Magnetoresistive element and magnetic memory device

• US 20030197984A1
• Filed: 05/23/2003
• Published: 10/23/2003
• Est. Priority Date: 09/16/1999
• Status: Active Grant

• Current Assignee: Toshiba Memory Corporation (Kioxia Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kishi, Tatsuya, Saito, Yoshiaki, Inomata, Koichiro, Sagoi, Masayuki, Nakajima, Kentaro
• Granted Patent: US 6,751,074 B2
• Time in Patent Office: Days
• US Class Current: 360/324.2
• 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 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: G11C 11/15 using multiple magnetic layers G11C11/155 takes precedence
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• 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 10/3281 only by use of asymmetry of the magnetic film pair itself, i.e. so-called pseudospin valve [PSV] structure, e.g. NiFe/Cu/Co
• CPC Class Codes: H10B 61/10 comprising components having two electrodes, e.g. diodes or MIM elements
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/115 Magnetic layer composition

Abstract

A magnetoresistive element has a ferromagnetic double tunnel junction having a stacked structure of a first antiferromagnetic layer/a first ferromagnetic layer/a first dielectric layer/a second ferromagnetic layer/a second dielectric layer/a third ferromagnetic layer/a second antiferromagnetic layer. The second ferromagnetic layer that is a free layer consists of a Co-based alloy or a three-layered film of a Co-based alloy/a Ni—Fe alloy/a Co-based alloy. A tunnel current is flowed between the first ferromagnetic layer and the third ferromagnetic layer.

Claims

1. A magnetoresistive element comprising a ferromagnetic double tunnel junction having a stacked structure of a first antiferromagnetic layer/a first ferromagnetic layer/a first dielectric layer/a second ferromagnetic layer/a second dielectric layer/a third ferromagnetic layer/a second antiferromagnetic layer;

and

the second ferromagnetic layer consisting of a Co-based alloy or a three-layered film of a Co-based alloy/a Ni—

Fe alloy/a Co-based alloy.

2. The magnetoresistive element according to claim 1, wherein a thickness of the Co-based alloy or the three-layered film of the Co-based alloy/the Ni—

Fe alloy/the Co-based alloy is 1 to 5 nm.

3. A magnetic memory device, wherein memory cells each comprising the magnetoresistive element according to claim 1 and a transistor or a diode are arrayed.

4. The magnetic memory device according to claim 3, wherein at least the uppermost antiferromagnetic layer of the magnetoresistive element constitutes a part of a bit line.

5. A magnetoresistive element comprising a ferromagnetic double tunnel junction having a stacked structure of a first ferromagnetic layer/a first dielectric layer/a second ferromagnetic layer/a first antiferromagnetic layer/a third dielectric layer/a second dielectric layer/a fourth ferromagnetic layer;

and

the first and fourth ferromagnetic layers consisting of a Co-based alloy or a three-layered film of a Co-based alloy/a Ni—

Fe alloy/a Co-based alloy.

6. The magnetoresistive element according to claim 5, wherein a thickness of the Co-based alloy or the three-layered film of the Co-based alloy/the Ni—

Fe alloy/the Co-based alloy is 1 to 5 nm.

7. A magnetic memory device, wherein memory cells each comprising the magnetoresistive element according to claim 5 and a transistor or a diode are arrayed.

8. A magnetoresistive element comprising a ferromagnetic double tunnel junction having a stacked structure of a first antiferromagnetic layer/a first ferromagnetic layer/a first dielectric layer/a second ferromagnetic layer/a second antiferromagnetic layer/a third ferromagnetic layer/a second dielectric layer/a fourth ferromagnetic layer/a third antiferromagnetic layer;

and

the first and fourth ferromagnetic layers or the second and third ferromagnetic layers consisting of a Co-based alloy or a three-layered film of a Co-based alloy/a Ni—

Fe alloy/a Co-based alloy.

9. The magnetoresistive element according to claim 8, wherein a thickness of the Co-based alloy or the three-layered film of the Co-based alloy/the Ni—

Fe alloy/the Co-based alloy is 1 to 5 nm.

10. A magnetic memory device, wherein memory cells each comprising the magnetoresistive element according to claim 8 and a transistor or a diode are arrayed.

11. A magnetic memory device according to claim 10, wherein at least the uppermost antiferromagnetic layer of the magnetoresistive element constitutes a part of a bit line.

12. A magnetoresistive element comprising a ferromagnetic double tunnel junction having a stacked structure of a first ferromagnetic layer/a first dielectric layer/a second ferromagnetic layer/a first nonmagnetic layer/a third ferromagnetic layer/a second nonmagnetic layer/a fourth ferromagnetic layer/a second dielectric layer/a fifth ferromagnetic layer;

the second, third and fourth ferromagnetic layers adjacent to each other being antiferromagnetically coupled through the nonmagnetic layers; and

the first and fifth ferromagnetic layers consisting of a Co-based alloy or a three-layered film of a Co-based alloy/a Ni—

Fe alloy/a Co-based alloy.

13. The magnetoresistive element according to claim 12, wherein a thickness of the Co-based alloy or the three-layered film of the Co-based alloy/the Ni—

Fe alloy/the Co-based alloy is 1 to 5 nm.

14. A magnetic memory device, wherein memory cells each comprising the magnetoresistive element according to claim 12 and a transistor or a diode are arrayed.

15. A magnetic memory device comprising a first magnetization pinned layer whose magnetization direction is pinned, a first dielectric layer, a magnetic recording layer whose magnetization direction is reversible, a second dielectric layer, and a second magnetization pinned layer whose magnetization direction is pinned;

the magnetic recording layer comprising a three-layered film of a magnetic layer, a nonmagnetic layer and a magnetic layer, the two magnetic layers constituting the three-layered film being anti-ferromagnetically coupled; and

magnetization directions of the two magnetization pinned layers in regions in contact with the dielectric layer being substantially anti-parallel to each other.

16. A method for writing information to the magnetic memory device according to claim 15, comprising steps of:

supplying the magnetic recording layer with a spin current through the first or second magnetization pinned layer; and

flowing a current in a wire for writing so as to apply a current magnetic field to the magnetic recording layer.

17. A magnetic memory device comprising a first magnetization pinned layer whose magnetization direction is pinned, a first dielectric layer, a magnetic recording layer whose magnetization direction is reversible, a second dielectric layer, and a second magnetization pinned layer whose magnetization direction is pinned;

the magnetic recording layer comprising a three-layered film of a magnetic layer, a nonmagnetic layer and a magnetic layer, the two magnetic layers constituting the three-layered film being antiferromagnetically coupled;

the second magnetization pinned layer comprising a three-layered film of a magnetic layer, a nonmagnetic layer and a magnetic layer, the two magnetic layers constituting the three-layered film being antiferromagnetically coupled;

a length of the first magnetization pinned layer being formed longer than those of the second magnetization pinned layer and the magnetic recording layer; and

magnetization directions of the two magnetization pinned layers in regions in contact with the dielectric layer being substantially anti-parallel to each other.

18. A magnetoresistive element comprising a ferromagnetic double tunnel junction having a stacked structure of a first antiferromagnetic layer/a first ferromagnetic layer/a first tunnel insulator/a second ferromagnetic layer/a first nonmagnetic layer/a third ferromagnetic layer/a second nonmagnetic layer/a fourth ferromagnetic layer/a second tunnel insulator/a fifth ferromagnetic layer/a second antiferromagnetic layer;

the second and third ferromagnetic layers being antiferromagnetically coupled through a first nonmagnetic layer; and

the third and fourth ferromagnetic layers being antiferromagnetically coupled through a second nonmagnetic layer.

19. A magnetic memory device, wherein memory cells each comprising the magnetoresistive element according to claim 18 and a transistor or a diode are arrayed.