Highly oriented perpendicular magnetic recording media

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 hexagonal close-packed (hcp) perpendicular magnetic recording material formed thereon;
• and
• (iii) an hcp magnetically hard perpendicular main recording layer;
• wherein said interlayer structure comprises, in overlying sequence from a surface of said magnetically soft underlayer:
• (1) a first crystalline layer of a material having a first lattice parameter and a strong preferred growth orientation;
• (2) a second crystalline layer of a material having a second lattice parameter and the same strong preferred growth orientation as said first crystalline layer;
• and
• (3) a third crystalline layer of an hcp material, having a [0002] lattice parameter similar to or different from that of said second lattice parameter of said second crystalline layer and a strong <0002> preferred growth orientation;
• and
• said second crystalline layer has a lower interfacial energy with said first crystalline layer and a higher interfacial energy with said third crystalline layer, owing to a lower surface energy of said first crystalline layer and a higher surface energy of said second crystalline layer, and said second crystalline layer has a melting temperature (Tm) not less than about 2,100° C.

A layer structure for crystallographically orienting a layer of a hexagonal close-packed (hcp) material formed thereon, comprising, in overlying sequence:

• (a) a first crystalline layer of a material having a first lattice parameter and a strong preferred growth orientation;
• (b) a second crystalline layer of a material having a second lattice parameter and the same strong preferred growth orientation as said first crystalline layer;
• and
• (c) a third crystalline layer of a hcp material having a lattice parameter similar to or different from said second lattice parameter of said second crystalline layer and a strong preferred growth orientation;
• wherein said second crystalline layer has a lower interfacial energy with said first crystalline layer and a higher interfacial energy with said third crystalline layer, owing to a lower surface energy of said first crystalline layer and a higher surface energy of said second crystalline layer,
• said second crystalline layer comprises an hcp material,
• said third crystalline layer comprises a different hcp material, and
• said second crystalline layer comprises at least one material selected from the group consisting of:
• Ru, Re, Ir, Os, Co, Pt, Hf, Th, Gd, Mo, Nb, Ta, W, and alloys thereof.