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SiO2 added CoPtCr magnetic layers are employed for 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 mainly consisting 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 Ku of ∼4 × 106 erg/cm3 and a KuV/kT value of more than 80, even at a CoPtCr-SiO2 thickness of 12 nm, resulting in a high coercivity Hc (∼4 kOe) and high squareness Mr/Ms of ∼0.96. The CoPtCr-SiO2 medium shows excellent signal-to-medium-noise ratio performance together with high thermal stability at very thin thickness, indicating great potential for high-density perpendicular recording media.