Spontaneous formation of skyrmion structure in a hard magnetic film with low coercivity

Abstract

Magnetic skyrmions have attracted enormous research interest since the discovery a decade ago. In this experiment, the spontaneous formation of skyrmions was not observed in common soft-magnetic but in low coercivity hard-magnetic thin films. In this work, Ta (50 nm)/Nd-Fe-B (100 nm)/Ta (2 nm)/Ce-Fe-B (100 nm)/Ta (2 nm)/Nd-Fe-B (100 nm)/Ta (40 nm) multilayer film was prepared by magnetron sputtering. Skyrmion-like bubbles which correspond to vortex structure appeared in the annealed film. Through the OOMMF simulation, We got the formation conditions of the spontaneous vortex. The results of the simulation were consistent with the test results, and the formation mechanism of a skyrmion was pointed out. On the other hand, it could be inferred that skyrmions can be regulated by adjusting or controlling technology for heating processing since it appears spontaneously in annealed hard magnetic films.