Patent ID: 7799447

Claim:
A perpendicular magnetic recording medium including a soft magnetic layer, a non-magnetic intermediate layer, and a magnetic recording layer disposed on a substrate, said magnetic recording layer having a granular structure in which crystal grains are separated by grain boundary layers, wherein a grain boundary layer in said magnetic recording layer contains a ferromagnetic element, and wherein said crystal grains have a substantially columnar structure and have a magnetic easy axis substantially perpendicular to a substrate surface of said substrate, wherein an adhesion layer comprising an alloy selected from NiTa, NiTaZr, CrTi, CrTiTa, or TiAl, is present between the substrate and the soft magnetic layer, wherein a ratio of the ferromagnetic element in said grain boundary layer is 30 at. % or more and 50 at. % or less in atomic percent with respect to a solid element which constitutes said grain boundary layer.