Distribution of coercivity and anisotropy through thickness direction in sputtered Co-Cr films and its relationship to noise characteristics in perpendicular magnetic recording

The relationship between c-axis orientation of crystallites and distribution of the perpendicular coercivity H/sub c/spl perp// in Co-Cr films has been investigated through the evaluation of the H/sub c/spl perp// of surface layer H/sub c/spl perp//(s) measured by a Kerr hysteresis loop tracer. Better c-axis orientation, higher Cr content and addition of Ta seemed to be essential requirements to get higher H/sub c/spl perp// of initial growth layer H/sub c/spl perp//(i) and good uniformity of H/sub c/spl perp// through the thickness direction. Lower /spl Delta/H/sub c/ and relatively high H/sub c/spl perp//(i) caused better recording characteristics and lower media noise level.