The simultaneous presence of 2 substitutional cations within solid solutions of fluorite-type, Ca1-xYx(1-z)NdxzF2+x, resulted (for each series of materials corresponding to a fixed x-value) in an enhancement of the fluoride ion conduction as compared to that of the end-member compounds, Ca1-xYxF2+x (z = 0) and Ca1-xNdxF2+x (z = 1). It was found that the material which had the highest conductivity within each series was characterized by a Y/Nd ratio that was close to 2. The results were explained in terms of a clustering model.

M.Wahbi, B.Tanouti, A.Ammar, J.M.Reau: Materials Letters, 1996, 28[1-3], 165-73