Dynamics of the vortex core in magnetic nanodisks with a ring of magnetic impurities

In this work, we used numerical simulations to study the effect of a ring of magnetic impurities on the vortex core dynamics in nanodisks of Permalloy. The presence of the ring not only allowed us to modulate the gyrotropic frequency but also provided us a way to confine the vortex core. We observed that the gyrotropic frequency depends on the ring parameters. Moreover, we have noticed that the switching of the vortex core polarity can be obtained from the vortex core-impurity interaction under peculiar conditions, in particular, when the ring works for pinning the vortex core.