Patent ID: 6548194
Filing Date: 2003-04-15
Classification: G11B,Y10S,Y10T

Abstract:
A perpendicular magnetic recording disk, comprising:a nonmagnetic substrate; a cobalt alloy bias layer formed on said nonmagnetic substrate; a soft magnetic layer formed on said cobalt alloy bias layer and containing iron or cobalt; and a perpendicular magnetic recording layer; wherein the direction of residual magnetization of said cobalt alloy bias layer faces one direction of its radial direction, and said perpendicular magnetic recording medium satisfies the relationship given below: MssoftÃ—(tsoftâˆ’40 nm)>MssoftÃ—40 nm+MsbiasÃ—tbias where, tbias denotes the thickness of said cobalt alloy bias layer, Msbias denotes the saturation magnetization of the cobalt alloy bias layer, tsoft denotes the thickness of said soft magnetic layer, which falls within a range of between 40 nm and 200 nm, and Mssoft denotes the saturation magnetization of said soft magnetic layer.