Performance of a fully superconducting microwave cavity made of the high T c superconductor Y1Ba2Cu3Oy

We report the successful fabrication and characterization of a high Tc superconducting microwave cavity. The cavity made of bulk Y1Ba2Cu3Oy (Tc=93 K) and dielectrically loaded with sapphire was resonant at 8.00 GHz in the TE011 mode. At 77 K the Q was 104, which represents an improvement of a factor of 11 from the normal state. At 4.2 K the Q was nearly 105. The temperature dependence of the Q correlates extremely well with the microwave surface resistance of a test sample measured independently, clearly showing that the Q was limited by the intrinsic materials preparation and not by extraneous factors.