The mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO<sub>3</sub> ceramics.

Gao, Xiaoyi; Cheng, Zhenxiang; Chen, Zibin; Liu, Yao; Meng, Xiangyu; Zhang, Xu; Wang, Jianli; Guo, Qinghu et al. · Nat Commun · 2021

basic_science · Level V

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Abstract

(K,Na)NbO<sub>3</sub> based ceramics are considered to be one of the most promising lead-free ferroelectrics replacing Pb(Zr,Ti)O<sub>3</sub>. Despite extensive studies over the last two decades, the mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO<sub>3</sub> ceramics has not been fully understood. Here, we combine temperature-dependent synchrotron x-ray diffraction and property measurements, atomic-scale scanning transmission electron microscopy, and first-principle and phase-field calculations to establish the dopant-structure-property relationship for multi-elements doped (K,Na)NbO<sub>3</sub> ceramics. Our results indicate that the dopants induced tetragonal phase and the accompanying high-density nanoscale heterostructures with low-angle polar vectors are responsible for the high dielectric and piezoelectric properties. This work explains the mechanism of the high piezoelectricity recently achieved in (K,Na)NbO<sub>3</sub> ceramics and provides guidance for the design of high-performance ferroelectric ceramics, which is expected to benefit numerous functional materials.