Structural investigation of anion-deficient manganites La0.7Sr0.3MnO3-δ

The crystal structure of the anion-deficient manganites La0.7Sr0.3MnO3-delta (delta = 0, 0.10, 0.15, 0.20) is investigated using high-resolution neutron diffraction. At room temperature, the crystal structure of the stoichiometric manganite La0.7Sr0.3MnO3 and the anion-deficient manganite La0.7Sr0.3MnO2.9 is satisfactorily described in rhombohedral space group c. The anion-deficient manganite La0.7Sr0.3MnO2.85 is characterized by two perovskite phases with space groups R14/mcm. The crystal structure of the La0.7Sr0.3MnO2.8 manganite corresponds to the structure of a perovskite phase with space group 14/mcm. It is established that the phase separation in the crystal structure of the La0.7Sr0.3MnO3-delta manganites at a temperature of 293 K is associated with a nonuniform distribution of oxygen vacancies.