Abstract
The complex oxide PrBaMnFeO6−δ (PBMF) was successfully synthesized through the organo-metallic precursor’s combustion. At high temperatures the obtained perovskite was shown to crystallize either in cubic or in tetragonal phase depending on external conditions applied. Magnetic studies additionally confirmed the significant difference of these phases. The coulometric titration method was carefully implemented in order to define the equilibrium values of oxygen content in PBMF as a function of oxygen partial pressure in a 973–1223 K temperature region. The obtained data revealed the existence of the transitory area between cubic and tetragonal phases enabling their mutual presence in a narrow range of oxygen partial pressures. The comprehensive analysis of defect structure was carried out by the development of independent thermodynamic models involving different sets of defect formation processes. As a result, the defect structure of the tetragonal phase was shown to be governed by averaged B-site cation reduction and oxygen disordering while independent iron and manganese reduction reactions occur to be dominant in the highly-symmetric cubic oxide. Based on the obtained data the equilibrium concentrations of point defects, as well as thermodynamic functions of weakly-bonded oxygen were calculated. Defect concentrations determined were further used to explain chemical deformation of manganites studied which revealed a positive impact of iron doping on lattice expansion of PBMF at reduction. A combination of elevated stability of the reduced phase and high values of stored heat compared to analogous oxides suggests PBMF can be considered as perspective oxygen and energy storage material.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call