Fabrication and magnetic properties of hexagonal arrays of NiFe elongated nanomagnets

Large area (∼cm2)(∼cm2) periodic arrays of 20 nm-thick NiFe nanomagnets have been fabricated using templates with undercut side-walls created by interference lithography (IL) and liftoff processing. Hexagonal arrays of 195×690nm2 and 190×320nm2 nanomagnets were investigated using both spatially resolved magneto-optical Kerr effect (MOKE) and alternating gradient magnetometry (AGM). The in-plane magnetization reversal is dominated by shape anisotropy and elements in both arrays reverse between single-domain states via incoherent rotation, either through a single switch or a series of switching events. These results are attributed to an increase in the magnetostatic interactions, which generates locally correlated magnetic configurations through the reversal of the array.