Co-Pt-TiO2 composite film for perpendicular magnetic recording medium

A new type of oxide composite film was proposed as perpendicular magnetic recording medium. The storage layer is composed of Co-Pt and Ti-oxide. By transmission electron microscopy (TEM) observation, the film exhibited a well isolated fine granular structure with small and uniform Co-Pt grains surrounded by TiO₂. More sufficient segregation by TiO₂ was realized from the beginning of the layer growth compared with other oxide addition film, resulting in a magnetically weak coupled structure. This film has a relatively large magnetic anisotropy constant (K_u) and saturation magnetization (M_s) of more than 5×10⁶ erg/cm³ and about 800 emu/cm³, respectively. The structure was brought about by a high sputtering gas pressure of Co-Pt-TiO₂ film deposition.