A method based on a dual frequency resonator to estimate physical parameters of superconductors from surface impedance measurements in a magnetic field

High frequency applications of superconductors in a dc magnetic field rely on the estimate of the characteristic crossover frequency nu(c) between low and high losses. Customarily, high sensitivity resonant techniques, intrinsically operating at discrete frequencies, are used to estimate nu(c). We exploit here a method based on a dual frequency resonator. We show that single-frequency evaluations of nu(c) lead to heavy underestimations of the superconductor surface resistance. We describe a combined analytical and experimental approach that gives more accurate estimates for nu(c), and additionally allows to test the underlying physical model.

Automated summary

The text discusses the estimation of characteristic crossover frequency ν(c) between low and high losses in high frequency applications of superconductors in a dc magnetic field. It highlights the limitations of single-frequency evaluations in underestimating the superconductor surface resistance. A combined analytical and experimental approach is proposed for more accurate estimates of ν(c) and testing the underlying physical model.