High-drive applications for new PMN-PT piezoelectric crystals require additional bias fields due to the relatively low coercivity (EC, ~ 2 kV/cm). However, this complicates the design of Navy devices, increases the cost, and makes the devices more susceptible to electrical failure. Thus, the goals of the proposed project are to increase EC, and extend the thermal stability of PMN-PT based transducers through compositional modifications (e.g., additions of lead indium niobate). We propose a budget of $749,908 for the growth and commercialization of PIN-PMN-PT transducer crystals, 3 inch in diameter, over a 2-year period. We will subcontract to the University of Illinois at Urbana-Champaign to support work for an understanding of the role of composition and structure on domain pinning and increased coercivity. We anticipate establishing manufacturing methods for the growth of PIN-PMN-PT based crystals with high EC (3x) and improved thermal stability (i.e., with de-poling temperature above 110 C). In addition, the piezoelectric, dielectric and elastic properties of the grown crystals will be systematically characterized to provide guidelines for their use in Navy transducer systems, and commercial ultrasound devices.
Benefit: The proposed work will lead to the availability of new and improved PIN-PMN-PT piezoelectric crystals, their growth, optimization and commercialization. Crystals of the new ternary composition harden EC by a factor of 3 compared with pure PMN-PT, with Ec values up to and beyond 6 kV/cm. In addition, the depoling temperature (TR/T) can be increased by ~ 20 C, with a TR/T of 120 C. Moreover, advantages for new piezoelectric crystals will be maintained (e.g., high d, high coupling k), with performance characteristics similar to PMN-PT crystals. Improvements in coercivity will obviate the need for applied bias fields currently required in Navy designs, thereby increasing simplicity, and reducing costs, and will engender more stable and reliable performance characteristics. In addition, systematic property determinations for the new and improved crystals will provide guidelines for their future use and commercial exploitation. The ability to grow large-sized crystals, with enhanced EC and thermal stability, and with detailed property information, will enable the production and use of the next generation of Navy transducers, and commercial ultrasound devices, particularly for high-drive applications.
Keywords: melt growth, melt growth, PMN-PT Piezoelectric Crystals, transducer, Transducers, hard coercivity, high drive, Doping, coercive field, and radiation damage., thermal de-poling, PMN-PT, PIN-PMN-PT, Piezoelectric Crystal, thermal stability, Reliability
