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/sub c/spl perp// and remanence ratio (M/sub r//M/sub s/)/sub /spl perp// in the plane perpendicular to the film. By optimizing a concentration of NaNO/sub 2/ in an oxidizing solution and the deposition rate, Co-Ni ferrite films with H/sub c/spl perp// of 3200 Oe and (M/sub r//M/sub s/)/sub /spl perp// of 0.6 were obtained without any heat-treatment. Disk media with higher H/sub c/spl perp// and (M/sub r//M/sub s/)/sub /spl perp//, exhibited reproduced waveforms of di-pluses shape and better frequency responses than that with lower /sub c/spl perp// and (M/sub r//M/sub s/)/sub /spl perp//. Media noise did not increase with increasing frequency, suggesting that the transition noise was low.