Crystal structure phase separation in anion-deficient La0.70Sr0.30MnO3 − δ manganite system

Abstract

The crystal structure of anion-deficient La0.70Sr0.30MnO3 − δ manganite powders (δ = 0, 0.10, 0.15, 0.20) has been investigated at room temperature by the neutron diffraction method using a high-resolution Fourier diffractometer. The structure data have been refined by the Rietveld method. The crystal structures of the stoichiometric La0.70Sr0.30MnO3 and anion-deficient La0.70Sr0.30MnO2.90 manganites are satisfactorily described by the rhombohedral space group R\(\bar 3\)c. A small amount of the non-perovskite MnO phase (space group Fm\(\bar 3\)m) has been found for the anion-deficient La0.70Sr0.30MnO2.90 sample. It has been found that the anion-deficient La0.70Sr0.30MnO2.85 sample consists of two perovskite phases described by space groups R\(\bar 3\)c and I4/mcm and the MnO phase (space group Fm\(\bar 3\)m). The crystal structure of the anion-deficient La0.70Sr0.30MnO2.80 sample is described by one perovskite phase with space group I4/mcm. The volume fraction of the MnO phase is ≪1% for all anion-deficient samples. Oxygen vacancies in the anion-deficient La0.70Sr0.30MnO3 − δ manganite system stimulate the structure phase separation at 293 K.