A variable temperature neutron diffraction study of dual ion conducting Sr3V2O8

Sr3V2O8 exhibits sizeable oxide ion and proton conductivity at 800 degrees C. In order to investigate any correlation between the crystal structure and electrical properties of Sr3V2O8, a variable temperature neutron diffraction study has been performed. Results show that there is no change in crystal symmetry upon heating. However, the VO4 tetrahedra are observed to become more distorted upon heating and more oblate in shape. The distortion arises due to a shortening of the apical V-O1 bond length and accompanying increase of the V-O2 bond length with temperature. Bond valence site energy analysis show that there is a reduction in the energy of the migration pathways for movement of the oxide ions as the Sr-V-Sr bottlenecks expand upon heating.