Structural Control of Electroless‐Plated Magnetic Recording Media by Underlayers

Abstract

The structural control of electroless‐plated film was investigated using underlayers of electroless‐plated and films. The film showed a high degree of orientation of the hcp Co c‐axis normal to the film plane, whereas the film hardly showed any preferred orientation. The film plated onto the underlayer showed a high degree of preferred orientation, while the film plated onto the underlayer showed a low degree of preferred orientation. Thus, the microstructure of the film is clearly influenced by the underlayer structure. In the case of the film onto the underlayer. an epitaxial‐like growth was observed up to a thickness of 0.25 μm, and this reduced to the intrinsic microstructure at a thickness of 0.5 μm. Recording characteristics were measured on the 5 in. flexible disks, fabricated by plating the high‐oriented film or the low‐oriented film with a ringtype head of a commercial VHS video head. Perpendicular recording was performed on the high‐oriented film to demonstrate the best characteristics. The use of an oriented underlayer is thus confirmed to be a useful method of controlling the structure of the magnetic film in addition to controlling the bath plating parameters.