CoPt Antidot Arrays Fabricated with Dry-Etching Using AAO Templates

We demonstrate a technique to fabricate large-area, highly ordered CoPt antidot arrays with perpendicular orientation. Using ultrathin anodic aluminum oxide (AAO) templates as a dry etching mask, the pattern of the pore array was transferred to the film without deteriorating the magnetic properties, in particular coercivity and preferential perpendicular orientation. The size, spacing, and density of the nonmagnetic nano-columns within the CoPt antidot arrays can be adjusted by changing the fabrication parameters of the AAO templates. The nano-columns can serve as pinning sites, impeding the magnetic domain wall motion, which can influence the magnetic properties of the film. The magnetic properties of the antidot arrays depend sensitively on the antidot morphology. The coercivity (H_c) of the CoPt antidot array with a pore density of 2.6 × 10¹¹ in ^-2 fabricated using the AAO template anodized at 20 V is increased from 9.2 to 12.5 kOe due to the existence of such pinning sites.