US5591532A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Giant magnetoresistance single film alloys
Assignee: University of California
•
Filing: 1994-04-01
•
Granted: 1997-01-07
•
Expires: 2014-04-01
Abstract
Abstract A single layer film is deposited onto a substrate at room temperature from two sources, one source being a magnetic material, the other being a less-magnetic material. The film is annealed for predetermined times in order to induce phase separation between the magnetic clusters and the less-magnetic matrix, and to form stable clusters of a size such that each magnetic particle, or cluster, comprises a single domain and has no dimensions greater than the electron spin flip mean free path within the particle. The creation of two magnetic phases makes it possible to establish exchange coupling between the phases so that a relatively low saturation field is required to induce GMR.
Inventors
- 👤 Ami Berkowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:47
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; B; B82; B82Y; B82Y10/00; B82Y25/00; H; H01; H01F; H01F10/00; H01F10/007; H10; H10N; H10N50/00; H10N50/80; H10N50/85; G11B2005/3996; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
229 words
A single layer film which exhibits giant magnetoresistance upon application of a magnetic field of about 100 Oersted or less, the film comprising: a magnetic metallic matrix on a substrate, said magnetic metallic matrix having a first magnetic phase; a plurality of magnet particles having a second magnetic phase of greater magnetism than said first magnetic phase suspended within said magnetic metallic matrix wherein each magnetic particle comprises a single magnetic domain having a size less than a mean free path within said magnetic particle and such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU9## where ##EQU10## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said magnetic metallic matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles; and a biasing means comprising an antiferromagnetic film which is exchange coupled with said magnetic metallic matrix; wherein exchange coupling is established between said first magnetic phase and said second magnetic phase.
Claim 2
Dependent Claim
229 words
A single layer film which exhibits giant magnetoresistance upon application of a magnetic field of about 100 Oersted or less, the film comprising: a magnetic metallic matrix on a substrate, said magnetic metallic matrix having a first magnetic phase; a plurality of magnet particles having a second magnetic phase of greater magnetism than said first magnetic phase suspended within said magnetic metallic matrix wherein each magnetic particle comprises a single magnetic domain having a size less than a mean free path within said magnetic particle and such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU9## where ##EQU10## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said magnetic metallic matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles; and a biasing means comprising an antiferromagnetic film which is exchange coupled with said magnetic metallic matrix; wherein exchange coupling is established between said first magnetic phase and said second magnetic phase.
Claim 3
Dependent Claim
16 words
A single layer film as in claim 1 wherein said magnetic particles are Fe 2 B.
Claim 4
Dependent Claim
14 words
A single layer film as in claim 1 wherein said magnetic particles are FeNi.
Claim 5
Dependent Claim
15 words
A single layer film as in claim 1 wherein said magnetic metallic matrix is FeSi.
Claim 6
Dependent Claim
15 words
A single layer film as in claim 3 wherein said magnetic metallic matrix is NiCu.
Claim 7
Dependent Claim
219 words
A single layer film which exhibits giant magnetoresistance upon application of a magnetic field of about 100 Oersted or less, the film comprising: a magnetic metallic matrix on a substrate, said magnetic metallic matrix, said metallic matrix being NiCu and having a first magnetic phase; and a plurality of magnetic particles having a second magnetic phase of greater magnetism than said first magnetic phase suspended within said magnetic metallic matrix wherein each magnetic particle comprises a single magnetic domain having a size less than a mean free path within said magnetic particle and such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU11## where ##EQU12## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said magnetic metallic matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles; wherein exchange coupling is established between said first magnetic phase and said second magnetic phase.
Claim 8
Dependent Claim
219 words
A single layer film which exhibits giant magnetoresistance upon application of a magnetic field of about 100 Oersted or less, the film comprising: a magnetic metallic matrix on a substrate, said magnetic metallic matrix, said metallic matrix being NiCu and having a first magnetic phase; and a plurality of magnetic particles having a second magnetic phase of greater magnetism than said first magnetic phase suspended within said magnetic metallic matrix wherein each magnetic particle comprises a single magnetic domain having a size less than a mean free path within said magnetic particle and such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU11## where ##EQU12## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said magnetic metallic matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles; wherein exchange coupling is established between said first magnetic phase and said second magnetic phase.
Claim 9
Dependent Claim
213 words
A heterogeneous film having giant magnetoresistive response to an applied magnetic field of about 100 Oersted or less comprising: a plurality of magnetic particles; a matrix comprising a metallic material having a second magnetism less than a first magnetism of said magnetic particles, said plurality of magnetic particles being suspended within said matrix, said matrix being insoluble with said magnetic particles; and a biasing means comprising an antiferromagnetic material which is exchange coupled with said matrix; wherein each of said plurality of magnetic particles has a size which is less than a mean free path within each said magnetic particle and said size is such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU13## where ##EQU14## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles.
Claim 10
Dependent Claim
213 words
A heterogeneous film having giant magnetoresistive response to an applied magnetic field of about 100 Oersted or less comprising: a plurality of magnetic particles; a matrix comprising a metallic material having a second magnetism less than a first magnetism of said magnetic particles, said plurality of magnetic particles being suspended within said matrix, said matrix being insoluble with said magnetic particles; and a biasing means comprising an antiferromagnetic material which is exchange coupled with said matrix; wherein each of said plurality of magnetic particles has a size which is less than a mean free path within each said magnetic particle and said size is such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU13## where ##EQU14## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles.
Claim 11
Dependent Claim
16 words
A heterogeneous film as in claim 7 wherein each magnetic particle comprises a single magnetic domain.
Claim 12
Dependent Claim
44 words
A heterogeneous film as in claim 7 wherein said size of each magnetic particle is such that an interfacial scattering of electrons from an interface between said magnetic particles and said matrix is greater than a bulk scattering of electrons within said magnetic particles.
Claim 13
Dependent Claim
219 words
A single layer film which exhibits giant magnetoresistance upon application of a magnetic field of about 100 Oersted or less, the film comprising: a magnetic metallic matrix on a substrate, said magnetic metallic matrix having a first magnetic phase; and a plurality of magnetic particles, said magnetic particles being FeNi and having a second magnetic phase of greater magnetism than said first magnetic phase suspended within said magnetic metallic matrix wherein each magnetic particle comprises a single magnetic domain having a size less than a mean free path within said magnetic particle and such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU15## where ##EQU16## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said magnetic metallic matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles; wherein exchange coupling is established between said first magnetic phase and said second magnetic phase.
Claim 14
Dependent Claim
219 words
A single layer film which exhibits giant magnetoresistance upon application of a magnetic field of about 100 Oersted or less, the film comprising: a magnetic metallic matrix on a substrate, said magnetic metallic matrix having a first magnetic phase; and a plurality of magnetic particles, said magnetic particles being FeNi and having a second magnetic phase of greater magnetism than said first magnetic phase suspended within said magnetic metallic matrix wherein each magnetic particle comprises a single magnetic domain having a size less than a mean free path within said magnetic particle and such that an amount of spin-dependent interfacial scattering from an outer surface of said magnetic particles is increased relative to an amount of bulk scattering within said magnetic particles to increase giant magnetoresistance in accordance with the relationship ##EQU15## where ##EQU16## and r MR is an average radius of said magnetic particles, p S is a spin-dependent ratio for scattering at a surface of said magnetic particles, λ MX is a mean free path in said magnetic metallic matrix, λ MR is a mean free path in said magnetic particles, ξ is a scattering strength for said surface of said magnetic particles, and c is a concentration of said magnetic particles; wherein exchange coupling is established between said first magnetic phase and said second magnetic phase.
References Cited (Backward Citations)
US4585473A
Cited
EP0271657A2
Cited
US5186854A
Cited
US5268043A
Cited
US5315468A
Cited
US5373238A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-01-07 | 2000-07-08 | 2001-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-01-07 | 2004-07-08 | 2005-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-01-07 | 2008-07-08 | 2009-01-07 | $7700.00 | Window Closed / Lapsed |