Dielectric Dispersion of K₂SeO₄and Rb₂ZnCl₄around Incommensurate-Commensurate Transition Points

Abstract

The complex dielectric constants of K2SeO4 and Rb2ZnCl4 have been measured in the frequency range from 5 MHz to 900 MHz around the incommensurate-commensurate phase transition points Tc. It has been found that for both substances the relaxation frequencies are about 100 MHz at Tc and increases gradually with increasing temperature in the incommensurate phase. The dielectric relaxation of both substances could be described by a polydispersive process.