Temperature‐insensitive piezoelectricity in lead‐free NaNbO3‐based ceramics

Abstract In this work, we report a lead‐free piezoelectric ceramic of (0.9‐ x )NaNbO 3 ‐0.1BaTiO 3 ‐ x BaZrO 3 , and the effects of BaZrO 3 on the phase structure, microstructure, electrical properties and temperature stability are investigated. A morphotropic phase boundary‐like region consisting of rhombohedral (R) and tetragonal (T) phases is constructed in the compositions with x = 0.035‐0.04. More importantly, in situ temperature independence of the piezoelectric effect {piezoelectric constant ( d 33 ) and strain} can be achieved below the Curie temperature ( T c ). Intriguingly, the electric field‐induced strain is still observed at T ≥ T c due to the combined actions of the electrostrictive effect and the electric field‐induced phase transition. We believe that NaNbO 3 ‐based ceramics of this type have potential for applications in actuators and sensors.