Bulletin of the Russian Academy of Sciences: Physics最新文献

For the three-orbital model of a strongly correlated insulator with one electron per site filling, the orbital and spin order in the ground state is investigated taking into account local correlations. With a large crystal field, a continuous transition from the hidden-order phase to the weak ferromagnetic phase is obtained; the critical parameter of the Hund interaction at the transition point depends on the magnitude of the spin–orbit coupling.

Based on the theory describing the propagation of electromagnetic waves in a tangentially magnetized bi-gyrotropic layer, modulus P and the orientation of the Poynting vector are investigated for a special case of such a layer: an arbitrary surface–surface spin wave (the distribution of which over the layer’s thickness is described by two different wave numbers) in a ferrite plate. It is found that modulus P of the Poynting vector exhibits a jumpwise change on the surfaces of the plate, taking maximum values on both its surfaces. Most of the wave energy is localized near the surface, where the value of the Poynting vector is highest.

A new way of studying atmospherics is proposed that uses information about the electromagnetic spectrum of an initial discharge of lightning, obtained by analyzing high-speed video recordings. The parameters of optical sensors installed in high-speed and specialized video cameras of geostationary lightning cartographers are considered. The range of frequencies in which it is technically possible to obtain information about the spectrum of lightning radio emissions by analyzing data from video recordings is determined.

Superconducting FeSe_xTe_1–x films grown on an amorphous substrate were discovered to exhibit a Berezinskii–Kosterlitz–Thouless transition indicative of quasi-two-dimensional behavior, leading to a pronounced decrease in the superconducting transition temperature of the films. A stoichiometrically modified initial layer approximately 40 nm thick was identified, which explains the observed quasi‑two‑dimensionality.

A theoretical description is developed for the thermodynamic properties of liquid tantalum. An equation of state is proposed for this metal under conditions characteristic of shock compression and isentropic expansion processes, as well as isobaric heating by a powerful current pulse. Results from calculations agree with experimental data obtained at high pressures and temperatures.

A theory describing the propagation of electromagnetic waves in a tangentially magnetized bi-gyrotropic layer is used to calculate for the first time dependences of the orientation of the energy flow on the orientation of the wave vector for an arbitrary surface-surface spin wave (whose distribution over the layer’s thickness is described by two different wave numbers) in a ferrite plate, a special case of a bi-gyrotropic layer.

The authors study the possibility of creating modifications of iron oxides under conditions of underwater plasma. Iron ions are partially replaced with other ions of the iron family, ensuring a noticeable variation in the electromagnetic characteristics of the nanoparticles of the synthesized powders.

Compact 3D parts in the form of a hollow cylinder and angle were made of the SvAMg5 alloy by wire arc additive manufacturing (WAAM) using robotic MIG and CMT welding. The structure and phase composition of the surfaced metal were studied by complex and analytical methods, and the strength properties of the additively manufactured products were determined.

After treating seeds with liquid nitrogen and other liquefied gases with additional exposure to aqueous biostimulant solutions, several experimental variants display the preservation (as in control groups) or improvement of seed germination and seedling development in cultivated meadow clover cultivars. The cryotreatment of wild meadow clover seeds (in contrast to cultivated varieties) results in cotyledon detachment in some seedlings and delays their development.

The authors study the behavior of the Wigner current for different initial states of a particle in a one-dimensional quantum well. Particular attention is given to trajectories that are determined by the Wigner current. It is shown that the same features in the behavior of the trajectories are observed for different initial states.