Patent ID: 8021770
Filing Date: 2011-09-20
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium comprising: a substrate; a soft magnetic material section disposed on the substrate, the soft magnetic material section comprising a plurality of distinct layers each of soft magnetic material; an intermediate section comprising crystalline material disposed on the soft magnetic material section; and a recording section comprising a crystalline layer of magnetic material disposed on the intermediate section, wherein the intermediate section comprises a layer of material predisposed to control a crystallizing of the material of the recording section when the recording section is formed on the intermediate section, and of the plurality of layers of soft magnetic material, an uppermost one of the layers closest to the intermediate section is predisposed to impart a desired crystalline structure to material of the intermediate section when the intermediate section is formed on the soft magnetic material section, wherein the soft magnetic material section includes of a lowermost layer of soft magnetic material and an uppermost portion comprising at least one unit layer of soft magnetic material, of all of the layers of soft magnetic material of the medium, the lowermost layer of soft magnetic material is disposed closest to the substrate, and the lowermost layer of soft magnetic material generates an anisotropic magnetic field that is weaker than that generated by the uppermost portion of the soft magnetic material section, and wherein the uppermost portion of the soft magnetic material section comprises: a plurality of unit layers each of soft magnetic material, and spacers interposed between adjacent ones of the unit layers of soft magnetic layer material, and adjacent ones of the unit layers of soft magnetic material have a Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling structure, whereby the adjacent ones of the unit layers are magnetically coupled.