Effect of oxygen incorporation on microstructure and media performance in CoCrPt-SiO2 perpendicular recording media

The effect of oxygen incorporation on microstructure and media performance in CoCrPt-SiO2 films with various oxygen contents (OC) from 3 to 10 at% at different CoCrPt-SiO2 film thicknesses (t(MAG)) from 2 to 27 nm is investigated. Nonuniform microstructure with less grain isolation close to Ru and more grain isolation at the top region is clearly seen. Higher density of stacking faults is found at the top region. A higher OC is needed to reduce the thickness of the initial layer with less grain isolation. The increase in coercivity and saturation magnetization with increasing OC is due to the formation of lower Cr and higher Pt-containing core grains caused by the preferred oxidation of Cr. These excess Pt atoms mostly align along the c-axis direction. The magnetocrystalline anisotropy constant enhanced by the excess Pt improves thermal stability factor but it is sensitive to temperature. Crystallographic c-axis orientation and magnetic anisotropy dispersion deteriorate with increasing OC but are independent of t(MAG).