X-ray and neutron diffraction analysis of Ca-Sr-Ti-Fe-O compounds

Abstract

CaTiyFe1-yO3-δ, SrTiyFe1-yO3-δ and Ca0.5 Sr0.5TiyFe1-yO3-δ (y~0.65) compounds were synthesized by the polymeric precursor technique and by the ceramic route. The resins resulting from the chemical synthesis were calcined in the 400-1000ºC range producing powders with different average particle sizes, evaluated by the laser scattering technique. Room temperature and in situ high temperature (θ-θ Bragg-Brentano configuration up to 1200ºC with Anton Paar high temperature sample chamber and Braun position sensitive detector) X-ray diffraction, high resolution X-ray diffraction as well as room temperature neutron diffraction experiments (with improved data collection by position sensitive detectors) were carried out in powders heat treated for several hours to increase the average crystallite sizes. Rietveld analyses were performed for structural phase evaluation. Lattice parameter determinations show the partial substitution of Ca2+ for Sr2+, and the perovskite ABO3 cubic/orthorhombic structures.