Electrostructive Effects in Paraelectric-Ferroelectric-Antiferroelectric Phase Transitions

Abstract
Electrostrictive terms have been introduced into the Kittel free energy expression by means of a fourth-order cross term of the two-sublattice polarizations, giving rise to multiple phase transitions. Schematic p-T diagrams of the nonpolar, polar and antipolar phases are classified by the electrostrictive Ω coefficient. Spontaneous strain curves are derived for each of the four types of phase diagrams.