Enhanced electrostrains in PMN–xPZN solid solutions driven by a rather small electric field

Abstract

Pb(Mg1/3Nb2/3)O3 (PMN) relaxors have gained a lot of interest due to their unusual dielectric relaxation and high electrostrictive electrostrain. However, the Tm (temperature associated with maximum permittivity) of PMN is lower than room temperature, which limits their future development of electrostrain and practical applications. In this study, we increased the Tm by incorporating a relaxor ferroelectric (FE) end member Pb(Zn1/3Nb2/3)O3 (PZN) rather than a conventional high Curie temperature FE end member to create (1−x)PMN–xPZN solid solutions with x = 0.2–0.5. Their dielectric, FE, and electrostrain properties were systematically investigated. In x = 0.4 composition, we get a maximum electrostrain of 0.134% and an equivalent piezoelectric coefficient of 936 pm/V under a rather small driving field of 5 kV/cm. Furthermore, the electrostrain of the x = 0.5 is greater than 0.1% between 20 and 80°C, indicating its possible applicability in precision displacement actuators. Our findings not only clarify the electrostrain and electrostrictive properties of (1 − x)PMN–xPZN system but also show an innovative way to improve electrostrain properties by constructing relaxor–relaxor type solid solutions that can be applied to other FE systems.