grain boundaries is observed to be growing with increase of total boundary surface at low temperatures in samples with small D. Increase of thermal width of the forbidden band from 0.36+-0.02 to 0.44+-0.02 eV associated with increase of lattice parameter by 2.5% takes place as D changes from 10^-6 to approximately 2x10^-7 cm

[en] Atomic-ordered Fe(Pdsub(1-x)Ausub(x))₃ alloys have been studied by the method of Moessbauer spectroscopy within the concentration range of x=0.266-0.400 at temperatures of 77- 300 and 4.2 K at different stages of ordering annealina. Identification of spin states taking place at intermediate annealing stages has been carried out by a comparison of mean values and dispersions of effective magnetic fields distribu-- tions functions on ⁵⁷Fe nuclei restored from the Moessbauer spectra with those calculated in the framework of the phenomenological model and from the analysis of in superfine interaction mean values. ''Ferro-antiferromagnetic'' phase transition occurring in alloy atomic ordering has been studied in detail. It has been shown that a change in a topological picture of competing indirect exchange bonds through surrounding atoms produces a magnetic phase transition, which occurs due to formation of intermediate magnetic structures with random noncollinearity. The magnetic phase diagram in ''temperature-composition-annealing time'' coordinate is presented

[en] The first K₁ and the second K₂ anisotropy constants have been studied in the temperature range from 4.2 K to room temperature as well as magnetization of three monocrystals of the NiFesub(2-x)ScOsub(4)(x=0.5; 0.12; 0.3) system. Anomalous K₁ decrease in the low temperature range which can be attributed to the occurrence of a part of Ni²⁺ ions in tetrahedral points has been found. On the basis of these assumptions the absorption magneti-- zations at 0K and gsub(ef) are calculated to be in satisfactory agreement with the experimental results. The anisotropy in these crystals is shown to be single-ionic

[en] The H-T magnetic phase diagram of cerium hexaboride under conditions of hydrostatic compression at p <= 13 kbar in a magnetic field H <= 40 kOe in the 1.5 K <= T <= 4.2 K temperature range was investigated. A peak on the magnetic susceptibility chi(H) curve corresponding to a new region in phase 2 is observed in the antiferroquadrupole (AFQ) phase 2 in the field region H < or approximately 1.5 kOe. The uniform compression is shown to result in phase 2 expansion in the H-T coordinates. At that the Neel temperature Tsub(N) decreases while the temperature of transition from the paramagnetic phase 1 to phase 2 increases slowly

[en] Neutron-diffracrtion and magnetic studies of spin-reorientation transitions in the Hosub(x)Dysub(1-x)FeOsub(3) system with x=0.25, 0.5, 0.75 have been carried out. Two types of transitions were observed: high-temperature transition GITA₄-GITA₁ and low-temperature transition GITA₁-γITA₂. Competition of different mechanisms of spin reorientation manifests itself peculiarly on a dependence of GITA₄-GITA₁ transition character on x concentration. Reorientation of antiferromagnetism vector of ion sublattice from the X axis to Y one may be accomplished in a form of a jump (x=0.5), as in pure DyFeO₃, or may take place within a wide temperature range by a smooth turn in the XY plane (x=0.25) or in space (x--0.75). Fluctuation contribution to anisotropy is as a possible source of a nonmonotonic character of a dependence of GITA₄-GITA₁ transition on coAncentration. This contribution occurs as a result of random Ho³⁺ and Dy³⁺ ion distribution over a crystal