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Author van den Broek, W.; Van Aert, S.; van Dyck, D.
Title A model based atomic resolution tomographic algorithm Type A1 Journal article
Year (up) 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 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
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Author Van Aert, S.; Verbeeck, J.; Erni, R.; Bals, S.; Luysberg, M.; van Dyck, D.; Van Tendeloo, G.
Title Quantitative atomic resolution mapping using high-angle annular dark field scanning transmission electron microscopy Type A1 Journal article
Year (up) 2009 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 109 Issue 10 Pages 1236-1244
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract A model-based method is proposed to relatively quantify the chemical composition of atomic columns using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) images. The method is based on a quantification of the total intensity of the scattered electrons for the individual atomic columns using statistical parameter estimation theory. In order to apply this theory, a model is required describing the image contrast of the HAADF STEM images. Therefore, a simple, effective incoherent model has been assumed which takes the probe intensity profile into account. The scattered intensities can then be estimated by fitting this model to an experimental HAADF STEM image. These estimates are used as a performance measure to distinguish between different atomic column types and to identify the nature of unknown columns with good accuracy and precision using statistical hypothesis testing. The reliability of the method is supported by means of simulated HAADF STEM images as well as a combination of experimental images and electron energy-loss spectra. It is experimentally shown that statistically meaningful information on the composition of individual columns can be obtained even if the difference in averaged atomic number Z is only 3. Using this method, quantitative mapping at atomic resolution using HAADF STEM images only has become possible without the need of simultaneously recorded electron energy loss spectra.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000270015200004 Publication Date 2009-05-28
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 166 Open Access
Notes Fwo; Esteem 026019 Approved Most recent IF: 2.843; 2009 IF: 2.067
Call Number UA @ lucian @ c:irua:78585UA @ admin @ c:irua:78585 Serial 2748
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Author Verbeeck, J.; Van Aert, S.; Zhang, L.; Haiyan, T.; Schattschneider, P.; Rosenauer, A.
Title Computational aspects in quantitative EELS Type A1 Journal article
Year (up) 2010 Publication Microscopy and microanalysis Abbreviated Journal Microsc Microanal
Volume 16 Issue S:2 Pages 240-241
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge, Mass. Editor
Language Wos Publication Date 2010-08-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1431-9276;1435-8115; ISBN Additional Links UA library record
Impact Factor 1.891 Times cited Open Access
Notes Approved Most recent IF: 1.891; 2010 IF: 3.259
Call Number UA @ lucian @ c:irua:96556UA @ admin @ c:irua:96556 Serial 454
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 1: theory and simulations Type A1 Journal article
Year (up) 2010 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 5 Pages 527-534
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In order to interpret the amplitude and phase of the exit wave in terms of mass and position of the atoms, one has to invert the dynamic scattering of the electrons in the object so as to obtain a starting structure which can then be used as a seed for further quantitative structure refinement. This is especially challenging in case of a zone axis condition when the interaction of the electrons with the atom column is very strong. Based on the channelling theory we will show that the channelling map not only yields a circle on the Argand plot but also a circular defocus curve for every column. The former gives the number of atoms in each column, while the latter provides the defocus value for each column, which reveals the surface roughness at the exit plane with single atom sensitivity.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000279065700019 Publication Date 2009-12-12
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 25 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83691 Serial 723
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Author Van Aert, S.; Chen, J.H.; van Dyck, D.
Title Linear versus non-linear structural information limit in high-resolution transmission electron microscopy Type A1 Journal article
Year (up) 2010 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 11 Pages 1404-1410
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract A widely used performance criterion in high-resolution transmission electron microscopy (HRTEM) is the information limit. It corresponds to the inverse of the maximum spatial object frequency that is linearly transmitted with sufficient intensity from the exit plane of the object to the image plane and is limited due to partial temporal coherence. In practice, the information limit is often measured from a diffractogram or from Young's fringes assuming a weak phase object scattering beyond the inverse of the information limit. However, for an aberration corrected electron microscope, with an information limit in the sub-angstrom range, weak phase objects are no longer applicable since they do not scatter sufficiently in this range. Therefore, one relies on more strongly scattering objects such as crystals of heavy atoms observed along a low index zone axis. In that case, dynamical scattering becomes important such that the non-linear and linear interaction may be equally important. The non-linear interaction may then set the experimental cut-off frequency observed in a diffractogram. The goal of this paper is to quantify both the linear and the non-linear information transfer in terms of closed form analytical expressions. Whereas the cut-off frequency set by the linear transfer can be directly related with the attainable resolution, information from the non-linear transfer can only be extracted using quantitative, model-based methods. In contrast to the historic definition of the information limit depending on microscope parameters only, the expressions derived in this paper explicitly incorporate their dependence on the structure parameters as well. In order to emphasize this dependence and to distinguish from the usual information limit, the expressions derived for the inverse cut-off frequencies will be referred to as the linear and non-linear structural information limit. The present findings confirm the well-known result that partial temporal coherence has different effects on the transfer of the linear and non-linear terms, such that the non-linear imaging contributions are damped less than the linear imaging contributions at high spatial frequencies. This will be important when coherent aberrations such as spherical aberration and defocus are reduced.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000282562100008 Publication Date 2010-07-15
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 Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83689 Serial 1821
Permanent link to this record
 
 
Author van den Broek, W.; Van Aert, S.; van Dyck, D.
Title A model based reconstruction technique for depth sectioning with scanning transmission electron microscopy Type A1 Journal article
Year (up) 2010 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 5 Pages 548-554
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Depth sectioning in high angular annular dark field scanning transmission electron microscopy is considered a candidate for three-dimensional characterization on the atomic scale. However at present the depth resolution is still far from the atomic level, due to strong limitations in the opening angle of the beam. In this paper we introduce a new, parameter based tomographic reconstruction algorithm that allows to make maximal use of the prior knowledge about the constituent atom types and the microscope settings, so as to retrieve the atomic positions and push the resolution to the atomic level in all three dimensions.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000279065700022 Publication Date 2009-09-21
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 16 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83690 Serial 2104
Permanent link to this record
 
 
Author Van Aert, S.
Title Atomen in 3D : Antwerpenaren brengen atomaire structuur nanodeeltjes in beeld Type Newspaper/Magazine/blog article
Year (up) 2011 Publication Chemie magazine Abbreviated Journal
Volume 7 Issue 3 Pages 9
Keywords Newspaper/Magazine/blog article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0379-7651 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94122 Serial 163
Permanent link to this record
 
 
Author Van Aert, S.; Batenburg, J.; Van Tendeloo, S.
Title Atomen tellen Type A3 Journal article
Year (up) 2011 Publication Nederlands tijdschrift voor natuurkunde (1991) Abbreviated Journal
Volume 77 Issue 8 Pages 292-295
Keywords A3 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-4264 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94119 Serial 164
Permanent link to this record
 
 
Author de Backer, A.; Van Aert, S.; van Dyck, D.
Title High precision measurements of atom column positions using model-based exit wave reconstruction Type A1 Journal article
Year (up) 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 9/10 Pages 1475-1482
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In this paper, it has been investigated how to measure atom column positions as accurately and precisely as possible using a focal series of images. In theory, it is expected that the precision would considerably improve using a maximum likelihood estimator based on the full series of focal images. As such, the theoretical lower bound on the variances of the unknown atom column positions can be attained. However, this approach is numerically demanding. Therefore, maximum likelihood estimation has been compared with the results obtained by fitting a model to a reconstructed exit wave rather than to the full series of focal images. Hence, a real space model-based exit wave reconstruction technique based on the channelling theory is introduced. Simulations show that the reconstructed complex exit wave contains the same amount of information concerning the atom column positions as the full series of focal images. Only for thin samples, which act as weak phase objects, this information can be retrieved from the phase of the reconstructed complex exit wave.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461200004 Publication Date 2011-07-28
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; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:91879 Serial 1438
Permanent link to this record
 
 
Author Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D.
Title A method to determine the local surface profile from reconstructed exit waves Type A1 Journal article
Year (up) 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 8 Pages 1352-1359
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Reconstructed exit waves are useful to quantify unknown structure parameters such as the position and composition of the atom columns at atomic scale. Existing techniques provide a complex wave in a flat plane which is close to the plane where the electrons leave the atom columns. However, due to local deviation in the flatness of the exit surface, there will be an offset between the plane of reconstruction and the actual exit of a specific atom column. Using the channelling theory, it has been shown that this defocus offset can in principle be determined atom column-by-atom column. As such, the surface roughness could be quantified at atomic scale. However, the outcome strongly depends on the initial plane of reconstruction especially in a crystalline structure. If this plane is further away from the true exit, the waves of the atom columns become delocalized and interfere mutually which strongly complicates the interpretation of the exit wave in terms of the local structure. In this paper, we will study the delocalization with defocus using the channelling theory in a more systematic way.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461100049 Publication Date 2011-05-03
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 3 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:88941 Serial 2017
Permanent link to this record
 
 
Author Boschker, H.; Huijben, M.; Vailinois, A.; Verbeeck, J.; Van Aert, S.; Luysberg, M.; Bals, S.; Van Tendeloo, G.; Houwman, E.P.; Koster, G.; Blank, D.H.A.; Rijnders, G.
Title Optimized fabrication of high-quality La0.67Sr0.33MnO3 thin films considering all essential characteristics Type A1 Journal article
Year (up) 2011 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 44 Issue 20 Pages 205001-205001,9
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In this paper, an overview of the fabrication and properties of high-quality La0.67Sr0.33MnO3 (LSMO) thin films is given. A high-quality LSMO film combines a smooth surface morphology with a large magnetization and a small residual resistivity, while avoiding precipitates and surface segregation. In the literature, typically only a few of these issues are adressed. We therefore present a thorough characterization of our films, which were grown by pulsed laser deposition. The films were characterized with reflection high energy electron diffraction, atomic force microscopy, x-ray diffraction, magnetization and transport measurements, x-ray photoelectron spectroscopy and scanning transmission electron microscopy. The films have a saturation magnetization of 4.0 µB/Mn, a Curie temperature of 350 K and a residual resistivity of 60 µΩ cm. These results indicate that high-quality films, combining both large magnetization and small residual resistivity, were realized. A comparison between different samples presented in the literature shows that focussing on a single property is insufficient for the optimization of the deposition process. For high-quality films, all properties have to be adressed. For LSMO devices, the thin-film quality is crucial for the device performance. Therefore, this research is important for the application of LSMO in devices.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000290150900001 Publication Date 2011-04-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 99 Open Access
Notes This research was financially supported by the Dutch Science Foundation, by NanoNed, a nanotechnology program of the Dutch Ministry of Economic Affairs, and by the NanOxide program of the European Science Foundation. This work is supported in part by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract DE-AC02-76SF00515. Approved Most recent IF: 2.588; 2011 IF: 2.544
Call Number UA @ lucian @ c:irua:89557UA @ admin @ c:irua:89557 Serial 2491
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Author Bals, S.; Casavola, M.; van Huis, M.A.; Van Aert, S.; Batenburg, K.J.; Van Tendeloo, G.; Vanmaekelbergh, D.
Title Three-dimensional atomic imaging of colloidal core-shell nanocrystals Type A1 Journal article
Year (up) 2011 Publication Nano letters Abbreviated Journal Nano Lett
Volume 11 Issue 8 Pages 3420-3424
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Colloidal coreshell semiconductor nanocrystals form an important class of optoelectronic materials, in which the exciton wave functions can be tailored by the atomic configuration of the core, the interfacial layers, and the shell. Here, we provide a trustful 3D characterization at the atomic scale of a free-standing PbSe(core)CdSe(shell) nanocrystal by combining electron microscopy and discrete tomography. Our results yield unique insights for understanding the process of cation exchange, which is widely employed in the synthesis of coreshell nanocrystals. The study that we present is generally applicable to the broad range of colloidal heteronanocrystals that currently emerge as a new class of materials with technological importance.
Address
Corporate Author Thesis
Publisher Place of Publication Washington Editor
Language Wos 000293665600062 Publication Date 2011-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984;1530-6992; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.712 Times cited 121 Open Access
Notes Esteem 026019; Fwo Approved Most recent IF: 12.712; 2011 IF: 13.198
Call Number UA @ lucian @ c:irua:91263 Serial 3643
Permanent link to this record
 
 
Author Van Aert, S.; Batenburg, K.J.; Rossell, M.D.; Erni, R.; Van Tendeloo, G.
Title Three-dimensional atomic imaging of crystalline nanoparticles Type A1 Journal article
Year (up) 2011 Publication Nature Abbreviated Journal Nature
Volume 470 Issue 7334 Pages 374-377
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Determining the three-dimensional (3D) arrangement of atoms in crystalline nanoparticles is important for nanometre-scale device engineering and also for applications involving nanoparticles, such as optoelectronics or catalysis. A nanoparticles physical and chemical properties are controlled by its exact 3D morphology, structure and composition1. Electron tomography enables the recovery of the shape of a nanoparticle from a series of projection images2, 3, 4. Although atomic-resolution electron microscopy has been feasible for nearly four decades, neither electron tomography nor any other experimental technique has yet demonstrated atomic resolution in three dimensions. Here we report the 3D reconstruction of a complex crystalline nanoparticle at atomic resolution. To achieve this, we combined aberration-corrected scanning transmission electron microscopy5, 6, 7, statistical parameter estimation theory8, 9 and discrete tomography10, 11. Unlike conventional electron tomography, only two images of the targeta silver nanoparticle embedded in an aluminium matrixare sufficient for the reconstruction when combined with available knowledge about the particles crystallographic structure. Additional projections confirm the reliability of the result. The results we present help close the gap between the atomic resolution achievable in two-dimensional electron micrographs and the coarser resolution that has hitherto been obtained by conventional electron tomography.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000287409100037 Publication Date 2011-02-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836;1476-4687; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 40.137 Times cited 341 Open Access
Notes Esteem 026019 Approved Most recent IF: 40.137; 2011 IF: 36.280
Call Number UA @ lucian @ c:irua:86745 Serial 3644
Permanent link to this record
 
 
Author Batenburg, J.; Van Aert, S.
Title Three-dimensional reconstruction of a nanoparticle at atomic resolution Type A2 Journal article
Year (up) 2011 Publication ERCIM news Abbreviated Journal
Volume 86 Issue Pages 52
Keywords A2 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Le Chesnay Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-4981 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94120 Serial 3655
Permanent link to this record
 
 
Author van den Broek, W.; Van Aert, S.; Goos, P.; van Dyck, D.
Title Throughput maximization of particle radius measurements by balancing size and current of the electron probe Type A1 Journal article
Year (up) 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 7 Pages 940-947
Keywords A1 Journal article; Engineering Management (ENM); Electron microscopy for materials research (EMAT); Vision lab
Abstract In thispaperweinvestigatewhichprobesizemaximizesthethroughputwhenmeasuringtheradiusof nanoparticlesinhighangleannulardarkfieldscanningtransmissionelectronmicroscopy(HAADFSTEM). The sizeandthecorrespondingcurrentoftheelectronprobedeterminetheprecisionoftheestimateofa particlesradius.Maximizingthroughputmeansthatamaximumnumberofparticlesshouldbeimaged withinagiventimeframe,sothataprespecifiedprecisionisattained.WeshowthatBayesianstatistical experimentaldesignisaveryusefulapproachtodeterminetheoptimalprobesizeusingacertainamount of priorknowledgeaboutthesample.Thedependenceoftheoptimalprobesizeonthedetectorgeometry and thediameter,variabilityandatomicnumberoftheparticlesisinvestigated.Anexpressionforthe optimalprobesizeintheabsenceofanykindofpriorknowledgeaboutthespecimenisderivedaswell.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461000026 Publication Date 2010-11-25
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 7 Open Access
Notes Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:89657 Serial 3659
Permanent link to this record
 
 
Author Batenburg, K.J.; Bals, S.; Van Aert, S.; Roelandts, T.; Sijbers, J.
Title Ultra-high resolution electron tomography for materials science : a roadmap Type A1 Journal article
Year (up) 2011 Publication Microscopy and microanalysis Abbreviated Journal Microsc Microanal
Volume 17 Issue S:2 Pages 934-935
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge, Mass. Editor
Language Wos Publication Date 2011-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1431-9276;1435-8115; ISBN Additional Links UA library record
Impact Factor 1.891 Times cited Open Access
Notes Approved Most recent IF: 1.891; 2011 IF: 3.007
Call Number UA @ lucian @ c:irua:96554 Serial 3792
Permanent link to this record
 
 
Author Van Tendeloo, G.; Bals, S.; Van Aert, S.; Verbeeck, J.; van Dyck, D.
Title Advanced electron microscopy for advanced materials Type A1 Journal article
Year (up) 2012 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 24 Issue 42 Pages 5655-5675
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Vision lab
Abstract The idea of this Review is to introduce newly developed possibilities of advanced electron microscopy to the materials science community. Over the last decade, electron microscopy has evolved into a full analytical tool, able to provide atomic scale information on the position, nature, and even the valency atoms. This information is classically obtained in two dimensions (2D), but can now also be obtained in 3D. We show examples of applications in the field of nanoparticles and interfaces.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000310602200001 Publication Date 2012-08-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 107 Open Access
Notes This work was supported by funding from the European Research Council under the 7th Framework Program (FP7), ERC grant No 246791 – COUNTATOMS. J.V. Acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The authors gratefully acknowledge funding from the Research Foundation Flanders (FWO, Belgium). The Qu-Ant-EM microscope was partly funded by the Hercules Fund from the Flemish Government. We thank Rafal Dunin-Borkowski for providing Figure 5d. The authors would like to thank the colleagues who have contributed to this work over the years, including K.J. Batenburg, R. Erni, B. Goris, F. Leroux, H. Lichte, A. Lubk, B. Partoens, M. D. Rossell, P. Schattschneider, B. Schoeters, D. Schryvers, H. Tan, H. Tian, S. Turner, M. van Huis. ECASJO_; Approved Most recent IF: 19.791; 2012 IF: 14.829
Call Number UA @ lucian @ c:irua:100470UA @ admin @ c:irua:100470 Serial 70
Permanent link to this record
 
 
Author Bals, S.; Van Aert, S.; Romero, C.P.; Lauwaet, K.; Van Bael, M.J.; Schoeters, B.; Partoens, B.; Yuecelen, E.; Lievens, P.; Van Tendeloo, G.
Title Atomic scale dynamics of ultrasmall germanium clusters Type A1 Journal article
Year (up) 2012 Publication Nature communications Abbreviated Journal Nat Commun
Volume 3 Issue 897 Pages 897
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract Starting from the gas phase, small clusters can be produced and deposited with huge flexibility with regard to composition, materials choice and cluster size. Despite many advances in experimental characterization, a detailed morphology of such clusters is still lacking. Here we present an atomic scale observation as well as the dynamical behaviour of ultrasmall germanium clusters. Using quantitative scanning transmission electron microscopy in combination with ab initio calculations, we are able to characterize the transition between different equilibrium geometries of a germanium cluster consisting of less than 25 atoms. Seven-membered rings, trigonal prisms and some smaller subunits are identified as possible building blocks that stabilize the structure.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000306099900024 Publication Date 2012-06-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 90 Open Access
Notes Fwo; Iap; Iwt Approved Most recent IF: 12.124; 2012 IF: 10.015
Call Number UA @ lucian @ c:irua:100340 Serial 183
Permanent link to this record
 
 
Author van den Broek, W.; Rosenauer, A.; Goris, B.; Martinez, G.T.; Bals, S.; Van Aert, S.; van Dyck, D.
Title Correction of non-linear thickness effects in HAADF STEM electron tomography Type A1 Journal article
Year (up) 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 116 Issue Pages 8-12
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In materials science, high angle annular dark field scanning transmission electron microscopy is often used for tomography at the nanometer scale. In this work, it is shown that a thickness dependent, non-linear damping of the recorded intensities occurs. This results in an underestimated intensity in the interior of reconstructions of homogeneous particles, which is known as the cupping artifact. In this paper, this non-linear effect is demonstrated in experimental images taken under common conditions and is reproduced with a numerical simulation. Furthermore, an analytical derivation shows that these non-linearities can be inverted if the imaging is done quantitatively, thus preventing cupping in the reconstruction.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000304473700002 Publication Date 2012-03-09
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 67 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:96558 Serial 518
Permanent link to this record
 
 
Author Van Aert, S.; Turner, S.; Delville, R.; Schryvers, D.; Van Tendeloo, G.; Salje, E.K.H.
Title Direct observation of ferrielectricity at ferroelastic domain boundaries in CaTiO3 by electron microscopy Type A1 Journal article
Year (up) 2012 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 24 Issue 4 Pages 523-527
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract High-resolution aberration-corrected transmission electron microscopy aided by statistical parameter estimation theory is used to quantify localized displacements at a (110) twin boundary in orthorhombic CaTiO3. The displacements are 36 pm for the Ti atoms and confined to a thin layer. This is the first direct observation of the generation of ferroelectricity by interfaces inside this material which opens the door for domain boundary engineering.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000299156400011 Publication Date 2011-12-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 150 Open Access
Notes Fwo Approved Most recent IF: 19.791; 2012 IF: 14.829
Call Number UA @ lucian @ c:irua:94110 Serial 717
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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 (up) 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
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Author Klingstedt, M.; Sundberg, M.; Eriksson, L.; Haigh, S.; Kirkland, A.; Grüner, D.; de Backer, A.; Van Aert, S.; Tarasaki, O.
Title Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on SbxWO3+y (x\sim0.11) Type A1 Journal article
Year (up) 2012 Publication Zeitschrift für Kristallographie Abbreviated Journal Z Krist-Cryst Mater
Volume 227 Issue 6 Pages 341-349
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A new tungsten bronze in the SbWO system has been prepared in a solid state reaction from Sb2O3, WO3 and W metal powder. The average structure was determined by single crystal X-ray diffraction. SbxWO3+y (x ∼ 0.11) crystallizes in the orthorhombic space group Pm21n (no. 31), a = 27.8135(9) Å, b = 7.3659(2) Å and c = 3.8672(1) Å. The structure belongs to the (n)-ITB class of intergrowth tungsten bronzes. It contains slabs of hexagonal channels formed by six WO6 octahedra. These slabs are separated by three layers of WO6 octahedra that are arranged in a WO3-type fashion. The WO6 octahedra share all vertices to build up a three-dimensional framework. The hexagonal channels are filled with Sb atoms to ∼80% and additional O atoms. The atoms are shifted out of the center of the channels. Exit-wave reconstruction of focal series of high resolution-transmission-electron-microscope (HRTEM) images combined with statistical paramäeter estimation techniques allowed to study local ordering in the channels. Sb atoms in neighbouring channels tend to be displaced in the same direction, which is in agreement with total energy calculations on ordered structure models, but the ratio of the occupation of the two possible Sb sites varies from channel to channel. The structure of SbxWO3+y exhibits pronounced local modulations.
Address
Corporate Author Thesis
Publisher Place of Publication München Editor
Language Wos 000307314200003 Publication Date 2012-06-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2194-4946; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.179 Times cited 4 Open Access
Notes Fwo; Esteem 026019 Approved Most recent IF: 3.179; 2012 IF: NA
Call Number UA @ lucian @ c:irua:101218 Serial 1131
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Author van den Broek, W.; Van Aert, S.; van Dyck, D.
Title Fully automated measurement of the modulation transfer function of charge-coupled devices above the Nyquist frequency Type A1 Journal article
Year (up) 2012 Publication Microscopy and microanalysis Abbreviated Journal Microsc Microanal
Volume 18 Issue 2 Pages 336-342
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The charge-coupled devices used in electron microscopy are coated with a scintillating crystal that gives rise to a severe modulation transfer function (MTF). Exact knowledge of the MTF is imperative for a good correspondence between image simulation and experiment. We present a practical method to measure the MTF above the Nyquist frequency from the beam blocker's shadow image. The image processing has been fully automated and the program is made public. The method is successfully tested on three cameras with various beam blocker shapes.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge, Mass. Editor
Language Wos 000302084700011 Publication Date 2012-02-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1431-9276;1435-8115; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.891 Times cited 15 Open Access
Notes Fwo Approved Most recent IF: 1.891; 2012 IF: 2.495
Call Number UA @ lucian @ c:irua:96557 Serial 1297
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Author Schryvers, D.; Van Aert, S.
Title High-resolution visualization techniques : structural aspects Type H1 Book chapter
Year (up) 2012 Publication Abbreviated Journal
Volume Issue Pages 135-149
Keywords H1 Book chapter; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Springer Place of Publication Berlin Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-3-642-20942-0 Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94124 Serial 1464
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Author Van Aert, S.; van den Broek, W.; Goos, P.; van Dyck, D.
Title Model-based electron microscopy : from images toward precise numbers for unknown structure parameters Type A1 Journal article
Year (up) 2012 Publication Micron Abbreviated Journal Micron
Volume 43 Issue 4 Pages 509-515
Keywords A1 Journal article; Engineering Management (ENM); Electron microscopy for materials research (EMAT); Vision lab
Abstract Statistical parameter estimation theory is proposed as a method to quantify electron microscopy images. It aims at obtaining precise and accurate values for the unknown structure parameters including, for example, atomic column positions and types. In this theory, observations are purely considered as data planes, from which structure parameters have to be determined using a parametric model describing the images. The method enables us to measure positions of atomic columns with a precision of the order of a few picometers even though the resolution of the electron microscope is one or two orders of magnitude larger. Moreover, small differences in averaged atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark field scanning transmission electron microscopy images. Finally, it is shown how to optimize the experimental design so as to attain the highest precision. As an example, the optimization of the probe size for nanoparticle radius measurements is considered. It is also shown how to quantitatively balance signal-to-noise ratio and resolution by adjusting the probe size.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000301702400003 Publication Date 2011-11-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0968-4328; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.98 Times cited 7 Open Access
Notes Fwo Approved Most recent IF: 1.98; 2012 IF: 1.876
Call Number UA @ lucian @ c:irua:94114 Serial 2099
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Author Wang, A.; Van Aert, S.; Goos, P.; van Dyck, D.
Title Precision of three-dimensional atomic scale measurements from HRTEM images : what are the limits? Type A1 Journal article
Year (up) 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 114 Issue Pages 20-30
Keywords A1 Journal article; Engineering Management (ENM); Electron microscopy for materials research (EMAT); Vision lab
Abstract In this paper, we investigate to what extent high resolution transmission electron microscopy images can be used to measure the mass, in terms of thickness, and surface profile, corresponding to the defocus offset, of an object at the atomic scale. Therefore, we derive an expression for the statistical precision with which these object parameters can be estimated in a quantitative analysis. Evaluating this expression as a function of the microscope settings allows us to derive the optimal microscope design. Acquiring three-dimensional structure information in terms of thickness turns out to be much more difficult than obtaining two-dimensional information on the projected atom column positions. The attainable precision is found to be more strongly affected by processes influencing the image contrast, such as phonon scattering, than by the specific choice of microscope settings. For a realistic incident electron dose, it is expected that atom columns can be distinguished with single atom sensitivity up to a thickness of the order of the extinction distance. A comparable thickness limit is determined to measure surface steps of one atom. An increase of the electron dose shifts the limiting thickness upward due to an increase in the signal-to-noise ratio.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000301954300003 Publication Date 2012-01-06
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 5 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:94116 Serial 2692
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Author Van Aert, S.
Title Statistical parameter estimation theory : a tool for quantitative electron microscopy Type H1 Book chapter
Year (up) 2012 Publication Abbreviated Journal
Volume Issue Pages 281-309
Keywords H1 Book chapter; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Wiley-VCH Place of Publication Weinheim Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-3-527-31706-6 Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:96693 Serial 3159
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Author Lichte, H.; Dunin-Borkowski, R.; Tillmann, K.; Van Aert, S.; Van Tendeloo, G.
Title 65th birthdays of W. Owen Saxton, David J. Smith and Dirk Van Dyck / PICO 2013 From multislice to big bang Type ME3 Book as editor
Year (up) 2013 Publication Abbreviated Journal
Volume Issue Pages
Keywords ME3 Book as editor; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:109918 Serial 19
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Author Schryvers, D.; Cao, S.; Tirry, W.; Idrissi, H.; Van Aert, S.
Title Advanced three-dimensional electron microscopy techniques in the quest for better structural and functional materials Type A1 Journal article
Year (up) 2013 Publication Science and technology of advanced materials Abbreviated Journal Sci Technol Adv Mat
Volume 14 Issue 1 Pages 014206-14213
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract After a short review of electron tomography techniques for materials science, this overview will cover some recent results on different shape memory and nanostructured metallic systems obtained by various three-dimensional (3D) electron imaging techniques. In binary NiTi, the 3D morphology and distribution of Ni4Ti3 precipitates are investigated by using FIB/SEM slice-and-view yielding 3D data stacks. Different quantification techniques will be presented including the principal ellipsoid for a given precipitate, shape classification following a Zingg scheme, particle distribution function, distance transform and water penetration. The latter is a novel approach to quantifying the expected matrix transformation in between the precipitates. The different samples investigated include a single crystal annealed with and without compression yielding layered and autocatalytic precipitation, respectively, and a polycrystal revealing different densities and sizes of the precipitates resulting in a multistage transformation process. Electron tomography was used to understand the interaction between focused ion beam-induced Frank loops and long dislocation structures in nanobeams of Al exhibiting special mechanical behaviour measured by on-chip deposition. Atomic resolution electron tomography is demonstrated on Ag nanoparticles in an Al matrix.
Address
Corporate Author Thesis
Publisher Place of Publication Sendai Editor
Language Wos 000316463800008 Publication Date 2013-03-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1468-6996;1878-5514; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.798 Times cited 6 Open Access
Notes Fwo; Iap; Esteem Approved Most recent IF: 3.798; 2013 IF: 2.613
Call Number UA @ lucian @ c:irua:107343 Serial 77
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Author Wang, A.; Turner, S.; Van Aert, S.; van Dyck, D.
Title An alternative approach to determine attainable resolution directly from HREM images Type A1 Journal article
Year (up) 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 133 Issue Pages 50-61
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The concept of resolution in high-resolution electron microscopy (HREM) is the power to resolve neighboring atoms. Since the resolution is related to the width of the point spread function of the microscope, it could in principle be determined from the image of a point object. However, in electron microscopy there are no ideal point objects. The smallest object is an individual atom. If the width of an atom is much smaller than the resolution of the microscope, this atom can still be considered as a point object. As the resolution of the microscope enters the sub-Å regime, information about the microscope is strongly entangled with the information about the atoms in HREM images. Therefore, we need to find an alternative method to determine the resolution in an object-independent way. In this work we propose to use the image wave of a crystalline object in zone axis orientation. Under this condition, the atoms of a column act as small lenses so that the electron beam channels through the atom column periodically. Because of this focusing, the image wave of the column can be much more peaked than the constituting atoms and can thus be a much more sensitive probe to measure the resolution. Our approach is to use the peakiness of the image wave of the atom column to determine the resolution. We will show that the resolution can be directly linked to the total curvature of the atom column wave. Moreover, we can then directly obtain the resolution of the microscope given that the contribution from the object is known, which is related to the bounding energy of the atom. The method is applied on an experimental CaTiO3 image wave.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000324471800007 Publication Date 2013-05-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record
Impact Factor 2.843 Times cited Open Access
Notes FWO; Hercules; Esteem2; esteem2_jra2 Approved Most recent IF: 2.843; 2013 IF: 2.745
Call Number UA @ lucian @ c:irua:109919 Serial 90
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