Directed motion of domain walls in biaxial ferromagnets under the influence of periodic external magnetic fields

TL;DR

This paper investigates how periodic external magnetic fields can induce directed motion of domain walls in biaxial ferromagnets, identifying conditions for motion and analyzing velocity dependence on system parameters.

Contribution

It develops a symmetry-based approach to determine conditions for directed domain wall motion and combines analytical and numerical methods to quantify velocity.

Findings

Directed DW motion occurs when magnetic field is along the easy axis.

Motion is prohibited if the field is along hard axes.

Average DW velocity depends on damping, amplitude, and frequency.

Abstract

Directed motion of domain walls (DWs) in a classical biaxial ferromagnet placed under the influence of periodic unbiased external magnetic fields is investigated. Using the symmetry approach developed in this article the necessary conditions for the directed DW motion are found. This motion turns out to be possible if the magnetic field is applied along the most easy axis. The symmetry approach prohibits the directed DW motion if the magnetic field is applied along any of the hard axes. With the help of the soliton perturbation theory and numerical simulations, the average DW velocity as a function of different system parameters such as damping constant, amplitude, and frequency of the external field, is computed.