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, M _s, 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, H_k. Simultaneously, however, for the low-cobalt-content region with high Ni content, the codeposition of rhenium increases H_k while decreasing M_s, making it possible to prepare perpendicular anisotropicallymagnetic films. Therefore, in the electroless plating method, lower M_s conditions with high Ni content is advantageous for making perpendicular anisotropically magnetic films.