Ultrafast Vortex-Core Reversal Dynamics in Ferromagnetic Nanodots

TL;DR

This study uses numerical simulations to explore the ultrafast reversal of magnetic vortex cores in nanodots, revealing the underlying physics and potential for controlled manipulation of vortex states.

Contribution

It provides detailed insights into the mechanisms and dynamics of vortex-core reversal in ferromagnetic nanodots under oscillating magnetic fields.

Findings

Revealed different dynamic responses of vortices to external fields.

Identified physics of 10 ps scale vortex-core reversal.

Demonstrated effective manipulation of vortex-core orientation.

Abstract

To verify the exact underlying mechanism of ultrafast vortex-core reversal as well as the vortex state stability we conducted numerical calculations of the dynamic evolution of magnetic vortices in Permalloy cylindrical nanodots under an oscillating in-plane magnetic field over a wide range of the frequency and amplitude. The calculated results reveal different kinds of the non-trivial dynamic responses of vortices to the driving external field. In particular, the results offer insight into the 10 ps scale underlying physics of the ulrafast vortex-core reversals driven by small amplitude (~10 Oe) in-plane fields. This work also provides fundamentals of how to manipulate effectively the dynamical switching of the vortex-core orientation.