Patent ID: 8440332

Claim:
A perpendicular magnetic recording medium comprising: a substrate having thereon at least a soft magnetic layer, a nonmagnetic intermediate layer, a perpendicular recording layer and a protective layer formed in that order, wherein the perpendicular recording layer consists of three or more layers of a first recording layer, a second recording layer and a third recording layer from the side nearer to the substrate; wherein the first recording layer and the second recording layer have a granular structure comprising a grain boundary of an oxide surrounding ferromagnetic crystal grains containing Co and Pt, and the third recording layer has a non-granular structure mainly comprising Co and not containing an oxide; wherein the grain boundary of the first recording layer contains Si, Cr and oxygen, and at least one element selected from Ti, Ta and Nb, and the grain boundary of the second recording layer contains Cr and oxygen and at least one element selected from W and V, wherein the first recording layer has a different composition than said second recording layer.