Precise control of the vortex chirality in magnetic nano-rings with deliberately introduced asymmetry

Recent studies on Co and permalloy rings have shown that a totally flux-closed magnetic vortex state could be stable at remanence. The two chiralities of the vortex, clockwise and counterclockwise, have been proposed as the carriers for the stored information in MRAM devices. Our micromagnetic simulations demonstrated that asymmetry in the shape of the ring was responsible for the vortex formation and chirality.