Spin-spray ferrite-plated Co ferrite films with high coercivity for perpendicular magnetic recording media

Effects of plating conditions on Co ferrite-plated films for perpendicular magnetic recording media were investigated to increase coercivity H-c perpe ndicular to and remanence ratio (M-r/M-S)(perpendicular to), in the plane p erpendicular to the film. By optimizing a concentration of NaNO2 in an oxid izing solution and the deposition rate, Co-Ni ferrite films with H-c perpen dicular to of 3200 Oe and (M-r/M-s)(perpendicular to) of 0.6 were obtained without any heat-treatment. Disk media with higher H-c<^> and (M-r/M-s)<^> exhibited reproduced waveforms of di-pluses shape and better frequency resp onses than that with lower H-c<^> and (M-r/M-s)(<^>). Media noise did not i ncrease with increasing frequency, suggesting that the transition noise was low.