High-Q YBa2Cu3O7-delta microwave ring oscillators

Abstract

YBa2Cu3O7-delta(YBCO) superconducting ring resonators with YBCO ground plane were fabricated. The resonators exhibit a high quality (Q > 10(4)) at 16 It, indicating high potential for applications. In addition, from the analyses of the surface resistance R-s(T) and reactance X-s(T), it was found that the derived London penetration depth lambda(T) - lambda(5 K) displays a linear behavior over a wide range of temperatures. The results suggest that a distinct line node feature in the gap function of a d-wave pairing superconductor may extend to temperatures higher than previously reported. (C) 2000 Elsevier Science B.V. All rights reserved.