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US3587069A
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Ferromagnetic thin-film memory element and a method of recording information therein
Assignee: Zaidan Hojin Parametron Kenkyusho (Parametron)
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Filing: 1969-11-24
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Granted: 1971-06-22
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Expires: 1989-11-24
Abstract
Abstract A ferromagnetic thin-film memory, made of two film layers of ferromagnetic material in which the thickness d, and anisotropy field constant Hk1 of the one layer and the thickness d2, anisotropy field constant Hk2 and saturation magnetization Ms2 of the second layer are selected so that the constant Hk2 is much larger than the constant Hk1 and satisfy the relationship: D1 X D2 X Ms2 X Hk2 1 X 10 6erg/cm 2 X 10 5 AND THE METHOD OF RECORDING ON THE FILM.
Inventors
- 👤 Eiichi Goto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:08
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/02; G11C11/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
A method for writing information on a multiple layer memory element, said element having adjacent layers of unlike substances, disposed in intimate molecular contact with each other, comprising Rotating a magnetic field in an X,Y plane of said memory element, said rotating magnetic field being started at an origin in said X,Y plane, and being rotated through said X,Y plane in a cyclical manner to terminate at said origin, wherein said field is rotated in a cyclical manner by applying a first pulse to direct the field in one direction along the Y-axis, applying a second pulse to direct the field in one direction along the X-axis while maintaining said first pulse, terminating said first pulse while maintaining said second pulse, applying a third pulse to direct the field in the other direction along said Y-axis while maintaining said second pulse, terminating said second pulse while maintaining said third pulse, and then terminating sad third pulse to complete a cycle.
Claim 2
Independent Claim
160 words
A method for writing information on a multiple layer memory element, said element having adjacent layers of unlike substances, disposed in intimate molecular contact with each other, comprising Rotating a magnetic field in an X,Y plane of said memory element, said rotating magnetic field being started at an origin in said X,Y plane, and being rotated through said X,Y plane in a cyclical manner to terminate at said origin, wherein said field is rotated in a cyclical manner by applying a first pulse to direct the field in one direction along the Y-axis, applying a second pulse to direct the field in one direction along the X-axis while maintaining said first pulse, terminating said first pulse while maintaining said second pulse, applying a third pulse to direct the field in the other direction along said Y-axis while maintaining said second pulse, terminating said second pulse while maintaining said third pulse, and then terminating sad third pulse to complete a cycle.
Claim 3
Independent Claim
164 words
A method of writing on a multiple layer thin film memory element including abutting hard and soft layers disposed in intimate molecular contact and having substantially common easy-axis directions of magnetization along the X-axis of an X,Y plane, at the abutting faces of said layers, comprising applying external fields to rotate a magnetic field of the soft layer through a cycle by starting at an origin point in said X, Y plane and rotating the direction of magnetization to finally return to said origin point, wherein said magnetic field is rotated by applying a first pulse to direct the field in one direction along the Y-axis, applying a second pulse to direct the field in one direction along the X-axis while maintaining said second pulse, applying a third pulse to direct the field in the other direction along said Y-axis while maintaining said second pulse, terminating said second pulse while maintaining said third pulse, and then terminating said third pulse to complete a cycle.
Claim 4
Independent Claim
164 words
A method of writing on a multiple layer thin film memory element including abutting hard and soft layers disposed in intimate molecular contact and having substantially common easy-axis directions of magnetization along the X-axis of an X,Y plane, at the abutting faces of said layers, comprising applying external fields to rotate a magnetic field of the soft layer through a cycle by starting at an origin point in said X, Y plane and rotating the direction of magnetization to finally return to said origin point, wherein said magnetic field is rotated by applying a first pulse to direct the field in one direction along the Y-axis, applying a second pulse to direct the field in one direction along the X-axis while maintaining said second pulse, applying a third pulse to direct the field in the other direction along said Y-axis while maintaining said second pulse, terminating said second pulse while maintaining said third pulse, and then terminating said third pulse to complete a cycle.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |