Epitaxial superconducting thin films Tl0.78Bi0.22Sr1.6Ba0.4Ca2O9−δ on (001) YSZ synthesized by laser ablation and post-annealing in pure argon

Abstract Epitaxial superconducting thin films of Tl 0.78 Bi 0.22 Sr 1.6 Ba 0.4 Ca 2 Cu 3 O 9−δ ((Tl,Bi)-1223) on (001) YSZ single crystal substrate have been successfully synthesized by laser ablation and post-annealing in a tube furnace with flowing pure argon through the tube all the time during annealing. X-ray diffraction (XRD) θ–2θ spectra showed that the films are c -axis aligned 1223 phase with a small amount of intergrown 1212 phase, while XRD φ-scans revealed that the films are also a - and b -axes aligned, with an epitaxy of the &.lang;100&.rang; of (Ti,Bi)-1223 film on the &.lang;110&.rang; of the YSZ substrate. Four-terminal electrical transport measurements showed that the zero-resistance transition temperature ( T c ) was 108.5 K, and the critical current density ( J c ) at 77 K and zero field was 1.1 × 10 6 A/cm 2 , both for the entire film width and 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) LaAlO 3 .