Patent ID: 8697261
Filing Date: 2014-04-15
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium comprising: a substrate, a non-magnetic granular layer formed on said substrate with a thickness in a range of 0.5 nm to 1.6 nm and having a granular structure in which a grain boundary part including one or a plurality of oxides is formed between non-magnetic grains each continuously grown in a columnar shape; and a magnetic recording layer formed continuously with the non-magnetic granular layer and having a granular structure in which a grain boundary part including one or a plurality of oxides is formed between magnetic grains continuously grown in a columnar shape in this order, wherein at least one oxide included in the grain boundary part of the non-magnetic granular layer and at least one oxide included in the grain boundary part of the magnetic recording layer are oxides of a same composition, wherein the magnetic recording layer includes a first magnetic recording layer formed continuously with the non-magnetic granular layer with a thickness in a range of 1.5 nm to 5.0 nm and having a granular structure in which a grain boundary part including a plurality of oxides is formed between magnetic grains continuously grown in a columnar shape, and a second magnetic recording layer formed continuously with the first magnetic recording layer with a thickness in a range of 10.0 nm to 12.0 nm and having a granular structure in which a grain boundary part including one or a plurality of oxides is formed between magnetic grains continuously grown in a columnar shape, wherein the compositions of the first magnetic recording layer and the second magnetic recording layer differ as to the chemical elements constituting the first magnetic layer and the second magnetic layer, and wherein at least one oxide included in the grain boundary part of the first magnetic recording layer and at least one oxide included in the grain boundary part of the second magnetic recording layer are oxides of a same composition.