Complex microwave conductivity of Pr1.85Ce0.15CuO4-δ thin films using a cavity perturbation method

We report a study of the microwave conductivity of electron-doped Pr1.85Ce0.15CuO4-delta superconducting thin films using a cavity perturbation technique. The relative frequency shifts obtained for the samples placed at a maximum electric field location in the cavity are treated using the high conductivity limit presented recently by Peligrad [Phys. Rev. B 58, 11652 (1998)].Using two resonance modes, TE102 (16.5 GHz) and TE101 (13 GHz) of the same cavity, only one adjustable parameter Gamma is needed to link the frequency shifts of an empty cavity to the ones of a cavity loaded with a perfect conductor. Moreover, by studying different sample configurations, we can relate the substrate effects on the frequency shifts to a scaling factor. These procedures allow us to extract the temperature dependence of the complex penetration depth and the complex microwave conductivity, properties that are highly sensitive on the quality of the films.