| Autor: |
Auckett JE; School of Chemistry , The University of Sydney , Sydney 2006 , Australia.; Department of Chemistry , Durham University , Durham DH1 3LE , United Kingdom., Lee WT; Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Lucas Heights 2234 , Australia., Rule KC; Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Lucas Heights 2234 , Australia., Bosak A; European Synchrotron Radiation Facility , BP 220, 38043 Grenoble Cedex , France., Ling CD; School of Chemistry , The University of Sydney , Sydney 2006 , Australia. |
| Abstrakt: |
The room-temperature structure of brownmillerite-type Sr 2 Fe 2 O 5 remains controversial, despite numerous published crystallographic studies utilizing X-ray, neutron, and electron diffraction data collected on single-crystalline and powder samples. The main disagreements concern the ordering of twisted FeO 4 tetrahedral chains within and between the layers stacked along the b axis, and the impact of this ordering on oxide-ionic conductivity. Here, we present new data along with a reinterpretation of previously published diffraction images, including the reassignment of satellite reflections, which harmonize the results of past studies in a unified description of tetrahedral chain ordering in Sr 2 Fe 2 O 5 at length scales relevant to X-ray and neutron diffraction. Implications for the prevailing model of oxide ion transport in this material are also discussed. |
