Self-epitaxial Co-Cr media: Preferable for fabrication by roll coater sputtering system

A roll coater system was investigated for establishment of a mass production system for Co-Cr perpendicular magnetic recording media. Improvements of the crystal orientation and the magnetic properties of Co-Cr films with new seed layers of Co-Cr itself are first described. In the light of these results, a Co-Cr film with a composition gradient in the growing direction but without any seed layer is proposed and its properties are discussed. It is found that the anisotropy field Hk can be remarkably increased for the film with a composition gradient over that of films with uniform composition. It is concluded that the newly developed Co-Cr film is very suitable for mass production by a roll coater because of its simplified process which requires no sputtering of any seed layers.