Method for producing a perpendicular magnetic recording medium
View Patent ↗To provide a method for manufacturing a perpendicular magnetic recording medium, which is capable of coping with the much higher recording density. Disclosed is a method for manufacturing a perpendicular magnetic recording medium to be used for recording information by a perpendicular magnetic recording system, including at least a soft magnetic layer, an intermediate layer, and a magnetic recording layer on a substrate, characterized in that the method includes the step of: composing the intermediate layer of consecutive N layers (provided that N is an integer of at least 3 or more), depositing a first layer containing ruthenium (Ru) as a main component, first; setting a gas pressure during the deposition to the pressure which is higher than or the same as that in the first layer; depositing a second layer containing ruthenium (Ru), or ruthenium (Ru) containing oxygen or an oxide as a main component; and adjusting so that the oxygen content remains constant, or increases toward the uppermost layer in the second layer and succeeding layers.
1. A method for manufacturing a perpendicular magnetic recording medium to be used for recording information by a perpendicular magnetic recording system, comprising on a substrate and in the order from the bottom, at least a soft magnetic layer, an intermediate layer composed of consecutive N layers, where N is an integer of 3 or more, and a magnetic recording layer, characterized in that the method comprises the steps of:
forming the intermediate layer of consecutive N layers by:
first depositing a first layer containing ruthenium (Ru) as a main component at a first gas pressure;
depositing on the first layer a second layer containing, as a main component, ruthenium (Ru) containing oxygen or Ru containing an oxide at a second gas pressure that is higher than the first gas pressure;
depositing on the second layer a third layer containing, as a main component, ruthenium (Ru) containing oxygen or Ru containing an oxide, wherein the third layer has an oxygen content that is higher than that of the second layer; and
when N is an integer more than 3, depositing on the third layer one or more succeeding layers each containing, as a main component, ruthenium (Ru) containing oxygen or Ru containing an oxide, such that the intermediate layer has an increasing oxygen content towards the magnetic recording layer.
2. The method for manufacturing a perpendicular magnetic recording medium according to claim 1 , wherein the oxygen content of each of the consecutive N layers is adjusted within a range from 0 ppm by weight to 20,000 ppm by weight.
3. The method for manufacturing a perpendicular magnetic recording medium according to claim 1 , wherein each of the oxides in the second layer, the third layer and the one or more succeeding layers contains a Si, Ti, Cr, Co, W, Ta, Al, Mg, Fe, Pd, Au, Mo, Zr or Pb material.
4. The method for manufacturing a perpendicular magnetic recording medium according to claim 1 , wherein the magnetic recording layer includes a ferromagnetic layer having a granular structure which includes crystal particles mainly containing cobalt (Co), and a boundary part mainly containing an oxide.
5. The method for manufacturing a perpendicular magnetic recording medium according to claim 1 , wherein a carbon-based protective layer is formed on the magnetic recording layer.
6. The method for manufacturing a perpendicular magnetic recording medium according to claim 1 , wherein the oxygen content of the second layer of the intermediate layer is adjusted to within a range of 1,000 ppm by weight to 4,000 ppm by weight, and the oxygen content of the third layer of the intermediate layer is adjusted to within a range of 2,000 ppm by weight to 8,000 ppm by weight.
7. The method for manufacturing a perpendicular magnetic recording medium according to claim 1 , wherein the first gas pressure is from 0.3 to 15 Pa.