Structural, ferroelectric, optical properties of A-site-modified Bi0.5(Na0.78K0.22)0.5Ti0.97Zr0.03O3 lead-free piezoceramics

We reported the role of A-site modification on the structural, ferroelectric, optical and electrical field-induced strain properties of Bi-0.5(Na0.78K0.22)(0.5)Ti0.97Zr0.03O3 lead-free piezoceramics. The Li+ ions with concentration from 0 to 5 mol% were used to substitute at A-site. There was no phase transition when Li+ ions was added up to 5 mol%. The electric field-induced strain (S-max/E-max) values increased from 600 to 643 pm/V for 2 mol% Li+-added which results from distortion both rhombohedral and tetragonal phase structures. The band gap reduced from 2.88 to 2.68 eV and the saturation polarization decreased from 46.2 to 26.1 mu C/cm(2) when Li+ ions concentration increased from 0 to 5 mol% respectively. We expect that this work could be helpful for further understanding the role of A-site dopants in comparison with B-site modification in lead-free Bi-0.5(Na,K)(0.5)TiO3-based ceramics. (C) 2014 Elsevier Ltd. All rights reserved.