Perpendicular magnetic recording medium with grain boundary controlling layers

Abstract

In one embodiment, a perpendicular magnetic recording medium includes an oxide recording layer including an oxide and a non-oxide recording layer which does not contain an oxide positioned above the oxide recording layer. The oxide recording layer includes a region Rwhere a grain boundary width in a direction parallel to a plane of formation of Rincreases therealong from a lowermost portion of the oxide recording layer toward a medium surface, a region Rpositioned above Rwherein a grain boundary width increases therealong toward the medium surface, a region Rwhere a grain boundary width of Rdecreases therealong from Rto R, with Rbeing positioned between Rand R, and a region Rwhere a grain boundary width of Rdecreases therealong from Rtoward the medium surface, with Rbeing positioned above Rand near an uppermost portion of the oxide recording layer.