Large electrostrictive effects in relaxor ferroelectrics

Abstract

Lead magnesium niobate and other relaxor ferroelectrics are promising transducer materials for use as active elements in adaptive optic systems and similar applications. These ceramics are dominantly in the paraelectric phase, and dimension control is obtained through the high intrinsic quadratic electrostrictive effect. Since stable ferroelectric domain structures do not occur, the problems of dimensional creep and non-reproducibility (aging and de-aging effects) of the conventional poled piezoelectric ceramic are largely eliminated. Suitably chosen compositions in the Pb3MgNb2O9-PbTiO3 family give electrostriction strains ten times larger than those of conventional BaTiO3-based ceramics. Low expansion coefficients are an added advantage for thermal stability.