Electrostrictive effect in perovskites and its transducer applications

Properties of new electrostrictive materials for displacive transducers are reviewed including theoretical, material and design studies. Intensive investigation of the electrostrictive effects in ferroelectric and antiferroelectric perovskites have led to some empirical rules: the product of the electrostriction coefficient Q and the Curie-Weiss constant C is constant for all perovskite crystals and the Q value is proportional to the square of the thermal expansion coefficient, α. Consistent with the empirical rules, the relaxor ferroelectric ceramic 0.9 Pb(Mg1/3Nb2/3)O3 −0.1 PbTiO3 possesses much larger strain with lower hysteresis, aging effects and thermal expansion than that obtained with piezoelectric lead zirconate titanate (PZT). Using a multilayer configuration similar to commercial capacitors, a new mirror control device capable of large strains with high reproducibility, up to ΔL/L ∼ 10−3, with only 200 V applied has been developed.