| Records |
| Author |
Mehta, A.N.; Gauquelin, N.; Nord, M.; Orekhov, A.; Bender, H.; Cerbu, D.; Verbeeck, J.; Vandervorst, W. |
| Title |
Unravelling stacking order in epitaxial bilayer MX₂ using 4D-STEM with unsupervised learning |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
| Volume |
31 |
Issue |
44 |
Pages |
445702 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Following an extensive investigation of various monolayer transition metal dichalcogenides (MX2), research interest has expanded to include multilayer systems. In bilayer MX2, the stacking order strongly impacts the local band structure as it dictates the local confinement and symmetry. Determination of stacking order in multilayer MX(2)domains usually relies on prior knowledge of in-plane orientations of constituent layers. This is only feasible in case of growth resulting in well-defined triangular domains and not useful in-case of closed layers with hexagonal or irregularly shaped islands. Stacking order can be discerned in the reciprocal space by measuring changes in diffraction peak intensities. Advances in detector technology allow fast acquisition of high-quality four-dimensional datasets which can later be processed to extract useful information such as thickness, orientation, twist and strain. Here, we use 4D scanning transmission electron microscopy combined with multislice diffraction simulations to unravel stacking order in epitaxially grown bilayer MoS2. Machine learning based data segmentation is employed to obtain useful statistics on grain orientation of monolayer and stacking in bilayer MoS2. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000561424400001 |
Publication Date |
2020-07-14 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0957-4484 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor  |
3.5 |
Times cited |
13 |
Open Access |
OpenAccess |
| Notes |
; J.V. acknowledges funding from FLAG-ERA JTC2017 project 'Graph-Eye'. N.G. acknowledges funding from GOA project 'Solarpaint' of the University of Antwerp. This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 823717-ESTEEM3. 4D STEM data was acquired on a hybrid pixel detector funded with a Hercules fund 'Direct electron detector for soft matter TEM' from the Flemish Government. M. N. acknowledges funding from a Marie Curie Fellowship agreement No 838001. We thank Dr Jiongjiong Mo and Dr Benjamin Groven for developing the CVD-MoS<INF>2</INF> growth on sapphire and providing the material used in this article. ; |
Approved |
Most recent IF: 3.5; 2020 IF: 3.44 |
| Call Number |
UA @ admin @ c:irua:171119 |
Serial |
6649 |
| Permanent link to this record |
| |
|
| |
| Author |
Woo, S.Y.; Gauquelin, N.; Nguyen, H.P.T.; Mi, Z.; Botton, G.A. |
| Title |
Interplay of strain and indium incorporation in InGaN/GaN dot-in-a-wire nanostructures by scanning transmission electron microscopy |
Type |
A1 Journal article |
| Year |
2015 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
| Volume |
26 |
Issue |
26 |
Pages |
344002 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
The interplay between strain and composition is at the basis of heterostructure design to engineer new properties. The influence of the strain distribution on the incorporation of indium during the formation of multiple InGaN/GaN quantum dots (QDs) in nanowire (NW) heterostructures has been investigated, using the combined techniques of geometric phase analysis of atomic-resolution images and quantitative elemental mapping from core-loss electron energy-loss spectroscopy within scanning transmission electron microscopy. The variation in In-content between successive QDs within individual NWs shows a dependence on the magnitude of compressive strain along the growth direction within the underlying GaN barrier layer, which affects the incorporation of In-atoms to minimize the local effective strain energy. Observations suggest that the interfacial misfit between InGaN/GaN within the embedded QDs is mitigated by strain partitioning into both materials, and results in normal stresses inflicted by the presence of the surrounding GaN shell. These experimental measurements are linked to the local piezoelectric polarization fields for individual QDs, and are discussed in terms of the photoluminescence from an ensemble of NWs. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Bristol |
Editor |
|
| Language |
|
Wos |
000359079500003 |
Publication Date |
2015-08-03 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0957-4484 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.44 |
Times cited |
19 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 3.44; 2015 IF: 3.821 |
| Call Number |
UA @ lucian @ c:irua:136278 |
Serial |
4504 |
| Permanent link to this record |
| |
|
| |
| Author |
Chen, B.; Gauquelin, N.; Reith, P.; Halisdemir, U.; Jannis, D.; Spreitzer, M.; Huijben, M.; Abel, S.; Fompeyrine, J.; Verbeeck, J.; Hilgenkamp, H.; Rijnders, G.; Koster, G. |
| Title |
Thermal-strain-engineered ferromagnetism of LaMnO3/SrTiO3 heterostructures grown on silicon |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
Phys. Rev. Materials |
| Volume |
4 |
Issue |
2 |
Pages |
024406 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The integration of oxides on Si remains challenging, which largely hampers the practical applications of oxide-based electronic devices with superior performance. Recently, LaMnO3/SrTiO3 (LMO/STO) heterostructures have gained renewed interest for the debating origin of the ferromagnetic-insulating ground state as well as for their spin-filter applications. Here we report on the structural and magnetic properties of high-quality LMO/STO heterostructures grown on silicon. The chemical abruptness across the interface was investigated by atomic-resolution scanning transmission electron microscopy. The difference in the thermal expansion coefficients between LMO and Si imposed a large biaxial tensile strain to the LMO film, resulting in a tetragonal structure with c/a∼ 0.983. Consequently, we observed a significantly suppressed ferromagnetism along with an enhanced coercive field, as compared to the less distorted LMO film (c/a∼1.004) grown on STO single crystal. The results are discussed in terms of tensile-strain enhanced antiferromagnetic instabilities. Moreover, the ferromagnetism of LMO on Si sharply disappeared below a thickness of 5 unit cells, in agreement with the LMO/STO case, pointing to a robust critical behavior irrespective of the strain state. Our results demonstrate that the growth of oxide films on Si can be a promising way to study the tensile-strain effects in correlated oxides, and also pave the way towards the integration of multifunctional oxides on Si with atomic-layer control. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000513552900003 |
Publication Date |
2020-02-12 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.4 |
Times cited |
6 |
Open Access |
Not_Open_Access |
| Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Universiteit Antwerpen; Vlaamse regering; Fonds Wetenschappelijk Onderzoek, G093417N ; Javna Agencija za Raziskovalno Dejavnost RS, J2-9237 P2-0091 ; European Commission, H2020-ICT-2016-1-732642 ; |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
| Call Number |
EMAT @ emat @c:irua:167782 |
Serial |
6375 |
| Permanent link to this record |
| |
|
| |
| Author |
Araizi-Kanoutas, G.; Geessinck, J.; Gauquelin, N.; Smit, S.; Verbeek, X.H.; Mishra, S.K.; Bencok, P.; Schlueter, C.; Lee, T.-L.; Krishnan, D.; Fatermans, J.; Verbeeck, J.; Rijnders, G.; Koster, G.; Golden, M.S. |
| Title |
Co valence transformation in isopolar LaCoO3/LaTiO3 perovskite heterostructures via interfacial engineering |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
Phys. Rev. Materials |
| Volume |
4 |
Issue |
2 |
Pages |
026001 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We report charge transfer up to a single electron per interfacial unit cell across nonpolar heterointerfaces from the Mott insulator LaTiO3 to the charge transfer insulator LaCoO3. In high-quality bi- and trilayer systems grown using pulsed laser deposition, soft x-ray absorption, dichroism, and scanning transmission electron microscopy-electron energy loss spectroscopy are used to probe the cobalt-3d electron count and provide an element-specific investigation of the magnetic properties. The experiments show the cobalt valence conversion is active within 3 unit cells of the heterointerface, and able to generate full conversion to 3d7 divalent Co, which displays a paramagnetic ground state. The number of LaTiO3/LaCoO3 interfaces, the thickness of an additional, electronically insulating “break” layer between the LaTiO3 and LaCoO3, and the LaCoO3 film thickness itself in trilayers provide a trio of control knobs for average charge of the cobalt ions in LaCoO3, illustrating the efficacy of O−2p band alignment as a guiding principle for property design in complex oxide heterointerfaces. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000513551200007 |
Publication Date |
2020-02-10 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.4 |
Times cited |
13 |
Open Access |
OpenAccess |
| Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Universiteit Antwerpen; Horizon 2020, 730872 ; Department of Science and Technology, Ministry of Science and Technology, SR/NM/Z-07/2015 ; Jawaharlal Nehru Centre for Advanced Scientific Research; |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
| Call Number |
EMAT @ emat @c:irua:167787 |
Serial |
6376 |
| Permanent link to this record |
| |
|
| |
| Author |
Lin, S.-C.; Kuo, C.-T.; Shao, Y.-C.; Chuang, Y.-D.; Geessinck, J.; Huijben, M.; Rueff, J.-P.; Graff, I.L.; Conti, G.; Peng, Y.; Bostwick, A.; Gullikson, E.; Nemsak, S.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Ghiringhelli, G.; Schneider, C.M.; Fadley, C.S. |
| Title |
Two-dimensional electron systems in perovskite oxide heterostructures : role of the polarity-induced substitutional defects |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physical review materials |
Abbreviated Journal |
|
| Volume |
4 |
Issue |
11 |
Pages |
115002 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The discovery of a two-dimensional electron system (2DES) at the interfaces of perovskite oxides such as LaAlO3 and SrTiO3 has motivated enormous efforts in engineering interfacial functionalities with this type of oxide heterostructures. However, the fundamental origins of the 2DES are still not understood, e.g., the microscopic mechanisms of coexisting interface conductivity and magnetism. Here we report a comprehensive spectroscopic investigation on the depth profile of 2DES-relevant Ti 3d interface carriers using depthand element-specific techniques like standing-wave excited photoemission and resonant inelastic scattering. We found that one type of Ti 3d interface carriers, which give rise to the 2DES are located within three unit cells from the n-type interface in the SrTiO3 layer. Unexpectedly, another type of interface carriers, which are polarity-induced Ti-on-Al antisite defects, reside in the first three unit cells of the opposing LaAlO3 layer (similar to 10 angstrom). Our findings provide a microscopic picture of how the localized and mobile Ti 3d interface carriers distribute across the interface and suggest that the 2DES and 2D magnetism at the LaAlO3/SrTiO3 interface have disparate explanations as originating from different types of interface carriers. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000592432200004 |
Publication Date |
2020-11-20 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.4 |
Times cited |
7 |
Open Access |
OpenAccess |
| Notes |
; We thank G. M. De Luca and L. Braicovich for discussions. Charles S. Fadley was deceased on August 1, 2019. We are grateful for his significant contributions to this work. We thank Advanced Light Source for the access to Beamline 8.0.3 (qRIXS) via Proposal No. 09892 and beamline 7.0.2 (MAESTRO) via Proposal No. RA-00291 that contributed to the results presented here. We thank synchrotron SOLEIL (via Proposal No. 99180118) for the access to Beamline GALAXIES. This work was supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231 (Advanced Light Source), and by DOE Contract No. DE-SC0014697 through the University of California, Davis (S.-C.L., C.-T.K, and C.S.F.), and from the Julich Research Center, Peter Grunberg Institute, PGI-6. I. L. G. wishes to thank Brazilian scientific agencies CNPQ (Project No. 200789/2017-1) and CAPES (CAPES-PrInt-UFPR) for their financial support. J.V. and N.G. acknowledge funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and the European Union's horizon 2020 research and innovation program ES-TEEM3 under grant agreement no 823717. The Qu-Ant-EM microscope used in this study was partly funded by the Hercules fund from the Flemish Government. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
| Call Number |
UA @ admin @ c:irua:174316 |
Serial |
6713 |
| Permanent link to this record |
| |
|
| |
| Author |
Monico, L.; Rosi, F.; Vivani, R.; Cartechini, L.; Janssens, K.; Gauquelin, N.; Chezganov, D.; Verbeeck, J.; Cotte, M.; D'Acapito, F.; Barni, L.; Grazia, C.; Buemi, L.P.; Andral, J.-L.; Miliani, C.; Romani, A. |
| Title |
Deeper insights into the photoluminescence properties and (photo)chemical reactivity of cadmium red (CdS1-xSex) paints in renowned twentieth century paintings by state-of-the-art investigations at multiple length scales |
Type |
A1 Journal article |
| Year |
2022 |
Publication |
The European Physical Journal Plus |
Abbreviated Journal |
Eur Phys J Plus |
| Volume |
137 |
Issue |
3 |
Pages |
311 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Antwerp X-ray Imaging and Spectroscopy (AXIS) |
| Abstract |
Cadmium red is the name used for denoting a class of twentieth century artists' pigments described by the general formula CdS1-xSex. For their vibrant hues and excellent covering power, a number of renowned modern and contemporary painters, including Jackson Pollock, often used cadmium reds. As direct band gap semiconductors, CdS1-xSex compounds undergo direct radiative recombination (with emissions from the green to orange region) and radiative deactivation from intragap trapping states due to crystal defects, which give rise to two peculiar red-NIR emissions, known as deep level emissions (DLEs). The positions of the DLEs mainly depend on the Se content of CdS1-xSex; thus, photoluminescence and diffuse reflectance vis-NIR spectroscopy have been profitably used for the non-invasive identification of different cadmium red varieties in artworks over the last decade. Systematic knowledge is however currently lacking on what are the parameters related to intrinsic crystal defects of CdS1-xSex and environmental factors influencing the spectral properties of DLEs as well as on the overall (photo)chemical reactivity of cadmium reds in paint matrixes. Here, we present the application of a novel multi-length scale and multi-method approach to deepen insights into the photoluminescence properties and (photo)chemical reactivity of cadmium reds in oil paintings by combining both well established and new non-invasive/non-destructive analytical techniques, including macro-scale vis-NIR and vibrational spectroscopies and micro-/nano-scale advanced electron microscopy mapping and X-ray methods employing synchrotron radiation and conventional sources. Macro-scale vis-NIR spectroscopy data obtained from the in situ non-invasive analysis of nine masterpieces by Gerardo Dottori, Jackson Pollock and Nicolas de Stael allowed classifying the CdS1-xSex-paints in three groups, according to the relative intensity of the two DLE bands. These outcomes, combined with results from micro-/nano-scale electron microscopy mapping and X-ray analysis of a set of CdS1-xSex powders and artificially aged paint mock-ups, indicated that the relative intensity of DLEs is not affected by the morphology, microstructure and local atomic environment of the pigment particles but it is influenced by the presence of moisture. Furthermore, the extensive study of artificially aged oil paint mock-ups permitted us to provide first evidence of the tendency of cadmium reds toward photo-degradation and to establish that the conversion of CdS1-xSex to CdSO4 and/or oxalates is triggered by the oil binding medium and moisture level and depends on the Se content. Based on these findings, we could interpret the localized presence of CdSO4 and cadmium oxalate as alteration products of the original cadmium red paints in two paintings by Pollock. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000765807600002 |
Publication Date |
0000-00-00 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2190-5444 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.4 |
Times cited |
3 |
Open Access |
OpenAccess |
| Notes |
g The research was financially supported by the EU FP7 and Horizon 2020 Projects CHARISMA (FP7-INFRASTRUCTURES, GA No. 228330), IPERION-CH (H2020-INFRAIA-2014-2015, GA No. 654028), IPERION-HS (H2020-INFRAIA-2019-1, GA No. 871034) and ESTEEM3 (Research and innovation programme, GA No. 823717) and the Italian project AMIS (Dipartimenti di Eccellenza 2018–2022, funded by MIUR and Perugia University). For the beamtime grants received, we thank ESRF-ID21 (Experiment No. HG156 and in-house beamtimes) and the CERIC-ERIC Research Infrastructure for the investigations at ESRF-BM08 (LISA) beamline (Proposal Id: 20207042). D.C. acknowledges TOP/BOF funding of the University of Antwerp.; esteem3reported; esteem3TA |
Approved |
Most recent IF: 3.4 |
| Call Number |
UA @ admin @ c:irua:187375 |
Serial |
7060 |
| Permanent link to this record |
| |
|
| |
| Author |
Lebedev, N.; Huang, Y.; Rana, A.; Jannis, D.; Gauquelin, N.; Verbeeck, J.; Aarts, J. |
| Title |
Resistance minimum in LaAlO3/Eu1-xLaxTiO3/SrTiO3 heterostructures |
Type |
A1 Journal article |
| Year |
2022 |
Publication |
Physical review materials |
Abbreviated Journal |
|
| Volume |
6 |
Issue |
7 |
Pages |
075003-75010 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
In this paper we study LaAlO3/Eu1-xLaxTiO3/SrTiO3 structures with nominally x = 0, 0.1 and different thicknesses of the Eu1-xLaxTiO3 layer. We observe that both systems have many properties similar to previously studied LaAlO3/EuTiO3/SrTiO3 and other oxide interfaces, such as the formation of a two-dimensional electron liquid for two unit cells of Eu1-xLaxTiO3; a metal-insulator transition driven by the increase in thickness of the Eu1-xLaxTiO3 layer; the presence of an anomalous Hall effect when driving the systems above the Lifshitz point with a back-gate voltage; and a minimum in the temperature dependence of the sheet resistance below the Lifshitz point in the one-band regime, which becomes more pronounced with increasing negative gate voltage. However, and notwithstanding the likely presence of magnetism in the system, we do not attribute that minimum to the Kondo effect, but rather to the properties of the SrTiO3 crystal and the inevitable effects of charge trapping when using back gates. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000834035300001 |
Publication Date |
2022-07-12 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
3.4 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
N.L. and J.A. gratefully acknowledge the financial support of the research program DESCO, which is financed by the Netherlands Organisation for Scientific Research (NWO). J.V. and N.G. acknowledge funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and the European Union’s horizon 2020 research and innovation programme under grant agreement №823717 – ESTEEM3. The QuAnt-EM microscope used in this study was partly funded by the Hercules fund from the Flemish Government. The authors want to thank M. Stehno, G. Koster, and F.J.G. Roesthuis for useful discussions.; esteem3reported; esteem3TA |
Approved |
Most recent IF: 3.4 |
| Call Number |
UA @ admin @ c:irua:189674 |
Serial |
7094 |
| Permanent link to this record |
| |
|
| |
| Author |
Samal, D.; Gauquelin, N.; Takamura, Y.; Lobato, I.; Arenholz, E.; Van Aert, S.; Huijben, M.; Zhong, Z.; Verbeeck, J.; Van Tendeloo, G.; Koster, G. |
| Title |
Unusual structural rearrangement and superconductivity in infinite layer cuprate superlattices |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Physical review materials |
Abbreviated Journal |
|
| Volume |
7 |
Issue |
5 |
Pages |
054803 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
001041792100007 |
Publication Date |
2023-05-30 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
3.4 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
Air Force Office of Scientific Research; European Office of Aerospace Research and Development, FA8655-10-1-3077 ; Office of Science, DE-AC02-05CH11231 ; National Science Foundation, DMR-1745450 ; Seventh Framework Programme, 278510 ; Bijzonder Onderzoeksfonds UGent; |
Approved |
Most recent IF: 3.4; 2023 IF: NA |
| Call Number |
EMAT @ emat @c:irua:196973 |
Serial |
8790 |
| Permanent link to this record |
| |
|
| |
| Author |
Akamine, H.; Van den Bos, K.H.W.; Gauquelin, N.; Farjami, S.; Van Aert, S.; Schryvers, D.; Nishida, M. |
| Title |
Determination of the atomic width of an APB in ordered CoPt using quantified HAADF-STEM |
Type |
A1 Journal article |
| Year |
2015 |
Publication |
Journal of alloys and compounds |
Abbreviated Journal |
J Alloy Compd |
| Volume |
644 |
Issue |
644 |
Pages |
570-574 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Anti-phase boundaries (APBs) in an ordered CoPt alloy are planar defects which disturb the ordered structure in their vicinity and decrease the magnetic properties. However, it has not yet been clarified to what extend the APBs disturb the ordering. In this study, high-resolution HAADF-STEM images are statistically analysed based on the image intensities estimated by the statistical parameter estimation theory. In the procedure, averaging intensities, fitting the intensity profiles to specific functions, and assessment based on a statistical test are performed. As a result, the APBs in the stable CoPt are found to be characterised by two atomic planes, and a contrast transition range as well as the centre of an inclined APB is determined. These results show that the APBs are quite sharp and therefore may have no notable effect on the net magnetic properties due to their small volume fraction. (C) 2015 Elsevier B.V. All rights reserved. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000357143900083 |
Publication Date |
2015-05-07 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0925-8388; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.133 |
Times cited |
12 |
Open Access |
|
| Notes |
FWO G036815N; G036915N; G037413N; 278510 VORTEX; Hercules; ECASJO_; |
Approved |
Most recent IF: 3.133; 2015 IF: 2.999 |
| Call Number |
c:irua:127008 c:irua:127008 |
Serial |
675 |
| Permanent link to this record |
| |
|
| |
| Author |
Jimenez-Mena, N.; Jacques, P.J.; Ding, L.; Gauquelin, N.; Schryvers, D.; Idrissi, H.; Delannay, F.; Simar, A. |
| Title |
Enhancement of toughness of Al-to-steel Friction Melt Bonded welds via metallic interlayers |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Materials science and engineering: part A: structural materials: properties, microstructure and processing |
Abbreviated Journal |
Mat Sci Eng A-Struct |
| Volume |
740-741 |
Issue |
|
Pages |
274-284 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
The toughness of Al-to-steel welds decreases with increasing thickness of the intermetallic (IM) layer formed at the interface. Co plating has been added as interlayer in Al-to-steel Friction Melt Bonded (FMB) welds to control the nature and thickness of the IM layer. In comparison to a weld without interlayer, Co plating brings about a reduction of the thickness of the IM layer by 70%. The critical energy release rate of the crack propagating in the weld is used as an indicator of toughness. It is evaluated via an adapted crack propagation test using an energy conservation criterion. For a weld without interlayer, critical energy release rate is found to increase when the thickness of the intermetallic layer decreases. When the intermetallic layer is thick, the crack propagates in a brittle manner through the intermetallic whereas, at low layer thickness, the crack deviates and partially propagates through the Al plate, which causes an increase of toughness. The use of a Co interlayer brings about an increase of toughness by causing full deviation of the crack towards the Al plate. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000453494500029 |
Publication Date |
2018-10-24 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0921-5093 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.094 |
Times cited |
4 |
Open Access |
Not_Open_Access: Available from 25.10.2020
|
| Notes |
The authors acknowledge the financial support of the Interuniversity Attraction Poles Program from the Belgian State through the Belgian Policy Agency, Belgium, contract IAP7/21 INTEMATE. N. Jimenez-Mena acknowledges the financial support of the (Fonds pour la formation à la recherchedans l'industrie et dans l'agriculture (FRIA), Belgium. A. Simar acknowledges the financial support of the (European Research Council – Starting Grant (ERC-StG), project ALUFIX, grant agreement no 716678. H. Idrissi is mandated by the Belgian National Fund for Scientific Research (FSR-FNRS), Belgium. The authors also acknowledge M. Coulombier for the help provided in the measurement of the friction coefficient, and T. Pardoen and F. Lani for the fruitful discussions. |
Approved |
Most recent IF: 3.094 |
| Call Number |
EMAT @ emat @c:irua:154866UA @ admin @ c:irua:154866 |
Serial |
5061 |
| Permanent link to this record |
| |
|
| |
| Author |
Bouwmeester, R.L.; de Hond, K.; Gauquelin, N.; Verbeeck, J.; Koster, G.; Brinkman, A. |
| Title |
Stabilization of the Perovskite Phase in the Y-Bi-O System By Using a BaBiO3 Buffer Layer |
Type |
A1 Journal Article |
| Year |
2019 |
Publication |
Physica Status Solidi-Rapid Research Letters |
Abbreviated Journal |
Phys Status Solidi-R |
| Volume |
13 |
Issue |
7 |
Pages |
1970028 |
| Keywords |
A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; |
| Abstract |
A topological insulating phase has theoretically been predicted for the thermodynamically unstable perovskite phase of YBiO3. Here, it is shown that the crystal structure of the Y-Bi-O system can be controlled by using a BaBiO3 buffer layer. The BaBiO3 film overcomes the large lattice mismatch with the SrTiO3 substrate by forming a rocksalt structure in between the two perovskite structures. Depositing an YBiO3 film directly on a SrTiO3 substrate gives a fluorite structure. However, when the Y–Bi–O system is deposited on top of the buffer layer with the correct crystal phase and comparable lattice constant, a single oriented perovskite structure with the expected lattice constants is observed. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
|
Publication Date |
2019-07-27 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1862-6254 |
ISBN |
|
Additional Links |
|
| Impact Factor |
3.032 |
Times cited |
|
Open Access |
|
| Notes |
The work at the University of Twente is financially supported by NWO through a VICI grant. N.G. and J.V. acknowledge financial support from the GOA project Solarpaint of the University of Antwerp. The microscope used for this experiment has been partially financed by the Hercules Fund from the Flemish Government. L. Ding is acknowledge for his help with the GPA analysis. |
Approved |
Most recent IF: 3.032 |
| Call Number |
EMAT @ emat @ |
Serial |
5358 |
| Permanent link to this record |
| |
|
| |
| Author |
Yin, C.; Krishnan, D.; Gauquelin, N.; Verbeeck, J.; Aarts, J. |
| Title |
Controlling the interfacial conductance in LaAlO3/SrTiO3 in 90 degrees off-axis sputter deposition |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Physical review materials |
Abbreviated Journal |
|
| Volume |
3 |
Issue |
3 |
Pages |
034002 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We report on the fabrication of conducting interfaces between LaAlO3 and SrTiO3 by 90 degrees off-axis sputtering in an Ar atmosphere. At a growth pressure of 0.04 mbar the interface is metallic, with a carrier density of the order of 1 x 10(13) cm(-2) at 3 K. By increasing the growth pressure, we observe an increase of the out-of-plane lattice constants of the LaAlO3 films while the in-plane lattice constants do not change. Also, the low-temperature sheet resistance increases with increasing growth pressure, leading to an insulating interface when the growth pressure reaches 0.10 mbar. We attribute the structural variations to an increase of the La/Al ratio, which also explains the transition from metallic behavior to insulating behavior of the interfaces. Our research shows that the control which is furnished by the Ar pressure makes sputtering as versatile a process as pulsed laser deposition, and emphasizes the key role of the cation stoichiometry of LaAlO3 in the formation of the conducting interface. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000461077100002 |
Publication Date |
2019-03-12 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.926 |
Times cited |
4 |
Open Access |
Not_Open_Access |
| Notes |
; We thank Nikita Lebedev, Aymen Ben Hamida, and Prateek Kumar for useful discussions and Giordano Mattoni, Jun Wang, Vincent Joly, and Hozanna Miro for their technical assistance. We also thank Jean-Marc Triscone and his group for sharing their design of the sputtering system with us. This work is part of the FOM research programme DESCO with Project No. 149, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO). C.Y. is supported by China Scholarship Council (CSC) with Grant No. 201508110214. N.G., D.K., and J.V. acknowledge financial support from the GOA project “Solarpaint” of the University of Antwerp. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:158547 |
Serial |
5243 |
| Permanent link to this record |
| |
|
| |
| Author |
Egoavil, R.; Gauquelin, N.; Martinez, G.T.; Van Aert, S.; Van Tendeloo, G.; Verbeeck, J. |
| Title |
Atomic resolution mapping of phonon excitations in STEM-EELS experiments |
Type |
A1 Journal article |
| Year |
2014 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
147 |
Issue |
|
Pages |
1-7 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Atomically resolved electron energy-loss spectroscopy experiments are commonplace in modern aberration-corrected transmission electron microscopes. Energy resolution has also been increasing steadily with the continuous improvement of electron monochromators. Electronic excitations however are known to be delocalized due to the long range interaction of the charged accelerated electrons with the electrons in a sample. This has made several scientists question the value of combined high spatial and energy resolution for mapping interband transitions and possibly phonon excitation in crystals. In this paper we demonstrate experimentally that atomic resolution information is indeed available at very low energy losses around 100 meV expressed as a modulation of the broadening of the zero loss peak. Careful data analysis allows us to get a glimpse of what are likely phonon excitations with both an energy loss and gain part. These experiments confirm recent theoretical predictions on the strong localization of phonon excitations as opposed to electronic excitations and show that a combination of atomic resolution and recent developments in increased energy resolution will offer great benefit for mapping phonon modes in real space. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000343157400001 |
Publication Date |
2014-05-29 |
| 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 |
246102 IFOX; 278510 VORTEX; 246791 COUNTATOMS; Hercules; 312483 ESTEEM2; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 2.843; 2014 IF: 2.436 |
| Call Number |
UA @ lucian @ c:irua:118332UA @ admin @ c:irua:118332 |
Serial |
177 |
| Permanent link to this record |
| |
|
| |
| Author |
Gauquelin, N.; van den Bos, K.H.W.; Béché, A.; Krause, F.F.; Lobato, I.; Lazar, S.; Rosenauer, A.; Van Aert, S.; Verbeeck, J. |
| Title |
Determining oxygen relaxations at an interface: A comparative study between transmission electron microscopy techniques |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
181 |
Issue |
181 |
Pages |
178-190 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Nowadays, aberration corrected transmission electron microscopy (TEM) is a popular method to characterise nanomaterials at the atomic scale. Here, atomically resolved images of nanomaterials are acquired, where the contrast depends on the illumination, imaging and detector conditions of the microscope. Visualization of light elements is possible when using low angle annular dark field (LAADF) STEM, annular bright field (ABF) STEM, integrated differential phase contrast (iDPC) STEM, negative spherical aberration imaging (NCSI) and imaging STEM (ISTEM). In this work, images of a NdGaO3-La0.67Sr0.33MnO3 (NGO-LSMO) interface are quantitatively evaluated by using statistical parameter estimation theory. For imaging light elements, all techniques are providing reliable results, while the techniques based on interference contrast, NCSI and ISTEM, are less robust in terms of accuracy for extracting heavy column locations. In term of precision, sample drift and scan distortions mainly limits the STEM based techniques as compared to NCSI. Post processing techniques can, however, partially compensate for this. In order to provide an outlook to the future, simulated images of NGO, in which the unavoidable presence of Poisson noise is taken into account, are used to determine the ultimate precision. In this future counting noise limited scenario, NCSI and ISTEM imaging will provide more precise values as compared to the other techniques, which can be related to the mechanisms behind the image recording. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000411170800022 |
Publication Date |
2017-06-03 |
| 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 |
34 |
Open Access |
OpenAccess |
| Notes |
The authors acknowledge financial support from Flanders (FWO, Belgium) through project fundings (G.0044.13N, G.0374.13N, G.0368.15N, G.0369.15N), and by a Ph.D. grant to K.H.W.v.d.B. The Qu-Ant-EM microscope used for this study was partly funded by the Hercules fund from the Flemish Government. A.B. and N.G. acknowledge the EUROTAPES project (FP7-NMP.2011.2.2-1 Grant no.280432) which partly funded this study. N.G., A.B. and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The research leading to these results has received funding from the Deutsche Forschungsgemeinschaft under Contract No. RO 2057/4-2 and the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2. We thank Prof. G. Koster from the University of Twente for kindly providing us with the LSMO-NGO test sample. |
Approved |
Most recent IF: 2.843 |
| Call Number |
EMAT @ emat @ c:irua:144435UA @ admin @ c:irua:144435 |
Serial |
4620 |
| Permanent link to this record |
| |
|
| |
| Author |
Wang, J.; Nguyen, M.D.; Gauquelin, N.; Verbeeck, J.; Do, M.T.; Koster, G.; Rijnders, G.; Houwman, E. |
| Title |
On the importance of the work function and electron carrier density of oxide electrodes for the functional properties of ferroelectric capacitors |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Physica Status Solidi-Rapid Research Letters |
Abbreviated Journal |
Phys Status Solidi-R |
| Volume |
14 |
Issue |
14 |
Pages |
1900520 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
It is important to understand the effect of the interfaces between the oxide electrode layers and the ferroelectric layer on the polarization response for optimizing the device performance of all-oxide ferroelectric devices. Herein, the effects of the oxide La0.07Ba0.93SnO3 (LBSO) as an electrode material in an PbZr0.52Ti0.48O3 (PZT) ferroelectric capacitor are compared with those of the more commonly used SrRuO3 (SRO) electrode. SRO (top)/PZT/SRO (bottom), SRO/PZT/LBSO, and SRO/PZT/2 nm SRO/LBSO devices are fabricated. Only marginal differences in crystalline properties, determined by X-ray diffraction and scanning transmission electron microscopy, are found. High-quality polarization loops are obtained, but with a much larger coercive field for the SRO/PZT/LBSO device. In contrast to the SRO/PZT/SRO device, the polarization decreases strongly with increasing field cycling. This fatigue problem can be remedied by inserting a 2 nm SRO layer between PZT and LBSO. It is argued that strongly increased charge injection into the PZT occurs at the bottom interface, because of the low PZT/LBSO interfacial barrier and the much lower carrier density in LBSO, as compared with that in SRO, causing a low dielectric constant, depleted layer in LBSO. The charge injection creates a trapped space charge in the PZT, causing the difference in fatigue behavior. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000506195600001 |
Publication Date |
2019-12-12 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1862-6254 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.8 |
Times cited |
6 |
Open Access |
OpenAccess |
| Notes |
; This work was supported by Nederlandse Organisatie voor Wetenschappelijk Onderzoek through grant no.13HTSM01. ; |
Approved |
Most recent IF: 2.8; 2020 IF: 3.032 |
| Call Number |
UA @ admin @ c:irua:165681 |
Serial |
6316 |
| Permanent link to this record |
| |
|
| |
| Author |
Lebedev, N.; Stehno, M.; Rana, A.; Gauquelin, N.; Verbeeck, J.; Brinkman, A.; Aarts, J. |
| Title |
Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO₃/SrTiO₃ interfaces |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
| Volume |
33 |
Issue |
5 |
Pages |
055001 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
We have studied the transport properties of LaTiO3/SrTiO3 (LTO/STO) heterostructures. In spite of 2D growth observed in reflection high energy electron diffraction, transmission electron microscopy images revealed that the samples tend to amorphize. Still, we observe that the structures are conducting, and some of them exhibit high conductance and/or superconductivity. We established that conductivity arises mainly on the STO side of the interface, and shows all the signs of the two-dimensional electron gas usually observed at interfaces between STO and LTO or LaAlO3, including the presence of two electron bands and tunability with a gate voltage. Analysis of magnetoresistance (MR) and superconductivity indicates the presence of spatial fluctuations of the electronic properties in our samples. That can explain the observed quasilinear out-of-plane MR, as well as various features of the in-plane MR and the observed superconductivity. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000588209300001 |
Publication Date |
2020-10-14 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.7 |
Times cited |
1 |
Open Access |
OpenAccess |
| Notes |
; NL and JA gratefully acknowledge the financial support of the research program DESCO, which is financed by the Netherlands Organisation for Scientific Research (NWO). The authors thank J Jobst, S Smink, K Lahabi and G Koster for useful discussion. ; |
Approved |
Most recent IF: 2.7; 2020 IF: 2.649 |
| Call Number |
UA @ admin @ c:irua:173679 |
Serial |
6545 |
| Permanent link to this record |
| |
|
| |
| Author |
Wang, J.; Shin, Y.; Gauquelin, N.; Yang, Y.; Lee, C.; Jannis, D.; Verbeeck, J.; Rondinelli, J.M.; May, S.J. |
| Title |
Physical properties of epitaxial SrMnO2.5−δFγoxyfluoride films |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
| Volume |
31 |
Issue |
36 |
Pages |
365602 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Recently, topotactic fluorination has become an alternative way of doping epitaxial perovskite oxides through anion substitution to engineer their electronic properties instead of the more commonly used cation substitution. In this work, epitaxial oxyfluoride SrMnO2.5−δ F γ films were synthesized via topotactic fluorination of SrMnO2.5 films using polytetrafluoroethylene as the fluorine source. Oxidized SrMnO3 films were also prepared for comparison with the fluorinated samples. The F content, probed by x-ray photoemission spectroscopy, was systematically controlled by adjusting fluorination conditions. Electronic transport measurements reveal that increased F content (up to γ = 0.14) systematically increases the electrical resistivity, despite the nominal electron-doping induced by F substitution for O in these films. In contrast, oxidized SrMnO3 exhibits a decreased resistivity and conduction activation energy. A blue-shift of optical absorption features occurs with increasing F content. Density functional theory calculations indicate that F acts as a scattering center for electronic transport, controls the observed weak ferromagnetic behavior of the films, and reduces the inter-band optical transitions in the manganite films. These results stand in contrast to bulk electron-doped La1−x Ce x MnO3, illustrating how aliovalent anionic substitutions can yield physical behavior distinct from A-site substituted perovskites with the same nominal B-site oxidation states. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000472232000002 |
Publication Date |
2019-09-11 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.649 |
Times cited |
5 |
Open Access |
|
| Notes |
Work at Drexel was supported by the National Science Foundation (NSF), grant number CMMI-1562223. Thin film synthesis utilized deposition instrumentation acquired through an Army Research Office DURIP grant (W911NF-14-1-0493). Y.S and J.M.R. were supported by NSF (Grant No. DMR-1454688). Calculations were performed using the QUEST HPC Facility at Northwestern, the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF Grant No. ACI-1053575, and the Center for Nanoscale Materials (Carbon Cluster). Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. J.V. and N. G. acknowledge funding from a GOA project “Solarpaint” of the University of Antwerp. D.J. acknowledges funding from FWO project G093417N from the Flemish fund for scientific research. |
Approved |
Most recent IF: 2.649 |
| Call Number |
EMAT @ emat @UA @ admin @ c:irua:161174 |
Serial |
5293 |
| Permanent link to this record |
| |
|
| |
| Author |
O'Donnell, D.; Hassan, S.; Du, Y.; Gauquelin, N.; Krishnan, D.; Verbeeck, J.; Fan, R.; Steadman, P.; Bencok, P.; Dobrynin, A.N. |
| Title |
Etching induced formation of interfacial FeMn in IrMn/CoFe bilayers |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Journal of physics: D: applied physics |
Abbreviated Journal |
J Phys D Appl Phys |
| Volume |
52 |
Issue |
16 |
Pages |
165002 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The effect of ion etching on exchange bias in IrMn3/Co70Fe30 bilayers is investigated. In spite of the reduction of saturation magnetization caused by the embedding of Tr from the capping layer into the Co70Fe30 layer during the etching process, the exchange bias in samples with the same thickness of the Co70Fe30 layer is reducing in proportion to the etching power. X-ray magnetic circular dichroism measurements revealed the emergence of an uncompensated Mn magnetization after etching, which is antiferromagnetically coupled to the ferromagnetic layer. This suggests etching induced formation of small interfacial FeMn regions which leads to the decrease of effective exchange coupling between ferromagnetic and antiferromagnetic layers. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000458524800001 |
Publication Date |
2019-01-31 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0022-3727 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
2.588 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
; This work was supported by Seagate Technology (Ireland). Beamline I10, Diamond Light Source, is acknowledged for provided beamtime. ; |
Approved |
Most recent IF: 2.588 |
| Call Number |
UA @ admin @ c:irua:157458 |
Serial |
5247 |
| Permanent link to this record |
| |
|
| |
| Author |
Fatermans, J.; den Dekker, Aj.; Müller-Caspary, K.; Gauquelin, N.; Verbeeck, J.; Van Aert, S. |
| Title |
Atom column detection from simultaneously acquired ABF and ADF STEM images |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
| Volume |
219 |
Issue |
|
Pages |
113046 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
In electron microscopy, the maximum a posteriori (MAP) probability rule has been introduced as a tool to determine the most probable atomic structure from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images exhibiting low contrast-to-noise ratio (CNR). Besides ADF imaging, STEM can also be applied in the annular bright-field (ABF) regime. The ABF STEM mode allows to directly visualize light-element atomic columns in the presence of heavy columns. Typically, light-element nanomaterials are sensitive to the electron beam, limiting the incoming electron dose in order to avoid beam damage and leading to images exhibiting low CNR. Therefore, it is of interest to apply the MAP probability rule not only to ADF STEM images, but to ABF STEM images as well. In this work, the methodology of the MAP rule, which combines statistical parameter estimation theory and model-order selection, is extended to be applied to simultaneously acquired ABF and ADF STEM images. For this, an extension of the commonly used parametric models in STEM is proposed. Hereby, the effect of specimen tilt has been taken into account, since small tilts from the crystal zone axis affect, especially, ABF STEM intensities. Using simulations as well as experimental data, it is shown that the proposed methodology can be successfully used to detect light elements in the presence of heavy elements. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000594768500005 |
Publication Date |
2020-06-01 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.2 |
Times cited |
9 |
Open Access |
OpenAccess |
| Notes |
The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (No. W.O.010.16N, No. G.0368.15N, No. G.0502.18N, EOS 30489208). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 823717 – ESTEEM3. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. K. M. C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association (Germany) under contract VH-NG-1317. The authors thank Mark Huijben from the University of Twente (Enschede, The Netherlands) for providing the LiMn2O4 sample used in section 4.2 of this study. N. G., J. V., and S. V. A. acknowledge funding from the University of Antwerp through the Concerted Research Actions (GOA) project Solarpaint and the TOP project. |
Approved |
Most recent IF: 2.2; 2020 IF: 2.843 |
| Call Number |
EMAT @ emat @c:irua:169706 |
Serial |
6373 |
| Permanent link to this record |
| |
|
| |
| Author |
Godet, M.; Vergès-Belmin, V.; Gauquelin, N.; Saheb, M.; Monnier, J.; Leroy, E.; Bourgon, J.; Verbeeck, J.; Andraud, C. |
| Title |
Nanoscale investigation by TEM and STEM-EELS of the laser induced yellowing |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Micron |
Abbreviated Journal |
Micron |
| Volume |
115 |
Issue |
|
Pages |
25-31 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Nd-YAG QS laser cleaning of soiled stone at 1064 nm can sometimes result in a more yellow appearance compared to other cleaning techniques. Especially in France, this yellowing effect is still considered as a major aesthetic issue by the architects and conservators. One explanation states that the yellowing is linked to the formation of iron-rich nanophase(s) through the laser beam interaction with black crusts that would re-deposit on the cleaned substrate after irradiation. To characterize these nanophases, a model crust containing hematite was elaborated and laser irradiated using a Nd-YAG QS laser. The color of the sample shifted instantaneously from red to a bright yellow and numerous particles were ablated in a visible smoke. Transmission electron microscopy (TEM) was used to examine the morphology and the crystallinity of the neo-formed compounds, both on the surface of the samples and in the ablated materials. In addition, an investigation of the chemical and structural properties of the nanophases was conducted by X-ray dispersive energy (EDX) and electron energy loss (EELS) spectroscopies. It was found that both the surface of the sample and the ablated materials are covered by crystallized nano-spheres and nano-residues, all containing iron and oxygen, sometimes along with calcium and sulfur. In particular an interfacial area containing the four elements was evidenced between some nanostructures and the substrate. Magnetite Fe3O4 was also identified at the nanoscale. This study demonstrates that the laser yellowing of a model crust is linked to the presence of iron-rich nanophases including CaxFeySzOδ nanostructures and magnetite Fe3O4 at the surface after irradiation. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000449125600004 |
Publication Date |
2018-08-18 |
| 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 |
9 |
Open Access |
Not_Open_Access: Available from 19.08.2020
|
| Notes |
The authors wish to thank Valérie Lalanne for the sample preparation for TEM and Stijn Van den Broeck for the FIB cut elaboration. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2 (Integrated Infrastructure Initiative–I3). |
Approved |
Most recent IF: 1.98 |
| Call Number |
EMAT @ emat @c:irua:154356UA @ admin @ c:irua:154356 |
Serial |
5056 |
| Permanent link to this record |
| |
|
| |
| Author |
Bhat, S.G.; Gauquelin, N.; Sebastian, N.K.; Sil, A.; Béché, A.; Verbeeck, J.; Samal, D.; Kumar, P.S.A. |
| Title |
Orthorhombic vs. hexagonal epitaxial SrIrO3 thin films : structural stability and related electrical transport properties |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
| Volume |
122 |
Issue |
2 |
Pages |
28003 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Metastable orthorhombic SrIrO3 (SIO) is an arch-type spin-orbit coupled material. We demonstrate here a controlled growth of relatively thick (200 nm) SIO films that transform from bulk “6H-type” structure with monoclinic distortion to an orthorhombic lattice by controlling growth temperature. Extensive studies based on high-resolution X-ray diffraction and transmission electron microscopy infer a two distinct structural phases of SIO. Electrical transport reveals a weak temperature-dependent semi-metallic character for both phases. However, the temperature-dependent Hall-coefficient for the orthorhombic SIO exhibits a prominent sign change, suggesting a multiband character in the vicinity of E-F. Our findings thus unravel the subtle structure-property relation in SIO epitaxial thin films. Copyright (C) EPLA, 2018 |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Paris |
Editor |
|
| Language |
|
Wos |
000435517300001 |
Publication Date |
2018-06-18 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0295-5075 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.957 |
Times cited |
4 |
Open Access |
Not_Open_Access |
| Notes |
; SGB and DS acknowledge useful discussions with E. P. Houwman, University of Twente, on X-ray diffraction. DS would like to thank H. Takagi, Max-Planck Institute for Solid State Research, Stuttgart, for the fruitful discussion on the transport properties of SIO thin films. SGB and NKS thank A. Aravind, Bishop Moore College, Mavelikara, for his valuable inputs while depositing the thin films of SIO. SGB, NKS and PSAK acknowledge Nano Mission Council, Department of Science & Technology, India, for the funding. DS acknowledges the financial support from Max-Planck Society through MaxPlanck Partner Group. NG, AB and JV acknowledge funding from GOA project “Solarpaint” of the University of Antwerp and FWO project G093417N. ; |
Approved |
Most recent IF: 1.957 |
| Call Number |
UA @ lucian @ c:irua:152074UA @ admin @ c:irua:152074 |
Serial |
5034 |
| Permanent link to this record |
| |
|
| |
| Author |
Grieten, E.; Schalm, O.; Tack, P.; Bauters, S.; Storme, P.; Gauquelin, N.; Caen, J.; Patelli, A.; Vincze, L.; Schryvers, D. |
| Title |
Reclaiming the image of daguerreotypes: Characterization of the corroded surface before and after atmospheric plasma treatment |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Journal of cultural heritage |
Abbreviated Journal |
J Cult Herit |
| Volume |
|
Issue |
|
Pages |
|
| Keywords |
A1 Journal article; Art; History; Electron microscopy for materials research (EMAT); Antwerp Cultural Heritage Sciences (ARCHES) |
| Abstract |
Technological developments such as atmospheric plasma jets for industry can be adapted for the conservation of cultural heritage. This application might offer a potential method for the removal or transformation of the corrosion on historical photographs. We focus on daguerreotypes and present an in-depth study of the induced changes by a multi-analytical approach using optical microscopy, scanning electron microscopy, different types of transmission electron microscopy and X-ray absorption fine structure. The H2-He afterglow removes S from an Ag2S or Cu2S layer which results in a nano-layer of metallic Ag or Cu on top of the deteriorated microstructure. In case the corrosion layer is composed of Cu-Ag-S compounds, our proposed setup can be used to partially remove the corrosion. These alterations of the corrosion results in an improvement in the readability of the photographic image. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000414230700007 |
Publication Date |
2017-06-16 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1296-2074 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.838 |
Times cited |
9 |
Open Access |
Not_Open_Access |
| Notes |
The authors thank Herman Maes for the daguerreotypes used in this study. The authors also acknowledge the opportunity to perform XAFS measurements at the DUBBLE beamline of the ESRF storage ring under the approval of the advisory Committee (beam time nr. 26-01-990) and acknowledge the DUBBLE beamline staff for their support. They are also grateful for the financial support by the EU-FP7 grant PANNA no. 282998 and the STIMPRO project FFB150215 of the University of Antwerp. Pieter Tack is funded by a Ph.D. grant of the Agency for Innovation by Science and Technology (IWT). |
Approved |
Most recent IF: 1.838 |
| Call Number |
EMAT @ emat @c:irua:144430 |
Serial |
4625 |
| Permanent link to this record |
| |
|
| |
| Author |
Gauquelin, N.; Zhang, H.; Zhu, G.; Wei, J.Y.T.; Botton, G.A. |
| Title |
Atomic-scale identification of novel planar defect phases in heteroepitaxial YBa2Cu3O7-\delta thin films |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
AIP advances |
Abbreviated Journal |
Aip Adv |
| Volume |
8 |
Issue |
5 |
Pages |
055022 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
We have discovered two novel types of planar defects that appear in heteroepitaxial YBa2Cu3O7-delta(YBCO123) thin films, grown by pulsed-laser deposition (PLD) either with or without a La2/3Ca1/3MnO3 (LCMO) overlayer, using the combination of highangle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging and electron energy loss spectroscopy (EELS) mapping for unambiguous identification. These planar lattice defects are based on the intergrowth of either a BaO plane between two CuO chains or multiple Y-O layers between two CuO2 planes, resulting in non-stoichiometric layer sequences that could directly impact the high-Tc superconductivity. (C) 2018 Author(s). |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
American Institute of Physics |
Place of Publication |
Melville, NY |
Editor |
|
| Language |
|
Wos |
000433954000022 |
Publication Date |
2018-05-21 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2158-3226 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.568 |
Times cited |
1 |
Open Access |
OpenAccess |
| Notes |
; We are thankful to Julia Huang for FIB TEM sample preparation. This work is supported by NSERC (through Discovery Grants to GAB and JYTW) and CIFAR. The electron microscopy work was carried out at the Canadian Centre for Electron Microscopy, a National Facility supported by McMaster University, the Canada Foundation for Innovation and NSERC. N.G. acknowledges H. Idrissi for useful discussions. ; |
Approved |
Most recent IF: 1.568 |
| Call Number |
UA @ lucian @ c:irua:152063 |
Serial |
5013 |
| Permanent link to this record |
| |
|
| |
| Author |
Pogosov, W.V.; Lin, N.; Misko, V.R. |
| Title |
Electron-hole symmetry and solutions of Richardson pairing model |
Type |
A1 Journal article |
| Year |
2013 |
Publication |
European physical journal : B : condensed matter and complex systems |
Abbreviated Journal |
Eur Phys J B |
| Volume |
86 |
Issue |
5 |
Pages |
235-236 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
Richardson approach provides an exact solution of the pairing Hamiltonian. This Hamiltonian is characterized by the electron-hole pairing symmetry, which is however hidden in Richardson equations. By analyzing this symmetry and using an additional conjecture, fulfilled in solvable limits, we suggest a simple expression of the ground state energy for an equally-spaced energy-level model, which is applicable along the whole crossover from the superconducting state to the pairing fluctuation regime. Solving Richardson equations numerically, we demonstrate a good accuracy of our expression. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Berlin |
Editor |
|
| Language |
|
Wos |
000320286200044 |
Publication Date |
2013-05-28 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1434-6028;1434-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.461 |
Times cited |
6 |
Open Access |
|
| Notes |
; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). W.V.P. acknowledges useful discussions with Monique Combescot and the support from the Dynasty Foundation, the RFBR (project No. 12-02-00339), and RFBR-CNRS programme (project No. 12-02-91055). ; |
Approved |
Most recent IF: 1.461; 2013 IF: 1.463 |
| Call Number |
UA @ lucian @ c:irua:109657 |
Serial |
935 |
| Permanent link to this record |
| |
|
| |
| Author |
Lin, N.S.; Misko, V.R.; Heitmann, T.W.; Yu, K.; Plourde, B.L.T. |
| Title |
Density dependence of the rectification of vortex motion in a circular asymmetric channel |
Type |
A1 Journal article |
| Year |
2012 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
| Volume |
479 |
Issue |
|
Pages |
137-139 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
We study the rectification of vortex motion in an asymmetric ring channel in a Corbino setup. With an applied ac current, the motion of vortices in the channel is rectified by the asymmetric potential and induces a dc net flow. The net flow in such a system strongly depends on vortex density, and we distinguish “single-vortex'' rectification regime (for low density, when each vortex is rectified individually) determined by the potential-energy landscape inside each cell of the channel and ”multi-vortex'', or "collective'', rectification (high density case) when the interaction between vortices becomes important. (C) 2012 Elsevier B.V. All rights reserved. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000308580600032 |
Publication Date |
2012-01-06 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0921-4534; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
1.404 |
Times cited |
|
Open Access |
|
| Notes |
; This work was supported by the "Odysseus'' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles (IAP) Programme – Belgian State – Belgian Science Policy, and the FWO-Vl (Belgium). ; |
Approved |
Most recent IF: 1.404; 2012 IF: 0.718 |
| Call Number |
UA @ lucian @ c:irua:101873 |
Serial |
635 |
| Permanent link to this record |
| |
|
| |
| Author |
Misko, V.R.; Lin, N.S.; Peeters, F.M. |
| Title |
Unconventional dynamics of vortex shells in mesoscopic superconducting corbino disks |
Type |
A1 Journal article |
| Year |
2010 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
| Volume |
470 |
Issue |
19 |
Pages |
939-941 |
| Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| Abstract |
The dynamics of vortex matter in mesoscopic superconducting Corbino disk is strongly influenced by the discrete vortex structure arranged in shells. While in previous works the vortex dynamics has been studied in large (macroscopic) and in very small mesoscopic disks (containing only few shells), in the intermediate-size regime it is much more complex and unusual, due to: (i) the competition between the vortexvortex interaction and confinement and (ii) (in)commensurability among the vortex shells. We found that the interplay between these effects can result in a very unusual vortex dynamical behavior: (i) unconventional angular melting (i.e., propagating from the boundary, where the shear stress is minimum, towards the center) and (ii) unconventional dynamics of shells (i.e., the inversion of shell velocities with respect to the gradient driving force). This unusual behavior is found for different number of shells. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
| Language |
|
Wos |
000282454400059 |
Publication Date |
2010-03-04 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0921-4534; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.404 |
Times cited |
3 |
Open Access |
|
| Notes |
; ; |
Approved |
Most recent IF: 1.404; 2010 IF: 1.415 |
| Call Number |
UA @ lucian @ c:irua:85036 |
Serial |
3799 |
| Permanent link to this record |
| |
|
| |
| Author |
Lin, N. |
| Title |
Dynamics of interacting clusters in low-dimensional superconductors |
Type |
Doctoral thesis |
| Year |
2012 |
Publication |
|
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
|
| Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
Antwerpen |
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:102534 |
Serial |
776 |
| Permanent link to this record |
| |
|
| |
| Author |
van der Torren, A.J.H.; Liao, Z.; Xu, C.; Gauquelin, N.; Yin, C.; Aarts, J.; van der Molen, S.J. |
| Title |
Formation of a conducting LaAlO3/SrTiO3 interface studied by low-energy electron reflection during growth |
Type |
A1 Journal Article |
| Year |
2017 |
Publication |
Physical Review Materials |
Abbreviated Journal |
Phys. Rev. Materials |
| Volume |
1 |
Issue |
7 |
Pages |
075001 |
| Keywords |
A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; |
| Abstract |
The two-dimensional electron gas occurring between the band insulators SrTiO 3 and LaAlO 3 continues to attract considerable interest, due to the possibility of dynamic control over the carrier density, and the ensuing phenomena such as magnetism and superconductivity. The formation of this conducting interface is sensitive to the growth conditions, but despite numerous investigations, there are still questions about the details of the physics involved. In particular, not much is known about the electronic structure of the growing LaAlO 3 layer at the growth temperature (around 800 ◦ C) in oxygen (pressure around 5 × 10 −5 mbar), since analysis techniques at these conditions are not readily available. We developed a pulsed laser deposition system inside a low-energy electron microscope in order to study this issue. The setup allows for layer-by-layer growth control and in-situ measurements of the angle-dependent electron reflection intensity, which can be used as a fingerprint of the electronic structure of the surface layers during growth. By using different substrate terminations and growth conditions we observe two families of reflectivity maps, which we can connect either to samples with an AlO 2 -rich surface and a conducting interface; or to samples with a LaO-rich surface and an insulating interface. Our observations emphasize that substrate termination and stoichiometry determine the electronic structure of the growing layer, and thereby the conductance of the interface. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000418770200003 |
Publication Date |
2017-12-06 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2475-9953 |
ISBN |
|
Additional Links |
|
| Impact Factor |
|
Times cited |
2 |
Open Access |
Not_Open_Access |
| Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Fonds Wetenschappelijk Onderzoek, G.0044.13N ; European Cooperation in Science and Technology, MP 1308 ; We want to acknowledge Ruud Tromp, Daniel Gee- len, Johannes Jobst, Regina Dittmann, Gert Jan Koster, Guus Rijnders and Jo Verbeek for discussions and ad- vice and Ruud van Egmond and Marcel Hesselberth for technical assistance. This work was supported by the Netherlands Organization for Scientific Research (NWO) by means of an ”NWO Groot” grant and by the Leiden- Delft Consortium NanoFront. The work is part of the re- search programmes NWOnano and DESCO, which are fi- nanced by NWO. N.G. acknowledges funding through the GOA project “Solarpaint” of the University of Antwerp and from the FWO project G.0044.13N (Charge order- ing). The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. We would also like to acknowledge networking support by the COST Action MP 1308 (COST TO-BE). |
Approved |
Most recent IF: NA |
| Call Number |
EMAT @ emat @ |
Serial |
4903 |
| Permanent link to this record |
| |
|
| |
| Author |
Groenendijk, D.J.; Autieri, C.; van Thiel, T.C.; Brzezicki, W.; Hortensius, J.R.; Afanasiev, D.; Gauquelin, N.; Barone, P.; van den Bos, K.H.W.; van Aert, S.; Verbeeck, J.; Filippetti, A.; Picozzi, S.; Cuoco, M.; Caviglia, A.D. |
| Title |
Berry phase engineering at oxide interfaces |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
|
Abbreviated Journal |
Phys. Rev. Research |
| Volume |
2 |
Issue |
2 |
Pages |
023404 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Three-dimensional strontium ruthenate (SrRuO3) is an itinerant ferromagnet that features Weyl points acting as sources of emergent magnetic fields, anomalous Hall conductivity, and unconventional spin dynamics. Integrating SrRuO3 in oxide heterostructures is potentially a novel route to engineer emergent electrodynamics, but its electronic band topology in the two-dimensional limit remains unknown. Here we show that ultrathin SrRuO3 exhibits spin-polarized topologically nontrivial bands at the Fermi energy. Their band anticrossings show an enhanced Berry curvature and act as competing sources of emergent magnetic fields. We control their balance by designing heterostructures with symmetric (SrTiO3/SrRuO3/SrTiO3 and SrIrO3/SrRuO3/SrIrO3) and asymmetric interfaces (SrTiO3/SrRuO3/SrIrO3). Symmetric structures exhibit an interface-tunable single-channel anomalous Hall effect, while ultrathin SrRuO3 embedded in asymmetric structures shows humplike features consistent with multiple Hall contributions. The band topology of two-dimensional SrRuO3 proposed here naturally accounts for these observations and harmonizes a large body of experimental results. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000603642700008 |
Publication Date |
2020-06-25 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2643-1564 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
58 |
Open Access |
OpenAccess |
| Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Fonds Wetenschappelijk Onderzoek; European Research Council; Horizon 2020, 677458 770887 731473 ; Fondazione Cariplo, 2013-0726 ; Narodowe Centrum Nauki, 2016/23/B/ST3/00839 ; Fundacja na rzecz Nauki Polskiej; Universiteit Antwerpen; Vlaamse regering; |
Approved |
Most recent IF: NA |
| Call Number |
EMAT @ emat @c:irua:172462 |
Serial |
6401 |
| Permanent link to this record |
| |
|
| |
| Author |
Herzog, M.J.; Gauquelin, N.; Esken, D.; Verbeeck, J.; Janek, J. |
| Title |
Increased Performance Improvement of Lithium-Ion Batteries by Dry Powder Coating of High-Nickel NMC with Nanostructured Fumed Ternary Lithium Metal Oxides |
Type |
A1 Journal article |
| Year |
2021 |
Publication |
ACS applied energy materials |
Abbreviated Journal |
ACS Appl. Energy Mater. |
| Volume |
4 |
Issue |
9 |
Pages |
8832-8848 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Dry powder coating is an effective approach to protect the surfaces of layered cathode active materials (CAMs) in lithium-ion batteries. Previous investigations indicate an incorporation of lithium ions in fumed Al2O3, ZrO2, and TiO2 coatings on LiNi0.7Mn0.15Co0.15O2 during cycling, improving the cycling performance. Here, this coating approach is transferred for the first time to fumed ternary LiAlO2, Li4Zr3O8, and Li4Ti5O12 and directly compared with their lithium-free equivalents. All materials could be processed equally and their nanostructured small aggregates accumulate on the CAM surfaces to quite homogeneous coating layers with a certain porosity. The LiNixMnyCozO2 (NMC) coated with lithium-containing materials shows an enhanced improvement in overall capacity, capacity retention, rate performance, and polarization behavior during cycling, compared to their lithium-free analogues. The highest rate performance was achieved with the fumed ZrO2 coating, while the best long-term cycling stability with the highest absolute capacity was obtained for the fumed LiAlO2-coated NMC. The optimal coating agent for NMC to achieve a balanced system is fumed Li4Ti5O12, providing a good compromise between high rate capability and good capacity retention. The coating agents prevent CAM particle cracking and degradation in the order LiAlO2 ≈ Al2O3 > Li4Ti5O12 > Li4Zr3O8 > ZrO2 > TiO2. A schematic model for the protection and electrochemical performance enhancement of high-nickel NMC with fumed metal oxide coatings is sketched. It becomes apparent that physical and chemical characteristics of the coating significantly influence the performance of NMC. A high degree of coating-layer porosity is favorable for the rate capability, while a high coverage of the surface, especially in vulnerable grain boundaries, enhances the long-term cycling stability and improves the cracking behavior of NMCs. While zirconium-containing coatings possess the best chemical properties for high rate performances, aluminum-containing coatings feature a superior chemical nature to protect high-nickel NMCs. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000703338600018 |
Publication Date |
2021-09-27 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2574-0962 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
15 |
Open Access |
OpenAccess |
| Notes |
For his support in scanning electron microscopy analysis, the authors thank Erik Peldszus. N. G. and J. V. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp and from the Flemish Research Fund (FWO) project G0F1320N. The Qu-Ant-EM microscope and the direct electron detector were partly funded by the Hercules fund from the Flemish Government |
Approved |
Most recent IF: NA |
| Call Number |
EMAT @ emat @c:irua:183949 |
Serial |
6823 |
| Permanent link to this record |
