Effect of CeO₂ on dielectric, ferroelectric and piezoelectric properties of PMN–PT (67/33) compositions

Lead magnesium niobate–lead titanate [Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃] powders doped with different mole % of CeO₂ were prepared by a modified columbite route with compositions corresponding to morphotropic phase boundary (MPB) region. These powders were calcined at 800 °C for 4 h and circular test specimens were prepared by uniaxial pressing. The specimens were sintered at 1150 °C/2 h, poled at 2 kV/mm d.c. voltage and were characterized for dielectric, ferroelectric and piezoelectric properties. It was observed that the piezoelectric and ferroelectric properties initially increase up to 2 mol% of ceria addition and then decrease with increase in ceria concentration. The diffusivity of the dielectric curves increases with increase in ceria concentration. The decrease in Curie temperature was observed from 173 °C corresponding to pure PMN–PT to a temperature of 138 °C for 10 mol% of ceria addition.