Piezoelectric and Electrostrictive Materials for Transducer Applications. Volume 1

Highlights of the years activity include Participation of a number of senior faculty in program to better define the role of ferroelectrics in smart materials and the manner in which these developing interests will impact the needs for transducers as both actuators and sensors. New progress has been made with the flextensional moonie type structures and with the evolution of the 13 composites towards commercial development as large area actuators. The year has seen major advance in the understanding of the relaxor type ferroelectrics which are most useful as dielectrics and electrostrictors. It has become clear that the original superparaelectric model is only a first approximation valid for the very high temperature behaviour and that in fact both the Lead magnesium niobate and the PZT materials are close analogues of the magnetic spin glasses. Interaction between the polar micro-regions leads to a Vogel-Fulcher like slowing down and freezing, and provides understanding of the micros to macrodomain transitions, the hysteretic behaviour and the coupled elastic responses. An essential component of the program is the excellent capability in synthesis and processing which has been developed to provide the many new compositions and controlled microstructures which are essential for the proper understanding of the properties.