Effect of oxygen on magnetic properties of Co-Pt-Cr-SiO2 thin films for perpendicular recording media

The effect of oxygen on magnetic properties of Co-Pt-Cr-SiO2 films deposited with various sputtering conditions of Ar gas pressure and deposition speed was investigated. It was suggested that optimum oxygen composition in the film for obtaining large Hc was to have the oxygen/silicon ratio of 2 in Co-Pt-Cr-Si-O films. No X-ray photoelectron spectroscopy spectrum of Co-O or Cr-O was observed in this film, while the Si spectrum shifted to higher energy indicating Si-O bonding. The film exhibited a well-isolated fine grain structure, and the oxygen/silicon ratio was almost constant throughout the depth. It is suggested that the granular structure with SiO2 grain boundaries is formed from the initial deposition stage.