Nonlinear magnetoelectric effects in an isotropic disordered dielectric in nonuniform fields

Theoretical analysis allowing experimental observation of nonlinear magnetoelectric effects in isotropic disordered dielectric in nonuniform electric and magnetic fields is carried out.     

Magnetoelectric effect in garnet films with the induced magnetic anisotropy in a nonuniform electric field

The mechanism underlying the strong magnetoelectric effect in epitaxial films of magnetic garnet is proposed. This mechanism is not related to the existence of the electrically charged domain walls. It results from the effect of a nonuniform electric field on the induced magnetic anisotropy and depends on the crystallographic orientation of the films.     

Induced and parametric excitation of spin waves by a light field with a discrete spectrum and optically induced spin echo

Induced and parametric excitation of spin waves by a light field and light-induced spin echo are considered. The static and steady-state dynamic magnetizations in the light field are determined, and the phase diagrams of the system in magnetic and light fields are constructed. The threshold of parametric excitation, the amplitude of stationary oscillations, and the trajectories described by the end point of the magnetic moment vector are calculated for the case of light-induced nonlinear ferromagnetic resonance. The trajectories can be topologically different. The transition between states with different trajectories occurs as a phase transition. The parameters of the light-induced spin echo are determined.     

Flexomagnetoelectric effect in nonuniform external fields in isotropic centrosymmetric nonlinear media with spatial dispersion

The flexomagnetoelectric effects in isotropic centrosymmetric nonlinear media with spatial dispersion in nonuniform external fields are theoretically analyzed. General theoretical concepts are applied to the case of a capacitor with metallic plates in the form of two infinite cylinders with confocal elliptic generatrices that is filled with a nonlinear dielectric. The developed theory is generalized to the case of an isotropic centrosymmetric collinear antiferromagnet in a disordered phase.     

Nonuniform elastomagnetoelectric effects in a disordered medium

A system of nonlinear equations for the determination of the ground state and the analysis of the possibility of the existence of different elastomagnetoelectric effects in the presence of nonuniform external influences has been obtained by the method of variation of the thermodynamic potential of the disordered medium over the electric and magnetic field strengths and elastic strains. It has been shown that the nonuniform strains created by the gravitational or centrifugal forces can serve as a source of the internal electric fields.     

Elastoelectric effect in a disordered homogeneous nonconducting medium under centrosymmetric external influences

Within a variational approach, a system of nonlinear equations is obtained to analyze elastoelectric effects in a disordered homogeneous nonconducting medium. The results of analysis are applied to the case of a spherical shell subject to centrosymmetric hydrostatic pressure from outside and inside.     

Coupled waves of linear velocity,angular velocity,and temperature in a liquid with internal rotation

Equations of motion for a locally nonequilibrium liquid with internal rotation are derived, and the thermospin effect is considered. It is demonstrated that high-frequency transverse coupled waves of linear velocity, angular velocity of internal rotation, and temperature may propagate a liquid with internal rotation. A dispersion relation and a frequency dependence of the damping ratio are deduced. Comparison between theoretical and experimental values of the transverse sound velocity dispersion shows their satisfactory agreement. Low-frequency transverse waves do not penetrate into the liquid: they decay over a distance on the order of the wavelength. It is shown that frequencies and their corresponding wavenumbers exist in a liquid with internal rotation at which either waves do not decay or a phase shift in the skin layer is absent. It is found that the excitation spectrum may contain a cutoff frequency or an energy gap due to interaction between the linear and angular velocity fields. The dispersion and damping ratio for the coupled waves near synchronism points, where uncoupled waves resonantly interact with each other, are determined.     

Transformation of Hybrid Transverse Elastic Waves in Nonuniform Micropolar Media

Acoustical Physics - The features of propagation of coupled hybrid transverse elastic waves in a nonuniform dense micropolar medium with spatial dispersion are studied. It is shown that in the...     

Locally nonequilibrium magnetic excitations in insulators

The equation of motion for the magnetic moment vector M in a locally nonequilibrium medium is derived. The dispersion and attenuation of the coupled modes of the magnetic vector potential and magnetization are determined. It is shown that the continuous spectrum contains frequencies corresponding to undamped waves or constant-phase damped waves.     

Flexomagnetic and Flexoantiferromagnetic Effects in Centrosymmetric Antiferromagnetic Materials

Technical Physics - A concept of magnetic symmetry is used to show that centrosymmetric antiferromagnetic materials may exhibit linear flexomagnetic and flexoantiferromagnetic effects...