Magnetic recording medium exhibiting low noise and high coercive force

A magnetic recording medium, comprising:

• a substrate;
• a nonmagnetic underlayer;
• a magnetic layer;
• a protective layer;
• 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 underlayer has a body-centered cubic lattice structure, and
• the nonmagnetic underlayer, the magnetic layer, the protective layer, and the lubricant film are sequentially laminated on the substrate,
• a nonmagnetic intermediate layer with a hexagonal closed packed structure disposed between the magnetic layer and the underlayer, the nonmagnetic intermediate layer being a nonmagnetic metal comprising Ru, Os, and/or Re,
• a degree of mismatching Δ=|d1−d2|/d1 is at most 10%, where d1 is a spacing of lattice planes of crystal grains in the magnetic layer and d2 is a spacing of lattice planes of crystal grains in the nonmagnetic intermediate layer, and
• 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.

A magnetic recording medium, comprising:

• a substrate;
• a nonmagnetic underlayer having a body-centered cubic lattice structure;
• a nonmagnetic intermediate layer having a hexagonal closed packed structure;
• a magnetic layer having a granular structure including ferromagnetic crystal grains with a hexagonal closed packed structure and a nonmagnetic grain boundary region of an oxide intervening between the ferromagnetic crystal grains;
• a protective layer;
• and
• a lubricant film,
• wherein the nonmagnetic underlayer, the nonmagnetic intermediate layer, the magnetic layer, the protective layer, and the lubricant film are contiguous and respectively sequentially laminated on the substrate,
• the nonmagnetic intermediate layer is a nonmagnetic metal comprising Ru, Os, and/or Re,
• a degree of mismatching Δ=|d1−d2|/d1 is at most 10%, where d1 is a spacing of lattice planes of crystal grains in the magnetic layer and d2 is a spacing of lattice planes of crystal grains in the nonmagnetic intermediate layer, and
• 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.

A magnetic recording medium, comprising:

• a nonmagnetic underlayer having a body-centered cubic lattice structure;
• a nonmagnetic intermediate layer;
• and
• a magnetic layer having a granular structure including ferromagnetic crystal grains with a hexagonal closed packed structure and a nonmagnetic grain boundary region of an oxide intervening between the ferromagnetic crystal grains,
• wherein the nonmagnetic layer underlayer, the nonmagnetic intermediate layer, and the magnetic layer are positioned sequentially,
• the nonmagnetic intermediate layer is a nonmagnetic metal comprising Ru, Os, and/or Re, wherein a degree of mismatching Δ=|d1−d2|/d1 is at most 10%, where d1 is a spacing of lattice planes of crystal grains in the magnetic layer and d2 is a spacing of lattice planes of crystal grains in the nonmagnetic intermediate layer, and
• 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.