Improved Curie temperature, electromechanical properties and thermal stability in ZnO-modified 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 ceramics with coexisting monoclinic and tetragonal phases

Further improving electromechanical properties and overcoming relatively low Curie temperature (Tc) of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-100xPT) are still two scientific issues. Here, we demonstrate a stable coexistence of monoclinic-tetragonal (MC-T) phases in ZnO-modified PMN-32PT (PMN-32PT:xZnO) due to the diffusion-induced substitution of Zn2+ for Mg2+. The Curie temperature, saturated polarization, remnant polarization, piezoelectric coefficient (Tc, Ps, Pr, d33) are increased from (160 °C, 22.0 μC/cm2, 13.3 μC/cm2, 350 pC/N) for x = 0 to (180 °C, 30.3 μC/cm2, 22.4 μC/cm2, 470 pC/N) for x = 0.06. Moreover, the thermal stability is improved. After annealing at 150 °C, the x = 0.06 sample shows retrained d33 value of 209 pC/N, about 4 times larger than that of x = 0 counterpart. The improved properties are attributed to the substituting increased polar nanoregions and easy domain switching in MC phase.