Yu. I. Gorobets

Reflection and refraction of spin waves in uniaxial magnets in the geometrical-optics approximation

The laws governing the propagation of magnetization waves are investigated in the geometricaloptics approximation, in which a spin wave can be treated as a ray. The refractive index for a spin wave on the interface between two magnets with different exchange coupling constants and magnetic anisotropy constants is determined. The dependences of the intensity of the reflected wave and the refractive index on the spin-wave frequency and the strength of the external uniform magnetic field are calculated. Estimates of the dimensions of inhomogeneous inclusions that perform functions analogous to the functions of lenses and mirrors in optics are presented. The possibility of using the same inhomogeneities both as lenses and as mirrors, depending on the magnetic field strength, is pointed out.

Liquid-liquid phase separation occurring under the influence of inhomogeneous magnetic field in the process of the metal deposition and etching of the magnetized ferromagnetic ball

Liquid-liquid separation near a steel ball surface during etching and deposition processes in crossing gravity and magnetic field was investigated here both experimentally and theoretically. The influence of the Earth gravitation on the shape of the interface between the two quasi-stationary liquid phases in an electrolyte with different magnetic susceptibilities was experimentally observed. The shape of the interface is described theoretically based on the equation of the balance of osmotic, magnetic, and hydrostatic pressures in the Earth’s gravity. The impact of Earth’s gravity on the shape of the interface in electrolyte is described theoretically for the first time.

The effect of cooling on the bubble lattice structure

Abstract Structure transformations in a closely-packed bubble lattice due to the sample cooling-induced domain collapse have been examined. The bubble lattice base changes manifesting themselves by nonequivalence of the domains in the sign of d R /d T ( R is the bubble radius, T is the film temperature) were observed. Temperature decrease leads to collapse of every third domain and the structure turns from the hexagonal to graphite one.

Magnetophoretic potential at the movement of cluster products of electrochemical reactions in an inhomogeneous magnetic field

An electric field arises from the influence of a nonuniform static magnetic field on charged colloid particles with magnetic susceptibility different from that of the surrounding liquid. It arises, for example, under the influence of a nonuniform static magnetic field in clusters of electrochemical reaction products created during metal etching, deposition, and corrosion processes without an external electric current passing through an electrolyte near a magnetized electrode surface. The corresponding potential consists of a Nernst potential of inhomogeneous distribution of concentration of colloid particles and a magnetophoretic potential (MPP). This potential has been calculated using a thermodynamic approach based on the equations of thermodynamics of nonequilibrium systems and the Onsager relations for a mass flow of correlated magnetic clusters under a gradient magnetic force in the electrolyte. The conditions under which the MPP contribution to the total electric potential may be significant are discussed with a reference to the example of a corroding spherical ferromagnetic steel electrode.

Magnetic Ordering in Granular System

The conditions of the formation of different magnetic structures with ferromagnetic (FM) and antiferromagnetic (AFM) ordering in granular materials containing a subsystem of ferromagnetic granules are considered within the phenomenological approach. It is supposed that the magnetostatic field and the exchange interaction between conduction electrons and magnetic ions are responsible for the formation of magnetic structure.

Singular optics of spin waves in a two-sublattice antiferromagnet with uniaxial magnetic anisotropy

Based on exact 3D solutions of the Landau-Lifshitz equations in a two-sublattice antiferromagnet with uniaxial magnetic anisotropy, the existence of nonlinear spin waves with singular points on the wavefront is predicted. These waves are spin-wave analogs of optical singularities.

Spin waves in an antiferromagnet: A similar solution of the Landau-Lifshitz equation

In the paper, spin waves in an uniaxial two-sublattice antiferromagnet are studied. A similar solution of the Landau-Lifshitz equation is investigated. For different spin wave velocities, equations for this solution are obtained.

Dipole-exchange spin waves in a periodically layered ferromagnetic nanotube

Spin waves in a periodically layered ferromagnetic nanotube (nanotube magnetophotonic crystal) are investigated. An external magnetic field is considered to be applied parallel to the nanotube symmetry axis. A linearized Landau-Lifshitz equation in the magnetostatic approximation is used with taking account of the magnetic dipole-dipole interaction, the exchange interaction and the anisotropy effects. As a result, the local dispersion relation (for uniform nanotube sections), the radial wave number spectrum and the longitudinal quasi-wave number spectrum (for the entire nanotube) are found for spin waves in the above-described nanotube. Limitations on the transverse-angular modes are determined from the radial wave number spectrum. The longitudinal quasi-wave number spectrum in the “effective medium” limit is shown to have the same form as for a uniform nanotube (with averaged parameters).

Spiral magnetic configuration in a thin film with biaxial anisotropy

The conditions for the existence of a spiral magnetic configuration are determined for a thin ferromagnetic film with biaxial anisotropy.

Static and dynamic properties of an isolated strip domain in a thin ferromagnetic film

A perturbation theory is developed for the integrodifferential Landau-Lifshits equation that describes the state of 2π-domain walls in ferromagnetic films. The static and dynamic parameters of a 2π-domain wall are determined, taking into account its micromagnetic structure. The limits of applicability of geometric domain wall models are indicated.