Cadmium and lead solid solutions of lanthanum manganite

Phase formation in the MO-La2O3-MnO2 (M = Cd, ph) systems at 900 degreesC u nder an air atmosphere: was studied. A wide homogeneity region was shown to exist for LaMnO3 due to vacancy generation in the cation sublattice and to heterovalent substitution. The extent of La1-xMxMnO3 solid solutions, whic h show a magnetoresistive effect, was determined to be 0 less than or equal to x less than or equal to 0.30 for M = Cd and 0 less than or equal to x l ess than or equal to 0.40 for M = Pb. The phase composition found for the r egions adjacent to the region of the solid solutions was used to advance th e tetrahedrization pattern for the CdO-La2O3-Mn2O3-MnO2 and PbO-La2O3-Mn2O3 -MnO2 fragments of the phase diagrams.