SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 32: Topical Session: Defect Phases I
MM 32.6: Vortrag
Mittwoch, 29. März 2023, 17:30–17:45, SCH A 216
Oxygen vacancy formation energies at grain boundaries in perovskite-type electro-ceramics — •Cong Tao1, Daniel Mutter1, Daniel F. Urban1,2, and Christian Elsässer1,2 — 1Fraunhofer IWM, 79108 Freiburg — 2Freiburg Materials Research Center (FMF), University of Freiburg, 79104 Freiburg
Oxygen vacancy concentrations are assumed to play a major role in the electric-field assisted grain growth of technologically relevant single crystal perovskite phases. The underlying effect on the atomic scale is the redistribution of cationic and anionic point defects between grain boundaries and bulk phases due to different defect formation energies in the structurally different regions, accompanied by the formation of space charge zones. In this study, we present results of classical atomistic calculations of oxygen vacancy formation energy profiles across supercells containing the symmetric tilt grain boundaries Σ 5(210)[001], Σ 5(310)[001], and the asymmetric tilt grain boundary (430)||(100). The electro-ceramic perovskite materials SrTiO3, BaTiO3, and BaZrO3 were systematically analyzed. We discuss the dependence of formation energies and resulting concentration profiles on composition and grain boundary type.