The formation process and structure of the skyrmion bubble lattice in magnetic multilayers

Abstract

Magnetic skyrmions are attracting considerable interest in scientific research and practical applications. Recently, a novel phenomenon was observed in which a skyrmion bubble lattice could be induced by a slightly tilted in-plane magnetic field in a multilayer film. In this article, the formation process of a skyrmion bubble lattice was investigated by micromagnetic simulation considering the Dzyaloshinskii-Moriya (DM) interaction and distribution of magnetic anisotropy. The exchange field that prevents the reversal of moments was minimized when the magnetic moments were aligned by a slightly tilted in-plane magnetic field. Many small reversed domains were formed in the regions where the demagnetization field conquers the anisotropy field after the removal of the external field and developed into a stable skyrmion bubble array. The DM interaction has an obvious influence on the size and precise moment structure of the stable skyrmion bubbles but has little effect on the nucleation of reversed domains.