Co-Based Alloy Thin-Film Media on Carbon Substrates

The mechanical and magnetic properties of thin-film media using newly developed carbon substrates, which offer such advantages as light weight, high heat resistance and nonmagnetic properties, were investigated and compared with the properties of thin-film media prepared using conventional NiP/Al substrates. The adhesive strength of a thin-film medium sputtered onto a carbon substrate is higher than that of film sputtered onto a NiP/Al substrate, because of the formation of Cr-C compounds at the interface between the carbon substrate and the Cr underlayer. The coercivity of a thin-film medium sputtered onto a carbon substrate is also higher than that of film on NiP/Al substrate, because of the unique surface morphology. High coercivity can be obtained by using a circumferentially textured substrate and a bias sputtering method.