Thermal vortex dynamics in thin circular ferromagnetic nanodisks

摘要: The dynamics of gyrotropic vortex motion in a thin circular nanodisk soft ferromagnetic material is considered. demagnetization field calculated using two-dimensional Green's functions for the thin-film problem and fast Fourier transforms. At zero temperature, Landau-Lifshitz-Gilbert equation simulated fourth-order Runge-Kutta integration. Pure initial conditions at desired position are obtained with Lagrange multipliers constraint. These methods give accurate estimates restoring force constant ${k}_{F}$ frequency, showing that core described by Thiele to very high precision. finite second-order Heun algorithm applied Langevin dynamical thermal noise damping. A spontaneous takes place without application an external magnetic field, driven only fluctuations. statistics radial rotational velocity Boltzmann distributions determined mass ${m}_{G}={G}^{2}/{k}_{F}$, respectively, where $G$ gyrovector.