Chemical stability and microstucture on sputtered CoCr perpendicular media

Chemical stabilities, especially corrosion characteristics for sputtered CoCr perpendicular recording media have been investigated. The corrosions were analyzed by XPS and by measuring electrical resistance increase (ΔR/R
0
) for a CoCr film stripe pattern under exposure to 80°C and 85 % relative humidity. The corrosion rate strongly depended on the CoCr film preparation conditions. The correlation between ΔR/R
0
and test time t was expressed by the equation
\DeltaR/R_{0} = \alpha \log (t + 1)
, where α was a coefficient. In the regions of low sputtering pressure and high power, excellent corrosion resistances were obtained. These corrosion characteristics were attributed to the crystalline microstructures.