Co-based alloy media with a high coercivity prepared by heat treatment after sputtering

The effects of heat treatment on magnetic properties of Co-based alloy thin-film media using newly developed carbon substrates is discussed. High coercivity (Hc) can be obtained by heat treatment after sputtering using a Zr thin-film as a protective layer. In the case of Zr/Co/sub 62.5/Ni/sub 30/Cr/Cr thin-film media, Hc of 3500 Oe was obtained after heat treatment at 650 degrees C for one minute. No significant change was found in the grain size after heat treatment. From the results of a compositional analysis using X-ray energy dispersive spectroscopy (EDS) in high resolution scanning transmission electron microscopy (HRSTEM), it was found that Cr was segregated from the Cr underlayer to the grain boundary of the Co-based alloy with increasing heat treatment temperature. >