Perpendicular magnetic recording medium with grain isolation magnetic anistropy layer
A perpendicular magnetic recording (PMR) media including a non-magnetic or superparamagnetic grain isolation magnetic anisotropy layer (GIMAL) to provide a template for initially well-isolated small grain microstructure as well as improvement of K u in core grains of a magnetic recording layer. The GIMAL composition may be adjusted to have lattice parameters similar to a bottom magnetic recording layer and to provide a buffer for reducing interface strains caused by lattice mismatch between the bottom magnetic recording layer and an underlying layer.
1. A perpendicular magnetic recording disk, comprising:
a soft magnetic underlayer;
a first intermediate layer disposed over the soft magnetic layer, wherein the first intermediate layer is non-magnetic;
a second intermediate layer disposed over the first intermediate layer, the second intermediate layer comprising a non-magnetic or superparamagnetic Co alloy-oxide material; and
a magnetic recording layer disposed over the second intermediate layer,
wherein the magnetic recording layer is a Co alloy and is in contact with the second intermediate layer.
2. The perpendicular magnetic recording disk as in claim 1 , wherein the first intermediate layer is a substantially Co-free pseudo-HCP or substantially Co-free HCP material, and wherein the first intermediate layer comprises Ru.
3. The perpendicular magnetic recording disk as in claim 2 , wherein the non-magnetic or superparamagnetic Co alloy-oxide material comprises at least one non-cobalt oxide grain isolation material.
4. The perpendicular magnetic recording disk as in claim 3 , wherein the at least one non-cobalt oxide is selected from the group consisting of: SiO 2 , TiO 2 , Ti 2 O 3 , CrO 2 , Cr 2 O 3 , Ta 2 O 5 , Nb 2 O 5 , NiO, WO 2 , WO 3 , ZrO 2 , HfO 2 , V 2 O 5 and Al 2 O 3 .
5. The perpendicular magnetic recording disk as in claim 1 , further comprising an FCC intermediate layer disposed between the first intermediate layer and the soft magnetic underlayer, wherein the FCC intermediate layer is a material selected from the group consisting of: Ir, NiW, NiTi, NiFeCr, PtCr, PdCr and IrMn.
6. The perpendicular magnetic recording disk as in claim 5 , further comprising a BCC intermediate layer disposed between the first intermediate layer and the FCC intermediate layer, wherein the BCC intermediate layer is a material selected from the group consisting of: Cr and CrMn.
7. The perpendicular magnetic recording disk as in claim 1 , wherein the second intermediate layer is a superparamagnetic Co alloy with a saturation magnetization (M s ) less than approximately 200 emu/cm 3 .
8. The perpendicular magnetic recording disk as in claim 1 , wherein the second intermediate layer further comprises at least one of cobalt oxide and chromium oxide, and at least one non-cobalt oxide, non-chromium oxide grain isolation material.
9. The perpendicular magnetic recording disk as in claim 1 , wherein both the magnetic recording layer and the second intermediate layer comprise Cr with the second intermediate layer having a greater amount of Cr than the magnetic recording layer.
10. The perpendicular magnetic recording disk as in claim 9 , wherein the second intermediate layer further comprises at least one of Pt and Pd.
11. The perpendicular magnetic recording disk as in claim 10 , wherein the magnetic recording layer further comprises Pt.
12. The perpendicular magnetic recording disk as in claim 1 , wherein the second intermediate layer has a thickness between approximately 0.5 and 10 nanometers.
13. The perpendicular magnetic recording disk as in claim 1 , wherein the first intermediate layer is between two and five times the thickness of the second intermediate layer.
14. A disk drive, comprising:
a head having a magneto-resistive read element; and
the perpendicular magnetic recording disk of claim 1 operatively coupled to the head.
15. The disk drive as in claim 14 , wherein the first intermediate layer is a granular HCP material comprising at least one of Ru, Rh and Re, the first intermediate layer is between two and five times the thickness of the second intermediate layer, and wherein both the magnetic recording layer and the second intermediate layer comprise Cr with the second intermediate layer having a greater amount of Cr than the magnetic recording layer.
16. The disk drive as in claim 15 , wherein the magnetic recording layer further comprises Pt and the second intermediate layer further comprise at least one of Pd and Pt.
17. The disk drive as in claim 16 , the magnetic recording layer and second intermediate layer further comprise at least one of cobalt oxide and chromium oxide and at least one non-cobalt oxide, non-chromium oxide grain isolation material.
18. A method of manufacturing a perpendicular magnetic recording disk, the method comprising:
depositing a soft magnetic underlayer over a substrate;
depositing a first intermediate layer over the soft magnetic layer, the first intermediate layer being non-magnetic;
depositing second intermediate layer over the first intermediate layer, the second intermediate layer comprising a non-magnetic or superparamagnetic Co alloy-oxide material; and
depositing a magnetic recording layer over the second intermediate layer,
wherein the magnetic recording layer is a Co alloy and is in contact with the second intermediate layer.
19. The method as in claim 18 , wherein depositing the first intermediate layer further comprises depositing a substantially Co-free granular HCP material including at least one of Ru, Rh, and Re.
20. The method as in claim 18 , wherein depositing the second intermediate layer further comprises depositing a material to a thickness between approximately 0.5 and 10 nanometers.
21. The method as in claim 18 , wherein the magnetic recording layer is deposited directly on the second intermediate layer and wherein depositing the magnetic recording layer further comprises sputtering a target alloy comprising Co.
22. The method as in claim 18 , wherein depositing the second intermediate layer further comprises sputtering a target alloy comprising a non-cobalt oxide.
23. The method as in claim 22 , wherein depositing the second intermediate layer further comprises sputtering a target alloy including a greater amount of Cr than that of the target sputtered during deposition of the magnetic recording layer.
24. The method as in claim 23 , wherein depositing the second intermediate layer further comprises sputtering a target alloy including at least one of Pt or Pd, wherein depositing the magnetic recording layer further comprises sputtering a target alloy including Pt, and wherein the Pt content is approximately equal to that sputtered during deposition of the second intermediate layer.
25. The method as in claim 22 , wherein depositing the second intermediate layer further comprises reactively sputtering a target alloy comprising a cobalt oxide and a non-cobalt oxide with a compositional stoichiometric ratio between 1:10 and 10:1 cobalt oxide to non-cobalt oxide.
26. The method as in claim 25 , wherein depositing the second intermediate layer further comprises reactively sputtering the target alloy with an O 2 partial pressure between 0.2 mTorr and 3 mTorr.
27. A perpendicular magnetic recording disk, comprising:
a soft magnetic underlayer;
a first intermediate layer disposed over the soft magnetic layer, wherein the first intermediate layer is non-magnetic;
a second intermediate layer disposed over the first intermediate layer, the second intermediate layer comprising a non-magnetic or superparamagnetic Co alloy, wherein the second intermediate layer further comprises at least one of cobalt oxide and chromium oxide, and at least one non-cobalt oxide, non-chromium oxide grain isolation material; and
a magnetic recording layer disposed over the second intermediate layer.
28. The perpendicular magnetic recording disk as in claim 27 , wherein the second intermediate layer comprises at least one non-cobalt oxide selected from the group consisting of: SiO 2 , TiO 2 , Ti 2 O 3 , CrO 2 , Cr 2 O 3 , Ta 2 O 5 , Nb 2 O 5 , NiO, WO 2 , WO 3 , ZrO 2 , HfO 2 , V 2 O 5 and Al 2 O 3 .