Microwave Power Dependence of Surface Resistance of High-Temperature Superconductor YBa2Cu3Oy Films by Dielectric Resonator Method

The microwave power dependence of the surface resistance of YBa2Cu3Oy films of two different surface morphologies was measured using the dielectric resonator method. The dielectric resonator consisted of a high-quality sapphire rod sandwiched between two superconductor films. Measurements showed that the microwave power dependence of the surface resistance strongly depended on the surface morphology of the YBa2Cu3Oy film though the surface resistance of those films at low microwave power was comparable. In conclusion, the surface morphology is one of the reasons of the power dependence which is crucial for high power applications.