Strong pinning effect on domains in piezoelectrics

In high-power applications, since mechanical losses in piezoelectric devices always result in considerable heat generation, the temperature stability of the mechanical quality factor (Q_m) is particularly crucial and should be considered in real piezoelectric applications. Here, we propose a poling-aging-repoling strategy to make the defect dipoles aligned with the poling direction as much as possible, thereby resulting in the strong pinning of ferroelectric domains. A giant internal bias field E_i (11.6 kV cm⁻¹ @ 1 Hz) and a high Q_m (2074), accompanied by almost unchanged d₃₃, are obtained in the composition of CuO-doped (K_0.48Na_0.52)_0.94Li_0.06Nb_0.94Ta_0.06O₃ (KNNLT-Cu) ceramics with a diffused polymorphic phase transition. Furthermore, and this is more encouraging, the high electromechanical performance exhibits good temperature stability in the range from room temperature to 100 °C, suggesting that the thermal stability of Q_m can be effectively improved by combining the strong pinning of defect dipoles with composition design and providing a way for the development and design of future high-power piezoelectric devices.