US3725819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Supercurrent devices with enhanced self-field effects
Assignee: AT&T Inc
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Filing: 1971-07-26
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Granted: 1973-04-03
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Expires: 1991-07-26
Abstract
Abstract A supercurrent device comprising a pair of weak-link regions connected in a superconducting loop is driven by a current source. In series with the loop is an inductor for generating a magnetic field (i) proportional to the current flowing through the loop and (ii) the flux of which extends through the loop. The device, which exhibits both negative resistance and discrete supercurrent states at zero voltage, functions in several ways including: as a negative resistance oscillator, as a memory device, or as a highly sensitive linear magnetometer.
Inventors
- 👤 T Fulton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:48
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/44; G01; G01R; G01R33/00; G01R33/02; G01R33/035; G01R33/0354; H; H03; H03B; H03B15/00; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/853; Y10S505/854
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
106 words
A supercurrent device comprising a supercurrent interferometer to which a current source is connectable and which includes a pair of weak-link regions, and a closed superconducting path electrically connecting said regions in parallel with respect to the flow of current from said source, said path forming a ring-like structure enclosing an area capable of being penetrated by a magnetic field, and characterized by means adapted to be responsive to the flow of current from said source and through said interferometer for generating in said area a magnetic field proportional both to said current and to the magnetic coupling strength between said generating means and said structure.
Claim 2
Dependent Claim
106 words
A supercurrent device comprising a supercurrent interferometer to which a current source is connectable and which includes a pair of weak-link regions, and a closed superconducting path electrically connecting said regions in parallel with respect to the flow of current from said source, said path forming a ring-like structure enclosing an area capable of being penetrated by a magnetic field, and characterized by means adapted to be responsive to the flow of current from said source and through said interferometer for generating in said area a magnetic field proportional both to said current and to the magnetic coupling strength between said generating means and said structure.
Claim 3
Dependent Claim
22 words
The device of claim 1 wherein said responsive means comprises at least one inductance coil electrically connected in series with said interferometer.
Claim 4
Dependent Claim
126 words
The device of claim 1 wherein: in the absence of said responsive means the relationship between the critical supercurrent of said device and the magnitude of a magnetic field penetrating said area is a function which oscillates periodically with changing field; the total magnetic flux Phi TOT penetrating said area is given approximately by the equation Phi TOT Phi ext - MI where M is said coupling strength, I is the current flowing in said path and Phi ext is the magnitude of flux contributions of all other magnetic fields penetrating said area; and for a particular Phi ext the value of M is adjusted so that the line defined by said equation is approximately tangent to said function at a point of maximum slope thereof.
Claim 5
Dependent Claim
60 words
The device of claim 1 wherein the current-voltage characteristic of said device has at least one region of negative differential resistance, and including a resonant circuit electrically coupled to said device and having an equivalent resistance representing dissipative losses therein, and means for biasing said device in one of said regions so that said negative resistance exceeds said equivalent resistance.
Claim 6
Dependent Claim
52 words
The device of claim 4 wherein: said resonant circuit comprises at least one capacitor connected in parallel with at least one inductor; and the output taken across said circuit oscillates at an angular frequency of approximately (LC)thus 1/2, L and C being, respectively, the total parallel inductance and capacitance of said circuit.
Claim 7
Dependent Claim
20 words
The device of claim 5 including at least one blocking capacitor connected in series between said device and said circuit.
Claim 8
Dependent Claim
44 words
The device of claim 1 wherein the current-voltage characteristic of said device has a plurality of discrete supercurrent regimes at zero voltage separated by finite-voltage, nonsupercurrent regimes and including means for causing said device to operate in a selected one of said supercurrent regimes.
Claim 9
Dependent Claim
47 words
The device of claim 7 wherein operation in each of said discrete supercurrent regimes generates a different magnitude of magnetic field penetrating Said area of said ring-like structure, and including means for detecting said field to determine in which one of said regimes said device is operating.
Claim 10
Dependent Claim
15 words
The device of claim 1 in combination with a current source connected to said interferometer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |