Patent ID: 8197891

Claim:
A method for manufacturing a perpendicular magnetic recording medium that comprises a magnetic recording layer formed on a nonmagnetic substrate, the magnetic recording layer including a plurality of magnetic crystal grains, the method including a process for forming the magnetic recording layer that comprises: conducting a plurality of film depositions, from a first deposition conducted at an initial stage of the process at a substrate side to a final deposition conducted at a film surface side, and varying concentration of oxygen or nitrogen that is contained in a gas used in the film deposition steps, during each of the plurality of film depositions, wherein the concentration of oxygen or nitrogen increases with progression of the film depositions, wherein the plurality of film depositions while concentration is varied produces a plurality of magnetic crystal grains each having a laminated multilayer structure, in which each layer corresponds to one of the film depositions, and a diameter of the magnetic crystal grain deposited in the final deposition is less than a diameter of the magnetic crystal grain deposited in the first deposition.