Crystal structure of the mixed oxides La0.7Sr0.3Co1-zMnzO3±y (0 ≤ z ≤ 1)

The crystal structure and nonstoichiometry of several compositions in the system La0.7Sr0.3Co1-zMnzO3±y (0 ≤ z ≤ 1) have been investigated by powder X-ray diffraction (PXD), powder neutron diffraction (PND), thermogravimetry (TG), including full reduction in hydrogen, and chromatometric titration. The system formed solid solutions over the entire compositional range (0 ≤ z ≤ 1) crystallizing in the rhombohedral structure (space group R bar 3c). The lattice constant increased with increasing Mn content z. The cation stoichiometry (occupancy) was calculated from refinement of PXD data, and oxygen positions and occupancies were calculated from PND data. These results confer with the TG and chemical analysis of oxygen content in that the Co-rich compositions exhibit oxygen deficiency (oxygen vacancies), while the Mn-rich compositions exhibit oxygen excess in the form of metal vacancies