A Study of the Crystal Structure of SmCaCo1−xFexO4−δ and Sm0.9Ca1.1Fe1−yCoyO4−δ Solid Solutions

Resumo

Complex oxides with general compositions SmCaCo_1−xFe_xO_4−δ and Sm_0.9Ca_1.1Fe_1−yCo_yCO_4−δ are synthesized using the glycerol-nitrate technique at 1100 °C in air. By powder X-ray diffraction it is determined that SmCaCo_1−xFe_xO_4−δ solid solutions exist in a composition range 0 ≤ x ≤ 0.3 and Sm_0.9Ca_1.1Fe_1−yCo_yO_4−δ solid solutions exist in a composition range 0 ≤ y ≤ 0.7. The samples with high concentrations of cobalt ions are found to crystallize in the tetragonal unit cell (space group I4/mmm), whereas the solid solutions enriched with iron ions have the orthorhombic structure (space group Bmab). For all single phase samples the unit cell parameters and volume and the structural parameters (atomic coordinates and bond lengths) are calculated by the full-profile Rietveld method.