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

• Main Authors: Qian Wang, Hong-Ze Yan, Xian Zhao, Chun-Ming Wang
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Actuators
• Subjects: barium titanate (BaTiO₃); piezoelectric properties; polymorphic phase transition
• Online Access: https://www.mdpi.com/2076-0825/10/6/129

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 − <i>x</i>)BaTiO₃₋<i>x</i>CaSnO₃ (0.00 ≤ <i>x</i> ≤ 0.16, abbreviated as BT₋<i>x</i>CS) solid solutions, were prepared by traditional solid-state reaction methods. The phase transitions, microstructure, dielectric, piezoelectric, and ferroelectric properties of BT-<i>x</i>CS 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 ≤ <i>x</i> ≤ 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 <i>d</i>₃₃ of 620 pC/N, electromechanical coupling factors <i>k</i>_p of 58%, <i>k</i>_t of 40%, and a piezoelectric strain coefficient <i>d</i>₃₃* of 950 pm/V.