Perovskite-related manganites from the SrO-LaMnO3-MnO2(Mn3O4) system

The phase composition of lanthanum-strontium perovskite manganites that are formed upon a long-term thermal processing (T-max = 1500 degreesC, air atm osphere) of SrCO3, La2O3, and MnO2(Mn2O3) feeds was studied. Three solid so lutions, which are homologous Raddlesden-Popper (RP) (La,Sr)(n+1)MnO3n+1 ph ases, were shown to form under the specified conditions: La1-xSr1+xMnO4 (n = 1), 0.25 less than or equal to x less than or equal to 1.00; La2-2xSr1+2x Mn2O7 (n = 2), 0.20 less than or equal to x less than or equal to 0.90; and La1-xSrxMnO3 (n = infinity), 0 less than or equal to x less than or equal to 0.80. The last homologue, dissolving manganese and strontium, forms a re gion of LaMnO3-based solid solutions with variable lanthanum, strontium, an d manganese contents, which is confined to the compositions LaMnO3, La0.70M nO3, La0.20Sr0.80MnO3, and La0.92Sr0.08Mn0.92O3. The scenario of phase rela tions in the SrO-LaMnO3-MnO2(Mn3O4) system for 1500 degreesC is presented.