IP Library › Granted Patent US 7,227,773
Granted Patent B1
US 7,227,773 · App. 11/256,387 · Granted Jun 5, 2007

Magnetic element utilizing spin-transfer and half-metals and an MRAM device using the magnetic element

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Quick Facts
Patent No.
US 7,227,773
App. No.
11/256,387
Granted
Jun 5, 2007
Kind
B1
Abstract

A magnetic element that can be used in a memory array having high density includes a pinned layer, a half-metallic material layer, a spacer (or a barrier) layer and a free layer. The half-metallic material layer is formed on the pinned layer and preferably has a thickness that is less than about 100 Å. The half-metallic material layer can be formed to be a continuous layer or a discontinuous on the pinned layer. The spacer (or barrier) layer is formed on the half-metallic material layer, such that the spacer (or barrier) layer is nonmagnetic and conductive (or insulating). The free layer is formed on the spacer (or barrier) layer and has a second magnetization that changes direction based on the spin-transfer effect when a write current passes through the magnetic element.

Claims (67)

1. A magnetic memory device, comprising:

a plurality of magnetic cells including a plurality of magnetic elements, at least one magnetic element including,

a pinned layer and having a first magnetization that is pinned in a first direction,

a half-metallic material layer formed on the pinned layer,

a spacer layer formed on the half-metallic material layer, the spacer layer being nonmagnetic and conductive, and

a free layer formed on the spacer layer, the free layer having a second magnetization that changes direction based on the spin-transfer effect when a write current passes through the magnetic element;

a plurality of rows lines coupled to the plurality of magnetic cells; and

a plurality of column lines coupled to the plurality of magnetic cells, the plurality of row lines and the plurality of column lines selecting a portion of the plurality of magnetic cells for reading and writing;

wherein at least one magnetic element further includes:

a second spacer layer formed on the free layer, the second spacer layer being nonmagnetic and conductive;

a second half-metallic material layer formed on the second spacer layer; and

a second pinned layer formed on the second half-metallic layer, the second pinned layer having a third magnetization that is pinned in a direction that is different from the first direction,

wherein at least one second pinned layer of at least one magnetic element is formed from one of a ferromagnetic material and a ferrimagnetic material.

2. A magnetic memory device, comprising:

a plurality of magnetic cells including a plurality of magnetic elements, at least one magnetic element including,

a pinned layer and having a first magnetization that is pinned in a first direction,

a half-metallic material layer formed on the pinned layer,

a barrier layer formed on the half-metallic material layer, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer, and

a free layer formed on the barrier layer, the free layer having a second magnetization that changes direction based on the spin-transfer effect when a write current passes through the magnetic element;

a plurality of rows lines coupled to the plurality of magnetic cells; and

a plurality of column lines coupled to the plurality of magnetic cells, the plurality of row lines and the plurality of column lines selecting a portion of the plurality of magnetic cells for reading and writing.

3. The magnetic memory device according to claim 2 , wherein at least one pinned layer of at least one magnetic element is formed from one of a ferromagnetic material and a ferrimagnetic material.

4. The magnetic memory device according to claim 2 , wherein at least one pinned layer of at least one magnetic element is formed from a half-metallic material;

wherein the pinned layer and the half-metallic layer form a single layer; and

wherein and the free layer is configured such that the second magnetization changes direction based on the spin-transfer effect when a write current passes through the magnetic element.

5. The magnetic memory device according to claim 2 , wherein at least one half-metallic material layer forming at least one pinned layer of at least one magnetic element is one of Fe 3 O 4 , CrO 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

6. The magnetic memory device according to claim 2 , wherein at least one half-metallic material layer of at least one magnetic element is formed from one of Fe 3 O 4 , Cro 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

7. The magnetic memory device according to claim 2 , wherein at least one half-metallic material layer of at least one magnetic element has a thickness that is less than about 100 Å.

8. The magnetic memory device according to claim 2 , wherein at least one half-metallic material layer of at least one magnetic element is a continuous layer.

9. The magnetic memory device according to claim 2 , wherein at least one half-metallic material layer of at least one magnetic element is a discontinuous layer.

10. The magnetic memory device according to claim 2 , wherein at least one free layer of at least one magnetic element is formed from one of a ferromagnetic material and a ferrimagnetic material.

11. The magnetic memory device according to claim 10 , wherein at least one free layer of at least one magnetic element is formed from a half-metallic material.

12. The magnetic memory device according to claim 2 , wherein at least one half-metallic material layer of at least one magnetic element is formed from one of Fe 3 O 4 , CrO 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

13. The magnetic memory device according to claim 2 , wherein at least one magnetic element further includes:

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

a second half-metallic material layer formed on the second barrier layer; and

a second pinned layer formed on the second half-metallic layer, the second pinned layer having a third magnetization that is pinned in a direction that is different from the first direction.

14. The magnetic memory device according to claim 13 , wherein the second pinned layer is formed from one of a ferromagnetic material and a ferrimagnetic material.

15. The magnetic memory device according to claim 13 , wherein the second pinned layer is formed from a half-metallic material, and

wherein the second pinned layer and the second half-metallic layer form a single layer.

16. The magnetic memory device according to claim 15 , wherein the half-metallic material layer forming the second pinned layer is one of Fe 3 O 4 , CrO 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

17. The magnetic memory device according to claim 13 , wherein at least one half-metallic material layer of at least one magnetic element is formed from one of Fe 3 O 4 , CrO 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

18. The magnetic memory device according to claim 13 , wherein at least one half-metallic material layer of at least one magnetic element has a thickness that is less than about 100 Å.

19. The magnetic memory device according to claim 13 , wherein at least one half-metallic material layer of at least one magnetic element is formed as a continuous layer.

20. The magnetic memory device according to claim 19 , wherein at least one half-metallic material layer of at least one magnetic element is formed as a discontinuous layer.

21. The magnetic memory device according to claim 2 , wherein the at least one magnetic element further includes:

a spacer layer formed on the free layer, the spacer layer being nonmagnetic and conductive;

a second half-metallic material layer formed on the spacer layer; and

a second pinned layer formed on the second half-metallic layer, the second pinned layer having a third magnetization that is pinned in a direction that is different from the first direction.

22. The magnetic memory device according to claim 21 , wherein the second pinned layer is formed from one of a ferromagnetic material and a ferrimagnetic material.

23. The magnetic memory device according to claim 21 , wherein the second pinned layer is formed from a half-metallic material, and

wherein the second pinned layer and the second half-metallic layer form a single layer.

24. The magnetic memory device according to claim 23 , wherein the half-metallic material layer forming the second pinned layer is one of Fe 3 O 4 , CrO 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

25. The magnetic memory device according to claim 21 , wherein at least one half-metallic material layer of at least one magnetic element is formed from one of Fe 3 O 4 , CrO 2 , Sr 2 FeMoO 6 , (La0.7Sr0.3)MnO 3 , and NiMnSb.

26. The magnetic memory device according to claim 21 , wherein at least one half-metallic material layer of at least one magnetic element has a thickness that is less than about 100 Å.

27. The magnetic memory device according to claim 21 , wherein at least one half-metallic material layer of at least one magnetic element is formed as a continuous layer.

28. The magnetic memory device according to claim 21 , wherein at least one half-metallic material layer of at least one magnetic element is formed as a discontinuous layer.

29. A magnetic memory device, comprising:

a plurality of magnetic cells including a plurality of magnetic elements, at least one magnetic element including,

a pinned layer and having a first magnetization that is pinned in a first direction,

a half-metallic material layer formed on the pinned layer,

a barrier layer formed on the half-metallic material layer, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer, and

a free layer formed on the barrier layer, the free layer having a second magnetization that changes direction based on the spin-transfer effect when a write current passes through the magnetic element, wherein the free layer has a lateral dimension less than or equal to five hundred nanometer;

a plurality of rows lines coupled to the plurality of magnetic cells, and

a plurality of column lines coupled to the plurality of magnetic cells, the plurality of row lines and the plurality of column lines selecting a portion of the plurality of magnetic cells for reading and writing;

wherein and the free layer of the at least one magnetic element is configured such that the second magnetization changes direction based on the spin-transfer effect when a write current passes through the at least one magnetic element.

30. The magnetic memory device of claim 2 wherein and the free layer of the at least one magnetic element is configured such that the second magnetization changes direction based on the spin-transfer effect when a write current passes through the at least one magnetic element.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 29, 2016
From: GRANDIS, INC.
To: SAMSUNG SEMICONDUCTOR INC.
Reel/Frame 037958/0728 →