Parameter dependencies of characteristics of a high‐Tc dc superconducting quantum interference device

Comprehensive comparison between theory and experiment has been made on the characteristics of a high‐Tc dc superconducting quantum interference device (SQUID). Using the theoretical expressions for the SQUID characteristics, we can quantitatively predict the transfer function Vφ and the magnetic‐flux noise SΦ from SQUID parameters without any adjustable parameter. It is shown that the theoretical predictions agree well with the experimental results for a wide range of SQUID parameters. This agreement shows the usefulness of the present theory in the design of the high‐Tc SQUID. Exceptional deviations between theory and experiment are the absolute values, i.e., the factor of 0.6 difference in Vφ and the factor of 10 difference in SΦ. Possible reasons for these discrepancies are discussed.

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