Vol 88, No 11 (2024)

Using Maxwell's equations (without use of the magnetostatic approximation), the dispersion equation for spin waves in a tangentially magnetized ferrite plate, one of the surfaces of which borders with an ideal magnetic wall, is derived and the isofrequency dependences of these waves are calculated. It is found that the wave distribution along the plate thickness describes two wave numbers, and the isofrequency dependences for different modes of spin waves smoothly pass one into another and have sections corresponding to the volume-volume, volume-surface, and surface-surface wave distributions.

The problem of excitation of a semicylindrical dielectric resonator (DR) by the electromagnetic field of a slot made in the wide wall of a rectangular metal waveguide of the U-wavelength range has been simulated. The DR is made of a high-permeability dielectric with low losses. As a result of numerical modeling, the main technical parameters of the dielectric resonator antenna were obtained.

Methods of X-ray diffraction and Mössbauer spectroscopy in combination with measurements of magnetic characteristics were used to study the crystal structure, morphology and magnetic properties of nanocomposite powders based on transition metals Ni, Co, Cu, Fe, first synthesized in low cold temperature underwater plasma. The results obtained indicate the possibility of synthesizing nanocomposites with a given content of ferrites NiFe₂O₄, CoFe₂O₄, Ni_1-xCu_хFe₂O₄, which provide low values of the ferromagnetic resonance linewidth, as well as ε-Fe₂O₃, which exhibits high frequency resonance in the millimeter range of electromagnetic radiation.

We presented the results obtained in the experimental and theoretical analysis of quasi-stationary magnetization reversal of ferrite-garnet films with complex anisotropy. Using a magneto-optical setup based on the Faraday effect, the conditions under which it is possible to reduce the area of occurrence of the domain structure are revealed, and the presence of destruction of the state of homogeneous magnetization of the magnetic film in four narrow regions located relative to each other at right angles is also established. A theory that is in good agreement with the experimental results is proposed.

We studied the parameters of the electromagnetic field when heating ferromagnetic steels in induction-resistive heating devices. Calculation methods were obtained and the characteristics of the electromagnetic field in multilayer systems were determined. An assessment was made of the influence of the internal copper layer of the heater, as well as the presence of an air gap between the layers and the inductor current on the parameters of the electromagnetic field.

We studied the application of new materials for the magnetic circuits of the stator and rotor of hysteretic electromechanical energy converters of the end face design to increase the energy performances of the converters. Magnetic and hysteresis properties of new stator and rotor materials are investigated. Electromagnetic losses and their effect on the indicators of converters are being investigated.

The difference in the sizes of coverage areas of geostationary lightning detectors manufactured by specialists from different national space agencies is explained. The creation in the near future of a full-fledged geostationary constellation equipped with such detectors is predicted. New promising tasks for such constellation, not included in the NASA list for a single geostationary detector, have been proposed: monitoring in dual-use systems; using lightning as a source of electromagnetic waves in studies of plasma processes in the ionosphere; planetary monitoring of mega lightning.

We studied the frequency spectra of the dielectric and magnetic permittivity, as well as the dielectric and magnetic losses of ferrospinels made by sintering by solid-phase reaction from the initial reagent [(NiCuZn)OMnO₂]Fe₂O₃. We considered various systems of ferrites with a sign-varying temperature coefficient of magnetic saturation. Such systems are of practical interest for use in devices that require impedance matching, while at the same time providing stability magnetization in the specified temperature range (from –40 to 100 °C), which can vary by no more than 5%. The results of studying ferrospinels in the frequency ranges from 1 MHz to 3 GHz are discussed.

Two particle transverse momentum correlations have been investigated for proton-proton and deuteron-deuteron interactions at center-of-mass energy of NN collisions of 10 GeV. The correlations between Λ-hyperons and К-, π- mesons and protons are calculated in Geant4 FTF and Pythia 6.4 models. It is shown that P_T-correlations between Λ-hyperons and strange particles are stronger in the FTF model than in Pythia one. The two particle P_T-correlations can be studied at NICA SPD experiment. A study of the two particle correlations can help to clarify the mechanism of quark-gluon string fragmentation.

The characteristics of proton beams at 1 GeV have been studied using an experimental setup based on a telescope of pixel detectors. Such parameters as pixel cluster multiplicity, the beam emittance and the setup resolution in each geometry were investigated.

The adsorption process of complexes UO₂(NO₃)₂·2TBP in a heterogeneous system at the interface of polar solution of 5.6 М HNO₃ and the surface of nonpolar polypropylene(C₃H₆)ₙ is studied. The isotopic distribution of uranium changes at the vertical interface of the media. The kinetics of the extraction process of complexes UO₂(NO₃)₂·2TBP in the heterogeneous system is described by the pseudo-first-order model of Erofeev–Kolmogorov and pseudo-second-order model of Ho and McKay.

Previously, the authors estimated the neutron flux from the Petersburg Nuclear Physics Institute synchrotron for various moderator configurations near the internal target used to create a neutron flux using the spallation reaction. In this work, an attempt to transmute Am-241 was successful.

Using the resonance optical-model code OptModel there were fitted all available experimental data of deuteron elastic scattering on ¹⁶O nuclei: differential cross section data at deuteron energies E_d from 0.98 to 200 MeV and ¹⁶O+d total reaction cross section from 38 to 97 MeV. Violation of scattering matrix unitarity (optical-model + resonance) at several energies did not exceed 14% what corresponds to mean errors of the data analyzed.

For the Fe₆₀Co₂₀Si₈B₁₂ и Fe₅₈Co₂₀Si₁₂B₁₀ alloys, the temperature dependences of the Hall coefficient, electrical resistivity, and saturation magnetization in the amorphous and crystalline states were studied. A relationship between these parameters has been established, which is explained from the standpoint of the theory of the anomalous Hall effect. The spin-orbit interaction parameters are estimated on the base of the experimental data.

The methods of implantation of O₂⁺ ions into a single-crystal CdTe/Mo(111) film followed by annealing at Т = 800 K for 30 min resulted in the obtained CdTeO₃ film. It has been established that in the valence band of the CdTeO₃ film there is a 3rd maximum due to the excitation of electrons from 5s Cd electrons and 2p O electrons and bending 5s Cd + 2pO electrons. At implantation of O₂⁺ ions with E₀ ≥ 10 keV, Cd-Te-O type compounds were formed in the near-surface layer; therefore, a three-layer nanosystem of the CdTe/CdTeO/CdTe type was formed.