| Tartalmi leírás: |
New methods for defect analysis can lead to improved interpretation of
experimental data
and thus better understanding of material properties. Although
transmission electron microscopy (TEM) has been used to study defects for many
decades, interpretive ambiguities can arise for cases that seem simple or even trivial.
Using geometric phase analysis (GPA), an image processing procedure, we show that
an apparent simple line defect in pyrite has an entirely different character. It appears to
be a
b= ˝[100] edge dislocation as viewed in a [001] high-resolution TEM (HRTEM)
image, but the measured
ux and uy displacements are asymmetric, which is inconsistent
with a simple line dislocation. Instead, the defect is best understood as a terminating
(101) marcasite slab in pyrite. The simulated HRTEM image based on this model
reproduces the defect contrast and illustrates the power of GPA analysis for (1) avoiding
potential pitfalls of misinterpreting apparently
simple defects in HRTEM images, (2)
detecting differences in elastic properties at the atomic scale, and (3) providing data for
the
positions of atom columns, thereby facilitating the construction of structure models
for complex defects.
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| Azonosító: |
Németh, Péter and Dódony, István and Pósfai, Mihály (2013) Complex Defect in Pyrite and Its Structure Model Derived from Geometric Phase Analysis. MICROSCOPY AND MICROANALYSIS, Online. pp. 1-5. ISSN 1431-9276
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