Stability and Dynamics of Skyrmions in Ultrathin Magnetic Nanodisks Under Strain

Abstract

Understanding the switching mechanism of magnetic skyrmions is critical for realizing their potential applications in future spintronic devices. Here we study the thermodynamic stability and dynamics of a Néel skyrmion in an ultrathin magnetic nanodisk under biaxial in-plane strains using a combination of phase-field simulations and analytical theory. We demonstrated the switching of a circular skyrmion to a variety of magnetic configurations, including an out-of-plane monodomain or an in-plane vortex under isotropic strains and to an elliptical skyrmion or a stripe domain under anisotropic strains. We successfully formulated a Lagrangian-mechanics-based model to analytically describe the switching dynamics of a skyrmion. Both our simulations and analytical model revealed that the strain-mediated breathing dynamics of skyrmions lead to a counter-intuitive phenomenon in which a lager strain may lead to slower skyrmion-to-monodomain switching.

Keywords: Phase-field Modeling, Skyrmions, Nanostructures, Lagrangian Mechanics