Antidot shape dependence of switching mechanism in permalloy samples

We study antidot shape dependence of the switching magnetization for various permalloy samples with square and triangular arrays of nanometer scale antidots. The remnant magnetization, squareness ratio, and coercive fields of the samples are extracted from the hysteresis loops which are obtained by solving the Landau-Lifshitz-Gilbert (LLG) equation numerically. We find several different magnetic spin configurations which reveal the existence of superdomain wall structures. Our results are discussed in terms of the local shape anisotropy, array geometry, and symmetry properties in order to explain the formation of inhomogeneous domain structures.