Incommensurate Structure and Stress-Induced Phase in {N(CD₃)₄}₂ZnCl₄

Abstract

Incommensurate-commensurate transition in {N(CD₃)₄}₂ZnCl₄ has been studied by simultaneous measurements of X-ray scattering and dielectric constant. The incommensurate satellite reflections are found at (h 0 l±ζ) with ζ=0.423 at room temperature. The dielectric constant along the a-axis drops discontinuously at 8.8°C on cooling, and ζ changes to 0.429. Below 1.8°C, the value of ζ locks into the commensurate value of (Remark: Graphics omitted.). A monoclinic phase is found under an external stress between the incommensurate and the commensurate phases. This new phase takes a commensurate structure with (Remark: Graphics omitted.). Some part of the crystal does not show the anomaly observed at 8.8°C in other sample.