Thermally Induced Domain Reconfiguration in Ferroelectric Alkaline Niobate

Abstract Suppressing losses that originate from domain‐wall motion in ferroelectrics is essential to high‐power piezoelectric applications. Conventional models of the hardening effect assume that domain‐wall mobility can be greatly impeded due to the pinning of lattice defects or charge carriers. However, these models cannot satisfactorily explain the dramatical increase of mechanical quality factor from ≈500 to ≈2500 in ferroelectric sodium lithium niobate induced by annealing. In the present study, the specific hardening effect is systematically investigated from multiple perspectives, including kinetics, phase transition, and domain configuration. The enhancement is proposed to be associated with the thermally induced domain reconfiguration at the nanoscale approaching the ferroelectric‐paraelectric phase transition temperature. The comprehensive experimental observations reveal a unique mechanism of the hardening effect in ferroelectrics, shedding light on the enhancement of the performance of high‐power piezoelectric applications.