Energetic molding of chiral magnetic bubbles

TL;DR

This paper investigates how the Dzyaloshinskii-Moriya Interaction influences the shape and growth of chiral magnetic bubbles in thin films, providing a model to understand their anisotropic behavior and growth asymmetry.

Contribution

It introduces a model based on energetic calculations and the Wulff construction to explain the anisotropic domain shapes caused by DMI in magnetic thin films.

Findings

Domains form non-elliptical teardrop shapes influenced by in-plane fields.

The shape reversal occurs at large applied fields.

The energetic model accurately predicts domain shapes and growth asymmetry.

Abstract

Topologically protected magnetic structures such as skyrmions and domain walls (DWs) have drawn a great deal of attention recently due to their thermal stability and potential for manipulation by spin current, which is the result of chiral magnetic configurations induced by the interfacial Dzyaloshinskii-Moriya Interaction (DMI). Designing devices that incorporate DMI necessitates a thorough understanding of how the interaction presents and can be measured. One approach is to measure growth asymmetry of chiral bubble domains in perpendicularly magnetized thin films, which has been described elsewhere by thermally activated DW motion. Here, we demonstrate that the anisotropic angular dependence of DW energy originating from the DMI is critical to understanding this behavior. Domains in Co/Ni multi-layers are observed to preferentially grow into non-elliptical teardrop shapes, which vary with the magnitude of an applied in-plane field. We model the domain profile using energetic calculations of equilibrium shape via the Wulff construction, which explains both the teardrop shape and the reversal of growth symmetry at large fields.