Patent ID: 7175925

Claim:
A perpendicular magnetic recording medium, comprising: (a) a non-magnetic substrate having a surface; and (b) a layer stack formed over said substrate surface, said layer stack comprising, in overlying sequence from said substrate surface: (i) a magnetically soft underlayer; (ii) an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material formed thereon; and (iii) at least one crystallographically oriented magnetically hard perpendicular recording layer; wherein said interlayer structure comprises, in overlying sequence from a surface of said magnetically soft underlayer: (1) a first crystalline interlayer of a non-magnetic material formed in a gas atmosphere at a first pressure; and (2) a second crystalline interlayer of a non-magnetic material formed in a gas atmosphere at a second pressure greater than said first pressure, each of said first and said second crystalline interlayers comprises a non-magnetic material selected from the group consisting of Ru, RuCr, other Ru-based alloys, CoCrRu, Ti, CoCr, CoCrPt, CoCrTa, and CoCrMo, and wherein said interlayer structure provides said magnetically hard perpendicular magnetic recording layer formed thereon with a hexagonal close-packed crystal lattice with a <0002> out-of-plane growth orientation.