The effect of the ionic radii of rare-earth elements (La, Pr, Nd) upon anion transport parameters was studied in simple fluorides and in solid solutions which involved isovalent isomorphous substitution. The object was to optimize the ion transport characteristics of solid electrolytes with a tysonite-type structure. The anionic conductivity of monocrystals was studied by using impedance spectroscopic methods at frequencies which ranged from 0.1Hz to 1MHz. It was found that the temperature dependence of the conductivity of each material exhibited a change in slope at a so-called kink temperature of about 420K (table 192).

N.I.Sorokin, B.P.Sobolev: Kristallografiya, 1994, 39[1], 114-8 (Crystallography Reports, 1994, 39[1], 101-4)

Table 192

Parameters for Anionic Conduction in (La,Pr)F3