Chemical potential of quasi-equilibrium magnon gas driven by pure spin current

We show experimentally that the spin current generated by the spin Hall effect drives the magnon gas in a ferromagnet into a quasi-equilibrium state that can be described by the Bose-Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of spin current-driven Bose-Einstein condensation

Financial and Tax Consequences of Commercialization of Russian State Universities Intellectual Activity Results

В работе проанализированы финансовые и налоговые последствия решений о коммерциализации результатов интеллектуальной деятельности, принимаемых российскими государственными университетами.The paper analyzes the financial and tax consequences of the decisions on the commercialization of the intellectual activity results taken by Russian state universities

Proposal for an Enhanced Optical Cooling System Test in an Electron Storage Ring

We are proposing to test experimentally the new idea of Enhanced Optical Cooling (EOC) in an electron storage ring. This experiment will confirm new fundamental processes in beam physics and will demonstrate new unique possibilities with this cooling technique. It will open important applications of EOC in nuclear physics, elementary particle physics and in Light Sources (LS) based on high brightness electron and ion beams.Comment: 21 pages, pdf. The number of electrons in the bunch in the example is decreased, the volume of the paper is increased, Misprints are correcte

Micromagnetic modeling of autoresonance oscillations in yttrium-iron garnet films

One of the main problems of magnonics is finding the ways of efficiently spin waves excitation in a magnet. This paper considers the method of nonlinear amplification by phase locking of amplitude of dynamic magnetization in yttrium-iron garnet film performed by micromagnetic modeling with MuMAX3 software taking into account the real materials parameters. It is shown that the excited magnetization precession can be considered as a autoresonance phenomena. The intensity of the autoresonance in ferrimagnetic yttrium-iron garnet films has threshold dependence on the chirp rate of the exciting magnetic field. © Published under licence by IOP Publishing Ltd.Russian Foundation for Basic Research, RFBR: 19-32-90014Ural Branch, Russian Academy of Sciences, UB RAS: МК-4959.2018.2The work was carried out within the framework of the state assignment on the topic "Spin" №АААА-А18-118020290104-2, "Alloys" № АААА-А19-119070890020-3 and project №18-10-2-37 of the Program of the UB RAS, supported by Grant of the President of the Russian Federation № МК-4959.2018.2, also the reported study was funded by RFBR, project number 19-32-90014

A Model of the Electronic Structure of a FeRh Alloy Undergoing an Antferromagnetic–Ferromagnetic Phase Transition

Abstract: A new approach to describing the magnetic properties of FeRh alloys is proposed. It is based on two assumptions about the properties of 3d and 4d electrons in these alloys. The first is the assumption that the 4d band is submerged under the Fermi level to a depth that ensures its complete filling at a temperature T = 0 K. The second is the assumption that there are two different spatial distributions of 3d and 4d electrons that are compatible with one atomic structure. The first assumption makes it possible to explain the absence of uncompensated spins of 4d electrons in the low-temperature antiferromagnetic (AFM) phase of FeRh. The second assumption is proposed to explain the strong changes in the spin structure of the FeRh alloy upon the AFM–FM transition, while its atomic structure is almost unchanged. Attempts have been made to predict the new properties of the FeRh alloy that follow from these assumptions. Our second assumption proved to be successful and enabled us to predict the existence of local magnetic moments of 3d electrons in the AFM phase, which are larger than the magnetic moments of Fe ions. Measurements of the magnetic susceptibility of the FeRh alloy in the AFM phase confirmed this prediction. © 2022, The Author(s).Ministry of Education and Science of the Russian Federation, Minobrnauka, (AAAA-A18-118020190095-4)This work was carried out within a state task of the Ministry of Education and Science of the Russian Federation (subject “Quantum”, state registration no. AAAA-A18-118020190095-4)

Very high frequency gravitational wave background in the universe

Astrophysical sources of high frequency gravitational radiation are considered in association with a new interest to very sensitive HFGW receivers required for the laboratory GW Hertz experiment. A special attention is paid to the phenomenon of primordial black holes evaporation. They act like black body to all kinds of radiation, including gravitons, and, therefore, emit an equilibrium spectrum of gravitons during its evaporation. Limit on the density of high frequency gravitons in the Universe is obtained, and possibilities of their detection are briefly discussed.Comment: 14 page

Insulation Systems of Frame Cottages

• The article presents studies of the exploitation characteristics of the material, the results of a full-scale survey of a residential private house insulated with expanded polyethylene, as well as the main design solutions for the insulation of a frame cottage. The features of insulation systems of low-rise buildings, including those with a frame-bearing carrier system, are considered. It has been substantiated that the use as thermal insulation of mineral-wool plates used on non-loaded structures assumes the mandatory placement of vapor barrier (usually plastic film) from the inside of the insulated surface and the windproof membrane outside. The use of a rolled foamed polyethylene as an insulating material makes it possible to realize an insulating sheath without additional layers. Experimental determinations of diffusion moisture absorption, water absorption upon partial immersion in water, water absorption upon full immersion in water, tensile strength in the longitudinal direction, and adhesion strength of the adhesive layer to metal were performed. It was established that the diffusion moisture absorption of samples of expanded polyethylene is 0.51-0.75%, and taking into account the weld it is 0.70-0.75%. Water absorption of samples when fully immersed in water does not exceed 0.96% by volume. The tensile strength in the longitudinal direction for products with a metallized coating is 80-92 kPa, without a metallized coating - 80-87 kPa, and for a weld - 29-32 kPa. A field survey showed that the humidity of the pine timber is within the normative. The expediency of warming only the outer coating of expanded polyethylene of the calculated thickness without filling the frame is justified, which, with standard air exchange and observance of the conditioning conditions, will be sufficient to maintain the microclimate in the room