Perpendicular magnetic recording medium and magnetic recording and reproducing apparatus

Abstract

The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate, wherein the magnetic recording layer is constituted of two or more layers and includes a first magnetic recording layer and a second magnetic recording layer from the nonmagnetic substrate side and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher and the second magnetic recording layer has 2×106 erg/cc or lower, wherein the first magnetic recording layer is constituted of CoCrPtRu magnetic alloy crystal grains and grain boundaries made of an oxide and the area of grain boundaries is 30% or more based on the entire area in a planar TEM observation of the first magnetic recording layer. The present invention also relates to a magnetic recording and reproducing apparatus using the perpendicular magnetic recording medium.

Dependencies are inferred from the claim text.