Thickness and oxidation dependence of magnetic properties of ultrathin obliquely evaporated Co-CoO media

Magnetic properties of ultrathin obliquely evaporated Co-CoO media particularly targeted for a helical scanning tape system using high-sensitivity giant magnetoresistive heads were investigated. By introducing oxygen, decoupling of magnetostatic interaction between ferromagnetic particles led to a maximum value of coercivity at a certain oxygen amount. Coercivity was also sharply deteriorated by decreasing the magnetic layer thickness. Analysis of magnetic torque measurement revealed that obliquely evaporated Co-CoO media has an initial growth layer with a thickness of 10.2 nm. Application of a SiO/sub 2/ underlayer is effective in preventing the deterioration of coercivity for thin magnetic media design.