Long term stability of YBCO-based Josephson junctions

We report on a study of long term aging in three different types of YBa/sub 2/Cu/sub 3/O/sub 7-x/ Josephson junctions. Junction aging will affect the choices made in integrating this technology with actual applications. The junction types used in this study are (a) Co-doped barrier edge SNS junctions, (b) noble-metal SNS step-edge junctions, and (c) bicrystal junctions which are either unpassivated or passivated in situ with a normal metal shunt or an epitaxial insulator. While all the junctions show degradation, for some the long term survival rate is encouraging.