Micromagnetic simulation of magnetic vortex cores in circular permalloy disks: Switching behavior in external magnetic field

Switching behaviors of magnetic vortex cores under external magnetic field in submicron circular permalloy disks have been systematically studied by using micromagnetic simulations. Simulation results show that the vortex core is stable in out-of-plane field even when it is located at the edge of the disk. The out-of-plane switching field Hsw is strongly dependent on the thickness of the disk. The core polarity and the vortex chirality can be modulated simultaneously on purpose by using a tilted field far smaller than the out-of-plane switching field Hsw. Moreover, it is found that the core polarities in asymmetric disks do not follow the direction of the z projection of the external saturation field.

▸ The direction and orientation of vortex can be modulated on purpose using a small field. ▸ The direction of vortex core in asymmetric dot do not follow the external field. ▸ The vortex core is quite stable even when they locate at dot edge. ▸ The thickness, not the diameter, has a great influence on switch behavior.