Diagnostics of the high-T/sub c/ superconductive films in a strong electromagnetic field

The method for diagnostics of the nonlinear properties of the high-T/sub c/ superconductive films is proposed. It employs the experimentally obtained nonlinear radiocharacteristics of a superconductive resonator and takes into account the inhomogeneous distribution of the nonlinear surface impedance, caused by inhomogencity of the RF-magnetic field amplitude along a film surface. The last circumstance leads to the integral equation for surface impedance of a superconductor. The proposed method is based on solution of the inverse problem of electrodynamics. The dependences of surface resistance on the RF-magnetic field amplitude, and relationships between precision of the method and a measurement error are obtained.