US3868659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Serial access memory using thin magnetic films
Assignee: United States Department of the Navy
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Filing: 1973-04-10
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Granted: 1975-02-25
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Expires: 1993-04-10
Abstract
Abstract A serial access memory based on the propagation of cross-tie walls and Bloch lines along domain walls in thin magnetic films. Domain walls are placed on a Permalloy film on the order of 300 A thickness. Cross tie walls, Bloch lines, and inverted Neel walls are introduced into the domain walls to store the binary information. Variation of the current through conductors placed above the domain wall changes the fields along the walls causing the relocation of Bloch lines and cross ties in the wall which causes propagation of the information contained in the inverted Neel wall section along the wall.
Inventors
- 👤 Leonard J Schwee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:00
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/02; G11C19/08; G11C19/0808; G11C19/0841
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
50 words
A magnetic propagation arrangement comprising: a stationary domain wall containing Bloch lines, cross-ties, and Neel walls wherein digital information is stored in said Neel walls; means external to said domain wall for creating a field pattern on said domain wall whereby said digital information is propagated along said domain wall.
Claim 2
Dependent Claim
50 words
A magnetic propagation arrangement comprising: a stationary domain wall containing Bloch lines, cross-ties, and Neel walls wherein digital information is stored in said Neel walls; means external to said domain wall for creating a field pattern on said domain wall whereby said digital information is propagated along said domain wall.
Claim 3
Dependent Claim
20 words
A magnetic propagation arrangement as recited in claim 1 wherein said domain wall is formed on a thin film material.
Claim 4
Dependent Claim
21 words
A magnetic propagation arrangement as recited in claim 2 wherein said thin film is 80-20 Ni-Fe composition and approximately 320A thick.
Claim 5
Dependent Claim
36 words
A magnetic propagation arrangement as recited in claim 1 wherein said means external to said wall comprises variable current carrying conductors creating fields sufficient enough to move said Bloch line and relocate said cross-tie through annihilation.
Claim 6
Dependent Claim
19 words
A magnetic propagation arrangement as recited in claim 4 wherein digital ''''one'''' is contained in inverted Neel wall segments.
Claim 7
Dependent Claim
22 words
A magnetic propagation arrangement as recited in claim 5 further including means for serially inserting said digital information into said domain wall.
References Cited (Backward Citations)
US3129412A
Cited
US3138789A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |