Increased operating temperature range in La-modified Pb(Mg/sub 1/3/Nb/sub 2/3/)O/sub 3/-PbTiO/sub 3/ relaxor ferroelectric-based transducers

Abstract

The large E-field induced strains and electromechanical coupling in PMN-based relaxors have been utilized in actuator and transducer applications. The effect of La/sup 3+/ modifications on the field-dependent dielectric and piezoelectric properties was investigated for several (1-x)PMN-(x)PT compositions with transition regions near room temperature. The effect of La/sup 3+/ modifications, increasing the width of the micro-macro polar transition range (/spl Delta/T), defined as the difference between the temperature of maximum permittivity (T/sub max/) and the depolarization temperature (T/sub d/), results in a broader temperature range for obtaining large induced electromechanical coupling factors with negligible hysteresis.