Grain size reduction for perpendicular magnetic recording media using an Ar-ion etched Ru seedlayer

We report an approach to reduce grain size for perpendicular media by using an Ar-ion etched Ru seedlayer. The surface etching affects the microstructure of the subsequent high pressure deposited Ru2+SiO₂ interlayer and magnetic layer, whose grain size can be controlled. SiO₂ in the interlayer plays a more important role in grain size reduction on the etched seedlayer than the as-grown seedlayer. Small Ru2 grains ∼3.9 nm and magnetic grains ∼5.3 nm with uniform distribution have been obtained. Thinner Ru grain boundaries with reduced size could be the cause of nonideal one-to-one grain growth and degraded magnetic properties.