Magnetic Properties of Antidot Patterned Co/Pd Multilayer Film

Co/Pd multilayer media with an antidot structure have been fabricated on hole-patterned Si substrates. Si nanoholes were created by dry etching using a self-assembled diblock copolymer (DBCP) pattern as an etch mask. To enhance dry etching selectivity, thin Cr film was vacuum deposited on DBCP surface at an oblique incident angle. In comparison with the Co/Pd multilayer on a flat Si substrate, the magnetic hysteresis loop of the antidot structured Co/Pd multilayer revealed an enhanced coercive force largely independent of the amount of reactive etching time, while the shape of hysteresis loop was substantially altered as a function of dry etching time. In an optimized condition, high perpendicular magnetic anisotropy was obtained while no significant parallel magnetic anisotropy was seen, which is desirable for perpendicular recording media or pseudobit-patterned media application.