TEXTURE AND TRANSPORT IN SPRAY PYROLYZED TLBA2CA2CU3O9 THICK-FILMS

The electron backscattering pattern technique has been applied to the microstructural investigation of Tl(1223) thick films formed by vapor- phase thallination of Ag-containing Ba-Ca-Cu-oxide precursors. For sam ples grown on polycrystalline YSZ, considerable biaxial alignment is f ound in localized, multigrain regions as wide a 100 mu m or more. Howe ver, on scales above 1 mm the overall texture remains only uniaxial wi th the c-axes (i.e., [001]) aligned perpendicular to the plane of the substrate. On single-crystal KTaO3 an epitaxial relationship is eviden t which persists to the surface of a 3 mu m thick film. Modest variati ons in the processing protocol yield films containing grains oriented with the c-axis in the plane, resulting in the degradation of transpor t properties. The data suggest a growth mode in which sparse nucleatio n occurs at the substrate followed by rapid lateral crystallization.