The stability of ferroelectric phase near critical size

Abstract

The stability of ferroelectricity in ferroelectric films near the critical size (i.e. the size at which ferroelectricity disappears) is investigated using Landau free energy expansion. In the case of strong surface coupling, as the film thickness decreases, the ferroelectric phase becomes an unstable state before the critical size is reached, the size driven phase transition is of first order properties. When the surface coupling is weak, the ferroelectric phase is stable at any thickness larger than the critical size.