NEUTRON-SCATTERING EVIDENCE FOR FAST IONIC OXYGEN DIFFUSION IN THE HIGH-TEMPERATURE PHASES OF LA2O3

Evidence for fast oxygen diffusion in the H and X high temperature phases of La//2O//3 is presented from neutron diffraction background analysis and neutron quasielastic scattering data. In the X phase at 2 160 degree C the translational self diffusion coefficient is of the order of 3 multiplied by 10** minus **5 cm**2/s and the mean time between jumps on neighboring tetrahedral sites is around 1. 4 multiplied by 10** minus **1**2 s. These are typical values for good superionic conductors.