Generation of magnetic skyrmion bubbles by inhomogeneous spin Hall currents

TL;DR

This paper demonstrates through micromagnetic modeling that inhomogeneous spin Hall currents can generate magnetic skyrmion bubbles in thin films with Dzyaloshinskii-Moriya interactions, aligning with recent experimental findings.

Contribution

It introduces a micromagnetic model showing skyrmion bubble generation via inhomogeneous spin Hall torque in DMI-containing thin films, providing a theoretical basis for experimental observations.

Findings

Skyrmion bubbles can be generated by inhomogeneous spin Hall currents.

Generated skyrmions are stable or metastable in materials with small DMI.

The model aligns with recent experimental results on skyrmion creation.

Abstract

Recent experiments have shown that magnetic skyrmion bubbles can be generated and injected at room temperature in thin films [W. Jiang et al, Science vol. 349, 283 (2015)]. Here, we demonstrate, using micromagnetic modeling, that such skyrmions can be generated by an inhomogeneous spin Hall torque in the presence of Dzyaloshinskii-Moriya interactions (DMIs). In the experimental Ta/Co$_{20}$Fe$_{60}$B$_{20}$ thin films, the DMI is rather small; nevertheless, the skyrmion bubbles are stable, or at least metastable on observational time scales.