Quaternary piezoelectric ceramics with ultra-high mechanical quality factor

The development of piezoelectric ceramics with large piezoelectric coefficient (d₃₃), high Curie temperature (T_C) and high mechanical quality factor (Q_m) is still a key challenge for practical application for high-power device. Herein, a novel quaternary piezoelectric ceramics of (0.125-x) Pb_0.98Sr_0.02(Mg_1/3Nb_2/3)O₃–0.445PbTiO₃–0.43PbZrO₃-xPb(Mn_1/3Nb_2/3)O₃ (abbreviated as xPMnN-PSMN-PZT) were prepared by the solid-state sintering method. The hard dopant PMnN induced the morphotropic phase boundary (MPB) of PSMN-PZT into a tetragonal-rich region. In addition, the XPS and EPR analysis proved the existence of a large amount of oxygen vacancies ($V_o^{••}$) in PMnN-PSMN-PZT ceramic system. The composition near tetragonal-rich MPB region and the appearance of defect dipoles formed a strong coupling effect on the domain wall motion and leaded to an ultra Q_m value. The optimum piezoelectric properties were achieved at x = 9 mol% with d₃₃ = 260 pC/N, Q_m = 3880, tanδ = 0.009 and T_C = 332 °C. A significant internal bias field (E_bias) of 8.83 kV/cm was also observed in 0.09PMnN-PSMN-PZT ceramics. The origin of this excellent piezoelectric properties was explained by the phase structure, piezoelectric and dielectric analysis. This work demonstrated a rational strategy to obtain ultra Q_m value for high-power piezoceramics.