title: Atomic-resolution measurement of oxygen concentration in oxide materials.
abstract: Using high-resolution imaging at negative spherical aberration of the objective lens in an aberration-corrected transmission electron microscope, we measure the concentration of oxygen in Sigma3[111] twin boundaries in BaTiO3 thin films at atomic resolution. On average, 68% of the boundary oxygen sites are occupied, and the others are left vacant. The modified Ti2O9 group unit thus formed reduces the grain boundary energy and provides a way of accommodating oxygen vacancies occurring in oxygen-deficient material by the formation of a nanotwin lamellae structure. The atomically resolved measurement technique offers the potential for studies on oxide materials in which the electronic properties sensitively depend on the local oxygen content.
authors.affiliation: Institute for Solid State Research, Research Center Jülich, D-52425 Jülich, Germany.
authors.forename: C L
authors.initials: CL
authors.lastname: Jia
authors.forename: K
authors.initials: K
authors.lastname: Urban