Multi-layer structure and sensor and manufacturing process

• US 6,013,365 A
• Filed: 12/05/1996
• Issued: 01/11/2000
• Est. Priority Date: 12/15/1995
• Status: Expired due to Fees

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat A L'Atomique
• Inventors: Dieny, Bernard, Auffret, Stephane, Cowache, Christophe, Berthet, Franck
• Primary Examiner(s): KILIMAN, LESZEK B
• Application Number:
  US08/760,798
• Time in Patent Office: 1,132 Days
• Field of Search: 428/611, 428/332, 428/336, 428/660, 428/668, 428/673, 428/675, 428/694 R, 428/694 TS, 428/694 TM, 428/800, 428/694 TR, 428/692, 428/694 T, 427/128-130, 204/197.12, 204/192.2, 360/113, 324/252
• US Class Current: 428/811.3
• 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 15/205 using magneto-resistance devices, e.g. field plates
• 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: H01F 10/325 the spacer being noble metal
• CPC Class Codes: H10N 50/85 Magnetic active materials
• CPC Class Codes: Y10T 428/1129 Super lattice [e.g., giant magneto resistance [GMR] or colossal magneto resistance [CMR], etc.]
• CPC Class Codes: Y10T 428/115 Magnetic layer composition
• CPC Class Codes: Y10T 428/12465 having magnetic properties, or preformed fiber orientation coordinate with shape
• CPC Class Codes: Y10T 428/12806 Refractory [Group IVB, VB, or VIB] metal-base component
• CPC Class Codes: Y10T 428/12861 Group VIII or IB metal-base component
• CPC Class Codes: Y10T 428/12896 Ag-base component
• CPC Class Codes: Y10T 428/1291 Next to Co-, Cu-, or Ni-base component
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

This invention relates to a multilayered magnetic structure comprising an alternate stack of:

layers (6, 16) of a first type based on magnetic materials,

layers (12) of a second type, made of Ag or an Ag rich alloy,

a thin interface layer (8, 14) of Co or a Co rich alloy being located at the interface between layers of the first type and layers of the second type.

The invention also relates to a process for making this type of structure.

Applications to sensors based on magnetoresistive effects, such as current sensors or magnetic heads.

Claims

1. Multilayered magnetic structure including alternate stack of:

layers based on magnetic materials,

layers made of Ag or an Ag rich alloy,

an interfacial layer of Co or a Co rich alloy being located at the interfaces between said layers based on magnetic materials and said layers made of Ag or an Ag rich alloy, said interfacial layer having a thickness less than 1 nm.

2. Magnetic structure according to claim 1, the formula for the magnetic material being:

Ni_100-x-y-z Co_x Fe_y A_z where 0≦

x≦

100, 0≦

y≦

100 and 0≦

z≦

40 and x+y+z≦

100, and wherein A is an additive.

3. Magnetic structure according to either of claims 1 or 2, the layers based on magnetic material being based on Permalloy.

4. Magnetic structure according to either of claims 1 or 2, the Ag rich alloy composition being Ag_x Cu_1-x or Ag_x Au_1-x where 0<

x<

0.5.

5. Multilayered magnetic structure according to either of claims 1 or 2, the thickness of said layers made of Ag or of an Ag rich alloy being such that there is an antiferromagnetic coupling between said layers based on magnetic materials through said layers made of Ag or an Ag rich alloy and the interface layers.

6. Multilayered magnetic structure according to claim 5, the thickness of said layers made of Ag or an Ag rich alloy being between 0.8 to 1.5 nm.

7. Multilayered magnetic structure according to either of claims 1 or 2, including two layers based on magnetic materials and one layer made of Ag or an Ag rich alloy.

8. Magnetic structure according to either of claims 1 or 2, comprising three layers based on magnetic materials and two layers made of Ag or an Ag rich alloy.

9. Multilayered magnetic structure according to claim 7, the layer made of an Ag or an Ag rich alloy having a thickness such that there is no antiferromagnetic coupling between the layers based on magnetic materials.

10. Multilayered magnetic structure according to claim 9, the layer made of Ag or an Ag rich alloy having a thickness of between 2 and 5 nm.

11. Magnetic structure according to claim 8, the layers made of an Ag or an Ag rich alloy having a thickness such that there is no antiferromagnetic coupling between the layers of the first type.

12. Multilayered magnetic structure according to claim 11, the layer made of Ag or an Ag rich alloy having a thickness of between 2 and 5 nm.

13. Magnetic structure according to claim 7, an antiferromagnetic layer being deposited on one of the layers based on magnetic materials.

14. Magnetic structure according to claim 8, an antiferromagnetic layer being deposited on one of the layers based on magnetic material.

15. Magnetic structure according to claim 13, the antiferromagnetic layer being made of FeMn and with a thickness of between 7 and 12 nm.

19. Multilayer sensor with magnetoresistive effect comprising a magnetic structure in layers according to either of claims 1 or 2.

20. Multilayer sensor with magnetoresistive effect comprising a magnetic structure in layers according to claim 7.

21. Multilayer sensor with magnetoresistive effect comprising a magnetic structure in layers according to claim 8.

22. Current sensor designed to measure the current passing through an electric conductor consisting of a magnetoresistive tape surrounding the conductor and the ends of which are designed to be connected to a current measurement device, the tape being composed of a layered magnetic structure according to claim 1 or 2.

23. Current sensor designed to measure the current passing through an electric conductor consisting of a magnetoresistive uape surrounding the conductor and the ends of which are designed to be connected to a current measurement device, the tape being composed of a layered magnetic structure according to claim 7.

24. Current sensor designed to measure the current passing through an electric conductor consisting of a magnetoresistive tape surrounding the conductor and the ends of which are designed to be connected to a current measurement device, the tape being composed of a layered magnetic structure according to claim 8.

25. Magnetic write and/or read head comprising a layered magnetoresistant element according to either of claims 1 or 2.

26. Magnetic write and/or read head comprising a layered magnetoresistant element according to claim 7.

27. Magnetic write and/or read head comprising a layered magnetoresistant element according to claim 8.

28. Multilayered magnetic structure according to claim 7, the layer made of an Ag or an Ag rich alloy having a thickness such that the antiferromagnetic coupling between the layers based on magnetic materials is less than 10^-2 erg/cm².

29. Multilayered magnetic structure according to claim 8, the layer made of an Ag or an Ag rich alloy having a thickness such that the antiferromagnetic coupling between the layers based on magnetic materials is less than 10^-2 erg/cm².

30. Magnetic structure according to claim 1, wherein A is at least one of Cu, Cr, Mo, V and B.

31. Magnetic Structure according to claim 14, the antiferromagnetic layer being made of FeMn and with a thickness of between 7 and 12 nm.

16. Process for making a multilayered magnetic structure including the following steps of:

depositing layers based on magnetic materials,

depositing layers made of Ag or an Ag rich alloy,

forming a thin interface layer of Co or a Co rich alloy at interfaces between said layers based on magnetic materials and said layers made of Ag or an Ag rich alloy.

17. Process according to claim 16, the layers being deposited by condensation of metal vapors on a substrate, at a temperature below the ambient temperature.

18. Process according to claim 17, the layers being made by cathodic spraying.