Nonlinear gyration of a vortex

Nonlinear magnetic vortex gyration.
André Drews, Benjamin Krüger, Gunnar Selke, Thomas Kamionka, Andreas Vogel, Michael Martens, Ulrich Merkt, Dietmar Möller, and Guido Meier
Phys. Rev. B 85, 144417 (2012)

(a) Simulated trajectory (blue triangles) and trajectory obtained from Eq. (3) (solid line) in a permalloy square
with an edge length of 200 nm and a thickness of 10 nm. The dashed line denotes the solution for vanishing nonquadratic terms of the potential. The vortex is excited with j0 = 1 × 1011 Am−2 and gyrates resonantly at = 2.56 × 109 s−1 (2.71 × 109 s−1) for vanishing (nonvanishing) nonlinear terms. (b) Simulated magnetization patterns and corresponding isolines in the steady state at instants of time t = 0.57T , 0.74T , and 0.84T of one gyration period T.