Superconducting Tl-Ca-Ba-Cu-O thin film microstrip resonator and its power handling performance at 77 K

Measurements of the temperature- and power-dependent surface resistance, R/sub s/ of thin films of Tl-Ca-Ba-Cu-O at 9.55 GHz are reported. At 77 K these films are at least 20 times better than bulk OFHC (oxygen-free, high-frequency) Cu at the same temperature and frequency in microwave magnetic fields up to 10 G. Measurements of the power-handling performance at 77 K of a high-Q, thin-film microstrip resonator made with these films are reported. Loaded Qs up to 7300 at 2.6 GHz, more than 20 times higher than on identical silver resonators, are reported. At effective power levels in the resonator up to approximately 100 W, the Q was still at least three times higher than the silver resonator at all measured frequencies (2.6, 5.2, and 7.3 GHz).<>