The effect of vacancies on the annular dark field image contrast of grain boundaries: A SrTiO 3 case study

H. S. Lee, S. D. Findlay, T. Mizoguchi, Y. Ikuhara

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The analysis of grain boundary structure in high resolution electron microscopy is often hindered by contrast variation within the grain boundary region which is not explained by simple models of the grain boundary structure. Recent work suggests that structural disorder along the beam direction and the presence of vacancies contribute significantly to this effect. One might expect a significant reduction in contrast in a Z-contrast image of a grain boundary would imply that vacancies present must result from the absence of heavier elements. Using a [001](210) σ5 grain boundary in SrTiO 3 as a test case and first principles structure relaxation to calculate stable defect structures, we show that the reduction in the intensity from fully occupied Sr columns due to the structural distortion resulting from a nearby O vacancy can be as great as that due to introducing a Sr vacancy in the column itself. The effect on energy dispersive X-ray spectroscopy signals is also considered, but found to be smaller than that on Z-contrast images.

Original languageEnglish
Pages (from-to)1531-1539
Number of pages9
JournalUltramicroscopy
Volume111
Issue number11
DOIs
Publication statusPublished - 2011 Nov
Externally publishedYes

Keywords

  • Grain boundary structure
  • High-angle annular dark field (HAADF)
  • Scanning transmission electron microscopy (STEM)
  • SrTiO

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Instrumentation

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