Stationary states of superconducting interferometers with series junctions

Journal Article · Sat Feb 01 00:00:00 EST 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.2319· OSTI ID:7276271

Lewandowski, S J ^[1]

---

1. Instytut Fizyki PAN, Aleja Lotnikow 32, PL 02-668 Warszawa (Poland)

A superconducting interferometer composed of two parallel arrays of series connected Josephson junctions (a simplified model of a high-{ital T}{sub {ital c}} granular superconductor) is considered. The interferometer is supplied by dc current {ital J} from an external source and is linked by an externally applied magnetic flux {Phi}{sub {ital e}}. We consider the associated problems of finding the stationary values of the current in function of {Phi}{sub {ital e}} and stationary values of flux in function of {ital J}. It is shown that both problems have identical solutions, which can be obtained by finding the extrema of a properly defined energy function {ital G} relative to the conditions given by the set of differential equations {ital dJ}=0, {ital d}{Phi}{sub {ital e}}=0, and one of the two conditions found to be complementary, either the fluxoid conservation relationship or the definition of the induced flux {Phi}{sub {ital i}} in terms of currents {ital J}{sub 1} and {ital J}{sub 2} through the arrays ({ital J}={ital J}{sub 1}+{ital J}{sub 2}). The dc Josephson equations and the other of the two magnetic'' constraints are then derived as necessary conditions for the existence of energy extremum, i.e., it suffices that these relations are satisfied only locally at the extremum, a result which can be useful in the investigation of nonequilibrium processes. The stationary values, {ital G}{sup {l angle}{ital {cflx m}}{r angle}}, of {ital G} are found to depend only on {ital cphi}{sub 1} and {ital cphi}{sub 2}({ital cphi}{sub 1}), the superconducting phase differences across the weakest junction in each array.

• OSTI ID: 7276271
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 45:5; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HIGH-TC SUPERCONDUCTORS
GRAIN BOUNDARIES
SUPERCONDUCTING DEVICES
INTERFEROMETERS
SQUID DEVICES
HYSTERESIS
JOSEPHSON JUNCTIONS
CRYSTAL STRUCTURE
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUXMETERS
JUNCTIONS
MEASURING INSTRUMENTS
MICROSTRUCTURE
MICROWAVE EQUIPMENT
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTORS
665412* - Superconducting Devices- (1992-)