Patent ID: 8603650
Filing Date: 2013-12-10
Classification: B82Y,G11B,H01F

Abstract:
1. A perpendicular magnetic recording disk for use in perpendicular magnetic recording, said perpendicular magnetic recording disk characterized by comprising a substrate, a soft magnetic layer of a material selected from a group consisting of an Fe-based material and a Co-based material on said substrate, and a magnetic recording layer on said soft magnetic layer, wherein said magnetic recording layer comprises a ferromagnetic layer on said soft magnetic layer, having a granular structure, and comprising crystal grains mainly made of cobalt (Co) and grain boundary portions mainly made of SiO 2 , a spacer layer selected from a group consisting of a Pd layer and a Pt layer on said ferromagnetic layer, and a layer, on said spacer layer, having no granular structure and comprising alternating films of Co or an alloy thereof and Pd or alternating films of Co or an alloy thereof and Pt, the content of the SiO 2 in said ferromagnetic layer being 8 at% to 15 at%, said perpendicular magnetic recording disk comprising, on said substrate, said soft magnetic layer, said ferromagnetic layer having the granular structure, said spacer layer, and said layer having no granular structure in this order; wherein the layer having no granular structure comprises at least two films of Co or an alloy thereof and at least two films of Pd or Pt.