Elastic Anomaly of the Antiferroelectric CsH₃(SeO₃)₂ Single Crystal

Abstract

We have measured elastic compliance constants s_a, s_b and s_c for the elongation along the three crystallographic axes of the antiferroelectric CsH₃(SeO₃)₂ single crystal (triclinic, P\bar1) by the composite resonator method.
All the constants s_a, s_b and s_c have been found to exhibit large anomaly at the transition point (−128°C) and small anomaly near the temperature above it. This small anomaly suggests the existence of a new phase.