Ferroelectric materials for electromechanical transducer applications

Many advantages of ferroelectric compositions in the lead zirconate:lead titanate (PZT) solid solutions for both sensing and actuation are explored. The state of understanding of both intrinsic single domain and extrinsic domain wall and phase boundary contribution to response is described, and the composition manipulations used to modifiy the extrinsic responses explored. In lead magnesium niobate (PMN) based solid solution a nanometer scale ordering of Mg:Nb cations breaks up the conventional ferroelectric coupling leading to glass like relaxor ferroelectric response. The fact that problems arising from density and rigidity of PZT for large area transducers are markedly worked out in piezoceramic:polymer composites is also briefly explored.