Abstract
Antidot arrays with perpendicular anisotropy have been fabricated by depositing Co/Pt multilayers on the anodic aluminum oxide (AAO) templates prepared on Si wafers. The antidot arrays cover an area of about 10 cm2. The antidot size (D) and edge-to-edge (w) separation between two adjacent antidots are varied over a wide range from 7 to 46 nm and 14 to 53 nm, respectively. The magnetic properties and magnetization process exhibit strong dependence on the antidot size and separation. The perpendicular coercivity (Hc) increases from 140 Oe (continuous film) with the increase in D and shows a peak at about 1350 Oe for the D of around 30 nm. The Hc starts to decrease for the further increase in D due to the deteriorated perpendicular anisotropy. The magnetization reversal of the antidot arrays with D of 30 nm or less is governed by the strong domain-wall pinning and the switching field shows less sensitivity to the angular variation from the easy axis. The magnetic domain size decreases with increase in D. The evolutions of magnetic properties are ascribed to the pinning effects imposed by the AAO pores. The influence of antidot size on the pinning of domain wall, Hc and magnetization switching characteristics are also investigated by the micromagnetic modeling. © 2010 The American Physical Society.