Lattice dynamics and ionic conductivity of PbF₂:6%LiF superionic crystals

Abstract

Temperature studies of lattice dynamics and ionic conductivity, within the temperature range of 100 to 700 K, are performed for PbF2 and PbF2:6% LiF superionic crystals. The doped crystals exhibit a decreased activation energy of the conductivity. A decrease, by about 70 degrees, in the temperature at which the ionic conductivity changes and Raman spectra anomalies occur is observed. It is found that at temperatures significantly lower than that of the superionic state transition, the Raman line form is determined by processes of phonon scattering at thermally excited defects.

Lead difluoride and related systems

“…110 The PbF 2 -based solid solution region is very narrow. These data are in contradiction with the results of the study, 111 where single crystals of PbF 2 containing 6% of LiF (the percentage type was not reported) were prepared by melt crystallisation. The formation of a solid solution is evidenced by a substantial decrease in the lattice parameter from 5.94 to 5.83 # A.…”