Fabrication of Sr2AlTaO6/YBCO interface-controlled junctions

We fabricated ramp-edge Josephson junctions with barriers formed by interfa ce treatments instead of epitaxially grown barrier layers. A low-dielectric Sr2AlTaO6(SAT) layer was used as an ion-milling mask as well as an insulat ing layer for the ramp-edge junctions. An ion-milled YBa2Cu3O7-x (YBCO)-edg e surface was not exposed to solvent through all fabrication procedures. Th e barriers were produced by structural modification at the edge of the YBCO base electrode using high energy ion-beam treatment prior to deposition of the YBCO counterelectrode. We investigated the effects of high energy ion- beam treatment, annealing, and counterelectrode deposition temperature on t he characteristics of the interface-controlled Josephson junctions. The spr eads in the critical current (I,) as well as the junction parameters such a s T-c, I-c, R-N were measured and discussed in relation to the interface st ates.