Polymorphic Phase Transition and Piezoelectric Performance of BaTiO3-CaSnO3 Solid Solutions

Chun-Ming Wang,Xian Zhao,Hong-Ze Yan,Qian Wang

doi:10.3390/act10060129

Abstract

BaTiO3-based piezoelectric ceramics have attracted considerable attention in recent years due to their tunable phase structures and good piezoelectric properties. In this work, the (1 − x)BaTiO3−xCaSnO3 (0.00 ≤ x ≤ 0.16, abbreviated as BT−xCS) solid solutions, were prepared by traditional solid-state reaction methods. The phase transitions, microstructure, dielectric, piezoelectric, and ferroelectric properties of BT-xCS have been investigated in detail. The coexistence of rhombohedral, orthorhombic, and tetragonal phases near room temperature, i.e., polymorphic phase transition (PPT), has been confirmed by X-ray diffraction and temperature-dependent dielectric measurements in the compositions range of 0.06 ≤ x ≤ 0.10. The multiphase coexistence near room temperature provides more spontaneous polarization vectors and facilitates the process of polarization rotation and extension by an external electric field, which is conducive to the enhancement of piezoelectric response. Remarkably, the composition of BT-0.08CS exhibits optimized piezoelectric properties with a piezoelectric coefficient d33 of 620 pC/N, electromechanical coupling factors kp of 58%, kt of 40%, and a piezoelectric strain coefficient d33* of 950 pm/V.

Highlights

In recent years, BaTiO3 -based piezoelectric ceramics have attracted considerable attention because of their tunable phase structures and good piezoelectric response [1,2,3,4,5,6,7,8,9,10].Generally, the boosted piezoelectric response is always accompanied with the formation of morphotropic phase boundary (MPB) or polymorphic phase transition (PPT)
The boosted piezoelectric response is always accompanied with the formation of morphotropic phase boundary (MPB) or polymorphic phase transition (PPT)
The enhanced piezoelectric properties near MPB are associated with easy path for polarization rotation as revealed in anisotropic flattened free energy profiles [11,12,13,14,15]; and the mechanisms of the increased piezoelectric properties near PPT are related to the lower energy barriers of multiphase coexistence, as the composition-induced phase transitions at PPT can facilitate the process of polarization rotation and extension under an external electric field, leading to enhanced dielectric and piezoelectric properties [16,17,18,19,20,21,22]

Summary

Introduction

BaTiO3 -based piezoelectric ceramics have attracted considerable attention because of their tunable phase structures and good piezoelectric response [1,2,3,4,5,6,7,8,9,10]. The boosted piezoelectric response is always accompanied with the formation of morphotropic phase boundary (MPB) or polymorphic phase transition (PPT). The vital point of improving piezoelectric response of BaTiO3 is to induce the phase transitions by forming. Great efforts have been made to adjust phase transitions of BaTiO3 -based ceramics in order to enhance their dielectric, ferroelectric, and piezoelectric properties. The strontium-doped BaTiO3 ceramics exhibit diffused phase transitions due to compositional inhomogeneity [31,32,33]; the BaTiO3 -BiMO3

Methods

Results

Conclusion