Ru/Ru-oxide interlayer for CoCrPtO perpendicular recording media

A Ru/Ru-oxide interlayer combination on a Ta seedlayer was introduced in order to realize further intergranular exchange decoupling in the magnetic layer by forming Ru grains with small size and uniform distribution separated by a non-magnetic oxide phase. Higher coercivity and signal to noise ratio (SNR) were achieved with a thin Ru-oxide layer. TEM shows that both the magnetic layer and Ru/Ru-oxide interlayer have a well-defined columnar structure. It was also observed that good hetero-epitaxial relationship is maintained throughout the Ru/Ru-oxide and Ru-oxide/magnetic layer interfaces. Ru grains were also observed to be well-isolated and uniformly distributed at the top portion of the Ru/Ru-oxide interlayer . Intergranular decoupling in the magnetic layer can be realized by forming the magnetic grains on the well-isolated Ru grains without disturbing the epitaxial relationship between the magnetic layer and the interlayer.