Patent ID: 8828566
Filing Date: 2014-09-09
Classification: G11B

Abstract:
1. A perpendicular magnetic disk comprising, on a base, a granular magnetic layer and an auxiliary recording layer disposed above the granular magnetic layer, the granular magnetic layer having a granular structure in which a non-magnetic substance having an oxide as a main component is segregated around magnetic particles having a CoCrPt alloy as a main ingredient growing in a columnar shape to form a grain boundary part, and the auxiliary recording layer having a CoCrPtRu alloy as a main component and further containing, as an accessory component, a metal forming passivity and not being an antiferromagnet, wherein the accessory component is any one or more elements selected from the group of Al and Ti, and a content of the accessory component is equal to or larger than 1 atomic percent and equal to or smaller than 3 atomic percent, and wherein the auxiliary recording layer has a thickness of 1.5 nm to 4.0 nm.