PREPARATION AND CHARACTERIZATION OF TL-BA-CA-CU-O 2212 SUPERCONDUCTING THICK-FILMS

Tl2Ba2CaCu2Ogamma superconducting films of high phase purity with thic knesses from 3 to 4 mu m have been prepared on polycrystalline 3 mol% Y2O3-doped ZrO2 substrates. The precursor material was deposited from aerosols prepared by an ultrasonic nebulizer. Thallination was carried by wrapping a Tl-source with the precursor material in a silver foil and annealed at 830 and 815 degrees C. The resistance measurements sho wed T-c(0)-values of 98 K with transition widths of 6-7 K. The microst ructure of the film and the chemical composition of the well-developed crystallites were investigated by scanning electron microscopy in com bination with EDX. The superconducting films showed good adhesion to t he substrate and preferred c-axis orientation. Isolated particles (0.3 -1 mu m) of secondary phases, especially barium-copper-oxides were fou nd at the interface of the superconducting film and the substrate. (C) 1998 Elsevier Science B.V. All rights reserved.