Electrical Effects associated with the Mechanical Deformation of Single Crystals of Alkali Halides

Abstract

IT has been reported1 that when single crystals of natural rocksalt are plastically deformed, there is a temporary increase in their ionic conductivity. The increased conductivity appears to decay exponentially with a time constant of the order of 1 min. The effect has also been reported2 for synthetic crystals of potassium chloride and bromide, both pure and coloured by the presence of F-centres. In this case the time constant of decay was of the order of 0.5 sec. Experiments have been carried out here during the past three years to investigate this effect further, using synthetic crystals of various alkali halides3. The crystals were either grown from the melt using the Kyropoulos technique or obtained from other sources.