Lead free 0.9Na_1/2Bi_1/2TiO₃-0.1BaZr_0.2Ti_0.8O₃thin film with large piezoelectric electrostrain

A sodium bismuth titanate-based thin film is widely investigated lead-free piezoelectrics with potential applications for modern micro-devices such as PiezoMEMS. In this work, a 0.9Na1/2Bi1/2TiO3-0.1BaZr0.2Ti0.8O3 thin film was deposited on a Pt/Ti/SiO2/Si (001) substrate by the sol-gel spin coating method. The deposited piezoelectric film shows low dielectric loss and high remnant polarization. The measured ferroelectricity loop showed a coercive field of 110 kV/cm and a saturation polarization of 46.83 μC/cm2. The piezoelectric response of this thin film does not decrease from room temperature to around 100 °C. The fabricated piezoelectric device with bottom and top electrodes showed a large macro-scale strain value of ∼4% under the DC (30 V) and AC voltages (f = 800 kHz, Vpp = 10 V).