A vortex gyrating in a magnetic disc has two regimes of motion in the presence of disorder. At large amplitudes the vortex core moves quasi-freely through the disorder potential. As the amplitude decreases, the core can become pinned at a particular point in the potential and precess with a significantly increased frequency. In the pinned regime, the amplitude of the precession decreases more rapidly than in the quasi-free regime. In part, this decreased decay time is due to an increase in the effective damping constant and in part due to geometric distortion of the vortex. A simple model with a single pinning potential illustrates these two contributions.
Citation: Physical Review B
Pub Type: Journals
magnetic vortex, micromagnetics, gyration, magnetic damping, precession, Landau-Lifshitz-Gilbert