High-Temperature Internal Friction in Potassium Chloride

A theory for the strain-amplitude-independent damping due to electrically charged dislocations oscillating within their surrounding charge clouds and for the strain-amplitude-dependent damping caused by the dislocations ``breaking away'' from their charge clouds is discussed. Damping experiments on single crystals of KCl [〈100〉, 〈111〉, and 〈110〉 orientations] at temperatures of 450° to 760°C, frequencies ranging from 40 to 200 kc/sec, and strain...