Variable superconducting quantum-interference device: Theory

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.36.74· OSTI ID:5915264

Fink, H J; Gruenfeld, V; Roberts, S M

A dc superconducting quantum interference device (SQUID) consisting of a symmetric ring circuit with four Josephson junctions and two independent external currents I/sub 1/ and I/sub 2/, which enter the circuit at different points, has a phase boundary between the fully superconducting and the normal states that is different from that of a conventional SQUID. The control current I/sub 2/ modifies the magnetic flux (phi) periodicity and the value of the maximum measuring current I/sub 1//sub m/(phi). For values of I/sub 2/>I/sub c/ (critical current of Josephson junction) the fully resistive state exists over flux intervals centered around (n+(1/2)phi/sub 0/, where n is an integer and phi/sub 0/ is the fluxoid quantum. A superconducting circuit without Josephson junctions is suggested which should have a phase boundary similar to that found here. Minimization procedures which are usually employed in analyzing SQUID's are discussed.

• Research Organization: Department of Electrical and Computer Engineering, University of California, Davis, Davis, California 95616
• OSTI ID: 5915264
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 36:1; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CRITICAL CURRENT
CURRENTS
ELECTRIC CURRENTS
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUXMETERS
GINZBURG-LANDAU THEORY
JOSEPHSON JUNCTIONS
JUNCTIONS
MAGNETIC FLUX
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
ORDER PARAMETERS
RINGS
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTING JUNCTIONS
VARIATIONAL METHODS