HEAT ASSISTED MAGNETIC RECORDING MEDIUM AND METHOD FOR FABRICATING THE SAME

Abstract

A novel heat assisted magnetic recording (HAMR) medium and the fabrication method therefor are provided. The exchange coupling effect occurring at the interface of FePt/CoTb double layers is adopted, and thus the resulting magnetic flux would be sufficient enough to be detected and readout under the room temperature. The provided HAMR medium exhibits a relatively high saturation magnetization and perpendicular coercivity, and thus possesses a great potential for the ultra-high density recording application.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart illustrating the method for fabricating the heat assisted magnetic recording (HAMR) medium according to a preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view schematically illustrating the fabricated HAMR medium according to the preferred embodiment of the present invention;

FIG. 3 is a diagram illustrating the M-H loop of a pre-deposited Co₇₀Tb₃₀ layer under the ambient temperature;

FIG. 4(A) and FIG. 4(B) are diagrams respectively illustrating the XRD pattern and the M-H loop of the pre-deposited FePt(001)/Pt(001)/Cr(002) layer sequence according to the present invention;

FIG. 5 is a diagram illustrating the Ms value variation and the Hc⊥ value variation of the HAMR medium depending on the thickness of the Co₇₀Tb₃₀ layer thereof in accordance with the present invention;

FIG. 6 is a diagram illustrating the M-H loop of the provided Co₇₀Tb₃₀/FePt(001)/Pt(001)/Cr(002) layer sequence of the HAMR medium according to the presnet invention;

FIG. 7 is a diagram illustrating the comparison for M-H loop of the conventional Co₇₀Tb₃₀ recording layer, the provided FePt(001)/Pt(001)/Cr(002) layer sequence and the provided Co₇₀Tb₃₀/FePt(001)/Pt(001)/Cr(002) layer sequence of the HAMR medium according to the presnet invention;

FIG. 8 is a TEM photo showing the cross-sectional view of the provided Co₇₀Tb₃₀/FePt(001)/Pt(001)/Cr(002) layer sequence of the HAMR medium according to the presnet invention; and

FIG. 9 is a diagram illustrating the Ms value variation and the Hc⊥ value variation of the Co₇₀Tb₃₀/FePt(001) layer sequence of the HAMR medium depending on the temperature in accordance with the present invention.

Claims

1. A heat assisted magnetic recording medium, comprising: a substrate;an underlayer located on said substrate;a buffer layer located on said underlayer;a magnetic layer located on said buffer layer; anda recording and reading layer located on said magnetic layer.

2. The heat assisted magnetic recording medium according to claim 1, wherein said substrate is one of a glass substrate and an oxidized Si substrate.

3. The heat assisted magnetic recording medium according to claim 1, wherein said underlayer is a Cr layer.

4. The heat assisted magnetic recording medium according to claim 3, wherein said Cr layer has a thickness ranged from 10 to 100 nm.

5. The heat assisted magnetic recording medium according to claim 4, wherein said thickness of said Cr layer is 70 nm.

6. The heat assisted magnetic recording medium according to claim 1, wherein said buffer layer is a Pt layer.

7. The heat assisted magnetic recording medium according to claim 6, wherein said Pt layer has a thickness ranged from 1 to 10 nm.

8. The heat assisted magnetic recording medium according to claim 7, wherein said thickness of said Pt layer is 2 nm.

9. The heat assisted magnetic recording medium according to claim 1, wherein said magnetic layer is a FexPt100-x layer and said recording and reading layer is a CoyTb100-y layer.

10. The heat assisted magnetic recording medium according to claim 9, wherein x is ranged from 45 to 55 and y is ranged from 65.8 to 71.9.

11. The heat assisted magnetic recording medium according to claim 10, wherein x is 50 and y is 70.44.

12. The heat assisted magnetic recording medium according to claim 9, wherein said FexPt100-x layer has a thickness ranged from 5 to 60 nm, and said CoyTb100-y layer has a thickness ranged from 20 nm to 60 nm.

13. The heat assisted magnetic recording medium according to claim 12, wherein said thickness of said FexPt100-x layer is 20 nm, and said thickness of said CoyTb100-y layer is 50 nm.

14. The heat assisted magnetic recording medium according to claim 1, further comprising a passiviation layer located on said recording and reading layer.

15. The heat assisted magnetic recording medium according to claim 14, wherein said passiviation layer is a layer of silicon nitride.

16. A method for fabricating a heat assisted magnetic recording medium, comprising steps of: (a) providing a substrate;(b) performing a thermal process to said substrate;(c) forming an underlayer of Cr on said substrate;(d) forming a buffer layer of Pt on said underlayer;(e) forming a layer of FexPt100-x on said buffer layer; and(f) forming a layer of CoyTb100-y on said layer of FexPt100-x.

17. The method according to claim 16, wherein said step (b) further comprising a step of: heating said substrate to a first temperature.

18. The method according to claim 17, wherein said first temperature is less than 800° C.

19. The method according to claim 18, wherein said first temperature is 350° C.

20. The method according to claim 17, wherein in said step (b), said thermal process is performed for 5 to 90 minutes.

21. The method according to claim 20, wherein in said step (b), said first temperature is 350° C., and said thermal process is performed for 30 minutes.

22. The method according to claim 16, wherein in said step (b), said thermal process is performed under a pressure ranged from 1×10−9 to 1×10−6 Torr.

23. The method according to claim 16, wherein in said step (c), said buffer layer of Cr is formed on said substrate under a temperature of 350° C.

24. The method according to claim 16, wherein in said step (d), said buffer layer of Pt is formed on said underlayer under a second temperature below 800° C.

25. The method according to claim 24, wherein said second temperature is 350° C.

26. The method according to claim 16, wherein in said step (e), said layer of FexPt100-x is formed on said buffer layer under a third temperature below 800° C.

27. The method according to claim 26, wherein said third temperature is 420° C.

28. The method according to claim 16, wherein in said step (f), said layer of CoyTb100-y is formed on said layer of FexPt100-x under a fourth temperature below 50° C.

29. The method according to claim 28, wherein said fourth temperature is an ambient temperature.

30. The method according to claim 16, wherein said underlayer of Cr, said buffer layer of Pt, said layer of FexPt100-x and said layer of CoyTb100-y are formed by DC magnetron sputtering in an ultrahigh vacuum sputtering chamber.

31. The method according to claim 30, wherein said underlayer of Cr, said buffer layer of Pt, said layer of FexPt100-x and said layer of CoyTb100-y are deposited under an argon pressure ranged from 2 to 12 mTorr.

32. The method according to claim 31, wherein said argon pressure is 5 mTorr.

33. The method according to claim 30, wherein said layer of FexPt100-x is deposited by DC magnetron sputtering with a first DC power ranged from 0.2 to 0.5 W/cm2.

34. The method according to claim 33, wherein said first DC power is 0.22 W/cm2.

35. The method according to claim 30, wherein said layer of CoyTb100-y is deposited by DC magnetron sputtering with a second DC power ranged from 1 to 4 W/cm2.

36. The method according to claim 35, wherein said second DC power is 2.96 W/cm2.

37. The method according to claim 16, further comprising a step of: (g) forming a passiviation layer on said layer of CoyTb100-y.

38. The method according to claim 37, wherein said passiviation layer is formed by magnetron sputtering with an RF power ranged from 2 to 7 W/cm2.

39. The method according to claim 38, wherein said RF power is 2.47 W/cm2.