CoPtCr-Sio2 granular media for high-density perpendicular recording

SiO2 added CoPtCr magnetic layer is employed for the perpendicular recording media. The microstructure, magnetic properties, and recording performance of these media are discussed. Very fine grains with size of less than 7 nm, surrounded by grain boundaries that mainly consisted of silicon oxide, are realized. The addition of SiO2 to CoPtCr is very effective in enhancing the well-isolated fine grain structure without disturbing the epitaxial growth of the CoPtCr grains on the Ru underlayer. The media show a large perpendicular anisotropy K-u of similar to4 x 10(6) erg/cm(3) and a KuV/kT value of more than 80, even at the CoPtCr-SiO2 thickness of 12 nm, resulting in a high coercivity H-c (similar to4 kOe) and high squareness M-r/M-s of similar to0.96. The CoPtCr-SiO2 medium shows excellent signal-to-medium-noise ratio performance together with high thermal stability at very thin thickness, indicating a great potential for high-density perpendicular recording media.