IMF2017

Lead-free piezoelectric materials have attracted great attention in recent past. However, despite worldwide research, the properties of these materials are still inferior to that of lead-based piezoelectric materials. Out of various techniques, dopant engineering has been very effective in improving the functional response of the lead-based piezoelectric ceramics. Though, the dopant engineering was not very fruitful in improving the piezoelectric response in lead-free piezoelectric ceramics. However, the anisotropy in piezoelectric properties provides opportunity to achieve enhanced piezoelectric response in oriented single crystals. But, the synthesis of single crystals is expensive and cannot be used for mass scale applications. The textured (grain–oriented) piezoelectric ceramics has been considered as an effective solution to this challenge. Here, we present a novel and cost-effective method for the synthesis of high performance textured Na_0.5Bi_0.5TiO₃ (NBT) based piezoelectric materials. The synthesis of [001]_pc (pc: pseudo cubic) grain oriented NBT-based ceramics was performed using NBT as seed template. The driving force for the growth of textured ceramics was found to be originated from the difference in the surface energy and the chemical potential gradient between the stable NBT seeds and the metastable liquid phase. The piezoelectric response was found to increase significantly with the increase in the degree of texturing. The optimized textured system was found to provide 2x enhancement in the magnitude of the piezoelectric coefficient as compared to its randomly oriented form. The NBT-based textured lead-free piezoelectric materials further exhibited giant electric field induced strain (~ 0.48%) with ultra low hysteresis (~ 5%).