Effect of purification on dielectric properties near the commensurate‐incommensurate transition point of Rb2ZnCl4

Abstract

Purification of Rb₂ZnCl₄ by recrystallization and zone melting is described in detail and the results of chemical analysis are given. Single crystals were grown from an aqueous solution which had been purified by repeated recrystallization. The thermal hysteresis of the dielectric constant in the purified crystal was reduced to 0.2 K from 2.8 K in the unpurified crystal. The switching time of the field-induced commensurate-incommensurate transition was shortened significantly in the vicinity of T_c . These indicate the weakening of pinning in the purified crystal. The low relaxation frequency of domain wall motion in the commensurate phase starts to rise abruptly when the transition to the incommensurate phase begins. This is understood to reflect a process in which the isolated domain walls are incorporated into the discommensuration lattice of the incommensurate phase. The mathematical analysis of the ordinary recrystallization process and the reverse process is given in Appendix.