Robust dynamics of antiferromagnetic skyrmion driven by spin-polarized current in small thin disks

Abstract

We investigate skyrmion configurations and dynamics in antiferromagnetic thin disks. It is shown that the skyrmion acquires oscillatory dynamics with well-defined amplitude and frequency, which may be controlled on demand by the spin-polarized current. Such a dynamics is also robust in the sense that an interface between two half-disks cannot change the dynamics appreciably whenever the exchange costs of these half-disks are not very different. Indeed, the skyrmion keeps its oscillatory motion despite crossing this interface but changes the shape of its core region in order to preserve its total energy. However, if exchange costs of the half-disks are quite distinct, the skyrmion is trapped in that half with less cost and cannot trespass the interface barrier.