US3640864A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferrimagnetic semiconducting material and devices made therefrom
Assignee: AT&T Inc
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Filing: 1969-11-18
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Granted: 1972-02-08
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Expires: 1989-11-18
Abstract
Abstract This discovery of a system of materials exhibiting ferrimagnetic and semiconducting properties at room temperature, makes possible the development of classes of devices not previously realizable in the absence of refrigeration. These materials in polycrystalline and single-crystal form find application in such devices as optically modulated magnetic devices, microwave amplifiers with built-in isolation and memory elements with built-in gain.
Inventors
- 👤 Murray Robbins
- 👤 Raymond Wolfe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:45
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/40; H01F1/401; H10; H10P; H10P95/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
56 words
A circuit element comprising a body consisting essEntially of a material possessing both ferrimagnetic and semiconducting properties together with conducting means for passing an electrical current therethrough characterized in that the composition of said material is represented by the chemical formula Fe1 xCr2 xS4, where the composition variable, x, has a value from 0.1 to 1.9.
Claim 2
Dependent Claim
21 words
Circuit element of claim 2 in which said composition variable, x, of the said material has a value greater than 0.3.
References Cited (Backward Citations)
US3448053A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |