Achieving high Curie temperature and prominent piezoelectric response via site engineering for BiFeO3-BaTiO3 ceramics

In this paper, we proposed an effective strategy to overcome the trade-off between piezoelectric coefficient and the Curie temperature via co-doping of K+ and Nb5+ ions at A/B sites, achieving a combination of high TC and d33 in BiFeO3-BaTiO3-based ceramics. The MPB region was confirmed in a very narrow range of x = 0.0075-0.01 by the Rietveld refinement of XRD patterns and Raman spectroscopy deconvolution. An optimized composition with 1 mol% K/Nb co-dopants possesses a high Curie temperature (TC = 604 degrees C) along with d33 = 163 pC/N, kp = 43 %, Pr = 57.94 mu C/cm2, and Ps = 68.18 mu C/cm2. An outstanding thermal stability to 540 degrees C was verified via the temperature dependence of d33 and in situ Raman spectroscopy. This work not only affords a potential lead-free candidate material for the high-temperature piezoelectric ap-plication, but also provides a feasible strategy to design high-temperature dielectrics by exploiting the site engineering. (c) 2023 Elsevier B.V. All rights reserved.