Influence of A- and B-site substitutions on crystal structure and oxygen content in air-prepared Ba1−xPrxFe1−yCoyO3−δ perovskites

• Published in: Journal of alloys and compounds 2021-04, Vol.860, p.1, Article 158438
• Main Authors: Volkova, N.E., Bazueva, M.V., Aisarinova, D.T., Alkhamova, A.D., Gavrilova, L.Ya, Cherepanov, V.A., Maignan, A.
• Format: Article
• Language: English
• Subjects: Crystal structure; Orthorhombic phase; Oxide materials; Oxygen content; Perovskites; Phase diagrams; Room temperature; Titration; Unit cell; X-ray diffraction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.158438

•The homogeneity ranges for the Ba1−xPrxFe1−yCoyO3−δ solid solutions were evaluated.•Crystal structure for the Ba1−xLnxFe1−yCoyO3−δ solid solutions was refined.•The values of oxygen content in Ba1−xPrxFe1−yCoyO3−δ were determined.•The pseudo-phase diagram has been constructed for the room temperature conditions. [Display omitted] The study of 96 samples of various compositions (x, y) in the Ba1−xPrxFe1−yCoyO3−δ system, prepared in air by the glycerol-nitrate method, made it possible to establish the compositional boundaries of stability for three types of crystal structure: 1) layered 112-type PrBaCo2−yFeyO5+δ (x = 0.5; 0 ≤ y ≤ 0.6) A-site ordered perovskite, 2) cubic perovskite phase (SG Pm-3m) within 0 ≤ x ≤ 0.6 and for which y depends on the Pr (x) content, and 3) orthorhombic phase (SG Pbnm) within 0.7 ≤ x ≤ 1. The unit cell parameters for the cubic and orthorhombic perovskites were refined by the Le-Bail or Rietveld analysis. The values of oxygen content, determined by the iodometric titration and TGA, are found to increase with Pr and Fe contents. The stability ranges for all three types of complex oxides, together with the multi-phase fields, were outlined for the room temperature conditions in a form of pseudo-phase diagram.