Achieving low field-induced large strain by La-Nb co-doping in PZST-based anti-ferroelectric ceramics for high-performance actuators

Abstract

Anti-ferroelectric (AFE) dielectrics are promising for actuators due to their large strain resulting from the phase transition from AFE phase to ferroelectric (FE) phase. However, their high phase transition electric field and strain hysteresis (Hs) limit their application in actuators. In this work, La-Nb co-doping in Pb(Zr0.85Sn0.08Ti0.07)O3 AFE ceramics realizes collaborative optimization of AFE-FE phase transition electric field (EAFE-FE), Hs and strain. La3+ ions replace Pb2+ ions to weaken long-range FE coupling and refine hysteresis loops. Nb5+ ions replacing B-site ions enhance the stability of FE phase in PZST ceramics, hence further reducing EAFE-FE. Furthermore, doping Nb5+ decreases grain size, which is conducive to producing higher field-induced strains. As a result, EAFE-FE decreases from 119 kV cm−1 to 47 kV cm−1 and Hs decreases from 75 % to 44 %, while strain remains at 0.47 %. The results demonstrate that La-Nb co-doping strategy promotes the application of large-strain AFE materials in actuators.