Abstract
A phase transition at T r = 365±10K is shown for Pb9Al2F24 by high-temperature X-ray diffraction, microcalorimetric and electrical measurements. The AC conductivity data of Pb9Al2F24 are analyzed in the Z*, M* and ε* formalisms and the conductivity relaxation parameters are determined. The high-temperature form of Pb9Al2F24 is characterized by an activation energy (Δσ)h.t. close to that of the (x = 0.12) limiting composition of the Pb1-.xAlxF2 2+x solid solution with fluorite-type structure.