Defect induced changes in the ferroelastic phase of LiKSO4 crystals

Abstract

Measurements of the specific heat, Cp, of lithium potassium sulphate (LiKSO4) crystals doped with thallium, Tl, and rubidium, Rb, with different contents have been carried out. This was done to investigate the effect of a dopant on the ferroelastic phase, at transition temperature T1 ≅ 700 K. The thermodynamic parameters, enthalpy change, ΔH, and entropy change, ΔS, at the transition point were obtained. The results showed that as the contents of thallium and rubidium increased (ΔCp)max, was found to decrease slowly to a minimum followed by sharp increase. The critical exponent was changed as the content of dopant increased and the model deviated from the 3d Ising model.