Oxygen nonstoichiometry and defect equilibrium in Ca1–xPrxMnO3–δ manganites

Resumo

The content of oxygen in Ca_1−xPr_xMnO_3−δ (x = 0.1) material with perovskite-like structure is determined at 750–950°C and oxygen partial pressures in the gas phase from 3 × 10⁻⁶ to 0.55 atm. The regions of existence of orthorhombic, tetragonal, and cubic structural modifications are determined. The equilibrium constants, enthalpies, and entropies of reactions of the formation of defects are determined, allowing us to describe the experimental δ (\({p_{{O_2}}}\),Т) dependences accurately and calculate the concentrations of manganese ions. It is shown that a change in Ca_0.9Pr_0.1MnO_3–δ structure has a considerable effect on the thermodynamic functions of reactions of the formation of defects.