Co-P electrodeposited alumite films with in-plane magnetization

The magnetic properties and corrosion resistance of a magnetic alumite film, in which micropores are filled with Co, are investigated. It is found that in-plane magnetizatlon film is obtained by adding a small amount of P to the Co. For example, the effective anisotropy energy of the film changes from +0.44×10⁵ erg/cm³ to -1.32×10⁵ erg/cm³ by the addition of 8 at.% P. The in-plane coercivity of the film can be controlled between 340 Oe and 1350 Oe by the P content. The corrosion resistance of the film filled with Co₉₄P₆ under the atmosphere of 40°C, 90% R. H. with 10 ppm SO₂ gas is tested. The corrosion resistance of the film under this condition is superior to that of sputtered Co-Ni thin film media with a carbon protective layer. Magnetic alumite film filled with Co-P alloy is considered to be a candidate for longitudinal magnetic recording media.