Magnetic recording medium, method of manufacturing magnetic recording medium and magnetic storage device
The present invention relates to a magnetic recording medium including a substrate; an underlayer laminated upon the substrate; and a magnetic layer laminated upon the underlayer, wherein the underlayer includes a first underlayer containing a compound represented by a following general formula: MgO (1-X) , where X is within a range of 0.07 to 0.25, the magnetic layer includes a first magnetic layer containing an alloy having a L1 0 structure, and the alloy having the L1 0 structure includes B, and the first underlayer is in contact with the first magnetic layer.
1. A thermal assist magnetic recording medium comprising:
a substrate;
an underlayer provided on the substrate; and
a magnetic recording layer provided on the underlayer, wherein
the underlayer includes a first underlayer including a compound represented by a formula MgO (1-X) , where X falls within a range of 0.07 to 0.25,
the magnetic recording layer includes a first magnetic layer consisting of an alloy having a L1 0 structure and including B, and a second magnetic layer consisting of an alloy having a L1 0 structure and provided on the first magnetic layer,
the first underlayer is in contact with the first magnetic layer.
2. The thermal assist magnetic recording medium as claimed in claim 1 , wherein a B-content in the alloy of the first magnetic layer having the L1 0 structure falls within a range of 2% by mol to 20% by mol.
3. The thermal assist magnetic recording medium as claimed in claim 1 , wherein a B-content in the alloy of the first magnetic layer having the L1 0 structure falls within a range of 2.5% by mol to 10% by mol.
4. The thermal assist magnetic recording medium as claimed in claim 1 , wherein
the underlayer further includes a second underlayer,
the first underlayer is provided on the second underlayer, and sandwiched between the second underlayer and the first magnetic layer, and
the second underlayer is selected from group consisting of (100)-oriented W, Cr, Cr alloys having a BCC structure, and Al alloys having B2 structure.
5. The thermal assist magnetic recording medium as claimed in claim 1 , wherein
the alloy of the second magnetic layer is selected from a group consisting of a first alloy having a L1 0 structure and including B, a second alloy having a L1 0 structure and including Pt, and Fe or Co, and a third alloy having a L1 0 structure and including B, Pt, and Fe or Co.
6. The thermal assist magnetic recording medium as claimed in claim 5 , wherein at least one of the first magnetic layer and the second magnetic layer has a granular structure.
7. The thermal assist magnetic recording medium as claimed in claim 1 , wherein
the substrate has a substrate surface on which the underlayer is provided, and
each of the first magnetic layer and the second magnetic layer is (001)-oriented.
8. A method of manufacturing the thermal assist magnetic recording medium of claim 1 , the method comprising:
depositing the first underlayer using a sputtering target including MgO, and a sputtering gas in which an amount of hydrogen added to an inert gas falls within a range of 1% by volume to 20% by volume.
9. A method of manufacturing the thermal assist magnetic recording medium of claim 1 , the method comprising:
depositing the first underlayer using a sputtering target including MgO, by causing discharge for a period of less than or equal to 0.5 second at a first sputtering gas pressure of 1 Pa or higher, and thereafter causing discharge at a second sputtering gas pressure of 0.5 Pa or lower.
10. A magnetic storage device comprising:
the thermal assist magnetic recording medium according to claim 1 ; and
a magnetic head configured to record information on and reproduce information from the thermal assist perpendicular magnetic recording medium.
11. A thermal assist magnetic recording medium comprising:
a substrate;
an underlayer provided on the substrate; and
a magnetic recording layer provided on the underlayer, wherein
the underlayer includes a first underlayer including a compound represented by a formula MgO (1-X) , where X falls within a range of 0.07 to 0.25,
the magnetic recording layer includes a first magnetic layer consisting of an alloy having a L1 0 structure and including B, Pt, and Fe or Co, and a second magnetic layer consisting of an alloy having a L1 0 structure and provided on the first magnetic layer,
the first underlayer is in contact with the first magnetic layer.
12. The thermal assist magnetic recording medium as claimed in claim 11 , wherein a B-content in the alloy of the first magnetic layer having the L1 0 structure falls within a range of 2% by mol to 20% by mol.
13. The thermal assist magnetic recording medium as claimed in claim 11 , wherein a B-content in the alloy of the first magnetic layer having the L1 0 structure falls within a range of 2.5% by mol to 1 0 % by mol.
14. The thermal assist magnetic recording medium as claimed in claim 11 , wherein
the underlayer further includes a second underlayer,
the first underlayer is provided on the second underlayer, and sandwiched between the second underlayer and the first magnetic layer, and
the second underlayer is selected from a group consisting of a (100)-oriented W, Cr, Cr alloys having a BCC structure, and Al alloys having B2 structure.
15. The thermal assist magnetic recording medium as claimed in claim 11 , wherein
the alloy of the second magnetic layer is selected from a group consisting of a first alloy having a L1 0 structure and including B, a second alloy having a L1 0 structure and including Pt, and Fe or Co, and a third alloy having a L1 0 structure and including B, Pt, and Fe or Co.
16. The thermal assist magnetic recording medium as claimed in claim 15 , wherein at least one of the first magnetic layer and the second magnetic layer has a granular structure.
17. The thermal assist magnetic recording medium as claimed in claim 11 , wherein
the substrate has a substrate surface on which the underlayer is provided, and
each of the first magnetic layer and the second magnetic layer is (001)-oriented.
18. A method of manufacturing the thermal assist magnetic recording medium of claim 11 , the method comprising:
depositing the first underlayer using a sputtering target including MgO, and a sputtering gas in which an amount of hydrogen added to an inert gas falls within a range of 1% by volume to 20% by volume.
19. A method of manufacturing the thermal assist magnetic recording medium of claim 11 , the method comprising:
depositing the first underlayer using a sputtering target including MgO, by causing discharge for a period of less than or equal to 0.5 second at a first sputtering gas pressure of 1 Pa or higher, and thereafter causing discharge at a second sputtering gas pressure of 0.5 Pa or lower.
20. A magnetic storage device comprising:
the thermal assist magnetic recording medium according to claim 11 ; and
a magnetic head configured to record information on and reproduce information from the thermal assist perpendicular magnetic recording medium.