Intermodulation measurements in YBaCuO films

A technique for measuring the intermodulation signal arising in a nonlinear high-temperature superconductor film is suggested. Using a one-port resonator, the technique significantly increases sensitivity of the measuring system as compared to that of a two-port-resonator design. Specifically, it lowers the minimum measurable power at a given magnetic field strength on the film surface. Measurements of the intermodulation signal power as a function of the input power for YBaCuO films differing in surface resistance and thickness are reported. Based on the measured data, the intermodulation characteristic magnetic field is computed. The quantity characterizes nonlinear film properties of the regardless of the measuring system employed. (C) 2000 MAIK "Nauka/Interperiodica".