Preparation and Magnetic Characterization of Ni Membranes With Controlled Highly Ordered Nanohole Arrays

A replica/antireplica method is here proposed for the fabrication of metallic membranes reproducing the ordering of precursor nanoporous alumina membranes. Densely packed arrays of Ni nanoholes with long range ordering of hexagonal symmetry have been prepared. The study includes the magnetic properties of Ni nanohole arrays and those for a continuous Ni film. The magnetization process has been studied by analysis of in-plane and perpendicular hysteresis loops. In addition, combined magnetic force microscopy and atomic force microscopy have allowed us to observe triangular-shaped magnetic domains related to that hexagonal symmetry. An effective in-plane magnetic anisotropy is deduced that determines an in-plane magnetization process by wall displacement which is hindered by the nanoholes in the case of noncontinuous films