PHYSICAL MECHANISMS CAUSING NONLINEAR MICROWAVE LOSSES IN HIGH-TC SUPERCONDUCTORS

We present a short overview of the mechanisms of microwave losses in high-Tc superconductors with special attention to high-power losses. An impedance plane analysis is used as a tool for quantitative comparison of the experimental data to the models. We discuss several models of nonlinear microwave performance of high-Tc superconductors, including coupled-grain and rf-critical state models, and estimate their characteristic time scales. 1