Periodic vortex core switching in curved magnetic nanodisk

Abstract

Periodic switching of magnetic vortex core driven by alternative magnetic field, applied perpendicularly, is investigated in a curved permalloy nanodisk by using micromagnetic simulation. Modulated by the curvature, the oscillations of the out-of-plane magnetization, caused by the external magnetic field, are confined in the center region, closed to the core, which reduces the threshold switching field down to 3 mT. While, the excitation of radial spin waves after a core switching dominates the reversal process generally in flat nanodisks, making it hard to control the final core polarity. The released spin waves in the center region during the core switching are relatively weak in curved nanodisk with most of radial spin waves dissipated to the thick edge part, resulting in a stable periodic vortex core switching.