Abstract
Various ways of recording magnetic media for high-density recording were investigated. The main characteristics required of a medium are low noise and high coercivity. We made a low-noise medium by simultaneous sputtering SiO2 and CoPt onto a Cr underlayer at high Ar pressure and room temperature, and attempted to raise the coercivity of the medium. It has hitherto been recognized that a CoPt-SiO2 medium is not influenced by a Cr underlayer. However, we showed that the extent of the influence of the Cr underlayer changed according to the quantity of SiO2. Our medium contained 10 at% of SiO2. Recognizing that the effect of the Cr underlayer influenced the magnetic layer, we added Mo to the Cr underlayer, and were able to increase the coercivity by adjusting the crystal with CoPt and the Cr underlayer and by increasing the lattice spacing of the Cr. The medium noise was also reduced by adjustment in crystal with CoPt and Cr underlayer, and, as a result, the S/N ratio was improved at 150 kfci.
