Dilatometric Study of Anisotropy of Thermal Expansion on RbLiSO₄

Abstract

The anisotropy of thermal expansion coefficients of RbLiSO₄ single crystal was measured by the dilatometric method. Anomalies along the b and c axes are larger than that along the a axis and those around the incommensurate phase are anomolously large. The thermal expansion coefficient along the c axis have a minus sign in the temperature range in which the successive phase transitions is observed. Ferroelasticity in the phase III is confirmed by the observation of domains which are able to moved easily by the shear stress.