Pinning Effect on Dynamical Dielectric Properties of Rb₂ZnCl₄ in the Incommensurate Phase

Abstract

Dielectric dispersion has been studied for several crystals of Rb₂ZnCl₄ prepared under different conditions in the frequency range from 10³ Hz to 10⁹ Hz around the incommensurate-commensurate phase transition temperature T_c. Although the dielectric dispersion of the relaxational type is observed for all the crystals, the apparent critical slowing down is found only for the less defective crystals in which the relaxation is monodispersive in the temperature range T>T_c+5 K, but becomes polydispersive near T_c in the incommensurate phase. In the defective crystals, a wide distribution of the relaxation times was observed in the whole temperature range of the incommensurate phase.