Enhanced Electric Field-Induced Strain Properties in Lead-Free BF-BT-Based Piezoceramics by Local Structure Inhomogeneity

The piezoelectric strain coefficient d(33)* always deteriorates rapidly with increasing temperature, which is one of the technical bottlenecks restricting practical applications of piezoelectric ceramics at high temperatures. Herein, we successfully prepared (1 - x)(0.7BFeO(3)-0.3Ba(Hf0.05Ti0.95)O-3)-x(Bi0.2Sr0.7)TiO3 by the conventional solid-state method, which possessed a high piezoelectric strain coefficient of d(33)* = 490 pm/V at 245 degrees C. In particular, d(33)* is insensitive to the temperature range of 25 to 245 degrees C. Microstructure characterization and electrical performance measurements showed that the optimal piezoelectric strain coefficient and its excellent thermal stability are mainly attributed to combining freezing temperature T-f with polar nanoregions (PNRs). Piezoelectric force microscopy showed the relaxor behavior, and high-resolution transmission electron microscopy images of the Moire fringe revealed the existence of PNRs. The conception and findings in this work will further push the practical application of BiFeO3-BaTiO3-based high-temperature piezoceramics.

Automated summary

This study successfully prepared a high-temperature piezoelectric material with excellent thermal stability, and the outstanding piezoelectric performance is mainly attributed to the combination of freezing temperature and polar nanoregions.