The phase diagram of a non-centrosymmetric ferromagnet in the presence of a biharmonic light field is constructed. The possibility of helical magnetic structures in instability zones is shown and their properties are analyzed. Practical application of the results is discussed.

Построена фазовая диаграмма нецентросимметричного ферромагнетика в присутствии бигармонического светового поля. Показана возможность существования в зонах неустойчивости спиральных магнитных структур и выполнен анализ их свойств. Обсуждена возможность практического использования полученных результатов.

It is shown that an inhomogeneous circularly polarized light wave induces components of the antiferromagnetism vector in centroantisymmetric antiferromagnets; a narrow beam of light can create a skyrmion. The analysis of the possibility of practical use of the predicted effects is carried out.

Possible schemes for creating superlattices for channeled waves in magnetically ordered media by modulating their parameters by extraneous waves are discussed.

A phase diagram of the dynamic magnetoelastic states of an easy-plane antiferromagnet is constructed. A dispersion relation is obtained for nonlinear magnetoelastic eigenwaves. It is shown that, at the point of the orientational phase transition, the dispersion of coupled spin and elastic waves depends only on wave amplitudes and parameters of magnetoelastic coupling.

This work proposes a new fractal model of a complex near-surface domain structure that assembles itself in highly anisotropic uniaxial single crystals, and which is based on a previously unknown modification of the Sierpinski carpet. The simulation algorithm is described and an example of its application is given.

A concept of magnetic symmetry is used to show that centrosymmetric antiferromagnetic materials may exhibit linear flexomagnetic and flexoantiferromagnetic effects (magnetization induced by gradient of elastic stress or gradient of antiferromagnetic moment, respectively).

AbstractA concept of magnetic symmetry is used to show that centrosymmetric antiferromagnetic materials may exhibit linear flexomagnetic and flexoantiferromagnetic effects (magnetization induced by gradient of elastic stress or gradient of antiferromagnetic moment, respectively).

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 region of the medium corresponding to the intersection point of unperturbed dispersion curves of elastic waves of different types, efficient transformation of a shear wave into a rotational wave or vice versa may occur.

Для цифровой магнитной записи кодированной информации с продольным намагничиванием ленты изучена связь между доменной структурой носителя и магнито-оптическим изображением его полей рассеяния, полученным с помощью магнитной пленки с перпендикулярной анизотропией и большим фарадеевским вращением. Для двухчастотного двоичного кода без возвращения к нулю разработан алгоритм, позволяющий на основе анализа изображения полей рассеяния однозначно расшифровать записанную на ленте информацию. DOI: 10.21883/PJTF.2017.09.44575.16321

For digital magnetic recording of encoded information with longitudinal magnetization of the tape, the connection between the domain structure of a storage medium and magneto-optical image of its stray fields obtained using a magnetic film with a perpendicular anisotropy and a large Faraday rotation has been studied. For two-frequency binary code without returning to zero, an algorithm is developed, that allows uniquely decoding of the information recorded on the tape based on analysis of an image of stray fields.

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

The form of phase diagrams has been determined for epitaxial magnetic films of the composition Y3–x–y Bi x Pr y Fe5O12 on the plane (H ‖ H ⊥), where H ‖ and H ⊥ are the external magnetic field components parallel and orthogonal, respectively, to the direction of the normal n to the surface of the film. The specific features have been revealed in the magnetization reversal of the objects under investigation, which are associated with their structural stratification.

The properties of epitaxial magnetic (LuBi)3(FeGa)5O12 iron garnet films grown on (210) substrates, which exhibit the magnetoelectric effect, are experimentally studied. The induced anisotropy and the behavior of the domain structure in the films are investigated in uniform and nonuniform external fields. The existing hypotheses about the nature of the magnetoelectric coupling in such films are critically analyzed.

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.

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.

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.