Magnetization Reversal Mechanism in Notched Elliptic Co Rings

The magnetization reversal in notched elliptic Co rings is studied with micromagnetic simulations. The magnetization configurations show that the magnetization reversal processes are dominated by the formation, propagation, and annihilation of domain walls and localized vortexes. A sector notch aligned perpendicular to H is favorable for the stable global vortex state with controllable chirality. By varying the notch angel, thickness, shape ratio, and inner-core size, the global vortex state can be achieved at remanence, which is valuable to the design of magnetic ring-shaped devices.