Kravchuk V. Vortex states of nanodots

Properties of vortex state nanomagnets of symmetrical shape were investigated theoretically within the phenomenological Landau-Lifshitz model. Ranges of nanoring sizes for which vortex state is ground one were determined. Availability of an intermediate vortex state was demonstrated. The transition between intermediate and planar vortex was described. The behaviour of different magnetization states of a nanodisk in transverse magnetic field was studied taking into account a non-local magnetostatic interaction. The gyrotropic vortex dynamics near the disk center was investigated within the collective variables model and the model of fixed boundary conditions. The influence of rotating external field with frequencies higher then vortex gyrofrequency was also studied. Using micromagnetic modeling the corresponding diagram of vortex polarity switching was built.