Low-temperature fabrication of Co ferrite thin films with high coercivity for perpendicular recording disks by wet process

Perpendicular anisotropic CoxFe3-xO4 films of thickness 25-200 nm for perpe ndicular magnetic recording media were successfully obtained by the spin-sp ray ferrite-plating method at 90 degrees C. The maximum perpendicular coerc ivity H-c perpendicular to of the films was found to be around x = 0.5, and the value of H-c perpendicular to was over 2000 Oe even for a film thickne ss of 25 nm. By optimizing the concentration of NaNO2 in the oxidizing solu tion, the in-plane coercivity H-c parallel to was reduced to 300 Oe, while H-c perpendicular to was kept at over 2000 Oe. Mossbauer analyses also show that the films have excellent perpendicular magnetic anisotropy. The angul ar dependence of the coercivity shows that a reversal of the magnetization takes place by rotation as in Co-Cr sputter-deposited films. (C) 1999 Elsev ier Science B.V. All rights reserved.