Patent ID: 8614862
Filing Date: 2013-12-24
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium, comprising: a ferromagnetic granular layer with perpendicular magnetic anisotropy and having a granular structure, wherein ferromagnetic grains of said granular layer have a columnar shape and a grain boundary between the ferromagnetic grains includes an oxide; and a cap layer above said granular layer, the cap layer being a ferromagnetic continuous layer with perpendicular magnetic anisotropy, wherein, near a first side of said granular layer nearest the cap layer, a grain diameter of the ferromagnetic grains decreases and a width of the grain boundary having the oxide increases toward the first side, wherein surfaces of the ferromagnetic grains of said granular layer facing the cap layer each have a domed shape defining undulations along the first side, wherein indentations in said ferromagnetic grains are filled by the oxide of the grain boundary in a vicinity of the first side of said granular layer, and wherein undulations on a granular layer side of said cap layer are flatter than the undulations of the ferromagnetic grains on the first side of said granular layer.