Perpendicular magnetization magnetic element utilizing spin transfer

• US 6,967,863 B2
• Filed: 02/25/2004
• Issued: 11/22/2005
• Est. Priority Date: 02/25/2004
• Status: Active Grant

• Current Assignee: Samsung Semiconductor Incorporated (Samsung Electronics Co. Ltd.)
• Original Assignee: Grandis, Inc. (Samsung Electronics Co. Ltd.)
• Inventors: Huai, Yiming
• Primary Examiner(s): Dinh, Son T.
• Application Number:
  US10/787,701
• Publication Number:
  US 20050185455A1
• Time in Patent Office: 636 Days
• Field of Search: 365/158, 365/171, 365/173
• US Class Current: 365/158
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: H01F 10/3236 made of a noble metal, e.g.(Co/Pt) n multilayers having perpendicular anisotropy H01F10/3286 takes precedence
• CPC Class Codes: H01F 10/3263 the exchange coupling being symmetric, e.g. for dual spin valve, e.g. NiO/Co/Cu/Co/Cu/Co/NiO
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 41/302 for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices spin-exchange-coupled multilayers H01F10/32
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The method and system include providing a first pinned layer, a barrier layer, a free layer, a conductive nonmagnetic spacer layer, and a second pinned layer. Each pinned layer has a pinned layer easy axis. At least a portion of the pinned layer easy axis is in a perpendicular direction. The barrier layer resides between the first pinned layer and the free layer. The spacer layer is between the free layer and the second pinned layer. The free layer has a free layer easy axis, at least a portion of which is in the perpendicular direction. The magnetic element is also configured to allow the free layer to be switched due to spin transfer effect when a write current is passed through the magnetic element. Because of the perpendicular magnetization(s), the writing current for spin transfer may be significantly reduced.

Claims

1. A magnetic element comprising:

a first pinned layer having a first pinned layer easy axis, at least a portion of the first pinned layer easy axis being in a perpendicular direction;

a spacer layer, the spacer layer being nonmagnetic and conductive;

a free layer, the spacer layer residing between the first pinned layer and the free layer, the free layer having a free layer easy axis, at least a portion of the free layer easy axis being in the perpendicular direction

a barrier layer, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer;

a second pinned layer having a second pinned layer easy axis, at least a portion of the second pinned layer easy axis being in the perpendicular direction, the barrier layer being between the free layer and the second pinned layer;

wherein the magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element.

2. The magnetic element of claim 1 wherein the free layer includes a bilayer of a ferromagnetic layer and a rare earth transition metal alloy layer.

3. The magnetic element of claim 2 wherein the rare earth transition metal alloy layer includes GdFe and/or GdFeCo.

4. The magnetic element of claim 2 wherein the ferromagnetic layer includes five to ten Angstroms of Co, Ni, Fe, their alloys, or CoX, CoFeX or CoNiFeX with X being between five and sixty atomic percent of Cu, B, Ru, Re, Rh, Pt and Pd.

5. The magnetic element of claim 1 wherein the free layer includes (Co/Pt)n or (CoCr/Pt)n, where n is an integer.

6. The magnetic element of claim 1 wherein the free layer includes (Fe/Pt)n or (CoFe/Pt)n, where n is an integer.

7. The magnetic element of claim 1 wherein the free layer includes [(CoPt)n/Co]/Ru/[(CoPt)n/Co] or [(CoCrPt)n/CoCr]/Ru/[(CoCrPt)n/CoCr] n, where n is an integer.

8. The magnetic element of claim 1 wherein the first pinned layer includes a bilayer of a ferromagnetic layer and a rare earth transition metal alloy layer.

9. The magnetic element of claim 8 wherein the rare earth transition metal alloy layer includes TbFe and/or TbFeCo.

10. The magnetic element of claim 1 wherein the first pinned layer includes (Co/Pt)n or (CoCr/Pt)n, where n is an integer.

11. The magnetic element of claim 1 wherein the first pinned layer includes (Fe/Pt)n or (CoFe/Pt)n, where n is an integer.

12. The magnetic element of claim 1 wherein the first pinned layer includes [(CoPt)n/Co]/Ru/[(CoPt)n/Co] or [(CoCrPt)n/CoCr]/Ru/[(CoCrPt)n/CoCr] n, where n is an integer.

13. The magnetic element of claim 1 wherein the first pinned layer includes [CoFe/Ru/CoFe].

14. The magnetic element of claim 1 wherein the second pinned layer includes a bilayer of a ferromagnetic layer and a rare earth transition metal alloy layer.

15. The magnetic element of claim 14 wherein the rare earth transition metal alloy layer includes TbFe and/or TbFeCo.

16. The magnetic element of claim 1 wherein the second pinned layer includes (Co/Pt)n or (CoCr/Pt)n, where n is an integer.

17. The magnetic element of claim 1 wherein the second pinned layer includes (Fe/Pt)n or (CoFe/Pt)n, where n is an integer.

18. The magnetic element of claim 1 wherein the second pinned layer includes [(CoPt)n/Co]/Ru/[(CoPt)n/Co] or [(CoCrPt)n/CoCr]/Ru/[(CoCrPt)n/CoCr] n, where n is an integer.

19. The magnetic element of claim 1 wherein the second pinned layer includes [(CoFePt)n/Ru/CoFePt].

20. The magnetic element of claim 1 wherein the free layer easy axis is in the perpendicular direction.

21. A method for providing a magnetic element comprising:

(a) providing a first pinned layer having a first pinned layer easy axis, at least a portion of the first pinned layer easy axis being in a perpendicular direction;

(b) providing a spacer layer, the spacer layer being nonmagnetic and conductive;

(c) providing a free layer, the spacer layer residing between the first pinned layer and the free layer, the free layer having a free layer easy axis, at least a portion of the free layer easy axis being in the perpendicular direction

(d) providing a barrier layer, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer; and

(e) providing a second pinned layer having a second pinned layer easy axis, at least a portion of the second pinned layer easy axis being in the perpendicular direction, the barrier layer being between the free layer and the second pinned layer;

wherein the magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element.

22. The method of claim 21 wherein the free layer providing step (c) includes providing a bilayer of a ferromagnetic layer and a rare earth transition metal alloy layer.

23. The method of claim 22 wherein the rare earth transition metal alloy layer includes GdFe and/or GdFeCo.

24. The method of claim 22 wherein the ferromagnetic layer includes five to ten Angstroms of Co, Ni, Fe, their alloys, or CoX, CoFeX or CoNiFeX with X being between five and sixty atomic percent of Cu, B, Ru, Re, Rh, Pt and Pd.

25. The method of claim 21 wherein the free layer providing step (c) includes providing (Co/Pt)n or (CoCr/Pt)n, where n is an integer.

26. The method of claim 21 wherein the free layer providing step (c) includes providing (Fe/Pt)n or (CoFe/Pt)n, where n is an integer.

27. The method of claim 21 wherein the free layer providing step (c) includes providing [(CoPt)n/Co]/Ru/[(CoPt)n/Co] or [(CoCrPt)n/CoCr]/Ru/[(CoCrPt)n/CoCr] n, where n is an integer.

28. The method of claim 21 wherein the first pinned layer providing step (a) includes providing a bilayer of a ferromagnetic layer and a rare earth transition metal alloy layer.

29. The method of claim 28 wherein the rare earth transition metal alloy layer includes TbFe and/or TbFeCo.

30. The method of claim 21 wherein the first pinned layer providing step (a) includes (Co/Pt)n or (CoCr/Pt)n, where n is an integer.

31. The method of claim 21 wherein the first pinned layer providing step (a) includes providing (Fe/Pt)n or (CoFe/Pt)n, where n is an integer.

32. The method of claim 21 wherein the first pinned layer providing step (a) further includes providing [(CoPt)n/Co]/Ru/[(CoPt)n/Co] or [(CoCrPt)n/CoCr]/Ru/[(CoCrPt)n/CoCr] n, where n is an integer.

33. The method of claim 21 wherein the first pinned layer providing step (a) further includes providing [CoFe/Ru/CoFe].

34. The method of claim 21 wherein the second pinned layer providing step (c) includes providing a bilayer of a ferromagnetic layer and a rare earth transition metal alloy layer.

35. The method of claim 34 wherein the rare earth transition metal alloy layer includes TbFe and/or TbFeCo.

36. The method of claim 21 wherein the second pinned layer providing step (c) includes providing (Co/Pt)n or (CoCr/Pt)n, where n is an integer.

37. The method of claim 21 wherein the second pinned layer providing step (c) includes providing (Fe/Pt)n or (CoFe/Pt)n, where n is an integer.

38. The method of claim 21 wherein the second pinned layer includes providing [(CoPt)n/Co]/Ru/[(CoPt)n/Co] or [(CoCrPt)n/CoCr]/Ru/[(CoCrPt)n/CoCr] n, where n is an integer.

39. The method of claim 21 wherein the second pinned layer providing step (c) includes providing [CoFe/Ru/CoFe].

40. The method of claim 21 wherein the free layer easy axis is in the perpendicular direction.