The dielectric constant of Na_{0.4}K_{0.6}Br and its large temperature variation

Abstract

Since polycrystals of alkali halides are highly useful as components in optical devices, a number of mixed crystals of NaBr and KBr have been prepared from melt by other workers. Among these crystals, it was reported that the polycrystal Na$_{0.4}$K$_{0.6}$Br exhibits the strongest temperature variation of the dielectric constant. Here, we show quantitatively that this is due to the temperature variation of the ionic polarizability.