Regensburg 2016 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 26: Poster session II

MM 26.40: Poster

Tuesday, March 8, 2016, 18:30–20:30, Poster B3

Oxygen vacancy diffusion in sodium bismuth titanate studied by density functional theory calculations — •Kai-Christian Meyer, Melanie Gröting, and Karsten Albe — TU Darmstadt, Jovanka-Bontschits-Str. 2, 64287 Darmstadt

Sodium bismuth titanate (Na_0.5Bi_0.5TiO₃, NBT) is a ferroelectric relaxor-like material at room temperature and has interesting electrical properties for application as a high strain actuator material. It shows a broad diffuse phase transition from a ferroelectric (rhombohedral/monoclinic) structure to a weakly polar (tetragonal) state. Recently, it has been shown that doped NBT exhibits a high ion conductivity, in contrast to other perovskites. [1] Thus, in this work we investigate by means of density functional theory calculations oxygen vacancy formation energies, association energies with different metal ions and migration barriers for different A-cation orders. We find among other things that the chemical order plays a strong role on the atomistic level, eg. for local phase transitions [2] and conductivity.

[1] M. Li, et al., Nat. Mater. 13, 31 - 36 (2014)

[2] K.-C. Meyer, et al., J. Solid State Chem. 227, 117 - 122 (2015)