High temperature superconducting microstrip resonators for the measurement of films made by pyrolysis

Microwave surface impedance measurements are reported for textured granular YBCO films made by a novel spray pyrolysis method on the surface of a YSZ substrate. A parallel plate resonator was formed by placing the film and substrate on top of a copper ground plane. Microwave measurements were made at nitrogen temperatures on the fundamental mode at /spl sim/4.7 GHz. A model has been developed to extract the penetration depth and impedance of the finite thickness granular film. We obtain values for penetration depth /spl lambda//sub g//spl sim/3.6 /spl mu/m and, using independent measurements of the critical current and grain size, a surface resistance R/sub g//spl sim/13 m/spl Omega/.