Abstract: A method of manufacturing a magnetic recording medium including: forming a diffusion preventing layer, wherein the magnetic recording medium includes a non-magnetic substrate; an underlayer; a perpendicular magnetic layer; the diffusion preventing layer; and a protective layer, wherein the perpendicular magnetic layer has a multi-layer structure, the perpendicular magnetic layer includes an uppermost layer and at least one layer other than the uppermost layer, the uppermost layer including Co or Fe in magnetic particles, and the at least one layer other than the uppermost layer including an oxide, the diffusion preventing layer is provided between the perpendicular magnetic layer and the protective layer, and the diffusion preventing layer includes at least one component selected from a group consisting of Si, Ti, Cr, B, and Ru, or either a carbide, an oxide, or both, of the at least one component.

Abstract: A dummy substrate is formed with a disk-shaped glass substrate having a center hole, and a magnetic recording film on an outer circumferential surface along a thickness direction of the glass substrate and an inner circumferential surface of the center hole, and a surface roughness (Ra) of one surface and the other surface of the glass substrate is in a range of 0.2 nm or more and 100 nm or less.