Ferroelectric-Ferroelastic Transitions in (Na0.5Bi0.5)TiO3-BaTiO3 Single Crystals

Geng Huangfu; Jianwei Chen; Jie Jiao; Yiping Guo; Haosu Luo

doi:10.1021/acsami.3c03381

Ferroelectric-Ferroelastic Transitions in (Na_0.5Bi_0.5)TiO₃-BaTiO₃ Single Crystals

ACS Appl Mater Interfaces. 2023 May 24;15(20):24614-24621. doi: 10.1021/acsami.3c03381. Epub 2023 May 10.

Authors

Geng Huangfu^{1

2}, Jianwei Chen¹, Jie Jiao¹, Yiping Guo², Haosu Luo¹

Affiliations

¹ Artificial Crystal Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China.
² State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.

PMID: 37163681
DOI: 10.1021/acsami.3c03381

Abstract

The comprehensive understanding of (Na_0.5Bi_0.5)TiO₃-BaTiO₃ (NBT-BT) lattice structure is highly desired to develop lead-free ferroelectric materials. However, most of the previous studies focused on the improvement of piezoelectric properties at room temperature, and many structural puzzles are left unclear. In this work, the lattice structure of a ferroelastic phase and the ferroelectric-ferroelastic transitions in both rhombohedral NBT and tetragonal NBT-8%BT single crystals are investigated in detail. Our results illustrate the complex process of the ferroelectric-ferroelastic transition of NBT. The variation of Ti-O modes and oxygen octahedra modes clearly indicates the gradual change of lattice symmetry from R3c to P4bm during a wide temperature range between 170 and 350 °C. A ferroelectric-ferroelastic transition is also confirmed in tetragonal NBT-8BT for the first time, and the lattice symmetry of P4bm is found to be maintained during the ferroelastic stage. This work reveals the lattice evolutions of the ferroelectric-ferroelastic transition of NBT-BT crystals and provides new insights for understanding the ferroelasticity and the evolution of phonon modes in a lead-free relaxor.

Keywords: Raman scattering; ferroelectric−ferroelastic transition; lead-free ferroelectric; relaxor ferroelectric.