Multiphased alkali halide mixed crystals: The conductivity activation energy

The preparation of mixed crystals of NaBr and KBr from melt as well as their physical characterization have been reported. Electrical measurements were carried out at various temperatures, which showed that their conductivity increases with the increase in temperature and varies nonlinearly with the bulk composition. We find that for most of the compositions studied, the activation energy deduced from the temperature variation of their conductivity obeys a thermodynamical model that interrelates the defect Gibbs energy with the bulk elastic and expansivity data.