CLUSTERING AND ANIONIC MOBILITY INSIDE THE SR1-XBIXF2-SOLUTION(X SOLID)

The conductivity parameters, number of charge carriers and frequency o f hopping, have been determined from an analysis of a.c.-conductivity data of the fluorite-type Sr1-xBixF2+x (0 less than or equal to x less than or similar to 0.50) solid solution. The composition dependence o f the fraction of charge carriers per unit cell is in agreement with t he estimations made on the basis of the clustering process model which assumes that the interstitial fluoride ions of F type are the charge carriers at long range in ST1-xBixF2+x. (C) 1997 Elsevier Science Ltd.