Patent ID: 7879466

Claim:
A perpendicular recording medium having at least a soft magnetic underlayer a crystalline orientation control layer, and a perpendicular magnetic recording layer on a non-magnetic substrate, wherein the crystalline orientation control layer is a non-magnetic layer and is formed between the soft magnetic underlayer and the perpendicular magnetic recording layer, wherein when Ku⊥ (erg/cm 3 ) is defined as a perpendicular magnetic anisotropic energy and Ms (emu/cm 3 ) is defined as a saturation magnetization of the soft magnetic underlayer, Ku⊥ of the soft magnetic underlayer has a negative value and Ku⊥<−2πMs 2 ; when Ku grain is defined as a crystal magnetic anisotropy energy, the soft magnetic underlayer comprises a material which has a negative Ku grain , and a hard axis of magnetization of the soft magnetic underlayer is perpendicular to a substrate surface plane and the soft magnetic underlayer comprises CoIr alloy as a main component.