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

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.

Automated summary

Lead-free (Bi0.5Na0.5)0.94Ba0.06Ti1-x(Y0.5Nb0.5)xO3 perovskite ceramics doped with (Y0.5Nb0.5)4+ ions showed a shift in transition temperature towards ambient temperature with increased composition, making the transformation of ferroelectric-to-relaxor phase easier under applied electric field at room temperature. Additionally, the ceramic composition x = 0.01 exhibited a large unipolar strain and excellent fatigue resistance under specific field conditions, indicating potential applications in electronic devices like actuators and sensors.