Structural observations on La2(Ni,Co)O4±δ phases determined from in situ neutron powder diffraction

In situ neutron powder diffraction data have been analysed for a number of compositions in the solid solution series La2Ni1−xCoxO4±δ over the temperature range 150–650 °C. High-quality Rietveld refinements indicate no major structural transitions have occurred in any of the compositions, although close examination of the Ni/Cosingle bondO bond distances highlight changes in the coordination environment with increasing temperature. Further, the changes in the coordination can be correlated to changes in both the oxide ion and electronic conductivity indicating a direct link between transport properties, bonding and transition metal valence state in these Co containing layered perovskites.