We study the magnon spectrum in a thin ferromagnetic-superconductor heterostructure in the presence of a single superconducting vortex. We employ the Bogolubov-de Gennes Hamiltonian which describes the magnons in the presence of the stray magnetic field and the non-uniform magnetic texture induced by the vortex. We find that the vortex localizes magnon states approximately in the same way as a charge center produces electron bound states due to screened Coulomb interaction in the two-dimensional electron gas. The number of these localized states is substantially determined by the material parameters of the ferromagnetic film only. We solve the scattering problem for an incident plane spin wave and compute the total and transport cross sections. We demonstrate that the vortex-induced non-uniform magnetic texture in chiral ferromagnetic film produces a skew scattering of magnons. We explore the peculiarities of the quantum scattering problem that correspond to orbiting in the classical limit.
Results are published in D.S. Katkov, S.S. Apostoloff, I. S. Burmistrov, ``Bound states and scattering of magnons on a superconducting vortex in ferromagnet-superconductor heterostructures’’, Pis'ma v ZhETF 120, 681 (2024) .(http://jetpletters.ru/ps/2486/article_36479.pdf)

The content of the talk is devoted to the possible integration of magnonic devices and interconnection between them with the use of magnonics, straintronics, spin-orbitronics. In recent years much research has been directed towards the use of spin waves for signal processing at microwave and subterahertz frequencies due to the possibility to carry the information signal without the transmission of a charge current. Recent theoretical and experimental studies suggest that strain can be used to engineer energy-efficient complicated 2D and 3D material and heterostructures. The main topic of the talk will be focused on the application of the magnonic unit for signal processing and interconnection routes in the magnonic networks. The part of the talk will be devoted to the the experimental observations of the strain-mediated spin-wave coupling phenomena in different magnonic structures based on the asymmetric adjacent magnonic crystals, adjacent magnetic yttrium iron garnet stripes and array of magnetic stripes, which demonstrates the collective spin-wave phenomena such as the discrete soliton formation. The voltage-controlled spin-wave transport along bilateral magnonic stripes was demonstrated. The model describing the spin-wave transmission response and predicting its value is proposed based on the self-consistent equations. It was shown that the strain-mediated spin-wave channels can be used to route the magnonic information signal and thus the composite magnon-straintronic structure could be used to fabricate magnonic platforms for energy-efficient signal processing. The obtained results open new perspectives for the future-generation electronics using integrated magnonic networks.

Magnetic quantum oscillations (MQO) provide a common tool to probe the electronic structure of various conductors. The Fermi surface of most metals is now known due to the MQO. This tool is more precise than its alternatives, but requires low temperatures, clean samples and rather strong magnetic fields. In this paper the MQO of Hall coefficient are measured in rare-earth tritelluride TmTe3 and shown to be much stronger and persist to higher temperature than the Shubnikov-de Haas oscillations. This amplitude enhancement simplifies the MQO experiments and is very general in strongly anisotropic metals. The combined measurements of Hall and diagonal magnetoresistance provide additional useful information. The ratio of their MQO amplitudes depends linearly on magnetic field, and its slope gives a simple and accurate measurement tool of the electron mean free time and its temperature dependence, unachievable from the usual Dingle plot. Our results expand the use and applications of MQO as a powerful tool to investigate the electronic structure.

Modeling the motion of ultracold neutrons (UCN) is important for estimating their losses, accurately measuring their lifetime, and describing other experiments. In material traps, it is necessary to take into account not only specular but also diffuse elastic reflection of UCN from the trap walls. Usually, such diffuse scattering is described using Lambert's cosine law for the angular distribution of scattered neutrons, which does not have a strict theoretical derivation and is often violated. In our work, we propose an experiment that allows measuring the deviation of the angular distribution of UCN during diffuse scattering from the Lambert law. This deviation can be determined by the difference in the number of neutrons emitted through the central and end windows of a long narrow UCN trap. Monte Carlo calculations were performed that correspond to a possible experiment and show a significant effect for different trap shapes. Other issues related to UCN losses during interaction with the walls of material traps were also investigated.

The quasi-two-dimensional organic metal κ-(BEDT-TTF)2Hg(SCN)2Cl upon cooling below T = 30 K passes into the Mott insulator state. External hydrostatic pressure P > 0.7 kbar restores the metallic state and makes it possible to study the behavior of resistance, magnetoresistance and Shubnikov-de Haas oscillations at helium temperatures in the range of external pressures P = 1-8 kbar. The spectrum of the observed Shubnikov-de Haas oscillations agrees well with theoretical calculations of the band structure. At the same time, the oscillation characteristics (cyclotron mass, frequency, amplitude) are significantly affected by electron correlations. Strongly correlated systems also have a specific temperature dependence of resistance. In this case, pressure is the main tool controlling the strength of correlations. Various versions of the influence of pressure on the behavior of the non-oscillating part of magnetoresistance are discussed.