arXiv subjects

M. A. Kuznetsov

Publications and source records attributed to M. A. Kuznetsov.

5 recordsLinked to original sources

arXiv2026

Modification of Damon-Eshbach magnetostatic mode spectra in ferromagnet/paramagnet bilayer

Using the magnetostatic approximation, we calculate the spectra of bulk and surface spin waves in an in-plane magnetized ferromagnet/paramagnet bilayer. Due to the dipolar coupling between the layers, the paramagnet becomes polarized, which in turn modifies the spectrum of the Damon-Eshbach magnetostatic modes. We assume that the paramagnet is characterized by a magnetic susceptibility, $\chi \propto 1/(T-T_C)$, which reaches large values when the system temperature $T$ is close to the Curie temperature $T_C$. We find the conditions under which surface spin waves become unidirectional, i.e., capable of carrying energy in only one direction, and determine the magnitude of their frequency nonreciprocity. We demonstrate the possibility of switching the unidirectional wave regime on and off by varying the external magnetic field or temperature, making the ferromagnet/paramagnet system an attractive platform for tunable magnonic logic devices.

cond-mat.mes-hall↗

arXiv2025

Torsion-induced Dzyaloshinskii-Moriya interaction in helical magnets

It has been shown that in magnets possessing an inversion center in the absence of deformations, a torsion-induced Dzyaloshinsky-Moriya interaction (tiDMI) can arise. A microscopic mechanism for this interaction is described, involving the transfer of angular momentum to the lattice upon electron reflection from the magnet's boundary. An estimate of the tiDMI constant is provided. It is demonstrated that tiDMI can lift the chiral degeneracy in helimagnets, and a way for experimentally observing this effect is proposed.

cond-mat.mes-hall↗

arXiv2023

Effective interfacial Dzyaloshinskii-Moriya interaction and skyrmion stabilization in ferromagnet/paramagnet and ferromagnet/superconductor hybrid systems

It is shown that a term in the form of Dzyaloshinskii-Moriya interaction (DMI) contributes to the free energy of a ferromagnetic (FM) film on a paramagnetic (PM) (an FM above the critical temperature, Tc) or superconducting (SC) substrate occurring in the London limit. This contribution results from magnetostatic interaction between the film and substrate under which the substrate affects FM magnetization back via its magnetic field produced by magnetization inhomogeneity in the film. Strikingly, in the FM/PM system this effective DMI stabilizes chiral magnetic textures, e.g., magnetic skyrmions (MSk's) of the Neel-type, which is in contrast to that in the FM/SC one. A strong temperature sensitivity of the effective DMI allows for tuning the coupling between the FM film and PM or SC substrate and thus controlling the MSk radius in FM/PM.

cond-mat.mes-hall↗

arXiv2022

Temperature-sensitive spin-wave nonreciprocity induced by interlayer dipolar coupling in ferromagnet/X (X=paramagnet, superconductor) hybrid systems

Spin-wave (SW) spectra have theoretically been studied in a thin film of a ferromagnet (FM) on a substrate from a paramagnet (PM) (an FM above the critical temperature) or from superconductor (SC). A spin wave propagating in the FM induces the dynamic magnetization and superconducting current in the underlying PM and SC, respectively, which affect the SW propagation by their magnetic fields. As a result of this interaction, the SW spectrum becomes nonreciprocal to depend on the sign of the SW wave vector q. We show that the nonreciprocal contribution to the SW spectra in FM/PM and FM/SC systems is given by the frequency shift of Δω(q)=ω(q)-ω(-q)=a(T)(τ{\cdot}q) with τ=(n{\times}M) being the toroidal magnetic moment, M the FM magnetization, n the unit vector normal to the FM/PM(SC) interface, and a(T) the temperature-dependent constant of a dipole nature, whose sign depends on the substrate type. As the Δω(T) dependence is strong at temperatures T close to the critical temperature Tc for the FM-PM or normal metal-SC transition, one gets a possibility to control the frequency SW nonreciprocity with temperature variation near Tc. The dipolar mechanism we propose for SW frequency nonreciprocity is promising for introducing this property of SW propagation into functional devices.

cond-mat.mes-hall↗

arXiv2018

Anisotropy of Neel "orange-peel" coupling in magnetic multilayers

We calculate the energy of the magnetostatic interaction between two ferromagnetic films with uniform magnetization and correlated interfaces (the "orange-peel" effect). The "orange-peel" coupling is anisotropic: the interaction is ferromagnetic when the films are magnetized in-plane; and it is antiferromagnetic when magnetization is out-of-plane. The interaction anisotropy can be used to distinguish the "orange-peel" effect from the interlayer exchange coupling.

cond-mat.mes-hall↗