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

TL;DR

This study investigates the significant temperature-dependent dielectric behavior of Na_{0.4}K_{0.6}Br, attributing it to changes in ionic polarizability, which is crucial for optical device applications.

Contribution

It provides a quantitative analysis linking dielectric constant variation to ionic polarizability changes in Na_{0.4}K_{0.6}Br.

Findings

Na_{0.4}K_{0.6}Br exhibits strong temperature variation of dielectric constant

The variation is quantitatively explained by ionic polarizability changes

Implications for optical device component design

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.