In situ observation of magnetic vortex in amorphous and nanocrystalline ribbons

Abstract

In this study, the factors influencing the nucleation of magnetic vortices in CeFeB ribbons were studied using Lorentz transmission electron microscopy. Magnetic vortices and cross-tie walls exist in Ce14Fe80B6 amorphous ribbons. Via proper annealing, the amorphous ribbon is crystallized into a nanocrystalline structure whereby a magnetic vortex can exist in grains with sizes of approximately 30∼150 nm, indicating the formation of magnetic vortices is closely related to shape limitation. Moreover, it has been demonstrated magnetic vortices are the intrinsic magnetic domain structures in the amorphous alloys due to their weak magnetocrystalline anisotropy. This study provides a way to promote magnetic vortex formation in the nanocrystalline structure.