Synthesis and properties of superconducting (Tl,Pb)-(Sr,Ba)-Ca-Cu-O thick films on Ag

We report successful texturing of screen-printed (Tl,Pb)-(Sr,Ba)-Ca-Cu-O thick (20 /spl mu/m) films on both LaAlO/sub 3/ and Ag foil using rapid thermal processing (RTP) followed by furnace annealing. An RTP cycle to /spl ap/915/spl deg/C for 20 seconds in Ar produces massive melting of the superconducting powder but not the Ag substrate. Subsequent annealing under O/sub 2/ in sealed Au foil with a Tl source yields a brick-wall microstructure consisting of c-axis aligned, plate-like grains. X-ray diffraction and Meissner data show a mixture of the Tl-1223 and Tl-1212 phases while energy-dispersive spectroscopy identifies the plate-like grains as the desired Tl-1223. Magnetization data suggest intergranular supercurrents flowing across the entire film. Critical current densities inferred from hysteresis are 9/spl times/10/sup 4/ A/cm/sup 2/ at 5 K in low fields, decreasing by a factor of 5 in 5 tesla.<
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