Magnetic vortex core dynamics in correlated double plates of permalloy.

In this work, we theoretically investigate the dynamics of magnetic vortex in a double-plate nanostructure, in which two square permalloy plates are joined together by imposing closely on a thin permalloy film. It is found that magnetic vortices have been formed in the two square permalloy plates. Due to the involving of the joint, the out-of-plane magnetization can also be observed at the sidewalls between the square plates and the joint area. The ground states with the vortex polarities (1,1) and (1,-1) are obtained when the thickness of the joint area is varied. By applying a short in-plane magnetic field pulse, the vortices deviate from their equilibrium positions and gyrate with damping radius. Interestingly, the vortex polarity can be switched if the strength of magnetic field approaches the threshold of switching field. Particularly by changing the strength of magnetic field, the two vortices can be switched alternatively in the double-plate nanostructure. The investigations may provide potential applications in magnetic vortex memories.