Strain Induced Change from Second Order to First Order Ferroelectric Phase Transition

Abstract

The classical Weiss model of ferroelectric phase transitions yields only a transition of the second order. If strain induced by the piezoelectric effect or by electrostriction is considered the model can be modified to describe also a first order phase transition. It is shown that the transition temperature is shifted to higher values if an external field is applied. Also the thermal hysteresis observed in transitions of the first order and a continuous transition can be explained within this model.