Electrical characteristics of thin-film Ba sub(2)YCu sub(3)O sub(7) superconducting ring resonators

The development of high-temperature superconducting thin films has opened up new opportunities for microstrip applications to exploit the low-loss properties of these films. It is reported that the microwave performance of superconducting microstrip ring resonators between 2 and 22 GHz for which both microstrip and ground plane were fabricated from Ba sub(2)YCu sub(3)O sub(7) films deposited on both sides of the same LaAlO sub(3) substrate. At 9.5 GHz, resonances were observed with intrinsic Q's of similar to 7500 at 75 K and similar to 20,000 at 25 K. The 75 K value represents an improvement of a factor 20 over Au.