Temperature dependent structures and properties of Bi0.5Na0.5TiO3-based lead free piezoelectric composite

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 45; no. 27; pp. 1891 - 1896
• Main Authors: Zhang, Ji, Sun, Lei, Geng, Xiao-Yu, Zhang, Bin-Bin, Yuan, Guo-Liang, Zhang, Shan-Tao
• Format: Journal Article
• Language: English
• Published: England 05.07.2016
• Subjects: Depolarization; Diffraction; Ferroelectric materials; Ferroelectricity; Lead free; Obstacles; Piezoelectricity; Solid solutions
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c6dt01880g

The thermal depolarization around 100 °C of the Bi 0.5 Na 0.5 TiO 3 -based piezoelectric solid solutions leads to the disappearance of macroscopic ferroelectric/piezoelectric properties and remains a long-standing obstacle for their actual applications. In this communication, we report lead-free piezoelectric composites of 0.94Bi 0.5 Na 0.5 TiO 3 -0.06BaTiO 3 :0.5ZnO (BNT-6BT:0.5ZnO, where 0.5 is the mole ratio of ZnO to BNT-6BT) with deferred thermal depolarization, which is experimentally confirmed by systematic temperature dependent dielectric, ferroelectric, piezoelectric measurements. Especially, based on temperature dependent X-ray diffraction measurements on unpoled and poled samples, thermal depolarization is confirmed to have no relationship with the structural phase transition, the possible mechanism for the deferred thermal depolarization is correlated with the ZnO-induced local electric field which can suppress the depolarization field. We believe our results may be helpful for understanding the origin of thermal depolarization in BNT-based piezoelectric materials, and thus provide an effective way to overcoming this obstacle. The thermal depolarization of Bi 0.5 Na 0.5 TiO 3 -BaTiO 3 is deferred by introducing ZnO to construct composite, the detailed crystal structures of unpoled and poled composites were comparatively investigated.