DETERMINATION OF CHARGE CARRIED CONCENTRATION IN SR1-XBIXF2-SOLUTION FROM AC CONDUCTIVITY ANALYSIS(X SOLID)

The bulk impedance parameters of polycrystalline samples of the Sr1-xB ixF2+x (0 less than or equal to x less than or similar to 0.50) solid solution with fluorite-type structure were determined from an analysis of ac conductivity data, using a modified Almond-West model. Hopping rates of mobile F- ions were extracted from frequency dependences of c onductivity at different temperatures. The fraction of charge carriers (per unit cell) in the samples investigated has been estimated. The n ature of charge carriers has been identified on the basis of the clust ering process model and neutron diffraction data: the interstitial ion s of F' type appear as responsible for long range motions in Sr1-xBixF 2+x.