Influence of donor and acceptor substitutions on the extrinsic behaviour of PZT piezoceramics

A study of the substitution influence of Nb5+ and Fe3+ impurities on piezoelectric behaviour has been carried out. Different substitution concentrations as well as undoped materials have been performed for ceramics Pb(Zr1 − xTix)O3 with x = 47 and 40. The different impurity concentrations, and their type, produce variations in the domain wall mobility related to the extrinsic coefficient. This dependence between extrinsic behaviour and impurity concentration is studied for different material structures: the rhombohedral and morphotropic phase boundary (MPB). Two methods are used to characterize the extrinsic and intrinsic behaviours. Elastic and piezoelectric non-linear characterization at resonance has been made in isothermal conditions by impedance and vibration velocity measurements. In order to obtain the intrinsic coefficients, linear characterization at very low temperature has been carried out.