Statics and field-driven dynamics of transverse domain walls in biaxial nanowires under uniform transverse magnetic fields

TL;DR

This paper presents analytical and numerical analysis of transverse domain wall behavior in biaxial nanowires under uniform transverse magnetic fields, revealing static symmetry properties and velocity enhancement effects.

Contribution

It provides a new analytical solution for static TDWs and explores the velocity enhancement effect under transverse magnetic fields in biaxial nanowires.

Findings

Static TDWs are symmetric and twisted without axial fields.

Transverse magnetic fields can enhance TDW velocity.

Numerical simulations support the analytical results.

Abstract

In this work, we report analytical results on transverse domain wall (TDW) statics and field-driven dynamics in quasi one-dimensional biaxial nanowires under arbitrary uniform transverse magnetic fields (TMFs) based on the Landau-Lifshitz-Gilbert equation. Without axial driving fields, the static TDW should be symmetric about its center meanwhile twisted in its azimuthal angle distribution. By decoupling of polar and azimuthal degrees of freedom, an approximate solution is provided which reproduces these features to a great extent. When an axial driving field is applied, the dynamical behavior of a TDW is viewed as the response of its static profile to external excitations. By means of the asymptotic expansion method, the TDW velocity in traveling-wave mode is obtained, which provides the extent and boundary of the "velocity-enhancement" effect of TMFs to TDWs in biaxial nanowires. Finally numerical simulations are performed and strongly support our analytics.