Patent ID: 8592061

Claim:
A magnetic recording medium comprising a substrate and a perpendicular magnetic recording layer formed over said substrate, wherein in said magnetic recording medium: said perpendicular magnetic recording layer comprises a magnetic layer containing magnetic grains and a nonmagnetic substance surrounding said magnetic grains in a section parallel to a main surface of said substrate, said magnetic layer is configured such that when, in said section, a ratio between a long diameter and a short diameter of each of said magnetic grains contained in said magnetic layer is calculated to derive a histogram of said ratios, a half width at half maximum of said histogram is 0.1 to 0.6, a variance of grain diameters of said magnetic grains in said section is 5 to 20% of an average grain diameter of said magnetic grains, and said nonmagnetic substance has a density of 4.0 g/cm 3 or more.