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| Author | Heidari, H.; van den Broek, W.; Bals, S. | ||||
| Title | Quantitative electron tomography : the effect of the three-dimensional point spread function | Type | A1 Journal article | ||
| Year | 2013 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
| Volume | 135 | Issue | Pages | 1-5 | |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The intensity levels in a three-dimensional (3D) reconstruction, obtained by electron tomography, can be influenced by several experimental imperfections. Such artifacts will hamper a quantitative interpretation of the results. In this paper, we will correct for artificial intensity variations by determining the 3D point spread function (PSF) of a tomographic reconstruction based on high angle annular dark field scanning transmission electron microscopy. The large tails of the PSF cause an underestimation of the intensity of smaller particles, which in turn hampers an accurate radius estimate. Here, the error introduced by the PSF is quantified and corrected a posteriori. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Amsterdam | Editor | ||
| Language | Wos | 000326941500001 | Publication Date | 2013-06-21 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.843 | Times cited | 6 | Open Access | |
| Notes | Esteem2; Sunflower; esteem2_jra4 | Approved | Most recent IF: 2.843; 2013 IF: 2.745 | ||
| Call Number | UA @ lucian @ c:irua:111397 | Serial | 2756 | ||
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| Author | Van Boxem, R.; Verbeeck, J.; Partoens, B. | ||||
| Title | Spin effects in electron vortex states | Type | A1 Journal article | ||
| Year | 2013 | Publication | Europhysics letters | Abbreviated Journal | Epl-Europhys Lett |
| Volume | 102 | Issue | 4 | Pages | 40010-40016 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
| Abstract | The recent experimental realization of electron vortex beams opens up a wide research domain previously unexplored. The present paper explores the relativistic properties of these electron vortex beams, and quantifies deviations from the scalar wave theory. It is common in electron optics to use the Schrodinger equation neglecting spin. The present paper investigates the role of spin and the total angular momentum J(z) and how it pertains to the vortex states. As an application, we also investigate if it is possible to use holographic reconstruction to create novel total angular momentum eigenstates in a transmission electron microscope. It is demonstrated that relativistic spin coupling effects disappear in the paraxial limit, and spin effects in holographically created electron vortex beams can only be exploited by using specialized magnetic apertures. | ||||
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| Publisher | Place of Publication | Paris | Editor | ||
| Language | Wos | 000321118600011 | Publication Date | 2013-06-11 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0295-5075;1286-4854; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 1.957 | Times cited | 11 | Open Access | |
| Notes | 312483 Esteem2; N246791 Countatoms; 278510 Vortex; esteem2jra1; esteem2jra3 ECASJO_; | Approved | Most recent IF: 1.957; 2013 IF: 2.269 | ||
| Call Number | UA @ lucian @ c:irua:109852 | Serial | 3087 | ||
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| Author | Lichtert, S.; Verbeeck, J. | ||||
| Title | Statistical consequences of applying a PCA noise filter on EELS spectrum images | Type | A1 Journal article | ||
| Year | 2013 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
| Volume | 125 | Issue | Pages | 35-42 | |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Principal component analysis (PCA) noise filtering is a popular method to remove noise from experimental electron energy loss (EELS) spectrum images. Here, we investigate the statistical behaviour of this method by applying it on a simulated data set with realistic noise levels. This phantom data set provides access to the true values contained in the data set as well as to many different realizations of the noise. Using least squares fitting and parameter estimation theory, we demonstrate that even though the precision on the estimated parameters can be better as the CramérRao lower bound, a significant bias is introduced which can alter the conclusions drawn from experimental data sets. The origin of this bias is in the incorrect retrieval of the principal loadings for noisy data. Using an expression for the bias and precision of the singular values from literature, we present an evaluation criterion for these singular values based on the noise level and the amount of information present in the data set. This criterion can help to judge when to avoid PCA noise filtering in practical situations. Further we show that constructing elemental maps of PCA noise filtered data using the background subtraction method, does not guarantee an increase in the signal to noise ratio due to correlation of the spectral data as a result of the filtering process. | ||||
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| Publisher | Place of Publication | Amsterdam | Editor | ||
| Language | Wos | 000314679700006 | Publication Date | 2012-10-27 | |
| 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 | 54 | Open Access | |
| Notes | Fwo; Countatoms; Vortex; Esteem 312483; esteem2jra3 ECASJO; | Approved | Most recent IF: 2.843; 2013 IF: 2.745 | ||
| Call Number | UA @ lucian @ c:irua:105293 | Serial | 3153 | ||
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| Author | Goris, B.; de Backer, A.; Van Aert, S.; Gómez-Graña, S.; Liz-Marzán, L.M.; Van Tendeloo, G.; Bals, S. | ||||
| Title | Three-dimensional elemental mapping at the atomic scale in bimetallic nanocrystals | Type | A1 Journal article | ||
| Year | 2013 | Publication | Nano letters | Abbreviated Journal | Nano Lett |
| Volume | 13 | Issue | 9 | Pages | 4236-4241 |
| Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
| Abstract | A thorough understanding of the three-dimensional (3D) atomic structure and composition of coreshell nanostructures is indispensable to obtain a deeper insight on their physical behavior. Such 3D information can be reconstructed from two-dimensional (2D) projection images using electron tomography. Recently, different electron tomography techniques have enabled the 3D characterization of a variety of nanostructures down to the atomic level. However, these methods have all focused on the investigation of nanomaterials containing only one type of chemical element. Here, we combine statistical parameter estimation theory with compressive sensing based tomography to determine the positions and atom type of each atom in heteronanostructures. The approach is applied here to investigate the interface in coreshell Au@Ag nanorods but it is of great interest in the investigation of a broad range of nanostructures. | ||||
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| Publisher | Place of Publication | Washington | Editor | ||
| Language | Wos | 000330158900043 | Publication Date | 2013-08-16 | |
| 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 | 90 | Open Access | |
| Notes | FWO; 246791 COUNTATOMS; 267867 PLASMAQUO; 262348 ESMI; 312483 ESTEEM2; Hercules 3; esteem2_jra4 | Approved | Most recent IF: 12.712; 2013 IF: 12.940 | ||
| Call Number | UA @ lucian @ c:irua:110036 | Serial | 3650 | ||
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| Author | Lubk, A.; Clark, L.; Guzzinati, G.; Verbeeck, J. | ||||
| Title | Topological analysis of paraxially scattered electron vortex beams | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review : A : atomic, molecular and optical physics | Abbreviated Journal | Phys Rev A |
| Volume | 87 | Issue | 3 | Pages | 033834-33838 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | We investigate topological aspects of subnanometer electron vortex beams upon elastic propagation through atomic scattering potentials. Two main aspects can be distinguished: (i) significantly reduced delocalization compared to a similar nonvortex beam if the beam centers on an atomic column and (ii) site symmetry dependent splitting of higher-order vortex beams. Furthermore, the results provide insight into the complex vortex line fabric within the elastically scattered wave containing characteristic vortex loops predominantly attached to atomic columns and characteristic twists of vortex lines around atomic columns. DOI: 10.1103/PhysRevA.87.033834 | ||||
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| Publisher | American Physical Society | Place of Publication | New York, N.Y | Editor | |
| Language | Wos | 000316790600011 | Publication Date | 2013-03-27 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1050-2947;1094-1622; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 2.925 | Times cited | 26 | Open Access | |
| Notes | Countatoms; Vortex; Esteem2; esteem2jra3 ECASJO; | Approved | Most recent IF: 2.925; 2013 IF: 2.991 | ||
| Call Number | UA @ lucian @ c:irua:108496 | Serial | 3673 | ||
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| Author | Lubk, A.; Guzzinati, G.; Börrnert, F.; Verbeeck, J. | ||||
| Title | Transport of intensity phase retrieval of arbitrary wave fields including vortices | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review letters | Abbreviated Journal | Phys Rev Lett |
| Volume | 111 | Issue | 17 | Pages | 173902-173905 |
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | The phase problem can be considered as one of the cornerstones of quantum mechanics intimately connected to the detection process and the uncertainty relation. The latter impose fundamental limits on the manifold phase reconstruction schemes invented to date, in particular, at small magnitudes of the quantum wave. Here, we show that a rigorous solution of the transport of intensity reconstruction (TIE) scheme in terms of a linear elliptic partial differential equation for the phase provides reconstructions even in the presence of wave zeros if particular boundary conditions are given. We furthermore discuss how partial coherence hampers phase reconstruction and show that a modified version of the TIE reconstructs the curl-free current density at arbitrary (in)coherence. Our results open the way for TIE-based phase retrieval of arbitrary wave fields, eventually containing zeros such as phase vortices. | ||||
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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | New York, N.Y. | Editor | ||
| Language | Wos | 000326148400006 | Publication Date | 2013-10-24 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0031-9007;1079-7114; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 8.462 | Times cited | 40 | Open Access | |
| Notes | Esteem2; Vortex; esteem2ta ECASJO; | Approved | Most recent IF: 8.462; 2013 IF: 7.728 | ||
| Call Number | UA @ lucian @ c:irua:111093 | Serial | 3726 | ||
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| Author | Zhang, L.-F.; Covaci, L.; Milošević, M.V.; Berdiyorov, G.R.; Peeters, F.M. | ||||
| Title | Vortex states in nanoscale superconducting squares : the influence of quantum confinement | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
| Volume | 88 | Issue | 14 | Pages | 144501 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | Bogoliubov-de Gennes theory is used to investigate the effect of the size of a superconducting square on the vortex states in the quantum confinement regime. When the superconducting coherence length is comparable to the Fermi wavelength, the shape resonances of the superconducting order parameter have strong influence on the vortex configuration. Several unconventional vortex states, including asymmetric ones, giant-multivortex combinations, and states comprising giant antivortices, were found as ground states and their stability was found to be very sensitive on the value of k(F)xi(0), the size of the sample W, and the magnetic flux Phi. By increasing the temperature and/or enlarging the size of the sample, quantum confinement is suppressed and the conventional mesoscopic vortex states as predicted by the Ginzburg-Laudau (GL) theory are recovered. However, contrary to the GL results we found that the states containing symmetry-induced vortex-antivortex pairs are stable over the whole temperature range. It turns out that the inhomogeneous order parameter induced by quantum confinement favors vortex-antivortex molecules, as well as giant vortices with a rich structure in the vortex core-unattainable in the GL domain. | ||||
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| Language | Wos | 000325498300004 | Publication Date | 2013-10-09 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121;1550-235X; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 19 | Open Access | |
| Notes | ; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and Methusalem Funding of the Flemish government. ; | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
| Call Number | UA @ lucian @ c:irua:111145 | Serial | 3891 | ||
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| Author | Krstajić, P.M.; Van Duppen, B.; Peeters, F.M. | ||||
| Title | Plasmons and their interaction with electrons in trilayer graphene | Type | A1 Journal article | ||
| Year | 2013 | Publication | Physical review : B : condensed matter and materials physics | Abbreviated Journal | Phys Rev B |
| Volume | 88 | Issue | 19 | Pages | 195423 |
| Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
| Abstract | The interaction between electrons and plasmons in trilayer graphene is investigated within the Overhauser approach resulting in the “plasmaron” quasiparticle. This interaction is cast into a field theoretical problem, and its effect on the energy spectrum is calculated using improved Wigner-Brillouin perturbation theory. The plasmaron spectrum is shifted with respect to the bare electron spectrum by ΔE(k)∼150−200meV for ABC stacked trilayer graphene and for ABA trilayer graphene by ΔE(k)∼30−150 meV[ ΔE(k) ∼1 −5meV] for the hyperbolic (linear) part of the spectrum. The shift in general increases with the electron concentration and electron momentum. The dispersion of plasmarons is more pronounced in ABC stacked than in ABA stacked trilayer graphene, because of the different energy band structure and their different plasmon dispersion. | ||||
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| Language | Wos | 000327239200003 | Publication Date | 2013-11-21 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1098-0121 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.836 | Times cited | 10 | Open Access | |
| Notes | ; This work was supported by the Flemish Science Foundation (FWO-Vl), by the ESF-EuroGRAPHENE project CON-GRAN, and by the Serbian Ministry of Education and Science, within the Project No. TR 32008. ; | Approved | Most recent IF: 3.836; 2013 IF: 3.664 | ||
| Call Number | CMT @ cmt @ c:irua:112702 | Serial | 4489 | ||
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| Author | Shuhui Sun, Gaixia Zhang, Nicolas Gauquelin, Ning Chen, Jigang Zhou, Songlan Yang, Weifeng Chen, Xiangbo Meng, Dongsheng Geng, Mohammad N. Banis, Ruying Li, Siyu Ye, Shanna Knights, Gianluigi A. Botton, Tsun-Kong Sham & Xueliang Sun | ||||
| Title | Single-atom Catalysis Using Pt/Graphene Achieved through Atomic Layer Deposition | Type | A1 Journal Article | ||
| Year | 2013 | Publication | Scientific Reports | Abbreviated Journal | |
| Volume | 3 | Issue | Pages | 1775 | |
| Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
| Abstract | Platinum-nanoparticle-based catalysts are widely used in many important chemical processes and automobile industries. Downsizing catalyst nanoparticles to single atoms is highly desirable to maximize their use efficiency, however, very challenging. Here we report a practical synthesis for isolated single Pt atoms anchored to graphene nanosheet using the atomic layer deposition (ALD) technique. ALD offers the capability of precise control of catalyst size span from single atom, subnanometer cluster to nanoparticle. The single-atom catalysts exhibit significantly improved catalytic activity (up to 10 times) over that of the state-of-the-art commercial Pt/C catalyst. X-ray absorption fine structure (XAFS) analyses reveal that the low-coordination and partially unoccupied densities of states of 5d orbital of Pt atoms are responsible for the excellent performance. This work is anticipated to form the basis for the exploration of a next generation of highly efficient single-atom catalysts for various applications. |
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| Language | Wos | 000318334300004 | Publication Date | 2013-05-03 | |
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| Impact Factor | Times cited | 345 | Open Access | ||
| Notes | Approved | Most recent IF: NA | |||
| Call Number | EMAT @ emat @ | Serial | 4543 | ||
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| Author | H. Zhang, N. Gauquelin, G.A. Botton and J.Y.T. Wei | ||||
| Title | Attenuation of superconductivity in manganite/cuprate heterostructures by epitaxially induced CuO intergrowths | Type | A1 Journal Article | ||
| Year | 2013 | Publication | Applied Physics Letters | Abbreviated Journal | |
| Volume | 103 | Issue | Pages | 052606 | |
| Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
| Abstract | We examine the effect of CuO intergrowths on the superconductivity in epitaxial La 2/3 Ca 1/3 MnO 3 / YBa 2 Cu 3 O 7−δ La2/3Ca1/3MnO3/YBa2Cu3O7−δ (LCMO/YBCO) thin-film heterostructures. Scanning transmission electron microscopy on bilayer LCMO/YBCO thin films revealed double CuO-chain intergrowths which form regions with the 247 lattice structure in the YBCO layer. These nanoscale 247 regions do not appear in x-ray diffraction, but can physically account for the reduced critical temperature (Tc) of bilayer thin films relative to unilayer films with the same YBCO thickness, at least down to ∼25 nm. We attribute the CuO intergrowths to the bilayer heteroepitaxial mismatch and the Tc reduction to the generally lower Tc seen in bulk 247 samples. These epitaxially-induced CuO intergrowths provide a microstructural mechanism for the attenuation of superconductivity in LCMO/YBCO heterostructures. |
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| Language | Wos | 000322723000063 | Publication Date | 2013-08-02 | |
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| Impact Factor | Times cited | 12 | Open Access | ||
| Notes | Approved | Most recent IF: NA | |||
| Call Number | EMAT @ emat @ | Serial | 4546 | ||
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| Author | L. Zhang, J. Kim, J. Zhang, F. Nan, N. Gauquelin, G.A. Botton, P. He, R. Bashyam, S. Knights | ||||
| Title | Ti4O7 supported Ru@Pt core–shell catalyst for CO-tolerance in PEM fuel cell hydrogen oxidation reaction | Type | A1 Journal Article | ||
| Year | 2013 | Publication | Applied Energy | Abbreviated Journal | |
| Volume | 103 | Issue | March 2013 | Pages | 507-513 |
| Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
| Abstract | A new method is developed for synthesizing Ti4O7 supported Ru@Pt core–shell catalyst (Ru@Pt/Ti4O7) through pyrolysis followed by microwave irradiation. The purpose is to improve the Ru durability of PtRu from core–shell structure and strong bonding to Ti4O7 oxide. In this method, the first step is to co-reduce the mixture of ruthenium precursor and TiO2 in a H2 reducing atmosphere under heat-treatment to obtain a Ru core on Ti4O7 support, and the second step is to create a shell of platinum via microwave irradiation. Energy dispersive X-ray spectrometry, X-ray Diffraction, High-resolution Scanning Transmission Electron Microscopy with the high-angle annular dark-field method and Electron Energy-Loss Spectroscopy are used to demonstrate that this catalyst with larger particles has a core–shell structure with a Ru core and a Pt shell. Electrochemical measurements show Ru@Pt/Ti4O7 catalyst has a higher CO-tolerance capability than that of PtRu/C alloy catalyst. | ||||
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| Language | Wos | 000314669500048 | Publication Date | 2012-11-11 | |
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| Impact Factor | Times cited | 33 | Open Access | ||
| Notes | Approved | Most recent IF: NA | |||
| Call Number | EMAT @ emat @ | Serial | 4547 | ||
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