SBIR Phase II: Development of a Crystal Growth Process for Relaxor Ferroelectric Single Crystals

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This Small Business Innovation Research Phase II project is aimed at the development of a process for the growth of Pb(Zn1/3,Nb2/3)03-PbTiO3 (PZN-PT) and Pb(Mg,1/3Nb2/3)03-PbTiO3 (PMN-PT) ferrorelaxor single crystals from high-temperature solutions (fluxes). PZN-PT and PMN-PT single crystals have unique properties that include very high coupling coefficients (90%), large dielectric constants (1000-5000), low dielectric loss (0.01), and exceptionally high piezoelectric coefficients (d33 2000 pC/N). These properties have established PZN-PT and PMN-PT as very attractive materials for low frequency acoustic transduction, ultrasonic biomedical imaging and actuation. However, large and good quality single crystals of PMN-PT and PZN-PT are not commercially available because of the lack of a growth technique. Two modifications of a growth process will be developed in Phase II, namely Immersion Seeded Solution Growth (ISSG) and Top Seeded Solution Growth (TSSG). As-grown crystals will be characterized and prototype multilayer stacked actuators will be fabricated and tested. Potential commercial applications of PZN-PT and PMN-PT single crystals will include piezoelectric devices with improved characteristics for defense, medical and electronic industries. In particular, they will be used in acoustic transducers, hydrophones, ultrasound sensors for biomedical imaging and electromechanical actuators for micropositioners and micro-motors.