Critical current gain in superconducting transistor quantum interference devices

• Published in: IEEE transactions on magnetics Vol. 25; no. 5; pp. 4350 - 4352
• Main Author: Glasser, L.A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-09-1989; Institute of Electrical and Electronics Engineers
• Subjects: 426001 - Engineering- Superconducting Devices & Circuits- (1990-); 656100 - Condensed Matter Physics- Superconductivity; AMPLIFICATION; Applied sciences; Artificial intelligence; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRITICAL CURRENT; CURRENTS; ELECTRIC CURRENTS; ELECTRONIC EQUIPMENT; Electronics; Equations; Exact sciences and technology; FLUXMETERS; GAIN; Inductors; Interference; INTERFEROMETERS; Josephson junctions; Logic devices; MEASURING INSTRUMENTS; MICROWAVE EQUIPMENT; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; SQUID DEVICES; SQUID magnetometers; SUPERCONDUCTING DEVICES; Superconducting logic circuits; Transistor; Current gain; Superconducting quantum interferometer device; Superconductivity
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/20.42603

A superconducting quantum interference device (SQUID) built with superconducting transistors is analyzed. The sensitivity of the critical current of the interferometer to gate charge is related to the sensitivity of the superconducting transistor critical current to gate charge by a gain parameter. For two-transistor interferometers with symmetric inductors, the gain varies from -1 to 2. An increase in critical current for either device of Delta I cannot decrease the critical current of the circuit by more than Delta I, nor can it increase it by more than 2 Delta I. In special situations, the number of stored flux quanta in the circuit can be both increased and decreased by the gate charge.< >