Influence of oxide on the structural and magnetic properties of CoPt alloy

Perpendicular recording media consisting of isolated CoPt magnetic grains separated with a nonmagnetic oxide grain boundary can be prepared by sputtering a Ru interlayer and then cosputtering CoPt with an oxide material, with low adatom mobility. The oxide material moves into the grain boundaries and isolates the magnetic grains. An increase in the oxide volume fraction in the magnetic layer does not affect the saturation magnetization but significantly reduces the magnetocrystalline anisotropy of magnetic grains. This may impose a limit on the areal density capability of this media design since media with smaller grains will require a larger oxide volume fraction that will reduce magnetocrystalline anisotropy of the CoPt based magnetic grains. (C) 2006 American Institute of Physics.