Giant piezoelectricity of Sm-doped Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> single crystals.

Li, Fei; Cabral, Matthew J; Xu, Bin; Cheng, Zhenxiang; Dickey, Elizabeth C; LeBeau, James M; Wang, Jianli; Luo, Jun et al. · Science · 2019

basic_science · Level V

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Abstract

High-performance piezoelectrics benefit transducers and sensors in a variety of electromechanical applications. The materials with the highest piezoelectric charge coefficients (<i>d</i> <sub>33</sub>) are relaxor-PbTiO<sub>3</sub> crystals, which were discovered two decades ago. We successfully grew Sm-doped Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> (Sm-PMN-PT) single crystals with even higher <i>d</i> <sub>33</sub> values ranging from 3400 to 4100 picocoulombs per newton, with variation below 20% over the as-grown crystal boule, exhibiting good property uniformity. We characterized the Sm-PMN-PT on the atomic scale with scanning transmission electron microscopy and made first-principles calculations to determine that the giant piezoelectric properties arise from the enhanced local structural heterogeneity introduced by Sm<sup>3+</sup> dopants. Rare-earth doping is thus identified as a general strategy for introducing local structural heterogeneity in order to enhance the piezoelectricity of relaxor ferroelectric crystals.