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Local Structure and Macroscopic Properties in PMN-PT and PZN-PT solid solutions

Ilya Grinberg·Andrew M. Rappe
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Abstract

We have examined the local structure of PMN-PT and PZN-PT solid solutions using density functional theory. We find that the directions and magnitudes of cation displacement can be explained by an interplay of cation-oxygen bonding, electrostatic dipole-dipole interactions and short-range direct and through oxygen Pb-B-cation repulsive interactions. We find that the Zn ions off-center in the PZN-PT system, which also enables larger Pb and Nb/Ti displacements. The off-centering behavior of Zn lessens Pb-B-cation repulsion, leading to a relaxor to ferroelectric and a rhombohedral to tetragonal phase transition at low PbTiO$_3$ content in the PZN-PT system. We also show that a simple quadratic relationship exists between Pb and B-cation displacements and the temperature maximum of dielectric constant, thus linking the enhanced displacements in PZN-PT systems with the higher transition temperatures.

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Ilya Grinberg, Andrew M. Rappe. 2004-10-13. Local Structure and Macroscopic Properties in PMN-PT and PZN-PT solid solutions. https://doi.org/10.1103/physrevb.70.220101

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