INFLUENCE OF THE POLING FIELD ON THE ELECTROMECHANICAL COUPLING FACTOR OF PZT CERAMIC DOPED WITH La203.

Lead zirconate titanate (PbZrO.53 Ti0.4703), near the morphotropic phase boundary, doped with 2.5% mol La203 was prepared using either standard ceramic or hot pressing techniques. Electrical measurements show that the dependence of the physical properties on the poling fields is similar for material prepared with either technique. X-ray diffraction patterns show the presence of the two, tetragonal and rhombohedral, perovskite phases, but the properties measured (loss tangent, electromechanical coupling coefficient, Curie temperature) for doping concentrations of 2.5% mol La203 are similar to those reported previously in the literature which used lower La concentrations. The maximum electromechanical coupling factor, kp= 0.60 was obtained with a poling field of 4 kV/m.