Patent ID: 6916530

Claim:
A perpendicular magnetic recording medium, comprising: a substrate; a soft-magnetic layer formed on the substrate; an oxide layer having an NaCl crystalline structure for orientation control formed on the soft-magnetic layer, having a thickness of from more than 0 to less than 10 nm; a magnetic recording layer formed on the oxide layer having an NaCl crystalline structure for orientation control, comprising a maghemite thin film, wherein a product (B s t) of a saturation magnetic flux density (B s ) and a thickness (t) of the soft-magnetic layer is in the range of 1.13 to 13.57×10 −6 Wb/m (80 to 1,100 G·μm), the perpendicular magnetic recording medium having a coercive force in perpendicular direction of not less than 159 kA/m (2,000 Oe); a squareness (M r /M s ) of not less than 0.7 obtained without compensation of demagnetizing field when magnetized in a direction perpendicular to a surface of the magnetic recording layer; an M r ratio (M r // /M r ⊥ ) of a residual magnetization (M r // ) obtained when magnetized in in-plane direction to a residual magnetization (M r ⊥ ) obtained when magnetized in perpendicular direction, of not more than 0.5; and an H c ratio (H c // /H c ⊥ ) of a coercive force (H c // ) obtained when magnetized in in-plane direction to a coercive force (H c ⊥ ) obtained when magnetized in perpendicular direction, of not more than 0.5.