Preparation and Ionic Conductivity of OH(-)-Free Sodium Fluoride Crystals Doped with Calcium,

Abstract : A series of OH(-)-free NaF single crystals has been prepared and the influence of substitutional calcium ions on the ionic conductivity has been studied. The activation energy for migration of a cation vacancy in NaF:Ca is 1.36 plus or minus 0.1 eV. An isothermal plot of ionic conductivity vs. divalent impurity concentration has been used to analyze several nominally pure NaF samples for divalent impurity levels. (Author)