The ionic conductivity of NaCl:SrCl2-dipole interactions

Previously reported small non-random differences between the calculated and experimental conductivity of NaCl doped with Sr 2+ in the temperature range 660-1050K are shown to be attributable to a single extrinsic process which immobilizes a small number of cation vacancies below about 723K. Impurity-vacancy dipole interactions with internal fields is considered as a viable process, and a theoretical analysis of the electrical interaction is developed. A size effect, deformation dependence and crystal-orientation dependence in the residual conductivity are implicated.