Long-Term Time-Dependent Conductivity in Alkali Halide Single Crystals

A very slow change in the dc conductivity below 200°C of certain alkali halide single crystals, not previously investigated, cannot be understood in terms of current theory of homogeneous crystals, but follows first-order kinetics and correlates with dislocation substructure. Electrical decoration of the dislocation substructure suggests that conduction flow is inhomogeneous, a conclusion confirmed by experiments on bicrystals and on specimens containing subboundaries.