Configurational anisotropy in hexagonal arrays of submicron Co elements

Abstract

The angular dependence of the in-plane magnetization reversal in hexagonally ordered Co arrays has been investigated. A sixfold anisotropy has been observed which mirrors the structural symmetry of the array. The arrays consist of polycrystalline, circular elements with constant center-to-center separation and diameters of 360nm and below. It has been observed that the anisotropy is strongly dependent on element diameter and disappears for densely packed elements. This anisotropic coupling cannot be explained by a simple model of interacting point dipoles situated at regular lattice sites, as this predicts an isotropic interaction field for a hexagonal array. Instead, it is believed that the anisotropy arises from interactions between unsaturated regions of the elements, particularly at adjacent edges.