Patent ID: 8481182

Claim:
A magnetic recording medium used for thermally assisted magnetic recording system provided with a substrate configured by glass, a heat radiation layer provided on said substrate, a heat retention layer provided on said heat radiation layer, and a recording layer provided on said heat retention layer via an intermediate layer; and said heat retention layer configured by a member having an effective refractive index lower than the effective refractive index of said recording layer and having a temperature diffusion coefficient determined by a specific heat, density, and heat conductivity rate higher than glass and lower than a metal, and wherein a temperature diffusion coefficient of the member configuring said heat retention layer is made higher than glass and lower than a metal using a temperature diffusion coefficient changing means for changing a ratio of materials configuring this heat retention layer or a density of the same; and as the material of the member configuring said heat retention layer, a nonmagnetic material with a refractive index of n<1 at the wavelength of a laser beam is used and, as said temperature diffusion coefficient changing means, a porous structure able to change the density is used.