What Can Be Expected From Lead-Free Piezoelectric Materials?

The reasons for the lower piezoelectric properties in the most studied lead-free piezoelectrics, modified (K,Na)NbO3 and (Bi0.5Na0.5)TiO3, are discussed. Contributions from domain wall motion and properties at the morphotropic phase boundary are considered and are compared to those in PZT. Lead-free, non-piezoelectric solutions to electromechanical coupling are discussed.