Comments on the dielectric discontinuties in PZT ceramics near the ferro-paraelectric transition

A new simple method to fit the temperature dependence of the spontaneous polarization by an effective field expression is discussed. This method relays upon the experimental values of Ps∗, spontaneous polarization at T∗ > Tc, where T∗ is the transition temperature, and the ratio T∗/Tc, from dielectric constant data, assumming h=−g in the effective field expression. Data for KNbO3, PbTiO3, BaTiO3 and PZT with x(Ti)=0.035 are analyzed and they give reasonably good fits.