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Imaging, Core-Loss, and Low-Loss Electron-Energy-Loss Spectroscopy Mapping in Aberration-Corrected STEM

2010; Oxford University Press; Volume: 16; Issue: 4 Linguagem: Inglês

10.1017/s1431927610013504

1435-8115

Sorin Lazar, Yang Shao, Lina Gunawan, Riad Nechache, A. Pignolet, Gianluigi A. Botton,

Advanced X-ray Imaging Techniques

Abstract High-angle annular dark-field and annular bright-field imaging experiments were carried out on an aberration-corrected transmission electron microscope. These techniques have been demonstrated on thin films of complex oxides Ba 3.25 La 0.75 Ti 3 O 12 and on LaB 6 . The results show good agreement between theory and experiments, and for the case of LaB 6 they demonstrate the detection of contrast from the B atoms in the annular bright-field images. Elemental mapping with electron-energy-loss spectroscopy has been used to deduce the distribution of Cr and Fe in a thin film of the complex oxide Bi 2 (Fe 1/2 Cr 3/2 )O 6 at the unit cell level and the changes in the near-edge structure within the inequivalent regions in the crystalline unit cell. Energy-filtered images in the low-loss region of the energy-loss spectrum show contrast and resolution consistent with the modulation of the signals from elastic scattering. High-resolution contrast, mediated by phonon scattering, is observed for interband transitions. The limitations in terms of detection and signal are discussed.