Magnetoresistive structure comprising ferromagnetic thin films and intermediate alloy layer having magnetic concentrator and shielding permeable masses

• US 5,617,071 A
• Filed: 02/06/1995
• Issued: 04/01/1997
• Est. Priority Date: 11/16/1992
• Status: Expired due to Term

• Current Assignee: NVE Corporation
• Original Assignee: Nonvolatile Electronics
• Inventors: Daughton, James M.
• Primary Examiner(s): Walberg, Teresa J.
• Assistant Examiner(s): VALENCIA, RAPHA
• Application Number:
  US08/384,647
• Time in Patent Office: 785 Days
• Field of Search: 338/32 R, 338/324, 338/325, 365/158, 365/173, 360/113, 360/126, 324/207.21, 324/252, 428/611
• US Class Current: 338/32.00R
• 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 5/3945 Heads comprising more than one sensitive element
• CPC Class Codes: G11B 5/3948 the sensitive elements being active read-out elements
• CPC Class Codes: H01F 10/324 Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
• CPC Class Codes: H01F 10/325 the spacer being noble metal
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A magnetoresistive layered structure having on a substrate two or more magnetoresistive, anisotropic ferromagnetic thin-films each two of which are separated by an intermediate layer on a substrate of less than 50 Å thickness formed of a substantially nonmagnetic, conductive alloy having two immiscible components therein. A further component to provide temperature stability in some circumstances is to be at least partially miscible in the first two components. Such structures can be formed as a sensor by having them electrically connected together with one positioned in a gap between magnetic material masses and one shielded by one of such masses. The magnetic material mass being used for shielding can be divided into two masses with one of those masses farthest from the gap serving as the shield.

Claims

1. A magnetic field sensor comprising:

a substrate having a major surface portion;

a pair of magnetoresistive thin-film layered structures provided on said substrate electrically connected to one another and with each also being electrically connected to an interconnection means suited for electrical connection to a source of electrical energy; and

a group comprising three permeable material masses provided on said substrate with one of said two layered structures being positioned adjacent a first gap between a first and second of said permeable material masses in said group thereof, and with that layered structure remaining positioned (a) adjacent a side of a third of said permeable material masses in said group thereof which side faces said substrate as supported thereon, but (b) spaced apart from said first gap and from a second gap between said second and third permeable masses in said group thereof in a direction at least in part paralleling an axis substantially parallel to said substrate passing through both of said second and third permeable material masses and said second gap.

2. The apparatus of claim 1 wherein said second gap follows a plurality of directions along its course as determined by boundaries of said second and third permeable material masses.

3. The apparatus of claim 2 wherein said second permeable material mass at least partially surrounds said third permeable material mass.

4. The apparatus of claim 1 wherein said layered structures are first and second structures each comprising a succession of layers including a magnetoresistive, anisotropic, first ferromagnetic thin-film provided on said substrate major surface portion;

an intermediate layer provided on said first ferromagnetic thin-film with a thickness of less than 50 Å

, said intermediate layer being formed of a substantially non-magnetic, conductive alloy having two substantially mutually immiscible components therein and a third component therein at least partially immiscible with each of those first two components; and

a magnetoresistive, anisotropic, second ferromagnetic thin-film provided on said intermediate layer.

5. The apparatus of claim 4 wherein said layered structures are electrically connected in a bridge circuit.

6. The apparatus of claim 1 wherein said layered structures are first and second structures each comprising a succession of layers including a magnetoresistive, anisotropic, first ferromagnetic thin-film provided on said substrate major surface portion;

an intermediate layer provided on said first ferromagnetic thin-film with a thickness of less than 50 Å

, said intermediate layer being formed of a substantially non-magnetic, conductive alloy having copper, silver and gold components therein; and

a magnetoresistive, anisotropic, second ferromagnetic thin-film provided on said intermediate layer.

7. A magnetic field sensor comprising:

a substrate having a major surface portion;

a pair of magnetoresistive thin-film layered structures provided on said substrate electrically connected to one another and with each also being electrically connected to an interconnection means suited for electrical connection to a source of electrical energy, said pair of magnetoresistive thin-film layered structures comprising magnetoresistive, anisotropic, first and second ferromagnetic thin-films separated by the intermediate layer having a thickness of less than 30 Å and

formed of a substantially non-magnetic conductive alloy having two substantially immiscible components therein; and

a pair of permeable material masses provided on said substrate with one of said two layered structures being positioned in a gap therebetween, and with that one remaining positioned near a side of one of said permeable material masses between surface locations thereon intersected by an axis substantially parallel to said substrate passing through both said permeable masses and said gap.

8. The apparatus of claim 7 wherein said two substantially immiscible components are copper and silver.

9. The apparatus of claim 7 wherein said two substantially immiscible components are copper and gold.

10. The apparatus of claim 7 wherein there is a third permeable material mass positioned in said gap to thereby form a pair of subgaps so that said layered structure positioned in said gap is also positioned in a first of said pair of subgaps located between said third permeable material mass and one of said pair of permeable material masses with a second of said pair of subgaps positioned between said third permeable material mass and that remaining one of said pair of permeable material masses.

11. The apparatus of claim 10 wherein said two substantially immiscible components are copper and silver.

12. The apparatus of claim 10 wherein said two substantially immiscible components are copper and gold.

13. A magnetic field sensor comprising:

a substrate having a major surface portion;

a pair of magnetoresistive thin-film layered structures provided on said substrate electrically connected to one another and with each also being electrically connected to an interconnection means suited for electrical connection to a source of electrical energy, said pair of magnetoresistive thin-film layered structures comprising magnetoresistive, anisotropic, first and second ferromagnetic thin-films provided on said substrate major surface portion separated by an intermediate layer with a thickness of less than 30 Å and

formed of a substantially non-magnetic, conductive alloy having copper and silver components therein; and

a pair of permeable material masses provided on said substrate with one of said two layered structures being positioned in a gap therebetween, and with that one remaining positioned near a side of one of said permeable material masses between surface locations thereon intersected by an axis substantially parallel to said substrate passing through both said permeable material masses and said gap.

14. The apparatus of claim 13 wherein there is a third permeable material mass positioned in said gap to thereby form a pair of subgaps so that said layered structure positioned in said gap is also positioned in a first of said pair of subgaps located between said third permeable material mass and one of said pair of permeable material masses with a second of said pair of subgaps positioned between said third permeable material mass and that remaining one of said pair of permeable material masses.

15. A magnetic field sensor comprising:

a substrate having a major surface portion;

a pair of magnetoresistive thin-film layered structures provided on said substrate electrically connected to one another and with each also being electrically connected to an interconnection means suited for electrical connection to a source of electrical energy, said pair of magnetoresistive thin-film layered structures comprising magnetoresistive, anisotropic, first and second ferromagnetic thin-films provided on said substrate major surface portion separated by an intermediate layer with a thickness of less than 30 Å and

formed of a substantially non-magnetic, conductive alloy having copper and gold components therein; and

a pair of permeable material masses provided on said substrate with one of said two layered structures being positioned in a gap therebetween, and with that one remaining positioned near a side of one of said permeable material masses between surface locations thereon intersected by an axis substantially parallel to said substrate passing through both said permeable material masses and said gap.

16. The apparatus of claim 15 wherein there is a third permeable material mass positioned in said gap to thereby form a pair of subgaps so that said layered structure positioned in said gap is also positioned in a first of said pair of subgaps located between said third permeable material mass and one of said pair of permeable material masses with a second of said pair of subgaps positioned between said third permeable material mass and that remaining one of said pair of permeable material masses.