Observation of the Domain Morphology of Pb(Mg1/3Nb2/3)O3-xPbTiO3 Single Crystals

Abstract

Relaxor-PbTiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Single crystals including Pb(Mg <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/3</inf> Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2/3</inf> )O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> -xPbTiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> (PMN-xPT) have been widely used and extensively studied in the last two decades due to their ultrahigh piezoelectric properties for acoustic devices. However, the piezoelectric properties of PMN-xPT single crystals are highly dependent on the PT contents. In this work, the domain morphologies of PMN-xPT with different PT compositions (x = 0.26 and 0.28, rhombohedral phase) after direct current poling (DCP) were observed by piezoresponse force microscopy (PFM). The domain morphologies and the domain wall densities were compared to study the influences of the PT compositions on the piezoelectric properties of PMN-xPT. The PFM images showed that after DCP, PMN-xPT single crystals of two different compositions all had the domain morphologies with ‘4R’ configuration in which both 109° and 71° domain walls could be clearly identified. Compared with PMN-0.26PT, PMN-0.28PT single crystals had similar 109° domain wall densities (Domain width: 1012 nm vs 1025 nm) but higher 71° domain wall densities (Domain width: 426 nm vs 645 nm). The higher piezoelectric properties of PMN-xPT single crystals were found to correlate with the higher 71° domain wall densities.