Correlation between Transition Entropy and the Rhodes-Wohlfarth Ratio in Ferroelectric Materials

Abstract

A systematic correlation is discovered for a number of ferroelectrics between transition entropy ΔS and the Rhodes-Wohlfarth ratio p_c⁄p_s, where p_c is the effective dipole moment determined from the Curie-Weiss constant assuming the existence of permanent dipoles, while p_s is the saturation moment. The unified theoretical model of ferroelectrics, which is capable of describing essential features of both displacive-type and order-disorder-type ferroelectrics, is shown to reproduce the above correlation strikingly well.