Irreversible domain evolutions and formation mechanism of relaxor ferroelectric 0.91PZN-0.09PT single crystals.

Relaxor-based ferroelectric PZN-PT crystals are well known with excellent piezoelectric properties. However, the inhomogeneity has been usually observed in this system, which are closely related to its complicated domain structures and phase transitions. In this work, 0.91PZN-0.09PT crystals have been grown by the flux-Bridgman method. The evolution of the domain structures of (001) oriented wafers have been studied with the in situ observation using high-temperature polarized light microscopy. Both reversible and irreversible domains have been observed during the heating and cooling cycles between 25 and 250 °C. Especially, the unique irreversible domain evolutions are observed in the region which contains remaining monoclinic phase after the thermal cycles. The results indicate that the irreversible domains in PZN-PT crystal are possibly correlated to the remaining monoclinic phase which is frozen to room temperature during the thermal cycles. It may provide deeper insight into the intriguing mechanism of phase transition and domain evolutions for relaxor ferroelectrics. [ABSTRACT FROM AUTHOR]