Current-induced nucleation, manipulation, and reversible switching of antiskyrmioniums

Abstract

Magnetic skyrmioniums are unique spin structures that can be viewed as two skyrmions with an opposite skyrmion number providing a zero topological charge. Here, we propose a unique method to nucleate magnetic antiskyrmioniums in ferromagnetic materials with D2d symmetry. Using micromagnetic simulations, we show the stabilization of isolated antiskyrmionium from ferromagnetic as well as antiskyrmionic ground states. By invoking material specific parameters, we have established the regions of the stable antiskyrmionium phase and investigated their dynamics under current in-plane as well as perpendicular to plane geometry. Our study shows that antiskyrmioniums can be moved with a large velocity at very small current density in comparison to antiskyrmions and their anisotropic magnetization distribution provides a distinct current driven dynamics in comparison to skyrmioniums. Most importantly, we demonstrate that an antiskyrmionium can be stabilized and switched reversibly from a single antiskyrmion. We have also shown that the antiskyrmionium can be driven efficiently in an anisotropy gradient, where the velocity varies inversely with the damping constant. The present results add a distinct direction to the realization of antiskyrmionium based racetrack devices using D2d symmetry based materials.