Domain switching contribution to the ferroelectric, fatigue and piezoelectric properties of lead-free Bi0.5(Na0.85K0.15)0.5TiO3 films

Lead-free Bi-0.5(Na0.85K0.15)(0.5)TiO3 films have been prepared via a solution-gelation technique. The microstructure, domain structure, ferroelectric, fatigue and piezoelectric properties were investigated systematically. This shows that the films have a single-phase perovskite structure and show outstanding ferroelectric, fatigue and piezoelectric properties at room temperature. The maximum piezoelectric coefficient value of the films reaches approximately 158.94 pm V-1, which is comparable to that of polycrystalline lead-based films. Thus good ferroelectric, fatigue and piezoelectric properties are attributed to the well-defined electrical domain structure and its switching for Bi-0.5(Na0.85K0.15)(0.5)TiO3 films. The present results suggest that Bi-0.5(Na0.85K0.15)(0.5)TiO3 films can be used as a candidate for lead-free films in piezoelectric micro-electro-mechanical systems.