Anomalous changes of the physical properties of LiKSO4crystals in the temperature region from 100 TO 300 K

Abstract

Abstract The pyroelectric, dielectric, piezoelectric and elastic properties of LiKSO4 crystals grown from aqueous solutions at 315 K were studied in the temperature range from 100 up to 300 K. The properties studied were found to exhibit anomalous temperature-dependent variations. It was found that LiKSO4 crystal undergo a structural phase transition at a temperature of about 190 K. In the vicinity of phase transition temperature changes in sign of the pyroelectric coeffiecient, σP, measured at constant stress σ, and also a relatively small anomalous changes of the dielectric properties of LiKSO4 crystals were observed. When the crystal was heated from 100 up to 300 K a marked anomalous decrease of the piezoelectric moduli dij and an increase of the elastic stiffnesses cij were also observedl. Furthermore both time and temperature changes of the physical properties of LiKSO4 crystal point out to the existence of a ferroelastic phase below 190 K. In this way the LiKSO4 crystal seems to behave different fro...