Unidirectional switching of magnetic vortex core in a nanocavity mediated nanodisk: Looking for a reliable low-power-driven and fast switching in terms of geometric parameters

Abstract

Reliable unidirectional switching of magnetic vortex core driven by continuous rotating magnetic field is investigated using a permalloy nanodisk with a nanocavity inserted in the center in combination with micromagnetic simulations. It is reported that once the vortex core is confined in a nanocavity of diameter is comparable to the core size, the modes of the core motion (divergence/convergence modes) are modulated differently by the nanocavity: the threshold field amplitude required for vortex core switching is reduced for convergence mode, but not for divergence mode. We found that the confinement of the nanocavity to the core is mediated by the cavity height as well. Low-power-driven fast unidirectional switching is found to be achievable by carefully choosing the value of the nanocavity height.