STABILITY OF HG-BASED HIGH-T-C SUPERCONDUCTING THIN-FILMS

Stability of Hg-based superconducting thin films has been studied in a ir, acetone, alcohol, water, and thermal cycling. T-c, J(c), and surfa ce microstructures were analyzed as functions of exposure period. In d ry air, fully reacted samples did not show degradation for a period of over one year, while samples which were not fully reacted due to air contamination or other reasons degraded within a few weeks. In humid a ir, samples were totally degraded within a few minutes. It has been fo und that the films degraded considerably in alcohol and acetone after they were immersed for a few hours, while this degradation was much se vere in water. The mechanism of sample degradation has been discussed as well. (C) 1998 Elsevier Science B.V. All rights reserved.