TRANSMISSION ELECTRON-MICROSCOPIC CHARACTERIZATION OF METAL-ORGANIC CHEMICAL-VAPOR DEPOSITION-DERIVED SUPERCONDUCTING TL2BA2CA1CU2OX THIN-FILMS ON AU-SUBSTRATES - EVIDENCE FOR AU-CU ALLOY FORMATION AND TEXTURING ON A NONPLANAR METAL-SUBSTRATE

The microstructure of superconducting Tl2Ba2CaCu2Ox thin films grown o n Au substrates by metal-organic chemical vapor deposition (MOCVD) has been investigated. Characterization techniques included X-ray diffrac tion, variable temperature magnetization, scanning and transmission el ectron microscopy (SEM and TEM, respectively) and energy dispersive X- ray spectroscopy (EDX) measurements. The films exhibit a magnetically derived T(c) almost-equal-to 80 K and a high degree of texturing with the crystallite c-axes oriented perpendicular to the Au substrate surf ace as evidenced by enhanced (001) X-my diffraction reflections. SEM/E DX and TEM/EDX provide evidence of Au-Cu alloy formation but no Au dif fusion into the film. The superconducting grains exhibit good composit ional uniformity and excellent alignment with the substrate, even thou gh the Au substrates were not smooth and exhibited a moderate density of steps.