Conductivity Transitions of La0.7Sr0.3MnO3±? and La0.6Sr0.4Co0.2Fe0.8O3?? in Ce0.9Gd0.1O2?? Matrix for Dual-Phase Oxygen Transport Membranes

Using van der Pauw method, the conductivity of disk samples La0.7Sr0.3MnO3±? (LSM) and La0.6Sr0.4Co0.2Fe0.8O3?? (LSCF) in a Ce0.9Gd0.1O2?? (GDC) matrix was accurately quasi-continuously measured over 800 °C to ?73 °C, transition points Arrhenius behavior were systematically obtained from extremum second derivatives. While LSM-containing showed reproducible trajectories, LSCF system exhibited unsystematic changes which may be related substantial oxidation/reduction reactions accompanying ferroelastic–paraelastic transitions with thermal hysteresis at 650 750 corresponding maxima. A sudden decrease activation energies on cooling corresponds para-to-ferromagnetic, weak insulator–metal Curie temperature LSM appears gradually composites 90 while exhibit blurred approximately ?40 °C. Relatively insulating paramagnetic phases are characterized by energy values ~0.2 eV, change high phase exhibiting 0.1 eV for small polaron hopping mechanisms 300 500 increasing GDC content two ?60 ?245 composites. single shows distinctly lower appear match singularly large c lattice parameter whereas decreasing amount together GDC. Van is feasible sensitive situ tool monitoring status oxygen transport membranes.