Allerton Press

Hyperfine interactions of 57Fe impurity nuclei are studied by probe Mössbauer spectroscopy in TmNiO3 and YbNiO3 perovskite-like nickelates in the ranges of temperature transitions of an insulator (T < T IM ) ↔ metal (T > T IM ) and antiferromagnetic (T < T N ) ↔ paramagnetic (T > T N ). The changing behavior of hyperfine interaction parameters of 57Fe nuclei in the ranges of phase transition temperatures (T IM and T N ) is analyzed. The results are interpreted in the context of the charge disproportionation of Ni3+ cations associated with the electronic localization in monoclinic-distorted nickelates at T < T IM .

The mechanism of change in the structural, chemical, physicochemical, and technological properties of Lavozero-deposit eudialyte, caused by the effect of high-voltage nanosecond pulses and combined (sequential) electropulse and acid treatment of mineral samples, is studied by means of X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, electrophoretic light scattering (zeta-potential), confocal laser scanning microscopy, microhardness testing, etc. The results show it is possible in principle to use pulsed energy and combined physical and physicochemical effects to improve the effectiveness of disintegration and softening, and to alter the hydrophobicity, sorption activity, and technological properties of eudialyte-group rock-forming minerals.

Features of the transition of Ni50Ti30Hf20, Ti50Ni25, Zr50Ni18Ti17Cu15, and Fe78B8.5Si9P4.5 crystalline alloys with different susceptibilities to amorphization upon annealing and in the amorphous state during intense deformation in a Bridgman chamber are considered. The single- and two-phase crystalline states of the chosen alloys are obtained in different annealing modes. It is shown that the amorphizing rate of crystalline alloys differ substantially at the same degree of deformation; i.e., single-phase crystalline alloys based on titanium nickelide and iron amorphize well, while zirconium-based alloy amorphizes weakly in a manner similar to two-phase iron alloy. We believe that the LDA of crystalline alloys and their corresponding crystalline phases is determined by mechanical, thermodynamic, and concentration factors.

An analytical expression for the EPR linewidth of an exchange-coupled 1/2-spin chain originating from uniform Dzyaloshinskii-Moriya interaction is derived using a quasi-classical approach. The expression successfully reproduces the results obtained by numerical quantum mechanical calculations based on Green’s function method at T > 2J/k B.

A theory of the ion sputtering of metal in the form of excited neutral and charged clusters with their subsequent fragmentation to the stable state is developed. This theory is based on simple physical assumptions and agrees well with experiments. The results are presented in the form of practical formulas. The overall yields of stable neutral and charged clusters of silver, indium, and niobium are calculated as an example.

Initial results are presented from studying the possibility of measuring different resonances on the experimental setup of the MPD spectrometer of the NICA accelerator, along with the first assessments of the impact the hadron phase has on the properties of resonances in heavy ion collisions at NICA energies.

A database of more than 700 rockburst events in the mines of Russian North is analyzed over the period 1947–2004 to determine the possible role of cosmophysical factors in the occurrence of rockbursts. The analysis reveals similarity between the seasonal distributions of rockbursts and geomagnetic disturbances in the auroral zone. A 22-year periodicity in the occurrence of rockbursts and natural earthquakes that is likely of extraterrestrial origin is observed. Possible reasons for the occurrence of rockbursts and their relations to cosmophysical factors are discussed.

Studies of the spin resonance spectra of electrons localized on donors and the conduction electrons in Si1 − x Ge x layers grown on silicon show that the phosphorous atoms in a SiGe layer can have two positions in the lattice. The line with g ∼ 1.998 refers to the electron localized in the phosphorous atom with a predominantly silicon environment; the line with g ∼ 1.994 is observed when there is a substantial concentration of germanium in the phosphorous environment.

A nonlinear model of particle spectra and nonadiabatic magnetic field amplification in supernova shells is presented. The effect super-diffusive particle propagation in the vicinity of a shock wave has on the spectra of accelerated particles and magnetic field fluctuations is studied in a Monte Carlo simulation.