Expanded Operating Domain Piezoelectric Single Crystals

For this Phase I STTR program, TRS proposes to investigate the synthesis of new single crystal piezoelectric compositions that will operate at higher temperature, higher electric field and/or higher stress than current state-of-the-art PMN-PT single crystals. PMN-PT single crystals are readily available for certain applications, however a broader operating range would allow for greater device design flexibility and therefore a wider range of potential applications. The base program will focus on establishing potential compositions with A and B site PMN-PT modifications and exploring ternary PMN-PT base compositions with novel end members. Proposed compositional modification arises from first principal calculations (ab initio) of crystal chemistry and local atomic structure of ferroelectric perovskites. The focus of the effort is to improve the stability of the PMN-PT system in order to expand the operating domain or establish new systems. The focus will be to increase the Curie temperature for increased temperature stability or coercive field for increased electrical stability. This effort has significant implications to high power transducer design and application, especially tonpilz transducers. Establishing new compositions with the potential of increased sensitivity, broader bandwidth, higher strains, and higher acoustic power may be enabling for a number of high drive applications.BENEFITS: At the conclusion of Phase I, we expect to have established the feasibility of growing novel compositions of expanded operating temperature range piezoelectric single crystals for broadband, high power Tonpilz transducers and acoustic sensors using the Bridgman or Flux-Bridgman growth technique. By the end of the Phase I Option, the best performance composition will be able to be down selected from the potential compositions. The growth of the chosen composition will be optimized in Phase II and to further scale up both diameter and total volume of grown crystal. Emphasis will be placed on ensuring high quality crystals by optimizing the growth conditions in parallel with scale-up efforts to minimize inclusions and other crystal defects. TRS' commercialization goal for this program is to develop high quality expanded operating range piezoelectric single crystals and apply them for high frequency transducer arrays constructed from assemblages of Tonpilz elements based on the single crystals. It is TRS' intention to develop the technology required to make transducer heads from single crystals and to sell these to sonar systems manufacturers such Northrop-Grumman for integration of the transducers with drive, control, and imaging electronics. To achieve this goal we will transfer technology developed by Penn State ARL on the Phase II program, hire a transducer engineer, and/or, collaborate with an established transducer company such as Blatek, Inc. At the conclusion of the Phase II program a pilot process will be developed to produce the single crystal material and the arrays for the targeted application to be determined specifically during Phase I and II. For Phase III follow-on funding TRS and its team members will seek development funds from the Navy for specific UUV or towed scanner device development. Successful commercialization of this technology will provide a source of broadband, high power, single crystal based, acoustic sensors.