JOSEPHSON TRANSPORT IN TL-CUPRATE BICRYSTAL WEAK LINKS

Superconducting epitaxial Tl2Ba2CaCu2O8 (Tl-2212) and Tl2Ba2CuO6 (Tl-2 2O1) thin films are synthesised on single crystal and bicrystal LaAlO3 substrates by an ex-situ process. Tl-2212 films were optically smooth , with T-c's from 105 to 108K and Delta T-c <2 K, I-c reaching 2.10(6) A/cm(2) at 77 K. Tl-2201 films exhibited tetragonal or orthorhombic s ymmetry depending on the thallium content. The T-c, of the as-synthesi sed Tl-2201 films was in the range 40-55 K. By oxygen depletion, T-c w as increased by 15 - 20 K. Properties of weak links in Tl-2212 and Tl- 2201 thin films are reported.