Vertical magnetic recording disk manufacturing method and vertical magnetic recording disk

1. A method of manufacturing a vertical magnetic recording disk comprising at least a magnetic recording layer on a substrate and used for vertical magnetic recording at a density greater than 100 Gb/in 2 , said method comprising:

providing the substrate; and

forming, on the substrate, the magnetic recording layer, said forming step further comprising (a) forming a ferromagnetic layer having a granular structure and (b) forming an exchange energy control layer on the ferromagnetic layer,

wherein at least the exchange energy control layer is formed through sputtering in an atmosphere of a rare gas having a greater mass than an argon gas, said sputtering being conducted at a gas pressure in a range of 1-10 m Torr and producing said energy control layer having a thickness of 2-5 nm,

wherein the exchange energy control layer is a laminated layer consisting of a plurality of first layers consisting of Co or a Co-alloy and a plurality of second layers consisting of palladium (Pd) with said rare gas embedded therein,

whereby the surface roughness of the disk having an exchange energy control layer that is formed through sputtering in an atmosphere of a rare gas having a greater mass than an argon gas, as determined by Ra and Rmax as measured by AFM, is less than that where an exchange energy control layer is formed through sputtering in an atmosphere of argon,

whereby the coercive force (Hc) of the resulting structure is equal to or greater than 4300 Oe,

wherein the magnetization reversal nucleation field (Hn) of the disk is −1300 Oe or smaller,

wherein the ferromagnetic layer has a crystal grain containing cobalt (Co) as a main constituent and a grain boundary portion containing a silicon (Si) or a silicon (Si) oxide as a main constituent, and

wherein a content of the silicon in the ferromagnetic layer is in a range of 8 to 15 atomic %,

wherein a thickness of the ferromagnetic layer is 8-16 nm,

wherein a ratio of the thickness of the ferromagnetic layer to the thickness of the exchange energy control layer is 3 to 4.

2. The method according to claim 1 , wherein the rare gas having a greater mass than the argon gas is a krypton (Kr) gas.

3. The method according to claim 1 , wherein a spacer layer is formed between the ferromagnetic layer and the exchange energy control layer.

4. The method according to claim 3 , wherein the spacer layer is formed in said atmosphere of a rare gas having a greater mass than an argon gas at a thickness of the spacer layer within a range of 0.1 nm to 2.0 nm.

5. The method according to claim 1 , wherein Rmax is 6 nm or less and Ra is 0.6 nm or less.

6. The method according to claim 1 , wherein the ferromagnetic layer also is produced in said atmosphere of a rare gas having a greater mass than argon gas.

7. The method according to claim 1 , wherein the sputtering is conducted at a gas pressure in a range of 3-4 m Torr.

8. The method according to claim 1 , wherein the ferromagnetic layer is formed through sputtering in a gas pressure of 15 to 30 mTorr.

9. The method according to claim 1 , further comprising forming, between the substrate and the magnetic recording layer, a soft magnetic layer having a coercive force (Hc) of 0.01 to 50 Oe.

10. The method according to claim 9 , wherein the soft magnetic layer has a saturation magnetic flux density (Bs) of 500-1920 emu/cc.

11. The method according to claim 9 , wherein a thickness of the soft magnetic layer is 30-1000 nm.

12. The method according to claim 9 , wherein a thickness of the soft magnetic layer is 50-200 nm.