Design of superior electrostriction in BaTiO3‐based lead‐free relaxors via the formation of polarization nanoclusters

• Published in: InfoMat 2023-01, Vol.5 (1), p.n/a
• Main Authors: Wang, Lu, Qi, He, Deng, Shiqing, Cao, Lingzhi, Liu, Hui, Hu, Shuxian, Chen, Jun
• Format: Article
• Language: English
• Subjects: Barium titanates; BaTiO3; Ceramics; Density functional theory; Electric fields; Electronic devices; Electrostriction; electrostrictive effect; Ferroelectric materials; Ferroelectricity; Ferroelectrics; Hysteresis; Lattice strain; Lead free; local structure; Monte Carlo simulation; Nanoclusters; Perovskites; Phase transitions; Polarization; relaxor ferroelectrics; Relaxors; Segregations; Solid solutions; Three dimensional models
• ISSN: 2567-3165; 2567-3165
• DOI: 10.1002/inf2.12362

Electrostrictive materials have wide applications in modern high‐precision electronic devices. Driven by growing environmental concerns, there is demand for lead‐free materials with superior electrostriction behaviors. In this study, we demonstrate a record‐high electrostrictive coefficient of ~0.0712 m4 C−2 in perovskite ferroelectric ceramics, along with hysteresis‐free strain as well as excellent frequency and thermal stabilities, in lead‐free BaTiO3‐based ceramics through a polarization nanocluster design. By appropriately introducing Li+ and Bi3+ into the BaTiO3 lattice matrix, the long‐range ferroelectric ordering can be broken, and polarization nanoclusters can be formed, resulting in a relaxor state with concurrently suppressed polarization and maintained electro‐strain. A three‐dimensional atomic model constructed using advanced neutron total‐scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale, which confirms the prediction made by density functional theory calculations. Such a short‐range chemical order destroys the long‐range ferroelectric order of the off‐centered Ti polar displacements and leads to the embedding of Li+/Bi3+‐rich polar nanoregions in the Ba2+‐rich polarization disorder matrix. Further, a completely reversible electric‐field‐induced lattice strain is observed, giving rise to pure electrostriction without hysteresis behavior. This work provides a novel strategy for developing lead‐free relaxor ferroelectrics with high electrostriction performance. A novel strategy that introducing chemical short‐range order forms polarization nanoclusters to achieve high electrostrictive performance. The substitution of small radius Li+ and strong polarity Bi3+ into BaTiO3 lattice matrix destroy the long‐range ferroelectric ordering and induce a relaxor state, resulting in a record‐high electrostrictive coefficient of ~0.0712 m4C−2, together with hysteresis‐free strain and excellent frequency and thermal stability.