| Records |
| Author |
Batenburg, K.J.; Bals, S.; Sijbers, J.; Kübel, C.; Midgley, P.A.; Hernandez, J.C.; Kaiser, U.; Encina, E.R.; Coronado, E.A.; Van Tendeloo, G. |
| Title |
3D imaging of nanomaterials by discrete tomography |
Type |
A1 Journal article |
| Year |
2009 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
109 |
Issue |
6 |
Pages |
730-740 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract  |
The field of discrete tomography focuses on the reconstruction of samples that consist of only a few different materials. Ideally, a three-dimensional (3D) reconstruction of such a sample should contain only one grey level for each of the compositions in the sample. By exploiting this property in the reconstruction algorithm, either the quality of the reconstruction can be improved significantly, or the number of required projection images can be reduced. The discrete reconstruction typically contains fewer artifacts and does not have to be segmented, as it already contains one grey level for each composition. Recently, a new algorithm, called discrete algebraic reconstruction technique (DART), has been proposed that can be used effectively on experimental electron tomography datasets. In this paper, we propose discrete tomography as a general reconstruction method for electron tomography in materials science. We describe the basic principles of DART and show that it can be applied successfully to three different types of samples, consisting of embedded ErSi2 nanocrystals, a carbon nanotube grown from a catalyst particle and a single gold nanoparticle, respectively. |
| Address |
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| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000265816400005 |
Publication Date |
2009-02-01 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
220 |
Open Access |
|
| Notes |
Fwo; Esteem 026019 |
Approved |
Most recent IF: 2.843; 2009 IF: 2.067 |
| Call Number |
UA @ lucian @ c:irua:74665 c:irua:74665 |
Serial |
12 |
| Permanent link to this record |
| |
|
| |
| Author |
Velazco, A.; Béché, A.; Jannis, D.; Verbeeck, J. |
| Title |
Reducing electron beam damage through alternative STEM scanning strategies, Part I: Experimental findings |
Type |
A1 Journal article |
| Year |
2022 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
232 |
Issue |
|
Pages |
113398 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The highly energetic electrons in a transmission electron microscope (TEM) can alter or even completely destroy the structure of samples before sufficient information can be obtained. This is especially problematic in the case of zeolites, organic and biological materials. As this effect depends on both the electron beam and the sample and can involve multiple damage pathways, its study remained difficult and is plagued with irreproducibility issues, circumstantial evidence, rumors, and a general lack of solid data. Here we take on the experimental challenge to investigate the role of the STEM scan pattern on the damage behavior of a commercially available zeolite sample with the clear aim to make our observations as reproducible as possible. We make use of a freely programmable scan engine that gives full control over the tempospatial distribution of the electron probe on the sample and we use its flexibility to obtain multiple repeated experiments under identical conditions comparing the difference in beam damage between a conventional raster scan pattern and a newly proposed interleaved scan pattern that provides exactly the same dose and dose rate and visits exactly the same scan points. We observe a significant difference in beam damage for both patterns with up to 11 % reduction in damage (measured from mass loss). These observations demonstrate without doubt that electron dose, dose rate and acceleration voltage are not the only parameters affecting beam damage in (S)TEM experiments and invite the community to rethink beam damage as an unavoidable consequence of applied electron dose. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000714819200002 |
Publication Date |
2021-10-02 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.2 |
Times cited |
18 |
Open Access |
OpenAccess |
| Notes |
A.V., D.J., A.B. and J.V. acknowledge funding from FWO project G093417N (’Compressed sensing enabling low dose imaging in transmission electron microscopy’) and G042920N (’Coincident event detection for advanced spectroscopy in transmission electron microscopy’). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 ESTEEM3. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. J.V. acknowledges funding from GOA project “Solarpaint” of the University of Antwerp.; JRA; reported |
Approved |
Most recent IF: 2.2 |
| Call Number |
EMAT @ emat @c:irua:183282 |
Serial |
6818 |
| Permanent link to this record |
| |
|
| |
| Author |
Schattschneider, P.; Stöger-Pollach, M.; Löffler, S.; Steiger-Thirsfeld, A.; Hell, J.; Verbeeck, J. |
| Title |
Sub-nanometer free electrons with topological charge |
Type |
A1 Journal article |
| Year |
2012 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
115 |
Issue |
|
Pages |
21-25 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The holographic mask technique is used to create freely moving electrons with quantized angular momentum. With electron optical elements they can be focused to vortices with diameters below the nanometer range. The understanding of these vortex beams is important for many applications. Here, we produce electron vortex beams and compare them to a theory of electrons with topological charge. The experimental results show excellent agreement with simulations. As an immediate application, fundamental experimental parameters like spherical aberration and partial coherence are determined. (C) 2012 Elsevier B.V. All rights reserved. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000302962400004 |
Publication Date |
2012-01-30 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
24 |
Open Access |
|
| Notes |
vortex ECASJO_; |
Approved |
Most recent IF: 2.843; 2012 IF: 2.470 |
| Call Number |
UA @ lucian @ c:irua:98279 |
Serial |
3344 |
| Permanent link to this record |
| |
|
| |
| Author |
Heidari, H.; van den Broek, W.; Bals, S. |
| Title |
Quantitative electron tomography : the effect of the three-dimensional point spread function |
Type |
A1 Journal article |
| Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
135 |
Issue |
|
Pages |
1-5 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The intensity levels in a three-dimensional (3D) reconstruction, obtained by electron tomography, can be influenced by several experimental imperfections. Such artifacts will hamper a quantitative interpretation of the results. In this paper, we will correct for artificial intensity variations by determining the 3D point spread function (PSF) of a tomographic reconstruction based on high angle annular dark field scanning transmission electron microscopy. The large tails of the PSF cause an underestimation of the intensity of smaller particles, which in turn hampers an accurate radius estimate. Here, the error introduced by the PSF is quantified and corrected a posteriori. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000326941500001 |
Publication Date |
2013-06-21 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
6 |
Open Access |
|
| Notes |
Esteem2; Sunflower; esteem2_jra4 |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
| Call Number |
UA @ lucian @ c:irua:111397 |
Serial |
2756 |
| Permanent link to this record |
| |
|
| |
| Author |
Xu, Q.; Zandbergen, H.W.; van Dyck, D. |
| Title |
Applying an information transmission approach to extract valence electron information from reconstructed exit waves |
Type |
A1 Journal article |
| Year |
2011 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
111 |
Issue |
7 |
Pages |
912-919 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
The knowledge of the valence electron distribution is essential for understanding the properties of materials. However this information is difficult to obtain from HREM images because it is easily obscured by the large scattering contribution of core electrons and by the strong dynamical scattering process. In order to develop a sensitive method to extract the information of valence electrons, we have used an information transmission approach to describe the electron interaction with the object. The scattered electron wave is decomposed in a set of basic functions, which are the eigen functions of the Hamiltonian of the projected electrostatic object potential. Each basic function behaves as a communication channel that transfers the information of the object with its own transmission characteristic. By properly combining the components of the different channels, it is possible to design a scheme to extract the information of valence electron distribution from a series of exit waves. The method is described theoretically and demonstrated by means of computer simulations. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000300461000024 |
Publication Date |
2011-02-02 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
1 |
Open Access |
|
| Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2011 IF: 2.471 |
| Call Number |
UA @ lucian @ c:irua:93623 |
Serial |
146 |
| Permanent link to this record |
| |
|
| |
| Author |
Lobato, I.; Van Dyck, D. |
| Title |
MULTEM : a new multislice program to perform accurate and fast electron diffraction and imaging simulations using graphics processing units with CUDA |
Type |
A1 Journal article |
| Year |
2015 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
156 |
Issue |
156 |
Pages |
9-17 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
The main features and the GPU implementation of the MULTEM program are presented and described. This new program performs accurate and fast multislice simulations by including higher order expansion of the multislice solution of the high energy Schrodinger equation, the correct subslicing of the three-dimensional potential and top-bottom surfaces. The program implements different kinds of simulation for CTEM, STEM, ED, PED, CBED, ADF-TEM and ABF-HC with proper treatment of the spatial and temporal incoherences. The multislice approach described here treats the specimen as amorphous material which allows a straightforward implementation of the frozen phonon approximation. The generalized transmission function for each slice is calculated when is needed and then discarded. This allows us to perform large simulations that can include millions of atoms and keep the computer memory requirements to a reasonable level. (C) 2015 Elsevier B.V. All rights reserved. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000361001800003 |
Publication Date |
2015-04-28 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
32 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.843; 2015 IF: 2.436 |
| Call Number |
UA @ lucian @ c:irua:127848 |
Serial |
4209 |
| Permanent link to this record |
| |
|
| |
| Author |
Radtke, G.; Botton, G.A.; Verbeeck, J. |
| Title |
Electron inelastic, scattering and anisotropy: the two-dimensional point of view |
Type |
A1 Journal article |
| Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
106 |
Issue |
11-12 |
Pages |
1082-1090 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The measurement of the electronic structure of anisotropic materials using energy loss near edge structure (ELNES) spectroscopy is an important field of microanalysis in transmission electron microscopy. We present a novel method to study the angular dependence of electron inelastic scattering in anisotropic materials. This method has been applied to the study of 1s -> pi* and sigma* transitions on the carbon K edge in pyrolitic graphite. An excellent agreement between experimental and theoretical two-dimensional scattering patterns has been found. In particular, the need of a fully relativistic calculation of the inelastic scattering cross-section to explain the experimental results is demonstrated. (c) 2006 Elsevier B.V. All rights reserved. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000241592900018 |
Publication Date |
2006-07-04 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
5 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
| Call Number |
UA @ lucian @ c:irua:61381UA @ admin @ c:irua:61381 |
Serial |
936 |
| Permanent link to this record |
| |
|
| |
| Author |
De Meulenaere, P.; Van Tendeloo, G.; van Landuyt, J.; van Dyck, D. |
| Title |
On the interpretation of HREM images of partially ordered alloys |
Type |
A1 Journal article |
| Year |
1995 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
60 |
Issue |
2 |
Pages |
265-282 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
The ordering for 11/20 alloys has been studied by high-resolution electron microscopy (HREM). The distribution of the intensity maxima in the HREM image have been statistically examined, which provides a profound basis for the image interpretation. Processing of the HREM images allows ''dark-field'' images to be obtained, exhibiting a two-dimensional distribution of those columns which contain the most information in order to interpret the short-range order correlations. Pair correlations and higher cluster correlations between projected columns can be visualised, providing unique information about the ordering as retrieved from an experimental result without any other assumption. The method has been applied to Au4Cr and to Au4Mn to interpret the quenched short-range order state and the transition to long-range order. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
A1995TZ14700008 |
Publication Date |
2002-07-25 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.436 |
Times cited |
20 |
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ lucian @ c:irua:13014 |
Serial |
2438 |
| Permanent link to this record |
| |
|
| |
| Author |
Schryvers, D.; Salje, E.K.H.; Nishida, M.; De Backer, A.; Idrissi, H.; Van Aert, S. |
| Title |
Quantification by aberration corrected (S)TEM of boundaries formed by symmetry breaking phase transformations |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
176 |
Issue |
|
Pages |
194-199 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The present contribution gives a review of recent quantification work of atom displacements, atom site occupations and level of crystallinity in various systems and based on aberration corrected HR(S)TEM images. Depending on the case studied, picometer range precisions for individual distances can be obtained, boundary widths at the unit cell level determined or statistical evolutions of fractions of the ordered areas calculated. In all of these cases, these quantitative measures imply new routes for the applications of the respective materials. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
|
| Language |
|
Wos |
000403992200026 |
Publication Date |
2017-01-09 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
1 |
Open Access |
OpenAccess |
| Notes |
The authors acknowledge financial support from the Fund for Scientific Research-Flanders (G.0064.10N, G.0393.11N, G.0374.13N, G.0368.15N, G.0369.15N) and the Flemish Hercules 3 program for large infrastructure as well as financial support from the European Union Seventh Framework Programme (FP7/2007 – 2013) under Grant agreement no. 312483 (ESTEEM2). EKHS thanks EPSRC (EP/ K009702/1) and the Leverhulme trust (EM-2016-004) for support. DS and MN acknowledge financial support from the Japan Society for the Promotion of Science (JSPS, Japan) through the Grant-in-Aid for Scientific Research (A: No. 26249090) and the Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation (R2408). |
Approved |
Most recent IF: 2.843 |
| Call Number |
EMAT @ emat @c:irua:149654 |
Serial |
4914 |
| Permanent link to this record |
| |
|
| |
| Author |
Schattschneider, P.; Verbeeck, J. |
| Title |
Theory of free electron vortices |
Type |
A1 Journal article |
| Year |
2011 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
111 |
Issue |
9/10 |
Pages |
1461-1468 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The recent creation of electron vortex beams and their first practical application motivates a better understanding of their properties. Here, we develop the theory of free electron vortices with quantized angular momentum, based on solutions of the Schrödinger equation for cylindrical boundary conditions. The principle of transformation of a plane wave into vortices with quantized angular momentum, their paraxial propagation through round magnetic lenses, and the effect of partial coherence are discussed. |
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000300461200002 |
Publication Date |
2011-07-26 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
57 |
Open Access |
|
| Notes |
Esteem 026019 |
Approved |
Most recent IF: 2.843; 2011 IF: 2.471 |
| Call Number |
UA @ lucian @ c:irua:91882 |
Serial |
3617 |
| Permanent link to this record |
| |
|
| |
| Author |
Béché, A.; Juchtmans, R.; Verbeeck, J. |
| Title |
Efficient creation of electron vortex beams for high resolution STEM imaging |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
178 |
Issue |
178 |
Pages |
12-19 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The recent discovery of electron vortex beams carrying quantised angular momentum in the TEM has led to an active field of research, exploring a variety of potential applications including the possibility of mapping magnetic states at the atomic scale. A prerequisite for this is the availability of atomic sized electron vortex beams at high beam current and mode purity. In this paper we present recent progress showing that by making use of the Aharonov-Bohm effect near the tip of a long single domain ferromagnetic Nickel needle, a very efficient aperture for the production of electron vortex beams can be realised. The aperture transmits more than 99% of all electrons and provides a vortex mode purity of up to 92%. Placing this aperture in the condenser plane of a state of the art Cs corrected microscope allows us to demonstrate atomic resolution HAADF STEM images with spatial resolution better than 1 Angstrom, in agreement with theoretical expectations and only slightly inferior to the performance of a non-vortex probe on the same instrument. |
| Address |
EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium |
| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
English |
Wos |
000403862900003 |
Publication Date |
2016-05-10 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
30 |
Open Access |
OpenAccess |
| Notes |
A.B. and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 278510 VORTEX. J.V. acknowledges funding from FWO project G.0044.13N ('Charge ordering').; ECASJO_; |
Approved |
Most recent IF: 2.843 |
| Call Number |
c:irua:134085 c:irua:134085UA @ admin @ c:irua:134085 |
Serial |
4094 |
| Permanent link to this record |
| |
|
| |
| Author |
Schattschneider, P.; Ennen, I.; Stoger-Pollach, M.; Verbeeck, J.; Mauchamp, V.; Jaouen, M. |
| Title |
Real space maps of magnetic moments on the atomic scale: theory and feasibility |
Type |
A1 Journal article |
| Year |
2010 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
110 |
Issue |
8 |
Pages |
1038-1041 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The recently discovered EMCD technique (energy loss magnetic chiral dichroism) can detect atom specific magnetic moments with nanometer resolution, exploiting the spin selectivity of electronic transitions in energy loss spectroscopy. Yet, direct imaging of magnetic moments on the atomic scale is not possible. In this paper we present an extension of EMCD that can overcome this limit. As a model system we chose bcc Fe. We present image simulations of the L3 white line signal, based on the kinetic equation for the density matrix of the 200 kV probe electron. With actual progress in instrumentation (high brightness sources, aberration corrected lenses) this technique should allow direct imaging of spin moments on the atomic scale. |
| Address |
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| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000281216600016 |
Publication Date |
2009-12-07 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
10 |
Open Access |
|
| Notes |
--- |
Approved |
Most recent IF: 2.843; 2010 IF: 2.063 |
| Call Number |
UA @ lucian @ c:irua:84439UA @ admin @ c:irua:84439 |
Serial |
2830 |
| Permanent link to this record |
| |
|
| |
| Author |
Verbeeck, J.; Hébert; Rubino, S.; Novák, P.; Rusz, J.; Houdellier, F.; Gatel, C.; Schattschneider, P. |
| Title |
Optimal aperture sizes and positions for EMCD experiments |
Type |
A1 Journal article |
| Year |
2008 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
108 |
Issue |
9 |
Pages |
865-872 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The signal-to-noise ratio (SNR) in energy-loss magnetic chiral dichroism (EMCD)the equivalent of X-ray magnetic circular dichroism (XMCD) in the electron microscopeis optimized with respect to the detector shape, size and position. We show that an important increase in SNR over previous experiments can be obtained when taking much larger detector sizes. We determine the ideal shape of the detector but also show that round apertures are a good compromise if placed in their optimal position. We develop the theory for a simple analytical description of the EMCD experiment and then apply it to dynamical multibeam Bloch wave calculations and to an experimental data set. In all cases it is shown that a significant and welcome improvement of the SNR is possible. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000258747600009 |
Publication Date |
2008-03-07 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
27 |
Open Access |
|
| Notes |
This work was supported by the European Commission under contract no. 508971 CHIRALTEM. J.V. and F.H. thank the financial support from the European Union under the Framework 6 program under a contract for an Integrated Infrastructure Initiative. Reference 026019 ESTEEM. Thanks to J.P. Morniroli for making the Fe sample available. |
Approved |
Most recent IF: 2.843; 2008 IF: 2.629 |
| Call Number |
UA @ lucian @ c:irua:76492UA @ admin @ c:irua:76492 |
Serial |
2480 |
| Permanent link to this record |
| |
|
| |
| Author |
Madsen, J.; Pennycook, T.J.; Susi, T. |
| Title |
ab initio description of bonding for transmission electron microscopy |
Type |
A1 Journal article |
| Year |
2021 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
231 |
Issue |
|
Pages |
|
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret their contrast and extract specimen features. This is especially true for high-resolution phase-contrast imaging of materials, but electron scattering simulations based on atomistic models are widely used in materials science and structural biology. Since electron scattering is dominated by the nuclear cores, the scattering potential is typically described by the widely applied independent atom model. This approximation is fast and fairly accurate, especially for scanning TEM (STEM) annular dark-field contrast, but it completely neglects valence bonding and its effect on the transmitting electrons. However, an emerging trend in electron microscopy is to use new instrumentation and methods to extract the maximum amount of information from each electron. This is evident in the increasing popularity of techniques such as 4D-STEM combined with ptychography in materials science, and cryogenic microcrystal electron diffraction in structural biology, where subtle differences in the scattering potential may be both measurable and contain additional insights. Thus, there is increasing interest in electron scattering simulations based on electrostatic potentials obtained from first principles, mainly via density functional theory, which was previously mainly required for holography. In this Review, we discuss the motivation and basis for these developments, survey the pioneering work that has been published thus far, and give our outlook for the future. We argue that a physically better justified ab initio description of the scattering potential is both useful and viable for an increasing number of systems, and we expect such simulations to steadily gain in popularity and importance. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000744190300006 |
Publication Date |
2021-03-18 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 2.843 |
| Call Number |
UA @ admin @ c:irua:183955 |
Serial |
6850 |
| Permanent link to this record |
| |
|
| |
| Author |
Rosenauer, A.; Schowalter, M.; Titantah, J.T.; Lamoen, D. |
| Title |
An emission-potential multislice approximation to simulate thermal diffuse scattering in high-resolution transmission electron microscopy |
Type |
A1 Journal article |
| Year |
2008 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
108 |
Issue |
12 |
Pages |
1504-1513 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Thermal diffuse scattered electrons significantly contribute to high-resolution transmission electron microscopy images. Their intensity adds to the background and is peaked at positions of atomic columns. In this paper we suggest an approximation to simulate intensity of thermal diffuse scattered electrons in plane-wave illumination transmission electron microscopy using an emission-potential multislice algorithm which is computationally less intensive than the frozen lattice approximation or the mutual intensity approach. Intensity patterns are computed for Au and InSb for different crystal orientations. These results are compared with intensities from the frozen lattice approximation based on uncorrelated vibration of atoms as well as with the frozen phonon approximation for Au. The frozen phonon method uses a detailed phonon model based on force constants we computed by a density functional theory approach. The comparison shows that our suggested emission-potential method is in close agreement with both the frozen lattice and the frozen phonon approximations. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000260808300002 |
Publication Date |
2008-04-21 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
25 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.843; 2008 IF: 2.629 |
| Call Number |
UA @ lucian @ c:irua:72919 |
Serial |
1033 |
| Permanent link to this record |
| |
|
| |
| Author |
Sentürk, D.G.; De Backer, A.; Friedrich, T.; Van Aert, S. |
| Title |
Optimal experiment design for element specific atom counting using multiple annular dark field scanning transmission electron microscopy detectors |
Type |
A1 Journal article |
| Year |
2022 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
242 |
Issue |
|
Pages |
113626 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
This paper investigates the possible benefits for counting atoms of different chemical nature when analysing multiple 2D scanning transmission electron microscopy (STEM) images resulting from independent annular dark field (ADF) detector regimes. To reach this goal, the principles of statistical detection theory are used to quantify the probability of error when determining the number of atoms in atomic columns consisting of multiple types of elements. In order to apply this theory, atom-counting is formulated as a statistical hypothesis test, where each hypothesis corresponds to a specific number of atoms of each atom type in an atomic column. The probability of error, which is limited by the unavoidable presence of electron counting noise, can then be computed from scattering-cross sections extracted from multiple ADF STEM images. Minimisation of the probability of error as a function of the inner and outer angles of a specified number of independent ADF collection regimes results in optimal experimental designs. Based on simulations of spherical Au@Ag and Au@Pt core–shell nanoparticles, we investigate how the combination of two non-overlapping detector regimes helps to improve the probability of error when unscrambling two types of atoms. In particular, the combination of a narrow low angle ADF detector with a detector formed by the remaining annular collection regime is found to be optimal. The benefit is more significant if the atomic number Z difference becomes larger. In
addition, we show the benefit of subdividing the detector regime into three collection areas for heterogeneous nanostructures based on a structure consisting of three types of elements, e.g., a mixture of Au, Ag and Al atoms. Finally, these results are compared with the probability of error resulting when one would ultimately use a pixelated 4D STEM detector and how this could help to further reduce the incident electron dose. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000873778100001 |
Publication Date |
0000-00-00 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.2 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert and Grant 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0346.21N and EOS 30489208) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF).; esteem3reported; esteem3jra |
Approved |
Most recent IF: 2.2 |
| Call Number |
EMAT @ emat @c:irua:190925 |
Serial |
7118 |
| Permanent link to this record |
| |
|
| |
| Author |
Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D. |
| Title |
Direct structure inversion from exit waves : part 2 : a practical example |
Type |
A1 Journal article |
| Year |
2012 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
116 |
Issue |
|
Pages |
77-85 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
This paper is the second part of a two-part paper on direct structure inversion from exit waves. In the first part, a method has been proposed to quantitatively determine structure parameters with atomic resolution such as atom column positions, surface profile and the number of atoms in the atom columns. In this part, the theory will be demonstrated by means of a Au[110] exit wave reconstructed from a set of focal-series images. The procedures to analyze the experimentally reconstructed exit wave in terms of quantitative structure information are described in detail. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000304473700011 |
Publication Date |
2012-03-28 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
8 |
Open Access |
|
| Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2012 IF: 2.470 |
| Call Number |
UA @ lucian @ c:irua:96660 |
Serial |
724 |
| Permanent link to this record |
| |
|
| |
| Author |
Müller-Caspary, K.; Krause, F.F.; Winkler, F.; Béché, A.; Verbeeck, J.; Van Aert, S.; Rosenauer, A. |
| Title |
Comparison of first moment STEM with conventional differential phase contrast and the dependence on electron dose |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
203 |
Issue |
203 |
Pages |
95-104 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
This study addresses the comparison of scanning transmission electron microscopy (STEM) measurements of momentum transfers using the first moment approach and the established method that uses segmented annular detectors. Using an ultrafast pixelated detector to acquire four-dimensional, momentum-resolved STEM signals, both the first moment calculation and the calculation of the differential phase contrast (DPC) signals are done for the same experimental data. In particular, we investigate the ability to correct the segment-based signal to yield a suitable approximation of the first moment for cases beyond the weak phase object approximation. It is found that the measurement of momentum transfers using segmented detectors can approach the first moment measurement as close as 0.13 h/nm in terms of a root mean square (rms) difference in 10 nm thick SrTiO3 for a detector with 16 segments. This amounts to 35% of the rms of the momentum transfers. In addition, we present a statistical analysis of the precision of first moment STEM as a function of dose. For typical experimental settings with recent hardware such as a Medipix3 Merlin camera attached to a probe-corrected STEM, we find that the precision of the measurement of momentum transfers stagnates above certain doses. This means that other instabilities such as specimen drift or scan noise have to be taken into account seriously for measurements that target, e.g., the detection of bonding effects in the charge density. |
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000465021000013 |
Publication Date |
2018-12-30 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
25 |
Open Access |
OpenAccess |
| Notes |
; The direct electron detector (Medipix3 Merlin) was funded by the Hercules fund from the Flemish Government. K. Muller-Caspary acknowledges funding from the Initiative and Network Fund of the Helmholtz Association within the framework of the Helmholtz Young Investigator Group moreSTEM (VH-NG-1317) at Forschungszentrum Julich, Germany. F. F. Krause acknowledges funding from the Central Research Development Fund of the University of Bremen, Germany. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) and the Research Fund of the University of Antwerp. ; |
Approved |
Most recent IF: 2.843 |
| Call Number |
UA @ admin @ c:irua:160213 |
Serial |
5242 |
| Permanent link to this record |
| |
|
| |
| Author |
Muller-Caspary, K.; Krause, F.F.; Grieb, T.; Loffler, S.; Schowalter, M.; Béché, A.; Galioit, V.; Marquardt, D.; Zweck, J.; Schattschneider, P.; Verbeeck, J.; Rosenauer, A. |
| Title |
Measurement of atomic electric fields and charge densities from average momentum transfers using scanning transmission electron microscopy |
Type |
A1 Journal article |
| Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
178 |
Issue |
178 |
Pages |
62-80 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
This study sheds light on the prerequisites, possibilities, limitations and interpretation of high-resolution differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). We draw particular attention to the well-established DPC technique based on segmented annular detectors and its relation to recent developments based on pixelated detectors. These employ the expectation value of the momentum transfer as a reliable measure of the angular deflection of the STEM beam induced by an electric field in the specimen. The influence of scattering and propagation of electrons within the specimen is initially discussed separately and then treated in terms of a two-state channeling theory. A detailed simulation study of GaN is presented as a function of specimen thickness and bonding. It is found that bonding effects are rather detectable implicitly, e.g., by characteristics of the momentum flux in areas between the atoms than by directly mapping electric fields and charge densities. For strontium titanate, experimental charge densities are compared with simulations and discussed with respect to experimental artifacts such as scan noise. Finally, we consider practical issues such as figures of merit for spatial and momentum resolution, minimum electron dose, and the mapping of larger-scale, built-in electric fields by virtue of data averaged over a crystal unit cell. We find that the latter is possible for crystals with an inversion center. Concerning the optimal detector design, this study indicates that a sampling of 5mrad per pixel is sufficient in typical applications, corresponding to approximately 10x10 available pixels. |
| Address |
Institut fur Festkr perphysik, Universitat Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany |
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
English |
Wos |
000403862900009 |
Publication Date |
2016-05-12 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
93 |
Open Access |
|
| Notes |
K.M.-C. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG) under contract MU3660/1-1. This work was further supported by the DFG under contract RO2057/4-2 and O2057/11-1. J.V. and A.B. acknowledge funding from the European Research Council (ERC) under the 7th Framework Program (FP7), and ERC Starting Grant No. 278510-VORTEX. Experimental results are obtained on the Qu-Ant-EM microscope partly funded by the Hercules fund from the Flemish government. J.V. also acknowledges funding through a GOA project “Solarpaint” of the University of Antwerp. SL and PS acknowledge financial support by the Austrian Science Fund (FWF) under grants No. I543-N20 and J3732-N27. ECASJO_; |
Approved |
Most recent IF: 2.843 |
| Call Number |
c:irua:134125UA @ admin @ c:irua:134125 |
Serial |
4098 |
| Permanent link to this record |
| |
|
| |
| Author |
Şentürk, DG.; Yu, CP.; De Backer, A.; Van Aert, S. |
| Title |
Atom counting from a combination of two ADF STEM images |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
255 |
Issue |
|
Pages |
113859 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
To understand the structure–property relationship of nanostructures, reliably quantifying parameters, such as the number of atoms along the projection direction, is important. Advanced statistical methodologies have made it possible to count the number of atoms for monotype crystalline nanoparticles from a single ADF STEM image. Recent developments enable one to simultaneously acquire multiple ADF STEM images. Here, we present an extended statistics-based method for atom counting from a combination of multiple statistically independent ADF STEM images reconstructed from non-overlapping annular detector collection regions which improves the accuracy and allows one to retrieve precise atom-counts, especially for images acquired with low electron doses and multiple element structures. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
001089064200001 |
Publication Date |
2023-09-23 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.2 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G034621N, G0A7723N, and EOS 40007495) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF). |
Approved |
Most recent IF: 2.2; 2024 IF: 2.843 |
| Call Number |
EMAT @ emat @c:irua:201008 |
Serial |
8964 |
| Permanent link to this record |
| |
|
| |
| Author |
van den Broek, W.; Van Aert, S.; van Dyck, D. |
| Title |
A model based atomic resolution tomographic algorithm |
Type |
A1 Journal article |
| Year |
2009 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
109 |
Issue |
12 |
Pages |
1485-1490 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
Tomography with high angular annular dark field scanning transmission electron microscopy at atomic resolution can be greatly improved if one is able to take advantage of prior knowledge. In this paper we present a reconstruction technique that explicitly takes into account the microscope parameters and the atomic nature of the projected object. This results in a more accurate estimate of the atomic positions and in a good resistance to noise. The reconstruction is a maximum likelihood estimator of the object. Moreover, the limits to the precision have been explored, allowing for a prediction of the amount of expected noise in the reconstruction for a certain experimental setup. We believe that the proposed reconstruction technique can be generalized to other tomographic experiments. |
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000271840200010 |
Publication Date |
2009-08-28 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
17 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.843; 2009 IF: 2.067 |
| Call Number |
UA @ lucian @ c:irua:78588 |
Serial |
2097 |
| Permanent link to this record |
| |
|
| |
| Author |
Tan, H.; Verbeeck, J.; Abakumov, A.; Van Tendeloo, G. |
| Title |
Oxidation state and chemical shift investigation in transition metal oxides by EELS |
Type |
A1 Journal article |
| Year |
2012 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
116 |
Issue |
|
Pages |
24-33 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Transition metal L2,3 electron energy-loss spectra for a wide range of V-, Mn- and Fe-based oxides were recorded and carefully analyzed for their correlation with the formal oxidation states of the transition metal ions. Special attention is paid to obtain an accurate energy scale which provides absolute energy positions for all core-loss edges. The white-line ratio method, chemical shift method, ELNES fitting method, two-parameter method and other methods are compared and their validity is discussed. Both the ELNES fitting method and the chemical shift method have the advantage of a wide application range and good consistency but require special attention to accurately measure the core-loss edge position. The obtained conclusions are of fundamental importance, e.g., for obtaining atomic resolution oxidation state information in modern experiments. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000304473700004 |
Publication Date |
2012-03-10 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
413 |
Open Access |
|
| Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2012 IF: 2.470 |
| Call Number |
UA @ lucian @ c:irua:96959UA @ admin @ c:irua:96959 |
Serial |
2541 |
| Permanent link to this record |
| |
|
| |
| Author |
Leuthner, G.T.; Hummel, S.; Mangler, C.; Pennycook, T.J.; Susi, T.; Meyer, J.C.; Kotakoski, J. |
| Title |
Scanning transmission electron microscopy under controlled low-pressure atmospheres |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
203 |
Issue |
203 |
Pages |
76-81 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Transmission electron microscopy (TEM) is carried out in vacuum to minimize the interaction of the imaging electrons with gas molecules while passing through the microscope column. Nevertheless, in typical devices, the pressure remains at 10(-7) mbar or above, providing a large number of gas molecules for the electron beam to crack, which can lead to structural changes in the sample. Here, we describe experiments carried out in a modified scanning TEM (STEM) instrument, based on the Nion UltraSTEM 100. In this instrument, the base pressure at the sample is around 2 x 10(-10 )mbar, and can be varied up to 10(-6) mbar through introduction of gases directly into the objective area while maintaining atomic resolution imaging conditions. We show that air leaked into the microscope column during the experiment is efficient in cleaning graphene samples from contamination, but ineffective in damaging the pristine lattice. Our experiments also show that exposure to O(2 )and H2O lead to a similar result, oxygen providing an etching effect nearly twice as efficient as water, presumably due to the two 0 atoms per molecule. H(2 )and N-2 environments have no influence on etching. These results show that the residual gas environment in typical TEM instruments can have a large influence on the observations, and show that chemical etching of carbon-based structures can be effectively carried out with oxygen. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000465021000010 |
Publication Date |
2019-02-04 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
4 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.843 |
| Call Number |
UA @ admin @ c:irua:165937 |
Serial |
6321 |
| Permanent link to this record |
| |
|
| |
| Author |
Potapov, P.L.; Verbeeck, J.; Schattschneider, P.; Lichte, H.; van Dyck, D. |
| Title |
Inelastic electron holography as a variant of the Feynman thought experiment |
Type |
A1 Journal article |
| Year |
2007 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
107 |
Issue |
8 |
Pages |
559-567 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
Using a combination of electron holography and energy filtering, interference fringes produced after inelastic interaction of electrons with hydrogen molecules are examined. Surprisingly, the coherence of inelastic scattering increases when moving from the surface of a hydrogen-containing bubble to the vacuum. This phenomenon can be understood in terms of the Feynman two-slit thought experiment with a variable ambiguity of the which-way registration. (C) 2006 Elsevier B.V. All rights reserved. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
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| Language |
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Wos |
000246937000001 |
Publication Date |
2006-12-16 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
|
Edition |
|
| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
13 |
Open Access |
|
| Notes |
Fwo G.0147.06 |
Approved |
Most recent IF: 2.843; 2007 IF: 1.996 |
| Call Number |
UA @ lucian @ c:irua:103588UA @ admin @ c:irua:103588 |
Serial |
1605 |
| Permanent link to this record |
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| Author |
Potapov, P.; Lichte, H.; Verbeeck, J.; van Dyck, D. |
| Title |
Experiments on inelastic electron holography |
Type |
A1 Journal article |
| Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
106 |
Issue |
11-12 |
Pages |
1012-1018 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
Using the combination of an electron biprism and an energy filter, the coherence distribution in an inelastically scattered wave-field is measured. It is found that the degree of coherence decreases rapidly with increasing distance between two superimposed points in the object, and with increasing energy-loss. In a Si sample, coherence of plasmon scattering increases in vacuum with the distance from the edge of the sample. (c) 2006 Published by Elsevier B.V. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
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| Language |
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Wos |
000241592900009 |
Publication Date |
2006-07-07 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
|
| ISSN |
0304-3991; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
28 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
| Call Number |
UA @ lucian @ c:irua:61380UA @ admin @ c:irua:61380 |
Serial |
1147 |
| Permanent link to this record |
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| Author |
Niermann, T.; Verbeeck, J.; Lehmann, M. |
| Title |
Creating arrays of electron vortices |
Type |
A1 Journal article |
| Year |
2014 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
136 |
Issue |
|
Pages |
165-170 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We demonstrate the production of an ordered array of electron vortices making use of an electron optical setup consisting of two electrostatic biprisms. The biprism filaments are oriented nearly orthogonal with respect to each other in a transmission electron microscope. Matching the position of the filaments, we can choose to form different topological features in the electron wave. We outline the working principle of the setup and demonstrate fist experimental results. This setup partially bridges the gap between angular momentum carried by electron spin, which is intrinsic and therefore present in any position of the wave, and angular momentum carried by the vortex character of the wave, which can be extrinsic depending on the axis around which it is measured. (C) 2013 Elsevier B.V. All rights reserved. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
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| Language |
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Wos |
000327884700021 |
Publication Date |
2013-10-15 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
9 |
Open Access |
|
| Notes |
FP7; Countatoms; Vortex ECASJO_; |
Approved |
Most recent IF: 2.843; 2014 IF: 2.436 |
| Call Number |
UA @ lucian @ c:irua:112837UA @ admin @ c:irua:112837 |
Serial |
538 |
| Permanent link to this record |
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| Author |
Schattschneider, P.; Löffler, S.; Stöger-Pollach, M.; Verbeeck, J. |
| Title |
Is magnetic chiral dichroism feasible with electron vortices? |
Type |
A1 Journal article |
| Year |
2014 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
136 |
Issue |
|
Pages |
81-85 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We discuss the feasibility of detecting magnetic transitions with focused electron vortex probes, suggested by selection rules for the magnetic quantum number. We theoretically estimate the dichroic signal strength in the L2,3 edge of ferromagnetic d metals. It is shown that under realistic conditions, the dichroic signal is undetectable for nanoparticles larger than View the MathML source. This is confirmed by a key experiment with nanometer-sized vortices. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
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| Language |
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Wos |
000327884700011 |
Publication Date |
2013-07-26 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0304-3991; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
64 |
Open Access |
|
| Notes |
Countatoms; Vortex; Esteem2; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 2.843; 2014 IF: 2.436 |
| Call Number |
UA @ lucian @ c:irua:110952UA @ admin @ c:irua:110952 |
Serial |
1750 |
| Permanent link to this record |
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| Author |
Gorji, S.; Kashiwar, A.; Mantha, L.S.; Kruk, R.; Witte, R.; Marek, P.; Hahn, H.; Kübel, C.; Scherer, T. |
| Title |
Nanowire facilitated transfer of sensitive TEM samples in a FIB |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
219 |
Issue |
|
Pages |
113075 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
We introduce a facile approach to transfer thin films and other mechanically sensitive TEM samples inside a FIB with minimal introduction of stress and bending. The method is making use of a pre-synthetized flexible freestanding Ag nanowire attached to the tip of a typical tungsten micromanipulator inside the FIB. The main advantages of this approach are the significantly reduced stress-induced bending during transfer and attachment of the TEM sample, the very short time required to attach and cut the nanowire, the operation at very low dose and ion current, and only using the e-beam for Pt deposition during the transfer of sensitive TEM samples. This results in a reduced sample preparation time and reduced exposure to the ion beam or e-beam for Pt deposition during the sample preparation and thus also reduced contamination and beam damage. The method was applied to a number of thin films and different TEM samples in order to illustrate the advantageous benefits of the concept. In particular, the technique has been successfully tested for the transfer of a thin film onto a MEMS heating chip for in situ TEM experiments. |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
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Publication Date |
2020-07-15 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0304-3991 |
ISBN |
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Additional Links |
UA library record |
| Impact Factor |
2.2 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 2.2; 2020 IF: 2.843 |
| Call Number |
UA @ admin @ c:irua:183618 |
Serial |
6871 |
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| Author |
Müller, K.; Schowalter, M.; Jansen, J.; Tsuda, K.; Titantah, J.; Lamoen, D.; Rosenauer, A. |
| Title |
Refinement of the 200 structure factor for GaAs using parallel and convergent beam electron nanodiffraction data |
Type |
A1 Journal article |
| Year |
2009 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
109 |
Issue |
7 |
Pages |
802-814 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We present a new method to measure structure factors from electron spot diffraction patterns recorded under almost parallel illumination in transmission electron microscopes. Bloch wave refinement routines have been developed to refine the crystal thickness, its orientation and structure factors by comparison of experimentally recorded and calculated intensities. Our method requires a modicum of computational effort, making it suitable for contemporary personal computers. Frozen lattice and Bloch wave simulations of GaAs diffraction patterns are used to derive optimised experimental conditions. Systematic errors are estimated from the application of the method to simulated diffraction patterns and rules for the recognition of physically reasonable initial refinement conditions are derived. The method is applied to the measurement of the 200 structure factor for GaAs. We found that the influence of inelastically scattered electrons is negligible. Additionally, we measured the 200 structure factor from zero loss filtered two-dimensional convergent beam electron diffraction patterns. The precision of both methods is found to be comparable and the results agree well with each other. A deviation of more than 20% from isolated atom scattering data is observed, whereas close agreement is found with structure factors obtained from density functional theory [A. Rosenauer, M. Schowalter, F. Glas, D. Lamoen, Phys. Rev. B 72 (2005), 085326-1], which account for the redistribution of electrons due to chemical bonding via modified atomic scattering amplitudes. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Amsterdam |
Editor |
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| Language |
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Wos |
000266787900005 |
Publication Date |
2009-03-23 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0304-3991; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.843 |
Times cited |
8 |
Open Access |
|
| Notes |
Fwo; G.0425.05; Esteem; Ant 200611271505 |
Approved |
Most recent IF: 2.843; 2009 IF: 2.067 |
| Call Number |
UA @ lucian @ c:irua:77361 |
Serial |
2856 |
| Permanent link to this record |
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| Author |
De wael, A.; De Backer, A.; Van Aert, S. |
| Title |
Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
219 |
Issue |
|
Pages |
113131 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000594770500003 |
Publication Date |
2020-10-03 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.2 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887 and No. 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through grants to A.D.w. and A.D.B. and projects G.0502.18N and EOS 30489208. |
Approved |
Most recent IF: 2.2; 2020 IF: 2.843 |
| Call Number |
EMAT @ emat @c:irua:172449 |
Serial |
6417 |
| Permanent link to this record |
