Synthesis and Structural Characterization of Hg(Re)-Pb-Ca-Ba-Cu-O Superconducting Thin Films Grown by Spray Pyrolysis

Abstract

We present a statistical study of the crystalline phase distribution in Pb-Ca-Ba-Cu-O precursor films grown by spray pyrolysis technique, with thickness and composition suitable to incorporate Hg by the sealed quartz tube technique in a subsequent treatment. A series of 9 precursor thin films were deposited on MgO substrates. Interdependence among deposition temperature, solution concentration, annealing temperature and annealed time and the effect in the relative percentage of each precursor phases was studied, applying a fractional factorial design 3IV-II. Chemical composition was obtained from atomic absorption measurements. Crystalline phase identification was performed by X-ray diffraction technique (XRD) and the quantification of each one was carried out by Rietveld method. The BaPbO3, Ba4Pb3O10 ternary phases were obtained at 810°C, and the BaCuO2 phase was got between 835°C and 860°C. Deposition temperature and molarity of the solution have clear influence on the thickness of the film. The effect of deposition temperature on the film composition was observed. Introduction