Patent ID: 7247395
Filing Date: 2007-07-24
Classification: G11B

Abstract:
1. A magnetic recording medium, comprising: a substrate; a nonmagnetic underlayer; a nonmagnetic intermediate layer; a magnetic layer; a protective layer; and a lubricant film, wherein the magnetic layer has a granular structure comprising ferromagnetic crystal grains with a hexagonal closed packed structure and a nonmagnetic grain boundary region of an oxide intervening between the ferromagnetic crystal grains, the nonmagnetic underlayer has a body-centered cubic lattice structure, the nonmagnetic underlayer, the nonmagnetic intermediate layer, the magnetic layer, the protective layer, and the lubricant film are sequentially laminated on the substrate, the nonmagnetic intermediate layer is a nonmagnetic metal comprising Ru, Os, and/or Re, a degree of mismatching Δ=|d a proportion of the crystal grains in the nonmagnetic intermediate layer with respect to a grain size of equal to or greater than 8 nm is at most 10% of the crystal grains in the nonmagnetic intermediate layer and a standard deviation of said grain size is at most 1.4 nm.