Patent US3876994A successfully refreshed from Google Patents.
US3876994A
Expired / Lapsed
US
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Planar bias field control of magnetic bubble domain apparatus
Assignee: International Business Machines Corp
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Filing: 1972-06-22
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Granted: 1975-04-08
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Expires: 1992-06-22
Abstract
Abstract A bias magnetic field H.sub.p is produced in the plane of the magnetic sheet in which bubble domains exist, in any type of bubble domain apparatus. This planar bias field alters the spin system within the domain wall which leads to a change in domain wall mobility. Thus, the presence and absence of the planar bias field can be used as a control to trigger domain propagation and domain collapse throughout the entire magnetic sheet, or in selected portions of the magnetic sheet. Block access of domain information is thereby made possible as well as gating and decoding functions.
Inventors
- 👤 Bertram A Calhoun
- 👤 Hsu Chang
- 👤 Laurence L Rosier
- 👤 John C Slonczewski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:10
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/02; G11C19/08; G11C19/0875; G11C19/0808; G11C19/0816; G11C19/0841; G11C19/085
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
57 words
A magnetic bubble domain apparatus, a magnetic medium in which said domains exist, planar bias means for producing a magnetic bias field substantially in the plane of said magnetic medium, propagation means adjacent said magnetic medium for moving domains in said medium where said planar bias field is applied in selected localized regions of said magnetic medium.
Claim 2
Dependent Claim
57 words
A magnetic bubble domain apparatus, a magnetic medium in which said domains exist, planar bias means for producing a magnetic bias field substantially in the plane of said magnetic medium, propagation means adjacent said magnetic medium for moving domains in said medium where said planar bias field is applied in selected localized regions of said magnetic medium.
Claim 3
Dependent Claim
22 words
The apparatus of claim 1, where said planar bias means is comprised of an electrical conductor located adjacent to said magnetic medium.
Claim 4
Dependent Claim
28 words
The apparatus of claim 1, where said planar bias means is comprised of a plurality of electrical current carrying conductors arranged in coordinate fashion across said magnetic medium.
Claim 5
Dependent Claim
87 words
A magnetic bubble domain apparatus, comprising: a magnetic medium in which said domains exist, planar bias means for producing a magnetic bias field substantially in the plane of said magnetic medium, propagation means adjacent said magnetic medium for moving domains in said medium, where said planar bias field H.sub.p is related to the properties of said magnetic medium by the following expression: H.sub.p .congruent.! .gtorsim. 4(2.pi.A).sup.1/2 /h where: A is the exchange coefficient of the magnetic medium material, and h is the thickness of said magnetic medium.
Claim 6
Dependent Claim
87 words
A magnetic bubble domain apparatus, comprising: a magnetic medium in which said domains exist, planar bias means for producing a magnetic bias field substantially in the plane of said magnetic medium, propagation means adjacent said magnetic medium for moving domains in said medium, where said planar bias field H.sub.p is related to the properties of said magnetic medium by the following expression: H.sub.p .congruent.! .gtorsim. 4(2.pi.A).sup.1/2 /h where: A is the exchange coefficient of the magnetic medium material, and h is the thickness of said magnetic medium.
Claim 7
Dependent Claim
25 words
The apparatus of claim 4, where said planar bias means is comprised of conductors located adjacent to said magnetic sheet, having current drivers connected thereto.
Claim 8
Dependent Claim
16 words
The apparatus of claim 5, where said conductors are arranged in coordinate fashion across said medium.
Claim 9
Dependent Claim
93 words
In a magnetic bubble domain apparatus including a magnetic medium in which said bubble domains can be propagated and a propagation means for moving said bubble domains in said magnetic medium, the improvement being additional magnetic field means for producing a planar magnetic bias field substantially in the plane of said magnetic medium, said bias field being substantially constant in direction and magnitude during propagation of said domains by said propagation means, where said planar bias field is related to the properties of said magnetic medium by the expression: H.sub.p .gtorsim. 4(2.pi.A).sup.1/2 /h
Claim 10
Dependent Claim
93 words
In a magnetic bubble domain apparatus including a magnetic medium in which said bubble domains can be propagated and a propagation means for moving said bubble domains in said magnetic medium, the improvement being additional magnetic field means for producing a planar magnetic bias field substantially in the plane of said magnetic medium, said bias field being substantially constant in direction and magnitude during propagation of said domains by said propagation means, where said planar bias field is related to the properties of said magnetic medium by the expression: H.sub.p .gtorsim. 4(2.pi.A).sup.1/2 /h
Claim 11
Independent Claim
114 words
An apparatus for moving magnetic bubble domains in a magnetic medium, comprising: a propagation means which is sufficient to move domains in said medium only when their mobility in said medium has a first value, bias means for making the mobility of domains in said medium have said first value, said bias means being independent of said propagation means and not essential to the operation of said propagation means, where said bias means produces a planar bias field H.sub.p substantially in the plane of said magnetic medium having a magnitude H.sub.p .gtorsim. 4(2.pi.A).sup.1/2 /h , where A is the exchange coefficient of the magnetic medium, and h is the thickness of the magnetic medium.
Claim 12
Independent Claim
114 words
An apparatus for moving magnetic bubble domains in a magnetic medium, comprising: a propagation means which is sufficient to move domains in said medium only when their mobility in said medium has a first value, bias means for making the mobility of domains in said medium have said first value, said bias means being independent of said propagation means and not essential to the operation of said propagation means, where said bias means produces a planar bias field H.sub.p substantially in the plane of said magnetic medium having a magnitude H.sub.p .gtorsim. 4(2.pi.A).sup.1/2 /h , where A is the exchange coefficient of the magnetic medium, and h is the thickness of the magnetic medium.
Claim 13
Dependent Claim
121 words
In an apparatus for moving magnetic bubble domains in a magnetic medium which includes said magnetic medium and first means for applying magnetic fields to said medium for moving bubble domains therein, the improvement comprising: second means for producing a planar bias field in the plane of said magnetic medium which is dependent only on material parameters of said magnetic medium, said planar bias field being substantially independent of any other magnetic fields which are applied to said magnetic medium, said planar bias field H.sub.p being related to the material parameters of the magnetic medium by the expression: H.sub.p .gtorsim. 4(2.pi.A).sup.1/2 /h where A is the exchange coefficient of the magnetic medium and h is the thickness of the magnetic medium.
Claim 14
Dependent Claim
121 words
In an apparatus for moving magnetic bubble domains in a magnetic medium which includes said magnetic medium and first means for applying magnetic fields to said medium for moving bubble domains therein, the improvement comprising: second means for producing a planar bias field in the plane of said magnetic medium which is dependent only on material parameters of said magnetic medium, said planar bias field being substantially independent of any other magnetic fields which are applied to said magnetic medium, said planar bias field H.sub.p being related to the material parameters of the magnetic medium by the expression: H.sub.p .gtorsim. 4(2.pi.A).sup.1/2 /h where A is the exchange coefficient of the magnetic medium and h is the thickness of the magnetic medium.
References Cited (Backward Citations)
US3602911A
Cited
US3662359A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |