DEVELOPMENT OF ELECTROLESS PLATED MAGNETIC MEDIA FOR PERPENDICULAR RECORDING.

Cobalt alloy films for perpendicular magnetic recording media were developed and their recording characteristics were evaluated by using eight-inch disks with Winchester ring head. The following results were obtained: 1) The hcp structure of Co alloy was oriented normal to the film plane with the Mn codeposition into the films. 2) Nickel codeposition caused a decrease in Ms, and further Re codeposition made it possible to produce perpendicular magnetic anisotropy films because of effective Ms decrease. 3) Eight-inch perpendicular recording disks using Co-Ni-Re-Mn-P alloy were prepared from an ammoniacal malonate-tartrate-succinate mixed complex agents bath with high qualified magnetic uniformity. 4) Recording performance using Winchester heads under practical usable conditions gave excellent results, such as D//5//0 equals 51 kFRPI with favorable overwrite and SNR under the condition of 0. 50 mu thick medium, 0. 33 mu m gap length head and 0. 20 mu m head-medium spacing.