Perpendicular media with Cr-doped Fe-alloy containing soft underlayer (SUL)
View Patent ↗A perpendicular magnetic recording medium having a substrate, a Cr-doped Fe-alloy-containing underlayer containing about 8 to 18 at % Cr and a perpendicular recording magnetic layer, and a process for improving corrosion resistance of the recording medium and for manufacturing the recording medium are disclosed.
1. A perpendicular magnetic recording medium comprising:
a substrate;
a perpendicular magnetic recording layer; and
an underlayer between the substrate and the perpendicular magnetic recording layer, the underlayer comprising Fe and at least about 8 at, percent Cr;
wherein the underlayer is substantially amorphous and comprises at least one of Zr, Ta, and B.
2. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer comprises a soft magnetic underlayer.
3. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer further comprises Co.
4. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer comprises less than about 40 at, percent Cr.
5. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer comprises about 8 to about 25 at, percent Cr.
6. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer has a thickness greater than 30 nanometers.
7. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer has a thickness between about 100 nm and about 200 nm.
8. The perpendicular magnetic recording medium of claim 1 , wherein the perpendicular magnetic recording layer has a thickness between about 5 nm and about 30 nm.
9. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer is configured to provide a return path for a recording head.
10. The perpendicular magnetic recording medium of claim 1 , further comprising a seedlayer between the substrate and underlayer, wherein the seedlayer is configured to change the magnetostriction of the underlayer.
11. The perpendicular magnetic recording medium of claim 1 , wherein the underlayer has a surface roughness below 0.4 nm.
12. A perpendicular magnetic recording medium comprising:
a substrate;
a perpendicular magnetic recording layer; and
an underlayer between the substrate and the perpendicular recording magnetic layer, the underlayer comprising Fe, Co, and at least about 8 at, percent Cr, wherein the underlayer is substantially amorphous and comprises at least one of Zr, Ta, and B.
13. The perpendicular magnetic recording medium of claim 12 , wherein the underlayer comprises a soft magnetic underlayer.
14. The perpendicular magnetic recording medium of claim 12 , wherein the underlayer comprises B.
15. The perpendicular magnetic recording medium of claim 12 , wherein the underlayer comprises at least about 11 at, percent Cr.
16. The perpendicular magnetic recording medium of claim 12 , wherein the underlayer comprises about 8 to about 25 at, percent Cr.
17. The perpendicular magnetic recording medium of claim 12 , wherein the underlayer has a thickness greater than 30 nanometers.
18. A method for manufacturing a perpendicular magnetic recording medium, the method comprising:
depositing an underlayer on a substrate, the underlayer comprising Fe and at least about 8 at, percent Cr, wherein the underlayer is substantially amorphous and comprises at least one of Zr, Ta, and B; and
depositing a perpendicular magnetic recording layer on the underlayer.
19. The method of claim 18 , wherein the underlayer further comprises Co.
20. The method of claim 18 , wherein the underlayer comprises about 8 to about 25 at, percent Cr.