Oxygen diffusion and surface exchange studies on (La0.75Sr0.25)0.95Cr0.5Mn0.5O3−δ

Oxygen tracer diffusion coefficient (D⁎) and surface exchange coefficient (k⁎) have been measured for (La0.75Sr0.25)0.95Cr0.5Mn0.5O3−δ using isotopic exchange and depth profiling by secondary ion mass spectrometry technique as a function of temperature (700–1000 °C) in dry oxygen and in a water vapour-forming gas mixture. The typical values of D⁎ under oxidising and reducing conditions at ∼ 1000 °C are 4 × 10− 10 cm2 s− 1 and 3 × 10− 8 cm2 s− 1 respectively, whereas the values of k⁎ under oxidising and reducing conditions at ∼ 1000 °C are 5 × 10− 8 cm s− 1 and 4 × 10− 8 cm s− 1 respectively. The apparent activation energies for D⁎ in oxidising and reducing conditions are 0.8 eV and 1.9 eV respectively.