IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society Distinguished Lecturer Award Recent Developments and Understanding of Ferroelectric and Piezoelectric Materials and Their Applications

Exciting developments are taking place in the field of electroceramics, in general and for ferroelectric and piezoelectric materials in particular. This presentation documents some of the impressive gains in useful and enabling properties obtained from newand improved materials designed for specific applications. Following a general introduction to ferroelectric and piezoelectric materials, with chronological developments, important milestones are highlighted where property limitations hindered future exploitation. The extent to which these problem areas have been solved or circumvented by improvements in materials and processing are outlined in the presentation. Two extreme examples are considered: the growth of large single crystals and the deposition and patterning of thin films. Their applicability to ultrasonics, ferroelectrics, and frequency control (UFFC) will be illustrated. For example, the crystal growth and properties of improved piezoelectrics in the system Pb3MgNb2O9 (PMN)PbTiO3 (PT) will be described with enhanced fieldinduced strains of 1 to 2%, piezoelectric coefficients over 4000 pC/N and electromechanical energy conversion efficiencies greater than 90%. The high signal-to-noise feature is of great interest for imaging devices, including medical microprobes. For the second example, thin films and patterning, novel chemical-solution deposition methods are outlined for the fabrication of integrated ferroelectric and piezoelectric devices. An additive patterning technique of microcontact printing with a molecular resist of self-assembled monolayers is described as a newlift-off process. A variety of materials and structures have been fabricated for potential ferroelectric and piezoelectric applications, including device integration on curved surfaces. Concluding remarks address the future of ferroelectric and piezoelectric materials.