From Magnetostatics to Topology: Antiferromagnetic Vortex States in NiO‐Fe Nanostructures

Abstract

Magnetic vortices are topological spin structures frequently found in ferromagnets, yet novel to antiferromagnets. By combining experiment and theory, it is demonstrated that in a nanostructured antiferromagnetic‐ferromagnetic NiO(111)‐Fe(110) bilayer, a magnetic vortex is naturally stabilized by magnetostatic interactions in the ferromagnet and is imprinted onto the adjacent antiferromagnet via interface exchange coupling. Micromagnetic simulations are used to construct a corresponding phase diagram of the stability of the imprinted antiferromagnetic vortex state. The in‐depth analysis reveals that the interplay between interface exchange coupling and the antiferromagnet magnetic anisotropy plays a crucial role in locally reorienting the Néel vector out‐of‐plane in the prototypical in‐plane antiferromagnet NiO and thereby stabilizing the vortices in the antiferromagnet.