Lead-Free BiFeO3-BaTiO3 Ceramics with High Curie Temperature: Fine Compositional Tuning across the Phase Boundary for High Piezoelectric Charge and Strain Coefficients

Bowei Xun; Aizhen Song; Jingru Yu; Yang Yin; Jing-Feng Li; Bo-Ping Zhang

doi:10.1021/acsami.0c20381

Lead-Free BiFeO₃-BaTiO₃ Ceramics with High Curie Temperature: Fine Compositional Tuning across the Phase Boundary for High Piezoelectric Charge and Strain Coefficients

ACS Appl Mater Interfaces. 2021 Jan 27;13(3):4192-4202. doi: 10.1021/acsami.0c20381. Epub 2021 Jan 13.

Authors

Bowei Xun¹, Aizhen Song¹, Jingru Yu¹, Yang Yin¹, Jing-Feng Li², Bo-Ping Zhang¹

Affiliations

¹ The Beijing Municipal Key Laboratory of New Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing, China.
² State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.

PMID: 33438390
DOI: 10.1021/acsami.0c20381

Abstract

BiFeO₃-BaTiO₃ is a promising high-temperature piezoelectric ceramic that possesses both good electromechanical properties and a Curie temperature (T_C). Here, the piezoelectric charge constants (d₃₃) and strain coefficients (d*₃₃) of (1 - x)BiFeO₃-xBaTiO₃ (BF-xBT; 0.20 ≤ x ≤ 0.50) lead-free piezoelectrics were investigated at room temperature. The results showed a maximum d₃₃ of 225 pC/N in the BF-0.30BT ceramic and a maximum d*₃₃ of 405 pm/V in the BF-0.35BT ceramic, with T_Cs of 503 and 415 °C, respectively. To better understand the performance enhancement mechanisms, a phase diagram was established using the results of XRD, piezoresponse force microscopy, TEM, and electrical property measurements. The superb d₃₃ of the BF-0.30BT ceramic arose because of its location in the optimum point in the morphotropic phase boundary, low oxygen vacancy (V_O^··) concentration, and domain heterogeneity. The superior d*₃₃ of the BF-0.35BT ceramic was attributed to a weak relaxor behavior between coexisting macrodomains and polar nanoregions. The presented strategy provides guidelines for designing high-temperature BF-BT ceramics for different applications.

Keywords: BiFeO3-BaTiO3; domain switching; electrostrain; phase diagram; piezoelectricity; relaxors.