title: Atomic scale characterization of vacancy ordering in oxygen conducting membranes.
abstract: This article presents a comprehensive investigation of (La, Sr)FeO3 by correlated atomic resolution annular dark field imaging and electron energy loss spectroscopy. Here, the ability of these techniques to characterize point defect formation and phase transitions under reducing conditions in situ in the scanning transmission electron microscope is evaluated and the influence of oxygen vacancies on the structure-property relationships is discussed. In particular, the evolution of the Ruddlesden-Popper, Brownmillerite, and Aurivillius phases can be associated directly with the ionic and electronic conductivity of the bulk material under different thermodynamic conditions. These results lead naturally to an atomistic defect chemistry model to explain the high temperature ionic and electronic conductivity in this and other perovskite materials.
authors.affiliation: Department of Physics, University of Illinois at Chicago, 845 West Taylor Street, #2236, Chicago, IL 60607, USA. rfklie@uic.edu
authors.forename: Robert F
authors.initials: RF
authors.lastname: Klie
authors.forename: Nigel D
authors.initials: ND
authors.lastname: Browning
mesh_terms: D004553:Electric Conductivity; D005290:Ferric Compounds / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D007811:Lanthanum / Q000737:chemistry; D008567:Membranes, Artificial; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods*; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D005290:Ferric Compounds; D008567:Membranes, Artificial; D010087:Oxides; C000499:ferric oxide; C103829:lanthanum oxide; D007811:Lanthanum; D010100:Oxygen