Abstract
We reconsider the problem of the measurements of the microwavecomplex surface impedance in thin superconducting films deposited onSrTiO3 substrates. We perform measurements of the complex surface impedanceZs′ = Rs′+iΔXs′ of thinYBa2Cu3O7−δ films deposited bylaser ablation on SrTiO3 substrates. The typical oscillations due to the strong temperature variation of theSrTiO3 permittivityare confirmed in Rs′ and observed in ΔXs′.The effects of the SrTiO3 substrate are evident even well below the superconducting transition temperature ofYBa2Cu3O7−δ. Similarly to previous works, we describe the overall response in terms of impedancetransformations. We extend the known results by (i) considering the measurements of theimaginary part, (ii) comparing the measurements to the absolute dc resistivity measured onthe same sample, and (iii) suggesting a method for measuring the intrinsic thin filmsurface impedance by adjusting the substrate impedance. To demonstrate thefeasibility of microwave measurements of intrinsic properties of films grown ontoSrTiO3 substrates, we check the proposed method by measuring the field dependent surfaceimpedance before and after removal of the substrate resonance.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
