Characterization of the Parameters of Superconducting NbN and NbTiN Films Using Parallel Plate Resonator

This work is dedicated to the determination of parameters of superconducting NbN and NbTiN films such as critical temperature, normal state conductivity, ratio between the gap and critical temperature and parameter incorporating the quasiparticle states inside the gap that emerge due to strong-coupling effects. The measurements were performed using a parallel plate resonator method. From the experiment, the dependence of London penetration depth on temperature was obtained. The experimental data were fitted using the expressions of Mattis-Bardeen theory extended by the consideration of strong-coupling effects. In order to design the experimental setup and visualize the results a modeling in Ansys HFSS was performed.