Progress in Studies on Fabrication and Properties of PZNT Relaxor Ferroelectrics

The present paper reviews the recent progress in studies on fabrication and dielectric piezoelectric and electrostrictive properties of relaxor ferroelectric PZNT. The dominant method offabrication of PZNT is the PbO flux method at high temperature, by which the single crystalswith size of 40mm have been grown. Studies on their dielectric properties indicated that thebehavior of phase transition of PZNT crystals would vary from diffused, mixed to first order transition type with the increase of PT concentration. The rhombohedral-tetragonal ferroelectric phasetransition is also diffused which can be induced by composition or electric field. Single crystalswith their composition at MPB or in the rhombohedral phase region near MPB have extremelystrong piezoelectric properties. The 001 oriented rhombohedral and tetragonal crystals arerespectively suitable for acoustic arrays and single element sensors and actuators with broaderbandwidth, improved sensitivity and optimum impedance matching. Crystallographically, highstrains are achieved for 001 oriented rhombohedral crystals and their levels reach an orderof magnitude of those available from conventional piezoelectric and electrostrictive ceramics suchas PZT series and PMNT ceramics, which make these crystals as promising candidates for highperformance solid actuators.