Prediction of the hardest BiFeO3 from first-principles calculations

Runqing Zhang; Lingling Bai; Xing Xie; Peiju Hu; Ziqiao Wu; Huafeng Dong; Minru Wen; Fugen Wu

doi:10.1039/d2cp05817k

Prediction of the hardest BiFeO₃ from first-principles calculations

Phys Chem Chem Phys. 2023 Feb 8;25(6):5049-5055. doi: 10.1039/d2cp05817k.

Authors

Runqing Zhang¹, Lingling Bai¹, Xing Xie¹, Peiju Hu¹, Ziqiao Wu¹, Huafeng Dong^{1

2}, Minru Wen¹, Fugen Wu^{2

3}

Affiliations

¹ School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou, 510006, China. hfdong@gdut.edu.cn.
² Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangdong University of Technology, Guangzhou, 510006, China.
³ School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, China.

PMID: 36722891
DOI: 10.1039/d2cp05817k

Abstract

BiFeO₃ is the only material with ferroelectric Curie temperature and Néel temperature higher than room temperature, making it one of the most well-studied multiferroic materials. Based on an ab initio evolutionary algorithm, we predicted a new cubic C-type antiferromagnetic structure (Fd3̄m-BiFeO₃) at ambient pressure. It was found that Fd3̄m-BiFeO₃ is the hardest BiFeO₃ (Vickers hardness ∼ 9.12 GPa), about 78% harder than R3c-BiFeO₃ (the well-known multiferroic material), which contributes to extending the life of BiFeO₃ devices. In addition, Fd3̄m-BiFeO₃ has the largest shear modulus (83.74 GPa) and the largest Young's modulus (214.72 GPa). Besides, we found an interesting phenomenon that among the common multiferroic materials (BiFeO₃, BaTiO₃, PbTiO₃, SrRuO₃, KNbO₃, and BiMnO₃), Pnma-BiMnO₃ has the largest bulk modulus, and its bulk modulus is about 15% larger than that of Fd3̄m-BiFeO₃. However, its Vickers hardness (4.47 GPa) is much smaller than that of Fd3̄m-BiFeO₃. This is because the Vickers hardness is proportional to the shear modulus and the shear modulus of Fd3̄m-BiFeO₃ is larger than that of Pnma-BiMnO₃. This work provides a deeper and more comprehensive understanding of BiFeO₃.