Method for producing multilayer film perpendicular magnetic recording medium
View Patent ↗A method for producing a magnetic recording medium in which the noise of the magnetic recording medium is reduced and the thermal stability of the recorded magnetization is improved, while enabling easy writing to be carried out by a recording head, is disclosed. The magnetic recording medium of the present invention includes an underlayer having an hcp crystal structure and a magnetic layer produced by a multilayer lamination of Co/Pt or the like. The deposition rate of the underlayer is equal to or lower than 0.7 nm/second. The magnetic layer contains added silicon oxide at 1 to 10 mol %. The present method includes a step for subjecting the surface of the underlayer to Ar gas mixed with oxygen of a mass/flow rate ratio of 1% to 10% under a gas pressure of 0.1 to 10 Pa for 1 to 10 second(s). The magnetic recording medium may include an orientation control layer and a soft magnetic backing layer. Ku, Ku 1 , and Ku 2 are controlled to provide both of thermal stability and easy writing.
1. 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.
2. A method for producing a perpendicular magnetic recording medium according to claim 1 , wherein the underlayer is formed using a sputter method.
3. A method for producing a perpendicular magnetic recording medium according to claim 1 , wherein the silicon oxide is SiO 2 .
4. A method for producing a perpendicular magnetic recording medium according to claim 1 , wherein the silicon oxide is added to at least one of the first or second magnetic layers in an amount equal to or higher than 1 mol % and equal to or lower than 10 mol %.
5. A method for producing a perpendicular magnetic recording medium according to claim 1 , additionally comprising forming an orientation control layer between the non-magnetic substrate and the underlayer.
6. A method for producing a perpendicular magnetic recording medium according to claim 5 , wherein the orientation control layer is formed by laminating a first orientation control layer and a second orientation control layer, the first orientation control layer being a Ta layer and the second orientation control layer being any one of a NiFeNbB layer, a NiFeCr layer, and a NiFeSi layer.
7. A method for producing a perpendicular magnetic recording medium according to claim 5 , additionally comprising forming a soft magnetic backing layer between the non-magnetic substrate and the orientation control layer.