Large electro-strain with excellent fatigue resistance of lead-free (Bi0.5Na0.5)0.94Ba0.06Ti1-x(Y0.5Nb0.5)xO3 perovskite ceramics

Abstract A series of lead-free (Bi0.5Na0.5)0.94Ba0.06Ti1-x(Y0.5Nb0.5)xO3 (for 0 ≤ x ≤ 0.03) perovskite ceramics were fabricated using a solid-state reaction technique. The effects of (Y0.5Nb0.5)4+ ions doping on phase structure, piezoelectric properties, AC impedance, and fatigue resistance were systematically studied. Crystal structure as a function of the composition revealed a single perovskite lattice structure with dense micromorphology. The transition temperature of the non-ergodic and ergodic relaxor ferroelectric phase shifted to near ambient temperature with increasing composition, which was related to the destruction of the long-range ordered ferroelectric domains. Hence, the transformation of ferroelectric-to-relaxor phase was easier under applied electric field at room temperature. The ceramic for x = 0.01 composition attained a large unipolar strain of ~ 0.452% with a corresponding normalized strain (d33*) of ~ 603 pm/V under applied 75 kV/cm field. Besides, the excellent fatigue resistance of the sample was obtained after 105 switching cycles under 70 kV/cm. These phenomena demonstrated that (Bi0.5Na0.5)0.94Ba0.06Ti1-x(Y0.5Nb0.5)xO3 ceramics might be suitable for a wide range of electronic equipment applications such as actuators and sensors.