Co-Cr films for perpendicular recording

Co-Cr films were prepared by means of RF-sputtering. The dependence of the magnetic parameters on the sputter conditions was investigated. It was found that for increasing Ar-pressure the c-axis of the hcp-structure gradually declines from normal to in-plane orientation. An optimum for the sputter voltage is found. The coercivity increases with decreasing target-substrate distance and this is probably due to surface heating by electron bombardment from the Ar-plasma. The recording characteristics of these Co-Cr films were then investigated by means of stand-still recording experiments. A 6.7 mm thick permalloy single-pole head (SPH) was used for creating a head print in a 1 mm thick Co-Cr layer. The flux reversals are detected by means of a magneto-resistive transducer (MRT). The response was analyzed, using a analytical method for calculating the magnetization distribution in the Co-Cr layer. For this purpose the head field of the SPH was also determined with the same MRT.