Characteristic Features of the Modulated Phases in (MgGeF₆)·6H₂O Crystals

Abstract

The temperature dependences of the optical birefringence δ(∆nc) in (MgGeF 6 ) · 6H 2 O crystal have been investigated. Specific properties observed in experiment such as global hysteresis, kinetic effect, thermooptic memory effect, localization of the incommensurability wave vector on the commensurate values of higher order, sensibility to the external mechanical stress confirm the existence of the incommensurate phase in current crystals.