V. L. Sobolev

Domain wall dynamics in the presence of an external magnetic field normal to the anisotropy axis

Abstract The generalized Slonczewski equations have been applied to study the influence of the field normal to the anisotropy axis on the Walker critical field, critical velocity and the maximum velocity of the steady-state domain wall motion. It is shown that the maximum value of the drive field dependence of the velocity of the steady-state motion is the Schlomann limiting velocity. The dependences of the Walker critical field and velocity as well as the Schlomann limiting velocity on the field normal to the anisotropy axis have been obtained.

Generalized equations for domain wall dynamics

Generalized domain wall dynamic equations have been derived. The influence of the external magnetic field normal to the anisotropy axis on the critical parameters of the domain wall motion has been studied and illustrated.

Equations of Domain Wall Motion In Ferromagnetic -- Medium With Q /spl ges/ 1

The domain wall dynamics in an infinite ferromagnetic medium with material quality factor Q>or=1 in the presence of a magnetic field normal to the anisotropy axis and at the same time parallel or normal to the wall plane are studied. Generalized equations reduce exactly to those of Slonczewski when the quality factor Q is much greater than unity. >

One-magnon light scattering in exchange-noncollinear Nd2CuO4

Abstract It is shown that in an exchange-noncollinear four-sublattice antiferromagnet Nd 2 CuO 4 an anomalously high intensity of light scattering from the exchange magnon should be observed. It makes it possible to determine directly the constant of the biquadratic exchange interaction.

Domain wall structure dependence on the arbitrarily oriented external field

Abstract Simultaneous variation of the magnetization angles (ϑ, ϕ) across the DW proper and the DW energy variation versus the transverse magnetic field h t has been studied for the pinned domain wall. When the ψ H angle of the magnetic field is π/2 the DW will undergo the phase transition to a homogeneous state at a relatively small field of h t = 0.225.

Pinned domain‐wall structure in magnetic field

The pinned domain‐wall (DW) structure is investigated using a perturbational approach in terms of the inverse quality factor 1/Q and the ratio of H∥/Hk (H∥ being the component magnetic field parallel to the anisotropy axis, Hk being the anisotropy field). The parallel component field gives rise to asymmetric boundary conditions which asymmetrize the DW structure. Dependence of the DW energy, static DW structure, and width on the orientation and the strength of the magnetic field has been evaluated and the corresponding Kondorsky function obtained.

Domain wall structure and the re-modified Kondorsky function

The dependence of domain wall energy on an external magnetic field arbitrarily oriented with respect to the domain wall normal is considered. The analytical expression obtained for a uniaxial ferromagnetic material with a large value of quality factor is used to remodify the Kondorsky function. >

Light scattering on magnons in many-sublattice antiferromagnets in a magnetic field

A study is made of Raman light scattering on magnons in a many-sublattice antiferromagnet in a magnetic field parallel to the easy axis. An investigation method is developed which makes possible the optimum use of the magnetic symmetry. As an example, the scattering in a four-sublattice rhombic antiferromagnet at T=0 for all realised magnetically ordered phases is investigated. The form of the scattering tensor is obtained and the dependence of its components on the magnetic field is calculated. Emphasis is given to the study of light scattering on exchange modes. The contribution of the exchange mechanism to the single-magnon scattering tensor is discussed.

180° domain wall with the coordinate dependent azimuthal angle of magnetization

Structure of 180° one‐dimensional domain wall (DW) in a uniaxial ferromagnet in the presence of an external magnetic field arbitrarily oriented with respect to the DW has been investigated. Solutions of the system of equations which describe the behavior of the magnetic moment inside the DW in the case when the magnetization azimuthal angle is dependent upon the coordinate normal to the DW have been obtained and influence of magnetic field on the structure of the DW analyzed. Dependences of the effective widths of the distributions of both the polar and azimuthal angles of magnetization across the DW proper have been obtained. The effective width due to the azimuthal angle variation along the DW normal was found to increase with increasing transverse field.

New equations for the domain wall dynamics

Abstract The Slonczewski type equations for the domain wall (DW) dynamics have been derived based on the Landau-Lifshitz equation with the relaxation term taking into account the spatial dispersion of the relaxation.