Temperature dependence of microwave SQUID response

摘要

The response of a microwave SQUID using a Ta point contact has been measured at various temperatures giving a progression of operating conditions from the nonhysteretic to the hysteretic mode. The responses calculated by Soerensen and by Burhman and Jackel are in good qualitative agreement with the measurements. However, these theories do not appear to account for the response reported by Rachford, Wolf, Nisenoff, and Huang for thin‐film bridges. We present a calculation that exhibits explicitly the dependence of the response on Ω=Φ0ν/IcR, where ν is the microwave frequeny, Ic and R are the critical current and resistance of the junction, and Φ0 is the fluxoid quantum, and that agrees with their data and their interpretation of it in terms of a limiting time τ for the supercurrent response with τ∝Δ (T)-1 where Δ (T) is the BCS gap parameter.