Measurement of strain fields in an edge dislocation

Dong, Zhaoshi; Zhao, Chunwang

doi:10.1016/j.physb.2009.08.051

Cited by 5 publications

(6 citation statements)

References 18 publications

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“…Dislocations are typically studied by transmission electron microscopy (TEM). With atomic resolution, comprehensive information can be gathered on, for example, the strain field in a dislocation core (Dong & Zhao, 2010) or the 3D arrangement of dislocations in networks (Barnard et al, 2006;Ramar et al, 2010;Liu et al, 2014). However, TEM is inherently limited to the study of thin foils.…”

Section: Introductionmentioning

confidence: 99%

Mapping of individual dislocations with dark-field X-ray microscopy

et al. 2019

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This article presents an X-ray microscopy approach for mapping deeply embedded dislocations in three dimensions using a monochromatic beam with a low divergence. Magnified images are acquired by inserting an X-ray objective lens in the diffracted beam. The strain fields close to the core of dislocations give rise to scattering at angles where weak beam conditions are obtained. Analytical expressions are derived for the image contrast. While the use of the objective implies an integration over two directions in reciprocal space, scanning an aperture in the back focal plane of the microscope allows a reciprocal-space resolution of ÁQ/Q < 5 Â 10 À5 in all directions, ultimately enabling highprecision mapping of lattice strain and tilt. The approach is demonstrated on three types of samples: a multi-scale study of a large diamond crystal in transmission, magnified section topography on a 140 mm-thick SrTiO 3 sample and a reflection study of misfit dislocations in a 120 nm-thick BiFeO 3 film epitaxially grown on a thick substrate. With optimal contrast, the half-widths at half-maximum of the dislocation lines are 200 nm. A. C. Jakobsen et al. Mapping of dislocation networks 127 Figure 5Projection images of a large single-crystal diamond in the transmission experiment. (Left) Nearfield detector image with no X-ray objective and (right) corresponding dark-field image acquired with the diffraction microscope, both for À 0 = 0.002 . The magnification of the microscope is M ¼ 16:2. The direction of the rotation axis is marked by an arrow.q q 2 andq q roll are parallel to the x and y axes of these subfigures, respectively.

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Section: Introductionmentioning

confidence: 99%

Mapping of individual dislocations with dark-field X-ray microscopy

et al. 2019

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“…Here, we present a detailed interfacial structure analysis on a pair of oxide heterostructures—STO/MgO and MgO/STO—using aberration-corrected high-resolution scanning transmission electron microscopy (Cs-corrected STEM) in combination with geometric phase analysis (GPA) (Hytch et al, 1998). GPA is an image processing method used for mapping lattice displacement and has been successfully applied to misfit dislocations and their associated strain fields (Hytch et al, 2003; Sanchez et al, 2007; Dong & Zhao, 2010). Important details of the interface structure at the incoherent heterointerface, such as the termination planes, cation disorder, and nature of the substrate terraces, were investigated at the atomic scale.…”

Section: Introductionmentioning

confidence: 99%

Cs-Corrected Scanning Transmission Electron Microscopy Investigation of Dislocation Core Configurations at a SrTiO₃/MgO Heterogeneous Interface

et al. 2013

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Heterostructures and interfacial defects in a 40-nm-thick SrTiO(3) (STO) film grown epitaxially on a single-crystal MgO (001) were investigated using aberration-corrected scanning transmission electron microscopy and geometric phase analysis. The interface of STO/MgO was found to be of the typical domain-matching epitaxy with a misfit dislocation network having a Burgers vector of ½ a(STO) <100>. Our studies also revealed that the misfit dislocation cores at the heterogeneous interface display various local cation arrangements in terms of the combination of the extra-half inserting plane and the initial film plane. The type of the inserting plane, either the SrO or the TiO(2) plane, alters with actual interfacial conditions. Contrary to previous theoretical calculations, the starting film planes were found to be dominated by the SrO layer, i.e., a SrO/MgO interface. In certain regions, the starting film planes change to the TiO(2)/MgO interface because of atomic steps at the MgO substrate surface. In particular, four basic misfit dislocation core configurations of the STO/MgO system have been identified and discussed in relation to the substrate surface terraces and possible interdiffusion. The interface structure of the system in reverse--MgO/STO--is also studied and presented for comparison.

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“…On the other hand, boundary regions are represented with an intense color. The centers of the blue and red pairs are located at the dislocations and the round shapes of these cells show the typical shape of strain fields around dislocations of the PeierlsNabarro dislocation model [3]. , respectively, due to the slight asymmetry of the relaxed configuration.…”

Section: Boundary Relaxationsmentioning

confidence: 95%

“…Geometrical phase analysis (GPA) is an innovation in the area of materials science, and has been improved over the past few decades [1]. This novel method allows us to describe the exact strain fields that are present around dislocations by utilizing high resolution TEM images or atomistic simulations [2,3]. When the coordination numbers of the atoms around a dislocation change, it is not trivial to understand its compression or expansion behaviors.…”

Section: Introductionmentioning

confidence: 99%

Strain analysis based on EAM and applications on surface, vacancy, and boundary of Al

Nishitani

2019

Preprint

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Stress or strain analysis for each atom around structural defects in a crystal is difficult. We propose a new analytical approach based on the eminent Embedding Atom Method(EAM) potential. We observe that the ratio R between the repulsive and binding terms of the EAM is a definite measure for calculating the strain field of a single atom subject to an irregular coordination number. The determination of adequate potential parameters and their application to the calculation of the properties of surface, vacancy, and boundary of pure Al are shown.

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Measurement of strain fields in an edge dislocation

Cited by 5 publications

References 18 publications

Mapping of individual dislocations with dark-field X-ray microscopy

Mapping of individual dislocations with dark-field X-ray microscopy

Cs-Corrected Scanning Transmission Electron Microscopy Investigation of Dislocation Core Configurations at a SrTiO₃/MgO Heterogeneous Interface

Strain analysis based on EAM and applications on surface, vacancy, and boundary of Al

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Measurement of strain fields in an edge dislocation

Cited by 5 publications

References 18 publications

Mapping of individual dislocations with dark-field X-ray microscopy

Mapping of individual dislocations with dark-field X-ray microscopy

Cs-Corrected Scanning Transmission Electron Microscopy Investigation of Dislocation Core Configurations at a SrTiO3/MgO Heterogeneous Interface

Strain analysis based on EAM and applications on surface, vacancy, and boundary of Al

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Cs-Corrected Scanning Transmission Electron Microscopy Investigation of Dislocation Core Configurations at a SrTiO₃/MgO Heterogeneous Interface