High electrostrictive strain induced by defect dipoles in acceptor-doped (K0.5Na0.5)NbO3 ceramics

Abstract

Acceptor doping is an efficient method to improve ferroelectric material performance through the formation of defect dipoles. Here, a high electrostrictive strain of 0.16–0.19%, and large of >300 pm V−1 are obtained in CuO-doped (K0.5Na0.5)NbO3 ceramics. We analyzed the orientation relationship and the interaction between defect dipole polarization (Pd) along 〈0 0 1〉 orientation and spontaneous polarization (Ps) parallel to 〈1 1 0〉 in orthorhombic (K0.5Na0.5)NbO3. Thus, a ‘coupling effect’ mechanism was suggested to explain how the Pd and Ps can work together to contribute to the electrostrictive strains in this lead-free piezoelectric ceramic.