Magnetic antidot to dot crossover in Co and Py nanopatterned thin films

Abstract

The crossover from antidot to dot magnetic behavior on arrays patterned in a ferromagnetic thin film has been achieved by modifying only the geometry. A series of antidot arrays has been fabricated on cobalt with fixed diameter $d$ and by reducing the period of the array $p$ from $p\ensuremath{\gg}\phantom{\rule{4pt}{0ex}}d$ to $p<d$. A dramatic change in the coercivity dependence with $p$, correlated with a significant modification in the magnetic domain structure observed by x-ray photoemission electron microscopy, evidences the crossover. An intermediate regime has been found between the superdomain structure present in antidot arrays and the array of astroid-state noncorrelated dots. The study has been reproduced for a different ferromagnetic material, permalloy, and supported by micromagnetic simulations.