Magnetic devices using nanocomposite materials

• US 6,713,195 B2
• Filed: 01/07/2002
• Issued: 03/30/2004
• Est. Priority Date: 01/05/2001
• Status: Expired due to Term

• Current Assignee: Timothy Doyle
• Original Assignee: NVE Corporation
• Inventors: Wang, Dexin, Daughton, James M., Qian, Zhenghong, Fayfield, Robert T.
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): KOPPIKAR, VIVEK D
• Application Number:
  US10/041,910
• Publication Number:
  US 20020146580A1
• Time in Patent Office: 813 Days
• Field of Search: 428/692, 428/668, 428/678, 428/469, 428/698, 428/332, 428/333
• US Class Current: 428/811.2
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: H01F 10/3231 via a non-magnetic spacer
• CPC Class Codes: H10N 50/85 Magnetic active materials
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/12861 Group VIII or IB metal-base component
• CPC Class Codes: Y10T 428/12931 Co-, Fe-, or Ni-base components, alternative to each other
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/261 In terms of molecular thickness or light wave length

Abstract

A ferromagnetic thin-film based magnetoresistive device with a first ferromagnetic material based film having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a smaller electrical conductivity first nonmagnetic. The device may have an intermediate layer adjacent the first ferromagnetic material based film and a second film is on the other side of the intermediate layer of a substantially ferromagnetic material. The first film is less than 1.0 μm thick.

Claims

1. A ferromagnetic thin-film based magnetoresistive device, said device comprising:

a nonmagnetic intermediate layer, said intermediate layer having two major surfaces on opposite sides thereof;

a first ferromagnetic material based film on one of said intermediate layer major surfaces having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a smaller electrical conductivity; and

a second film on that remaining one of said intermediate layer major surfaces of a substantially ferromagnetic material.

2. The device of claim 1 wherein said material of said nanogranules is one of Fe, Co, Cr or alloys thereof.

3. The device of claim 1 wherein said ferromagnetic material of said second film is one of Fe, Co, Ni or alloys thereof.

4. The device of claim 1 wherein said intergranular material is one of HfO, TaN, HfCN, HfN, HfTa or CrO.

5. The device of claim 1 wherein said intermediate layer is formed of a nonmagnetic electrical conductor.

6. The device of claim 1 wherein said intermediate layer is formed of a nonmagnetic electrical insulator.

7. The device of claim 1 wherein said first ferromagnetic material based film is less than 1.0 μ

m in thickness.

13. The device of claim 1 further comprising an antiferromagnetic material film provided against said second film.

14. The device of claim 1 wherein said first ferromagnetic material based film has a permeability greater than 35.

15. The device of claim 1 wherein said first ferromagnetic material based film has a coercivity less than 300.

16. The device of claim 1 further comprising a substrate on which are supported said first ferromagnetic material based film, said intermediate layer and said second film.

17. The device of claim 1 further comprising an electrical conductor positioned across an electrical insulating layer from said first ferromagnetic material based film, said intermediate layer and said second film.

18. The device of claim 5 further comprising an antiferromagnetic material film provided against said second film.

19. The device of claim 6 further comprising an antiferromagnetic material film provided against said second film.

22. The device of claim 16 wherein said substrate comprises a monolithic integrated circuit.

45. The device of claim 1 further comprising a third film of a substantially ferromagnetic material positioned between said first ferromagnetic material based film and said nonmagnetic intermediate layer.

47. The device of claim 1 wherein said first ferromagnetic material based film is positioned between said intermediate layer and a second ferromagnetic material based film having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a small electrical conductivity.

49. The device of claim 1 connected between a pair of electrodes such that any current established between said electrodes primarily flows perpendicular to said first ferromagnetic material based film, said first nonmagnetic intermediate layer and said second film.

51. The device of claim 1 connected between a pair of electrodes such that current between said electrodes primarily flows parallel to said first ferromagnetic material based film, said first nonmagnetic intermediate layer and said second film.

8. A ferromagnetic thin-film based magnetoresistive device, said device comprising:

a nonmagnetic intermediate layer, said intermediate layer having two major surfaces on opposite sides thereof;

a first ferromagnetic material based film supported on one of said intermediate layer major surfaces having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a smaller electrical conductivity and having a coercivity; and

a second film on that remaining one of said intermediate layer surfaces of a substantially ferromagnetic material, said second film having a coercivity greater than that of said first ferromagnetic material based film.

9. The device of claim 8 wherein said material of said nanogranules is one of Fe, Co, Cr or alloys thereof.

10. The device of claim 8 wherein said intergranular material is one of HfO, TaN, HfCN, HfN, HfTa or CrO.

11. The device of claim 8 wherein a nonmagnetic electrical conductor layer is formed as said intermediate layer.

12. The device of claim 8 wherein a nonmagnetic electrical insulator layer is formed as said intermediate layer.

20. The device of claim 8 further comprising a substrate on which are supported said first ferromagnetic material based film, said intermediate layer and said second film.

21. The device of claim 8 further comprising an electrical conductor positioned across an electrical insulating layer from said first ferromagnetic material based film, said intermediate layer and said second film.

37. The device of claim 8 wherein said first ferromagnetic material based film is less than 1.0 μ

m in thickness.

38. The device of claim 8 wherein said ferromagnetic material of said second film is one of Fe, Co, Ni or alloys thereof.

39. The device of claim 8 further comprising an antiferromagnetic material film provided against said second film.

40. The device of claim 8 wherein said first ferromagnetic material based film has a permeability greater than 35.

41. The device of claim 8 wherein said first ferromagnetic material based film has a coercivity less than 300.

42. The device of claim 20 wherein said substrate comprises a monolithic integrated circuit.

43. The device of claim 11 further comprising an antiferromagnetic material film provided against said second film.

44. The device of claim 12 further comprising an antiferromagnetic material film provided against said second film.

46. The device of claim 8 further comprising a third film of a substantially ferromagnetic material positioned between said first ferromagnetic material based film and said nonmagnetic intermediate layer.

48. The device of claim 8 wherein said first ferromagnetic material based film is positioned between said intermediate layer and a second ferromagnetic material based film having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a small electrical conductivity.

50. The device of claim 8 connected between a pair of electrodes such that any current established between said electrodes primarily flows perpendicular to said first ferromagnetic material based film, said first nonmagnetic intermediate layer and said second film.

52. The device of claim 8 connected between a pair of electrodes such that current between said electrodes primarily flows parallel to said first ferromagnetic material based film, said first nonmagnetic intermediate layer and said second film.

23. A ferromagnetic thin-film based magnetoresistive device, said device comprising:

a substrate having a major surface; and

a first ferromagnetic material based film of a thickness less than 1.0 μ

m supported on said substrate major surface having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a smaller electrical conductivity so as to have a permeability greater than 35.

24. The device of claim 23 wherein said material of said nanogranules is one of Fe, Co, or Cr or alloys thereof.

25. The device of claim 23 wherein said intergranular material is one of HfO, TaN, HfCN, HfN, HfTa or CrO.

26. The device of claim 23 wherein a nonmagnetic electrical conductor layer is formed adjacent a side of said first ferromagnetic material based film.

27. The device of claim 23 wherein a nonmagnetic electrical insulator layer is formed adjacent a side of said first ferromagnetic material based film.

28. The device of claim 23 wherein said substrate comprises a monolithic integrated circuit.

29. The device of claim 23 further comprising an electrical conductor positioned across an electrical insulating layer from said first ferromagnetic material based film, said intermediate layer and said second film.

30. A ferromagnetic thin-film based magnetoresistive device, said device comprising:

a substrate having a major surface; and

a first ferromagnetic material based film of a thickness less than 1.0 μ

m supported on said substrate major surface having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a small electrical conductivity having a coercivity less than 300.

31. The device of claim 30 wherein said material of said nanogranules is one of Fe, Co, Cr or alloys thereof.

32. The device of claim 30 wherein said intergranular material is one of HfO, TaN, HfCN, HfN, HfTa or CrO.

33. The device of claim 30 wherein a nonmagnetic electrical conductor layer is formed adjacent a side of said first ferromagnetic material based film.

34. The device of claim 30 wherein a nonmagnetic electrical insulator layer is formed adjacent a side of said first ferromagnetic material based film.

35. The device of claim 30 wherein said substrate comprises a monolithic integrated circuit.

36. The device of claim 30 further comprising an electrical conductor positioned across an electrical insulating layer said first ferromagnetic based film, said intermediate layer and said second film.