Atomic Resolution Coordination Mapping in Ca2FeCoO5 Brownmillerite by Spatially Resolved Electron Energy-Loss Spectroscopy

作者：Turner Stuart^*; Verbeeck Johan; Ramezanipour Farshid; Greedan John E; Van Tendeloo Gustaaf; Botton Gianluigi A

来源：Chemistry of Materials, 2012, 24(10): 1904-1909.

DOI：10.1021/cm300640g

• oxygen coordination
• valency
• electron energy-loss spectroscopy
• EELS
• energy-loss near edge structure
• ELNES
• Fe-L-2,L-3 edge
• Co-L-2,L-3 edge
• brownmillerite

Using a combination of high-angle annular dark field scanning transmission electron microscopy and atomically resolved electron energy-loss spectroscopy at high energy resolution in an aberration-corrected electron microscope, we demonstrate the capability of coordination mapping in complex oxides. Brownmillerite compound Ca2FeCoO5, consisting of repetitive octahedral and tetrahedral coordination layers with Fe and Co in a fixed 3+ valency, is selected to demonstrate the principle of atomic resolution coordination mapping. Analysis of the Co-L-2,L-3 and the Fe-L-2,L-3 edges shows small variations in the fine structure that can be specifically attributed to Co/Fe in tetrahedral or in octahedral coordination. Using internal reference spectra, we show that the coordination of the Fe and Co atoms in the compound can be mapped at atomic resolution.

• 出版日期2012-5-22