Comparison of structural, ferroelectric, and strain properties between A-site donor and acceptor doped Bi1/2(Na0.82K0.18)1/2TiO3 ceramics

Effects of Li- and La-doping on the structural, ferroelectric, and strain properties of Bi1/2(Na0.82K0.18)1/2TiO3 (BNKT) ceramics were compared. In this study, Li+ was selected as the A-site acceptor and La3+ as the A-site donor. Li doping resulted in hardening of BNKT with an improved mechanical quality factor (Qm) of 253 and an increased coercive field (Ec), while La doping brought about a softening effect that was evidenced by an improved piezoelectric constant (d33) of 172 pC/N and decreased Ec. In addition, the large normalized bipolar strain (Smax/Emax) was obtained up to 650 pm/V in 3 mol% La-doped BNKT.