Oxygen mobility in the perovskite SrTi1-xFexO3-delta (x=0.8)

The dynamics of long range translation and local motions of oxygen in SrTi0.2Fe0.8O3-delta have been studied by electrical conductivity and quasielastic neutron scattering. The activation energy of the translational ionic diffusion measured by electrical conductivity is 0.97 eV for T > 900 degrees C. Both quasielastic linewidths and quasielastic intensities in neutron scattering show the presence of two motions. The Q independences indicate a localized character for these oxygen diffusion modes with activation energies of 0.43 and 0.27 eV for the fast and the slow local jumps, respectively. A model for the local oxygen motion is proposed involving oxygen jumps in the (0 k 0) plane either directly to the next unit cell or performing detours combining two and two site jumps resulting in the same final momentum transfer.