Records |
Author |
Bertoni, G.; Verbeeck, J. |
Title |
Accuracy and precision in model based EELS quantification |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
108 |
Issue |
8 |
Pages |
782-790 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We present results on model based quantification of electron energy loss spectra (EELS), focusing on the factors that influence accuracy and precision in determining chemical concentrations. Several sources of systematical errors are investigated. The spectrometer entrance aperture determines the collection angle, and the effects of its position with respect to the transmitted beam are investigated, taking into account the diffraction by the crystal structure. The effect of the orientation of the sample is tested experimentally and theoretically on SrTiO3, and finally, a simulated experiment on c-BN at different thicknesses confirms the superior results of the model based method with respect to the conventional method. A test on a set of experimental reference compounds is presented, showing that remarkably good accuracy can be obtained. Recommendations are given to achieve high accuracy and precision in practice. (C) 2008 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 |
|
Language |
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Wos |
000258241900010 |
Publication Date |
2008-02-22 |
Series Editor |
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Series Title |
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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 |
44 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2008 IF: 2.629 |
Call Number |
UA @ lucian @ c:irua:70550UA @ admin @ c:irua:70550 |
Serial |
42 |
Permanent link to this record |
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|
|
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 |
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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 |
000260808300002 |
Publication Date |
2008-04-21 |
Series Editor |
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Series Title |
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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 |
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 |
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|
|
Author |
Croitoru, M.D.; van Dyck, D.; Liu, Y.Z.; Zhang, Z. |
Title |
Measurement of specimen thickness by phase change determination in TEM |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
108 |
Issue |
12 |
Pages |
1616-1622 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
A non-destructive method for measuring the thickness of thin amorphous films composed of light elements has been developed. The method employs the statistics of the phase of the electron exit wave function. The accuracy of this method has been checked numerically by the multislice method and compared with that based on the mean inner potential. |
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 |
000260808300016 |
Publication Date |
2008-06-23 |
Series Editor |
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Series Title |
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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 |
2 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2008 IF: 2.629 |
Call Number |
UA @ lucian @ c:irua:75643 |
Serial |
1961 |
Permanent link to this record |
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|
|
Author |
Verbeeck, J.; Bertoni, G. |
Title |
Model-based quantification of EELS spectra: treating the effect of correlated noise |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
108 |
Issue |
2 |
Pages |
74-83 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Correlated noise is generally present in experimentally recorded electron energy loss spectra due to a non-ideal electron detector. In this contribution we describe a method to experimentally measure the noise properties of the detector as well as the consequences it has for model-based quantification using maximum likelihood. The effect of the correlated noise on the maximum likelihood fitting results can be shown to be negligible for the estimated (co)variance of the parameters while an experimentally obtained scaling factor is required to correct the likelihood ratio test for the reduction of noise power with frequency. Both effects are derived theoretically under a set of approximations and tested for a range of signal-to-noise values using numerical experiments. Finally, an experimental example shows that the correction for correlated noise is essential and should always be included in the fitting procedure. (c) 2007 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 |
|
Language |
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Wos |
000252816900002 |
Publication Date |
2007-03-25 |
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 |
2.843 |
Times cited |
16 |
Open Access |
|
Notes |
FWO nr G.0147.06; ESTEEM 026019 |
Approved |
Most recent IF: 2.843; 2008 IF: 2.629 |
Call Number |
UA @ lucian @ c:irua:67602UA @ admin @ c:irua:67602 |
Serial |
2103 |
Permanent link to this record |
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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 |
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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 |
000258747600009 |
Publication Date |
2008-03-07 |
Series Editor |
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Series Title |
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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 |
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 |
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|
Author |
Verbeeck, J.; Bertoni, G.; Schattschneider, P. |
Title |
The Fresnel effect of a defocused biprism on the fringes in inelastic holography |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Ultramicroscopy
T2 – 16th International Microscopy Congress, SEP 03-08, 2006, Sapporo, JAPAN |
Abbreviated Journal |
Ultramicroscopy |
Volume |
108 |
Issue |
3 |
Pages |
263-269 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We present energy filtered holography experiments on a thin foil of Al. By propagating the reduced density matrix of the probe electron through the microscope, we quantitatively predict the fringe contrast as a function of energy loss. Fringe contrast simulations include the effect of Fresnel fringes created at the edges of the defocused biprism, the effect of partial coherence in combination with inelastic scattering, and the effect of a finite energy distribution of the incoming beam. (c) 2007 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 |
000253389100011 |
Publication Date |
2007-11-02 |
Series Editor |
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Series Title |
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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 |
15 |
Open Access |
|
Notes |
Fwo G.0147.06; Esteem 026019 |
Approved |
Most recent IF: 2.843; 2008 IF: 2.629 |
Call Number |
UA @ lucian @ c:irua:104035 |
Serial |
3582 |
Permanent link to this record |
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|
Author |
Van Aert, S.; Geuens, P.; van Dyck, D.; Kisielowski, C.; Jinschek, J.R. |
Title |
Electron channelling based crystallography |
Type |
A1 Journal article |
Year |
2007 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
107 |
Issue |
6/7 |
Pages |
551-558 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000245341300015 |
Publication Date |
2006-12-13 |
Series Editor |
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Series Title |
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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 |
32 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2007 IF: 1.996 |
Call Number |
UA @ lucian @ c:irua:64286 |
Serial |
913 |
Permanent link to this record |
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|
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 |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000246937000001 |
Publication Date |
2006-12-16 |
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 |
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 |
van den Broek, W.; Verbeeck, J.; de Backer, S.; Scheunders, P.; Schryvers, D. |
Title |
Acquisition of the EELS data cube by tomographic reconstruction |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
106 |
Issue |
4/5 |
Pages |
269-276 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
Energy filtered TEM, EFTEM, provides three-dimensional data, two spatial and one spectral dimension. We propose to acquire these data by measuring a series of images with a defocused energy filter. It will be shown that each image is a projection of the data on the detector and that reconstruction of the data out of a sufficient number of such projections using a tomographic reconstruction algorithm is possible. This technique uses only a fraction of the electron dose an energy filtered series (EFS) needs for the same spectral and spatial resolution and the same mean signal-to-noise ratio. (c) 2005 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 |
000236042300003 |
Publication Date |
2005-11-30 |
Series Editor |
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Series Title |
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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 |
6 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
Call Number |
UA @ lucian @ c:irua:56910UA @ admin @ c:irua:56910 |
Serial |
55 |
Permanent link to this record |
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|
Author |
Kruse, P.; Schowalter, M.; Lamoen, D.; Rosenauer, A.; Gerthsen, D. |
Title |
Determination of the mean inner potential in III-V semiconductors, Si and Ge by density functional theory and electron holography |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
106 |
Issue |
2 |
Pages |
105-113 |
Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
Abstract |
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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 |
000234535900005 |
Publication Date |
2005-07-29 |
Series Editor |
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Series Title |
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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 |
50 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
Call Number |
UA @ lucian @ c:irua:56143 |
Serial |
678 |
Permanent link to this record |
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|
Author |
Croitoru, M.D.; van Dyck, D.; Van Aert, S.; Bals, S.; Verbeeck, J. |
Title |
An efficient way of including thermal diffuse scattering in simulation of scanning transmission electron microscopic images |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
106 |
Issue |
10 |
Pages |
933-940 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Vision lab |
Abstract |
We propose an improved image simulation procedure for atomic-resolution annular dark-field scanning transmission electron microscopy (STEM) based on the multislice formulation, which takes thermal diffuse scattering fully into account. The improvement with regard to the classical frozen phonon approach is realized by separating the lattice configuration statistics from the dynamical scattering so as to avoid repetitive calculations. As an example, the influence of phonon scattering on the image contrast is calculated and investigated. STEM image simulation of crystals can be applied with reasonable computing times to problems involving a large number of atoms and thick or large supercells. |
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 |
000240397200006 |
Publication Date |
2006-05-10 |
Series Editor |
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Series Title |
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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 |
18 |
Open Access |
|
Notes |
Fwo; Fwo-V |
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
Call Number |
UA @ lucian @ c:irua:87604UA @ admin @ c:irua:87604 |
Serial |
876 |
Permanent link to this record |
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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 |
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Place of Publication |
Amsterdam |
Editor |
|
Language |
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Wos |
000241592900018 |
Publication Date |
2006-07-04 |
Series Editor |
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Series Title |
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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 |
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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 |
|
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 |
|
Series Issue |
|
Edition |
|
ISSN |
0304-3991; |
ISBN |
|
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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|
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Author |
Verbeeck, J. |
Title |
Interpretation of “Energy-filtered electron-diffracted beam holography” by R.A. Herring |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
106 |
Issue |
6 |
Pages |
461-465 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
A straightforward application of the theoretical framework presented by Verbeeck et al. [Ultramicroscopy 102 (2005) 239] is presented to explain the energy-filtered electron-diffracted beam holography experiments published by Herring [Ultramicroscopy 104 (2005) 261]. It is shown that the theory is in agreement with all experimental findings, which leads to the interpretation that the experiments are mainly measuring the angular coherence of the source image rather than exposing details on the coherence properties of inelastic scattering. A change in experimental parameters is proposed, which could result in interesting information about the coherence in all inelastic scattering process. (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 |
000237491600002 |
Publication Date |
2006-01-18 |
Series Editor |
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Series Title |
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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 |
8 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
Call Number |
UA @ lucian @ c:irua:58283UA @ admin @ c:irua:58283 |
Serial |
1710 |
Permanent link to this record |
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Author |
Verbeeck, J.; Van Aert, S.; Bertoni, G. |
Title |
Model-based quantification of EELS spectra: including the fine structure |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
106 |
Issue |
11-12 |
Pages |
976-980 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
An extension to model-based electron energy loss spectroscopy (EELS) quantification is reported to improve the possibility of modelling fine structure changes in electron energy loss spectra. An equalisation function is used in the energy loss near edge structure (ELNES) region to model the differences between a single atom differential cross section and the cross section for an atom in a crystal. The equalisation function can be shown to approximate the relative density of unoccupied states for the given excitation edge. On a set of 200 experimental h-BN spectra, this technique leads to statistically acceptable models resulting into unbiased estimates of relative concentrations and making the estimated precisions come very close to the Cramer-Rao lower bound (CRLB). The method greatly expands the useability of model-based EELS quantification to spectra with pronounced fine structure. Another benefit of this model is that one also gets an estimate of the unoccupied density of states for a given excitation edge, without having to do background removal and deconvolution, making the outcome intrinsically more reliable and less noisy. (c) 2006 Elsevier B.V. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000241592900004 |
Publication Date |
2006-07-04 |
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 |
38 |
Open Access |
|
Notes |
Goa; Fwo Iap-V |
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
Call Number |
UA @ lucian @ c:irua:61379UA @ admin @ c:irua:61379 |
Serial |
2102 |
Permanent link to this record |
|
|
|
Author |
Bertoni, G.; Beyers, E.; Verbeeck, J.; Mertens, M.; Cool, P.; Vansant, E.F.; Van Tendeloo, G. |
Title |
Quantification of crystalline and amorphous content in porous TiO2 samples from electron energy loss spectroscopy |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
106 |
Issue |
7 |
Pages |
630-635 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA) |
Abstract |
We present an efficient method for the quantification of crystalline versus amorphous phase content in mesoporous materials, making use of electron energy loss spectroscopy. The method is based on fitting a superposition of core-loss edges using the maximum likelihood method with measured reference spectra. We apply the method to mesoporous TiO2 samples. We show that the absolute amount of the crystalline phase can be determined with an accuracy below 5%. This method takes also the amorphous phase into account, where standard X-ray diffraction is only quantitative for crystalline phases and not for amorphous phase. (c) 2006 Elsevier B.V.. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000238479300011 |
Publication Date |
2006-04-28 |
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 |
83 |
Open Access |
|
Notes |
Iap-V; Goa-2005; Fwo |
Approved |
Most recent IF: 2.843; 2006 IF: 1.706 |
Call Number |
UA @ lucian @ c:irua:58823UA @ admin @ c:irua:58823 |
Serial |
2741 |
Permanent link to this record |
|
|
|
Author |
den Dekker, A.J.; Van Aert, S.; van den Bos, A.; van Dyck, D. |
Title |
Maximum likelihood estimation of structure parameters from high resolution electron microscopy images: part 1: a theoretical framework |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
104 |
Issue |
2 |
Pages |
83-106 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000230526400001 |
Publication Date |
2005-04-09 |
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 |
70 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2005 IF: 2.490 |
Call Number |
UA @ lucian @ c:irua:57229 |
Serial |
1959 |
Permanent link to this record |
|
|
|
Author |
Van Aert, S.; den Dekker, A.J.; van den Bos, A.; van Dyck, D.; Chen, J.H. |
Title |
Maximum likelihood estimation of structure parameters from high resolution electron microscopy images : part 2 : a practical example |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
104 |
Issue |
2 |
Pages |
107-125 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000230526400002 |
Publication Date |
2005-04-08 |
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 |
37 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2005 IF: 2.490 |
Call Number |
UA @ lucian @ c:irua:57131 |
Serial |
1960 |
Permanent link to this record |
|
|
|
Author |
Bals, S.; Kilaas, R.; Kisielowski, C. |
Title |
Nonlinear imaging using annular dark field TEM |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
104 |
Issue |
3/4 |
Pages |
281-289 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Annular dark field TEM images exhibit a dominant mass-thickness contrast that can be quantified to extract single atom scattering cross sections. On top of this incoherent background, additional lattice fringes appear with a nonlinear information limit of 1.2 angstrom at 150 kV. The formation of these fringes is described by coherent nonlinear imaging theory and good agreement is found between experimental and simulated images. Calculations furthermore predict that the use of aberration corrected microscopes will improve the image quality dramatically. (c) 2005 Elsevier B.V. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000231297100012 |
Publication Date |
2005-06-16 |
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 |
15 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2005 IF: 2.490 |
Call Number |
UA @ lucian @ c:irua:64685 |
Serial |
2352 |
Permanent link to this record |
|
|
|
Author |
Verbeeck, J.; van Dyck, D.; Lichte, H.; Potapov, P.; Schattschneider, P. |
Title |
Plasmon holographic experiments: theoretical framework |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
102 |
Issue |
3 |
Pages |
239-255 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
A theoretical framework is described to understand the results of plasmon holography experiments leading to insight in the meaning of the experimental results and pointing out directions for future experiments. The framework is based on the formalism of mutual intensity to describe how coherence is transferred through an optical system. For the inelastic interaction with the object, an expression for the volume. plasmon excitations in a free electron gas is used as a model for the behaviour of aluminium. The formalism leads to a clear graphical intuitive tool for under-standing the experiments. It becomes evident that the measured coherence is solely related to the angular distribution of the plasmon scattering in the case of bulk plasmons. After describing the framework, the special case of coherence outside a spherical particle is treated and the seemingly controversial idea of a plasmon with a limited coherence length obtained front experiments is clarified. (C) 2004 Elsevier B.V. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000226436600010 |
Publication Date |
2004-11-05 |
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 |
43 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2005 IF: 2.490 |
Call Number |
UA @ lucian @ c:irua:57133UA @ admin @ c:irua:57133 |
Serial |
2643 |
Permanent link to this record |
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|
|
Author |
Potapov, P.L.; Schryvers, D. |
Title |
Measuring the absolute position of EELS ionisation edges in a TEM |
Type |
A1 Journal article |
Year |
2004 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
99 |
Issue |
|
Pages |
73-85 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000220804700005 |
Publication Date |
2003-08-12 |
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 |
29 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2004 IF: 2.215 |
Call Number |
UA @ lucian @ c:irua:48781 |
Serial |
1970 |
Permanent link to this record |
|
|
|
Author |
Verbeeck, J.; Van Aert, S. |
Title |
Model based quantification of EELS spectra |
Type |
A1 Journal article |
Year |
2004 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
101 |
Issue |
2/4 |
Pages |
207-224 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Recent advances in model based quantification of electron energy loss spectra (EELS) are reported. The maximum likelihood method for the estimation of physical parameters describing an EELS spectrum, the validation of the model used in this estimation procedure, and the computation of the attainable precision, that is, the theoretical lower bound on the variance of these estimates, are discussed. Experimental examples on An and GaAs samples show the power of the maximum likelihood method and show that the theoretical prediction of the attainable precision can be closely approached even for spectra with overlapping edges where conventional EELS quantification fails. To provide end-users with a low threshold alternative to conventional quantification, a user friendly program was developed which is freely available under a GNU public license. (C) 2004 Elsevier B.V. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000224046100016 |
Publication Date |
2004-07-23 |
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 |
2.843 |
Times cited |
147 |
Open Access |
|
Notes |
Fwo; Iuap P5/01 |
Approved |
Most recent IF: 2.843; 2004 IF: 2.215 |
Call Number |
UA @ lucian @ c:irua:57130UA @ admin @ c:irua:57130 |
Serial |
2101 |
Permanent link to this record |
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|
|
Author |
van Dyck, D.; Van Aert, S.; den Dekker, A.J.; van den Bos, A. |
Title |
Is atomic resolution transmission electron microscopy able to resolve and refine amorphous structures? |
Type |
A1 Journal article |
Year |
2003 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
98 |
Issue |
|
Pages |
27-42 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000186831500003 |
Publication Date |
2003-04-25 |
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 |
26 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2003 IF: 1.665 |
Call Number |
UA @ lucian @ c:irua:47516 |
Serial |
1749 |
Permanent link to this record |
|
|
|
Author |
Van Aert, S.; den Dekker, A.J.; van Dyck, D.; van den Bos, A. |
Title |
Optimal experimental design of STEM measurement of atom column positions |
Type |
A1 Journal article |
Year |
2002 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
90 |
Issue |
|
Pages |
273-289 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000174770900004 |
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 |
2.843 |
Times cited |
35 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2002 IF: 1.772 |
Call Number |
UA @ lucian @ c:irua:47517 |
Serial |
2483 |
Permanent link to this record |
|
|
|
Author |
den Dekker, A.J.; Van Aert, S.; van Dyck, D.; van den Bos, A.; Geuens, P. |
Title |
Does a monochromator improve the precision in quantitative HRTEM? |
Type |
A1 Journal article |
Year |
2001 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
89 |
Issue |
|
Pages |
275-290 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000172667000004 |
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 |
2.843 |
Times cited |
22 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2001 IF: 1.890 |
Call Number |
UA @ lucian @ c:irua:47518 |
Serial |
746 |
Permanent link to this record |
|
|
|
Author |
Chen, J.H.; van Dyck, D.; op de Beeck, M.; van Landuyt, J. |
Title |
Computational comparisons between the conventional multislice method and the third-order multislice method for calculating high-energy electron diffraction and imaging |
Type |
A1 Journal article |
Year |
1997 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
69 |
Issue |
|
Pages |
219-240 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
|
Address |
|
Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
A1997YG59500001 |
Publication Date |
0000-00-00 |
Series Editor |
|
Series Title |
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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 |
11 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 1997 IF: 1.600 |
Call Number |
UA @ lucian @ c:irua:21416 |
Serial |
455 |
Permanent link to this record |
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|
Author |
Zanaga, D.; Altantzis, T.; Sanctorum, J.; Freitag, B.; Bals, S. |
Title |
An alternative approach for ζ-factor measurement using pure element nanoparticles |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
164 |
Issue |
164 |
Pages |
11-16 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
It is very challenging to measure the chemical composition of hetero nanostructures in a reliable and quantitative manner. Here, we propose a novel and straightforward approach that can be used to quantify energy dispersive X-ray spectra acquired in a transmission electron microscope. Our method is based on a combination of electron tomography and the so-called ζ-factor technique. We will demonstrate the reliability of our approach as well as its applicability by investigating Au-Ag and Au-Pt hetero nanostructures. Given its simplicity, we expect that the method could become a new standard in the field of chemical characterization using electron microscopy. |
Address |
|
Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000373526200002 |
Publication Date |
2016-03-10 |
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 |
19 |
Open Access |
OpenAccess |
Notes |
The authors acknowledge financial support from the European Research Council (ERC Starting Grant # 335078-COLOURATOMS) and the European Union under the FP7 (Integrated Infrastructure Initiative N. 312483 – ESTEEM2). The authors would also like to thank Luis M. Liz-Marzán, Ana Sánchez-Iglesias, Stefanos Mourdikoudis and Cristina Fernández-López for sample provision and useful discussions.; esteem2jra4; ECASSara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); |
Approved |
Most recent IF: 2.843 |
Call Number |
EMAT @ emat @ |
Serial |
4019 |
Permanent link to this record |
|
|
|
Author |
Lobato, I.; Van Aert, S.; Verbeeck, J. |
Title |
Progress and new advances in simulating electron microscopy datasets using MULTEM |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
168 |
Issue |
168 |
Pages |
17-27 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
A new version of the open source program MULTEM is presented here. It includes a graphical user interface, tapering truncation of the atomic potential, CPU multithreading functionality, single/double precision calculations, scanning transmission electron microscopy (STEM) simulations using experimental detector sensitivities, imaging STEM (ISTEM) simulations, energy filtered transmission electron microscopy (EFTEM) simulations, STEM electron energy loss spectroscopy (EELS) simulations along with other improvements in the algorithms. We also present a mixed channeling approach for the calculation of inelastic excitations, which allows one to considerably speed up time consuming EFTEM/STEM-EELS calculations. |
Address |
EMAT, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium |
Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Wos |
000380754100003 |
Publication Date |
2016-06-11 |
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 |
43 |
Open Access |
|
Notes |
The authors acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative. Reference No. 312483- ESTEEM2. The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0374.13N, G.0369.15N and G.0368.15N).; esteem2jra3; esteem2na3; esteem2_jra2 |
Approved |
Most recent IF: 2.843 |
Call Number |
c:irua:134088 c:irua:134088UA @ admin @ c:irua:134088 |
Serial |
4093 |
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 |
|
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 |
|
|
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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 |
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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 |
English |
Wos |
000403862900009 |
Publication Date |
2016-05-12 |
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 |
93 |
Open Access |
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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 |