Journal of Vacuum Science & Technology A, Vol.27, No.4, 1062-1066, 2009
Preparation and properties of perpendicular CoPt magnetic nanodot arrays patterned by nanosphere lithography
Perpendicular anisotropy Co80Pt20 films were patterned into nanopillars of 40-90 nm using nanosphere lithography. A monolayer of polystyrene spheres was coated onto the sputtered films and size tailored by reactive ion etching in oxygen. These reduced spheres were used as masks for ion milling of the magnetic films. Increased coercivity and squareness resulted in decreasing nanopillar size. A significant increase in intrinsic coercivity was demonstrated with the decrease in pillar size. The reversal mechanism appears similar to reported results of nucleation of a small reversed volume followed by rapid domain wall motion.
Keywords:cobalt alloys;coercive force;magnetic anisotropy;magnetic domain walls;magnetic thin films;magnetisation reversal;monolayers;nanolithography;nanopatterning;nanostructured materials;nanotechnology;nucleation;platinum alloys;sputter etching