Patent ID: 7582193

Claim:
A method for producing a perpendicular magnetic recording medium, comprising: forming a non-magnetic underlayer consisting of Ru having a hexagonal close-packed crystal structure on a non-magnetic substrate; subjecting the surface of the underlayer to Ar gas mixed with oxygen of the mass/flow rate ratio of 1% to 10% under a gas pressure of 0.1 to 10 Pa for 1 to 10 seconds before forming the magnetic layer film; and forming a magnetic layer film comprising a multilayer lamination in which a Co layer as a first magnetic layer and a Pt layer or a Pd layer as a second magnetic layer are alternately laminated directly over the underlayer, wherein at least one of the first magnetic layer and the second magnetic layer comprises silicon oxide and is formed by sputtering using a target with added silicon oxide, wherein the underlayer is formed at a deposition rate equal to or lower than 0.7 nm/second.