Ionic conductivity, activation volumes, and high-pressure phase transitions in PbF2and SrCl2

Physical modeling of the electrical properties of PbI2 films

“…This result, combined with other data, led to conclusion about ionic character of the PbI 2 film's electrical conductivity. This conclusion coincides with early work [20] that investigated the ionic conductivity of PbI 2 crystals.…”

Point defect parameters in β-PbF2 revisited

“…1, we plot the experimental values of υ i versus h i from various sources as follows: First, four points (solid dots) correspond to the association parameters from the conductivity studies of Figueroa et al [3] in β-PbF 2 doped with Li, Na, K and Rb (see their Tables III and IV), whereas two other points obtained by the same authors in two undoped samples P 1 and P 2 . Second, three points (open, full and inverted triangle) correspond to the (free) fluorine vacancy migration parameters, as they have been reported by Oberschmidt and Lazarus [5], Samara [6] and Murin et al [7], respectively. Third, two points (solid and open square) show the (free) fluorine interstitial migration parameters reported by Samara [6] and Murin et al [7], respectively.…”

“…Third, two points (solid and open square) show the (free) fluorine interstitial migration parameters reported by Samara [6] and Murin et al [7], respectively. Finally, the two remaining points (full and open diamond) correspond to the values deduced for the anion Frenkel formation process by Oberschmidt and Lazarus [5] and Murin et al [7], respectively.…”

“…In accordance with this explanation, the ratio υ act /h act should solely be governed by macroscopic properties of the bulk solid. Actually, it was shown [4] that the migration enthalpy (h f,m ) and volume (υ f,m ) for the free ( f ) fluorine vacancy motion, as well as the corresponding quantities h m,i , υ m,i for the fluorine interstitial (i) migration, which have been determined from earlier conductivity measurements [5,6] under pressure, exhibit ratios υ f,m /h f,m and υ m,i /h m,i that are not only equal to those υ act /h act found by Figueroa et al [3] but also equal to the value predicted by the cBΩ model. In the meantime, however, new conductivity measurements in β-PbF 2 appeared [7] which lead to values of the ratio υ/h for the defect migration as well as for the anion Frenkel defect formation processes.…”

High-pressure polymorphism ofPbF2to 75 GPa

“…An impurity peak belonging to Pb metal was seen with varying intensity in some patterns, but disappeared above 18 GPa where Pb undergoes a phase transition. A notable feature of the dataset was that the (200) and (211) diffraction lines 7 of PbF 2 exhibit a remarkably rapid shift in d-spacing as a function of pressure relative to other diffraction lines, indicating a highly anisotropic compressibility (Fig. 3).…”