Criterion for transformation of transverse domain wall to vortex or antivortex wall in soft magnetic thin-film nanostripes

TL;DR

This paper establishes a criterion for when a transverse domain wall in soft magnetic nanostripes transforms into a vortex or antivortex wall, based on the growth of the edge-soliton core relative to the vortex core size.

Contribution

It introduces a specific criterion involving the growth of the edge-soliton core that predicts the dynamic transformation of domain walls in magnetic nanostripes.

Findings

Transformation occurs when the edge-soliton core reaches the vortex core size.

Field strengths above the Walker threshold are necessary but not sufficient for transformation.

The stabilized vortex or antivortex exhibits gyrotropic motion within the nanostripe.

Abstract

We report on the criterion for the dynamic transformation of the internal structure of moving domain walls (DWs) in soft magnetic thin-film nanostripes above the Walker threshold field, Hw. In order for the process of transformation from transverse wall (TW) to vortex wall (VW) or antivortex wall (AVW) occurs, the edge-soliton core of the TW-type DW should grow sufficiently to the full width at half maximum of the out-of-plane magnetizations of the core area of the stabilized vortex (or antivortex) by moving inward along the transverse (width) direction. Upon completion of the nucleation of the vortex (antivortex) core, the VW (AVW) is stabilized, and then its core accompanies the gyrotropic motion in a potential well (hill) of a given nanostripe. Field strengths exceeding the Hw, which is the onset field of DW velocity breakdown, are not sufficient but necessary conditions for dynamic DW transformation.