Evidence of latent heat in Rb2ZnCl4 commensurate-incommensurate phase transition

Abstract

The commensurate-incommensurate phase of a Rb2ZnCl4 crystal was studied using a conduction calorimeter. By identifying the contribution of specific heat to transition enthalpy it was possible to show, for the first time in a compound of this type, transition latent heat. It was stimated to be $Q=\SI{2.3}{\joule\per\mole}$. The result was compared with theoretical predictions for a domain wall model having repulsive-attractive interaction, obtaining satisfactory results for the first time. The same analysis was made in normal-incommensurate phase transition and no latent heat was observed as expected.