Polarization Effects in the Ionic Conductivity of Alkali Halide Crystals. I. AC Capacity

The three principal theories which have been advanced to explain ac polarization effects in ionic conductors are examined and the approximations inherent in them are discussed. Explicit formulas for the polarization capacity are extracted and used to predict the values of the frequency-dependent component of the capacity of potassium chloride crystals between platinum electrodes. The experimental results for pure KCl are in good agreement with these predictions, but for KCl crystals doped with SrCl2, the agreement is less satisfactory. It is concluded that the polarization observed at high temperatures is due to the blocking of the charge carriers at the electrodes and that the linearized theory gives, in general, a good account of this effect.