Patent ID: 8628866
Filing Date: 2014-01-14
Classification: G11B

Abstract:
1. A magnetic recording medium, comprising at least a non-magnetic substrate on which is laminated a soft magnetic underlayer formed by antiferromagnetic coupling of a plurality of soft magnetic layers, and a perpendicular magnetic layer for which an axis of easy magnetization is oriented mainly perpendicularly to the non-magnetic substrate, wherein the soft magnetic layers comprise Fe as a first main component, Co as a second main component, and also comprise Ta, in which the soft magnetic layer nearest to the perpendicular magnetic layer is obtainable by depositing by sputtering while applying a negative bias within a range from −150 to −400 V to the non-magnetic substrate, and the soft magnetic underlayer is antiferromagnetically coupled using a second peak or a subsequently appearing peak of an antiferromagnetic coupling force, which changes according to a thickness of a spacer layer sandwiched between the plurality of soft magnetic layers, and a magnetic permeability of the soft magnetic underlayer is not less than 1,000 H/m.