EPITAXIAL SUPERCONDUCTING THIN-FILMS TL0.78BI0.22SR1.6BA0.4CA2CU3O9-DELTA ON (001)YSZ SYNTHESIZED BY LASER-ABLATION AND POSTANNEALING IN PURE ARGON

Epitaxial superconducting thin films of Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9 -delta ((Tl,Bi)-1223) on (001) YSZ single crystal substrates have been successfully synthesized by laser ablation and post-annealing in a tu be furnace with flowing pure argon through the tube all the time durin g annealing. X-ray diffraction (XRD) theta-2 theta spectra showed that the films are c-axis aligned 1223 phase with a small amount of interg rown 1212 phase, while XRD phi-scans revealed that the films are also a- and b-axes aligned, with an epitaxy of the [100] of (Tl,Bi)-1223 fi lm on the [110] of the YSZ substrate. Four-terminal electrical transpo rt measurements showed that the zero-resistance transition temperature (T-c) was 108.5 K, and the critical current density (J(c)) at 77 K an d zero field was 1.1 X 10(6) A/cm(2), both for the entire film width a nd for a patterned bridge. The magnetic field dependent transport J(c) suggest that (Tl,Bi)-1223 films on (001) YSZ have better flux-pinning properties than high-J(c) (Tl,Bi)-1223 films on (001) LaAlO3.