High-temperature superconducting resonators

The authors report preliminary measurements on high-T/sub c/ superconducting resonators and discuss why these resonators are attractive candidates for incorporation in low-noise oscillators. Some of the important contributions to oscillator noise are reviewed, and it is shown that they depend on the resonator parameters. A preliminary YBa/sub 2/Cu/sub 3/O/sub 7//LaAlO/sub 3/ resonator with a Q of 9*10/sup 4/ at 6.9 GHz and 7*10/sup 4/ at 3.5 GHz has been fabricated. The temperature sensitivity, power dependence, and residual phase-noise are discussed. An upper limit on the coefficient of the 1/f component of fractional-frequency fluctuations has been measured to be -204 dB at 60 K.<
>