Electrically conductive underlayer to grow FePt granular media with (001) texture on glass substrates
A perpendicular magnetic recording medium, comprising: a substrate; a buffer layer deposited in a first orientation on top of the substrate; an underlayer deposited in a second orientation on top of the buffer layer, the underlayer comprising an electrically conductive oxide; and a magnetic recording layer deposited on top of the underlayer and having an axis of magnetic anisotropy substantially perpendicular to the surface thereof.
1. A perpendicular magnetic recording medium, comprising:
a substrate;
a buffer layer deposited in a first orientation on top of the substrate;
an underlayer deposited in a second orientation on top of the buffer layer, the underlayer comprising an electrically conductive oxide of Mg with one or more of Ti, Zr and Hf, the oxide comprising between 5 and 35 atomic percent Mg; and
a magnetic recording layer deposited on top of the underlayer and having an axis of magnetic anisotropy substantially perpendicular to the surface thereof.
2. The recording medium of claim 1 , wherein the oxide comprises between 15 and 25 atomic percent Mg.
3. The recording medium of claim 1 , wherein the oxide is MgTiO x .
4. The recording medium of claim 1 , wherein the oxide is MgTiO 2 .
5. The recording medium of in claim 1 , wherein the oxide is MgZrO 3 .
6. The recording medium of in claim 1 , wherein the oxide is MgHfO.
7. The recording medium of claim 1 , further comprising a second buffer layer deposited on top of the substrate, wherein the second buffer layer comprises NiTa.
8. The recording medium of claim 7 , wherein the NiTa is deposited on the substrate by way of DC sputtering.
9. The recording medium of claim 1 , wherein the buffer layer comprises Cr.
10. The recording medium of claim 9 , wherein the Cr is deposited in (200) orientation.
11. The recording medium of claim 9 , wherein the Cr is deposited by way of DC sputtering.
12. The recording medium of claim 1 , wherein the underlayer is deposited on the buffer layer in (001) orientation.
13. The recording medium of claim 12 , wherein the underlayer is deposited on the buffer layer by way of DC sputtering.
14. The recording medium of claim 1 , wherein the magnetic recording layer comprises FePtAgC.
15. The recording medium of claim 14 , wherein the magnetic recording layer is deposited on the underlayer by way of DC co-sputtering.
16. A method for fabricating a perpendicular magnetic recording medium, the method comprising:
depositing a buffer layer on a substrate;
depositing an underlayer over the buffer layer, the underlayer comprising an electrically conductive oxide of Mg with one or more of Ti, Zr and Hf, the oxide comprising between 5 and 35 atomic percent Mg;
heating the substrate and deposited layers; and
depositing a magnetic recording layer over the underlayer.
17. The method of claim 16 , wherein the oxide comprises between 15 and 25 atomic percent Mg.
18. The method of claim 16 , further comprising depositing a second buffer layer on the substrate, and modifying a top surface of the second buffer layer prior to depositing the buffer layer.
19. The method of claim 18 , wherein modifying the top surface comprises introducing oxygen for a predetermined amount of time and allowing the top surface to grow Cr in (200) orientation.
20. The method of claim 16 , wherein the oxide is MgTiO x .
21. The method of claim 16 , wherein the oxide is MgTiO 2 .
22. The method of in claim 16 , wherein the oxide is MgZrO 3 .
23. The method of in claim 16 , wherein the oxide is MgHfO.
24. The method of claim 16 , wherein depositing the buffer layer comprises depositing Cr on a first buffer layer in (200) orientation.
25. The method of claim 16 , wherein depositing the magnetic recording layer comprises depositing FePtAgC on the underlayer by way of DC co-sputtering.