Size dependence of C and S states in circular and square Permalloy dots

Abstract

From the micromagnetic simulation, it is found that the size-dependent stably existing regions of quasiuniform∕flower state, C, S, and vortex states are different in thin circular and square Permalloy dots. In very small dot’s size, the quasiuniform∕flower state is the most stable state both in circular and square Permalloy dots. For larger size, C, S, and vortex states may exist. The vortex state can stably exist from small diameter to large one both in square dot and circular dot. In circular dot, only one of the C and S states can exist for one given diameter and in some diameter range, none of the quasiuniform∕flower, C and S states can exist. Only the vortex state can be stable in this range. In square dot, C and S states can simultaneously exist, which are very different from the case in the circular dot.