Giant electrostrictive effects of NaNbO3-BaTiO3 lead-free relaxor ferroelectrics

A giant electrostrictive effect was observed in (1 - x)NaNbO3-xBaTiO(3) relaxor ferroelectric ceramics, which exhibit a high electrostrictive coefficient Q(33) of similar to 0.046 m(4)/C-2 twice as large as those of Pb- and Bi-based perovskite relaxor ferroelectric ceramics. The theoretical analysis suggests that Q(33) should be strongly correlated with chemical species of cations in a perovskite structure in which a strong ionic bond is of great benefit compared with a covalent bond. A hysteresis-free large electrostrictive strain of similar to 0.148% up to at least 70 Hz was obtained in the x = 0.25 sample, demonstrating significant advantages over piezoelectric effects in high-precision ceramic actuators. Published by AIP Publishing.