Defects and lattice distortions in the superionic conductor Ba0.84La0.16F2.16

Diffuse neutron scattering (DNS) experiments have been performed on a single crystal sample of Ba0.84La0.16F2.l6 at temperatures from 600 to 1000°C. The results confirm that the defects form clusters and cluster aggregates, the concentration of which diminishes upon heating. Furthermore, the data yield information about local lattice deformations and suggested that the mobile fluorine ions move in the closest vicinity of clusters, in agreement with the enhanced ionic motion model. Quenching is shown to influence the defect structure and the ionic conductivity.