Recent Publication in the Journal Science
“Giant piezoelectricity of Sm-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals”
The AIF instruments and users have contributed to a recent publication in the journal Science. By introducing small quantities of the rare earth element samarium, the piezoelectric properties of PMN-PT single crystals were increased by a factor of two. Piezoelectrics have many important applications such as in underwater sonar systems, ultrasound imaging, and actuators. Although only one in a thousand atoms is samarium, the effects on the crystal structure is significant. Using atomic resolution STEM imaging, and in agreement with simulations, it was found that the atomic structure of PMN-PT is significantly modified leading to significant increases in properties.
![Image and electromechanical properties of [001]-oriented Sm-doped PMN-PT crystals. (A) Image of as-grown Sm-PMN-PT crystal. The compositions of points A, B, C, and D are listed in table S1. (B) Dielectric and piezoelectric coefficients of Sm-PMN-PT crystals versus those of PMN-30PT (patterned). (C) Electric field–induced strains for Sm-PMN-PT (sample B: 0.66 mol % Sm-doped PMN-30PT) and PMN-30PT crystals.](https://aif.ncsu.edu/wp-content/uploads/sites/31/2019/04/F1.large_-7-600x217.jpg)
![Temperature-dependent dielectric behaviors of Sm-doped PMN-PT (sample B) and PMN-30PT crystals poled along the [001] direction. (A and B) Low- and high-temperature properties of Sm-doped PMN-PT crystals, respectively. (C and D) Low- and high-temperature properties of PMN-30PT crystals, respectively.](https://aif.ncsu.edu/wp-content/uploads/sites/31/2019/04/F2.large_-600x423.jpg)
![Atomic-resolution HAADF-STEM images for Sm-doped PMN-PT (sample B) and PMN-30PT crystals recorded along the [010] crystallographic direction. (A and B) Normalized intensities of the A sublattice for Sm-PMN-PT and PMN-30PT, respectively. The color of the circles indicates the intensity of each atom column. (C and D) Atomic distances between A sublattice positions in Sm-PMN-PT and PMN-30PT crystals, respectively. The color of the lines represents the distance between A-site atom columns. Although the long-range averaged phase of Sm-PMN-PT inferred by XRD diffractions is a mixture of tetragonal P4mm and orthorhombic Amm2 phases, the local symmetry can be much lower than that of P4mm and Amm2 because of the presence of cation disordering. As expected, the symmetry of a specific lattice observed by STEM (C) is lower than that of either tetragonal P4mm or orthorhombic Amm2. (E and F) Unit cell c/a ratios for Sm-PMN-PT and PMN-30PT crystals, respectively. The color of the circles indicates the c/a ratio for each unit cell.](https://aif.ncsu.edu/wp-content/uploads/sites/31/2019/04/F3.large_-15-424x600.jpg)

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