SUPERCONDUCTING AND STRUCTURAL-PROPERTIES OF EPITAXIAL BI2SR2CACU2O8-DELTA BI2SR2YCU2O8-DELTA/BI2SR2CACU2O(8-DELTA) HETEROSTRUCTURES/

We have prepared Cu2O8-delta/Bi2Sr2YCu2O8-delta/Bi2Sr2CaCu2O8-delta tr ilayer structures, using a ''in situ'' DC-sputtering process at high o xygen pressures on (001) SrTiO3 substrates. Bi2Sr2CaCU2O8-delta films were used for superconducting electrodes and semiconductor-like Bi2Sr2 YCu2O8-delta films with thickness down 5 nm were used as barrier layer s. Both materials have the same crystalline structures and allowed the epitaxial growth of the heterstructure as shown by X-ray, RBS measure ments and cross section TEM analysis. The superconducting properties w ere examined by resistance, AC-susceptibility and current-voltage char acteristics as function of the temperature. For junctions with areas o f 120x120 mu m(2) defined by photolitography a RSJ behavior was found at temperatures below T-c.