Superior Piezoelectric Properties in Potassium–Sodium Niobate Lead‐Free Ceramics

A superior piezoelectric coefficient (d₃₃ = 570 ± 10 pC N"1 ), the highest value reported to date in potassium-sodium niobate-based ceramics, is obtained in (1-x-y)K1-w Naw Nb1-z Sbz O3-y BaZrO3-x - Bi0.5 K0.5 HfO₃ ceramics. This high d₃₃ value can be ascribed to the co-existence of "nano-scale strain domains" (1-2 nm) and a high density of ferroelectric domain boundaries. Therefore, ternary KNN-based ceramics demonstrate the potential for applications.