Perpendicular-bias-field-dependent vortex-gyration eigenfrequency

Abstract

We found that the angular frequency ω0 of vortex-core gyrations is controllable by the application of static perpendicular bias fields Hp as studied by micromagnetic simulations and Thiele's-approach- based quantitative interpretation. The observed linear dependence of ω0 on Hp could be explained in terms of the dynamic variables of the vortex, the gyrovector constant G, and the potential stiffness constant , for cases of negligible damping. Here we calculated the values of G and κ as a function of Hp directly from the simulation numerical data using Thiele's equivalent force equations, providing a more correct understanding of the remarkable change of ω0 with Hp. This micromagnetic-simulation-based quantitative analysis is a straightforward, accurate, and effective means of understanding vortex dynamics in nanoscale magnetic elements.