Mobility of Charge Carriers in a Single Crystal and Nanoceramic of the Superionic Pb1 – xSnxF2 Conductor (x = 0.2)

Abstract

A crystallophysical model of ion transfer in the superionic Pb1 – xSnxF2 conductor with a fluorite (CaF2) structure is proposed. The concentration dependence of the ionic conductivity of Pb1 – xSnxF2 single crystals and poly- and nanocrystals is analyzed. The single-crystal form of the superionic conductor is characterized by the highest conductivity. The mobility and concentration of anionic charge carriers in a single crystal and ceramics of Pb1 – xSnxF2 (x = 0.2) is calculated on the basis of structural and electrophysical data. The mobility of carriers μmob = 2.5 × 10–6 cm2/s V (at 293 K) in a single crystal is seven times higher than in nanoceramic. The concentration of carriers nmob = 1.7 × 1021 and 3.6 × 1021 cm3 (4.5 and 9.5% of the total number of anions) for a single crystal and nanoceramic, respectively. The comparison of isostructural Pb0.8Sn0.2F2, Pb0.67Cd0.33F2, and Pb0.9Sc0.1F2.1 single crystals shows that anionic carriers have a maximum mobility in the β-PbF2 and SnF2 based solid solution.