Patent ID: 9472227
Filing Date: 2016-10-18
CPC Classification: G11B

Claim Text:
1. A perpendicular magnetic recording medium comprising: a base plate, and a laminate film including a first ground layer provided on the base plate, a second ground layer provided on the first ground layer, and a magnetic layer provided on the second ground layer and containing a magnetic material having a granular structure, wherein the magnetic layer contains a CoCrPt alloy, and the second ground layer consists of Ru-xCo wherein the first ground layer consists of Ru and is thicker than the second ground layer, wherein a film thickness of the second ground layer is 8 nm-15nm, wherein a total film thickness of the first and second ground layers is 11 nm-40 nm, and wherein the first ground layer is formed under a first gas pressure, the second ground layer is formed under a second gas pressure, and the second gas pressure is higher than the first gas pressure.