CORRELATION BETWEEN MAGNETIC PROPERTIES AND COMPOSITION OF ELECTROLESS-PLATED COBALT ALLOY FILMS FOR PERPENDICULAR MAGNETIC RECORDING MEDIA.

The magnetic properties of a perpendicular magnetic anisotropy film prepared by an electroless plating method was investigated, from viewpoints of film composition. The value of saturation magnetization, Ms, of the film decreases (9.4 emu cm-3, 30.8 emu cm-3 and 27.0 emu cm-3) by one atomic percentage codeposition of nickel, rhenium and phosphorus, respectively. The codepositions of nickel and phosphorus decrease the value of the perpendicular anisotropically magnetic field, Hk. Simultaneously, however, for the low-cobalt-content region with high Ni content, the codeposition of rhenium increases Hk while decreasing Ms, making it possible to prepare perpendicular anisotropicallymagnetic films. Therefore, in the electroless plating method, lower Ms conditions with high Ni content is advantageous for making perpendicular anisotropically magnetic films.