One-dimensional dynamics of domain walls in a three-layer ferromagnetic structure with different parameters of magnetic anisotropy and exchange of the layers

Abstract

The one-dimensional nonlinear dynamics of a domain wall under the effect of an external dc magnetic field in three-layer ferromagnets with different values of the parameters of magnetic anisotropy and exchange in the layers has been studied theoretically. Equations of motion for the coordinate of the center of a domain wall and for the velocity of its motion after passage from one layer into another has been found using perturbation-theory methods. It is shown that, in the case of small defects, the analytical results agree well with the numerical results. The minimum velocity required for a domain wall to pass from one layer into another has been found numerically as a function of the parameters of the material.