TEMPERATURE AND TWIST ANGLE DEPENDENCES O F JOSEPHSON EFFECT MEASUREDIN [001] TWIST BOUNDARY OF BI-SUPERCONDUCTOR BICRYSTALS

Josephson junctions both direct (S/S) and indirect (S/Ag/S) with a thi n silver layer were fabricated by solid state joining of (001) surface s of two flaky Bi2Sr2CaCu2Ox single crystals. A small area junction of 100-200 mu m in diameter was fabricated by Ar+ ion selective etching of one of the two thin single crystalline superconducting Bi2Sr2CaCu2O x flakes. A silver layer with a thickness of 2-100 nm was deposited on the (001) planes by a sputtering method just prior to joining to prod uce S/Ag/S junctions. The critical current I-c of S/Ag/S junction was the function temperature with I-c=I-OH(1-T/T-c)(2) for T greater than or equal to 0.6T(c), and I-c=I-OL exp (-GT(1/2)) for T less than or eq ual to 0.5T(c). High I-c values were obtained when the [001] twist ang le theta was 23 degrees, 28 degrees and 37 degrees. It was indicated t hat the Josephson effect is strongly influenced by both the temperatur e T and the [001] twist angle theta in the S/S and S/Ag/S junctions.