A CAPACITANCE ENHANCEMENT RESULTING FROM INTERACTION OF PLATINUM WITH ALKALI HALIDES

Sputtered platinum electrodes are frequently used on alkali halide crystals for the measurement of dielectric constant and conductivity. In the course of such work large capacity enhancements were observed in several alkali halide crystals at temperatures of a few hundred degrees centigrade. Evidence is presented that the effect is due to an interaction between the electrodes and the crystal, so that results on such systems at high temperatures must be interpreted with care. A model in which the conductivity is a linear function of depth through part of the crystal gives satisfactory agreement with the experimental results.