Microwave impedance of a thin-film superconducting ring containing a Notarys proximity effect weak link

Abstract

The properties of thin tin film superconducting rings containing a proximity effect weak link have been measured at 9.2 GHz. The impedance exhibits steps which at low order are uniformly spaced and are not hysteretic. The magnitude of the field‐modulated component of the power reflected from the cavity resonant at 9.2 GHz is approximately 10² times larger than the signal obtained at 30 MHz and has a signal‐to‐noise ratio of 10⁴ in a 10 cycle bandpass. Higher‐order steps exhibit unexpected features which might be due to the fact that the time between flux entry is comparable to the quasiparticle relaxation time.