The bulk impedance of polycrystalline samples of Sr1-xBixF2+x fluorite-structured solid solution, where x was between 0 and 50, was studied by analyzing alternating-current conductivity data. The hopping rates of mobile F- ions were deduced from the frequency dependences of the conductivity at various temperatures, and the fraction of charge carriers per unit cell in the samples was estimated. The nature of the charge carriers was determined on the basis of a clustering model, and neutron diffraction data. It was concluded that interstitial ions of F’ type were responsible for long-range motion.

E.F.Hairetdinov, N.F.Uvarov, M.Wahbib, J.M.Reau, X.J.Xu, P.Hagenmuller: Solid State Ionics, 1996, 86-88[1], 113-7