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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. | ||||
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Language | Wos | 000506195600001 | Publication Date | 2019-12-12 | |
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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 | ||
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Author | Do, M.T.; Gauquelin, N.; Nguyen, M.D.; Wang, J.; Verbeeck, J.; Blom, F.; Koster, G.; Houwman, E.P.; Rijnders, G. | ||||
Title | Interfacial dielectric layer as an origin of polarization fatigue in ferroelectric capacitors | Type | A1 Journal article | ||
Year | 2020 | Publication | Scientific Reports | Abbreviated Journal | Sci Rep-Uk |
Volume | 10 | Issue | 1 | Pages | 7310 |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Origins of polarization fatigue in ferroelectric capacitors under electric field cycling still remain unclear. Here, we experimentally identify origins of polarization fatigue in ferroelectric PbZr0.52Ti0.48O3 (PZT) thin-film capacitors by investigating their fatigue behaviours and interface structures. The PZT layers are epitaxially grown on SrRuO3-buffered SrTiO3 substrates by a pulsed laser deposition (PLD), and the capacitor top-electrodes are various, including SrRuO3 (SRO) made by in-situ PLD, Pt by in-situ PLD (Pt-inPLD) and ex-situ sputtering (Pt-sputtered). We found that fatigue behaviour of the capacitor is directly related to the top-electrode/PZT interface structure. The Pt-sputtered/PZT/SRO capacitor has a thin defective layer at the top interface and shows early fatigue while the Pt-inPLD/PZT/SRO and SRO/PZT/SRO capacitor have clean top-interfaces and show much more fatigue resistance. The defective dielectric layer at the Pt-sputtered/PZT interface mainly contains carbon contaminants, which form during the capacitor ex-situ fabrication. Removal of this dielectric layer significantly delays the fatigue onset. Our results clearly indicate that dielectric layer at ferroelectric capacitor interfaces is the main origin of polarization fatigue, as previously proposed in the charge injection model. | ||||
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Language | Wos | 000559953800003 | Publication Date | 2020-04-30 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2045-2322 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.6 | Times cited | 18 | Open Access | OpenAccess |
Notes | ; The authors acknowledge the financial support of the Nederlandse Organisatie voor Wetenschappelijk Onderzoek through Grant No. F62.3.15559. ; | Approved | Most recent IF: 4.6; 2020 IF: 4.259 | ||
Call Number | EMAT @ emat @c:irua:169865 | Serial | 6374 | ||
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Author | Marchetti, A.; Saniz, R.; Krishnan, D.; Rabbachin, L.; Nuyts, G.; De Meyer, S.; Verbeeck, J.; Janssens, K.; Pelosi, C.; Lamoen, D.; Partoens, B.; De Wael, K. | ||||
Title | Unraveling the Role of Lattice Substitutions on the Stabilization of the Intrinsically Unstable Pb2Sb2O7Pyrochlore: Explaining the Lightfastness of Lead Pyroantimonate Artists’ Pigments | Type | A1 Journal article | ||
Year | 2020 | Publication | Chemistry Of Materials | Abbreviated Journal | Chem Mater |
Volume | 32 | Issue | 7 | Pages | 2863-2873 |
Keywords | A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) | ||||
Abstract | The pyroantimonate pigments Naples yellow and lead tin antimonate yellow are recognized as some of the most stable synthetic yellow pigments in the history of art. However, this exceptional lightfastness is in contrast with experimental evidence suggesting that this class of mixed oxides is of semiconducting nature. In this study the electronic structure and light-induced behavior of the lead pyroantimonate pigments were determined by means of a combined multifaceted analytical and computational approach (photoelectrochemical measurements, UV-vis diffuse reflectance spectroscopy, STEM-EDS, STEM-HAADF, and density functional theory calculations). The results demonstrate both the semiconducting nature and the lightfastness of these pigments. Poor optical absorption and minority carrier mobility are the main properties responsible for the observed stability. In addition, novel fundamental insights into the role played by Na atoms in the stabilization of the otherwise intrinsically unstable Pb2Sb2O7 pyrochlore were obtained. | ||||
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Language | Wos | 000526394000016 | Publication Date | 2020-04-14 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0897-4756 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 8.6 | Times cited | 8 | Open Access | OpenAccess |
Notes | Universiteit Antwerpen; Belgian Federal Science Policy Office; | Approved | Most recent IF: 8.6; 2020 IF: 9.466 | ||
Call Number | EMAT @ emat @c:irua:168819 | Serial | 6363 | ||
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Author | Velazco, A.; Nord, M.; Béché, A.; Verbeeck, J. | ||||
Title | Evaluation of different rectangular scan strategies for STEM imaging | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | Issue | Pages | 113021 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | STEM imaging is typically performed by raster scanning a focused electron probe over a sample. Here we investigate and compare three different scan patterns, making use of a programmable scan engine that allows to arbitrarily set the sequence of probe positions that are consecutively visited on the sample. We compare the typical raster scan with a so-called ‘snake’ pattern where the scan direction is reversed after each row and a novel Hilbert scan pattern that changes scan direction rapidly and provides an homogeneous treatment of both scan directions. We experimentally evaluate the imaging performance on a single crystal test sample by varying dwell time and evaluating behaviour with respect to sample drift. We demonstrate the ability of the Hilbert scan pattern to more faithfully represent the high frequency content of the image in the presence of sample drift. It is also shown that Hilbert scanning provides reduced bias when measuring lattice parameters from the obtained scanned images while maintaining similar precision in both scan directions which is especially important when e.g. performing strain analysis. Compared to raster scanning with flyback correction, both snake and Hilbert scanning benefit from dose reduction as only small probe movement steps occur. | ||||
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Language | Wos | 000544042800007 | Publication Date | 2020-05-21 | |
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Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 13 | Open Access | OpenAccess |
Notes | A.V., A.B. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. M.N. received support for this work from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 838001. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:169225 | Serial | 6369 | ||
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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. | ||||
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Language | Wos | 000594768500005 | Publication Date | 2020-06-01 | |
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Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | 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 | ||
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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. | ||||
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Language | Wos | 000513552900003 | Publication Date | 2020-02-12 | |
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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 | ||
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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. | ||||
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Language | Wos | 000513551200007 | Publication Date | 2020-02-10 | |
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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 | ||
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Author | Das, P.P.; Guzzinati, G.; Coll, C.; Gomez Perez, A.; Nicolopoulos, S.; Estrade, S.; Peiro, F.; Verbeeck, J.; Zompra, A.A.; Galanis, A.S. | ||||
Title | Reliable Characterization of Organic & Pharmaceutical Compounds with High Resolution Monochromated EEL Spectroscopy | Type | A1 Journal article | ||
Year | 2020 | Publication | Polymers | Abbreviated Journal | Polymers-Basel |
Volume | 12 | Issue | 7 | Pages | 1434 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Organic and biological compounds (especially those related to the pharmaceutical industry) have always been of great interest for researchers due to their importance for the development of new drugs to diagnose, cure, treat or prevent disease. As many new API (active pharmaceutical ingredients) and their polymorphs are in nanocrystalline or in amorphous form blended with amorphous polymeric matrix (known as amorphous solid dispersion—ASD), their structural identification and characterization at nm scale with conventional X-Ray/Raman/IR techniques becomes difficult. During any API synthesis/production or in the formulated drug product, impurities must be identified and characterized. Electron energy loss spectroscopy (EELS) at high energy resolution by transmission electron microscope (TEM) is expected to be a promising technique to screen and identify the different (organic) compounds used in a typical pharmaceutical or biological system and to detect any impurities present, if any, during the synthesis or formulation process. In this work, we propose the use of monochromated TEM-EELS, to analyze selected peptides and organic compounds and their polymorphs. In order to validate EELS for fingerprinting (in low loss/optical region) and by further correlation with advanced DFT, simulations were utilized. | ||||
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Language | Wos | 000556786700001 | Publication Date | 2020-06-27 | |
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Series Volume | Series Issue | Edition | |||
ISSN | 2073-4360 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.364 | Times cited | 6 | Open Access | OpenAccess |
Notes | C.C., F.P., S.E. acknowledges the Spanish government for projects MAT2016-79455-P, Research Network RED2018-102609-T and the FPI (BES-2017-080045) grant of Ministerio de Ciència, Innovación y Universidades. G.G. acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek—Vlaanderen (FWO). P.P.D., A.G.P., S.N. gratefully acknowledge much helpful discussion on EELS study for organic compounds with Dr. Andrey Chuvilin (CIC NANOGUNE, Donostia—San Sebastian, Spain). The authors also acknowledge Raúl Arenal (University de Zaragoza, Spain) for useful discussion on EELS. The authors acknowledge also Ulises Julio Amador Elizondo (Universidad CEU San Pablo, Spain) for kindly provide the aripiprazole and piroxicam samples for EELS study.; EUSMI_TA; | Approved | Most recent IF: NA | ||
Call Number | EMAT @ emat @c:irua:170603 | Serial | 6400 | ||
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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. | ||||
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Language | Wos | 000603642700008 | Publication Date | 2020-06-25 | |
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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 | ||
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Author | Prabhakara, V.; Jannis, D.; Guzzinati, G.; Béché, A.; Bender, H.; Verbeeck, J. | ||||
Title | HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale | Type | A1 Journal article | ||
Year | 2020 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 219 | Issue | Pages | 113099 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras. | ||||
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Language | Wos | 000594768500006 | Publication Date | 2020-09-01 | |
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 4 | Open Access | OpenAccess |
Notes | A.B. D.J. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO). Special thanks to Dr. Thomas Nuytten, Prof. Dr. Wilfried Vandervorst, Dr. Paola Favia, Dr. Olivier Richard from IMEC, Leuven and Prof. Dr. Sara Bals from EMAT, Antwerp for their continuous support and collaboration with the project and to the IMEC processing group for the device fabrication. | Approved | Most recent IF: 2.2; 2020 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:172485 | Serial | 6404 | ||
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Author | Wang, J.; Gauquelin, N.; Huijben, M.; Verbeeck, J.; Rijnders, G.; Koster, G. | ||||
Title | Metal-insulator transition of SrVO 3 ultrathin films embedded in SrVO 3 / SrTiO 3 superlattices | Type | A1 Journal article | ||
Year | 2020 | Publication | Applied Physics Letters | Abbreviated Journal | Appl Phys Lett |
Volume | 117 | Issue | 13 | Pages | 133105 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The metal-insulator transition (MIT) in strongly correlated oxides is a topic of great interest for its potential applications, such as Mott field effect transistors and sensors. We report that the MIT in high quality epitaxial SrVO3 (SVO) thin films is present as the film thickness is reduced, lowering the dimensionality of the system, and electron-electron correlations start to become the dominant interactions. The critical thickness of 3 u.c is achieved by avoiding effects due to off-stoichiometry using optimal growth conditions and excluding any surface effects by a STO capping layer. Compared to the single SVO thin films, conductivity enhancement in SVO/STO superlattices is observed. This can be explained by the interlayer coupling effect between SVO sublayers in the superlattices. Magnetoresistance and Hall measurements indicate that the dominant driving force of MIT is the electron–electron interaction. | ||||
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Language | Wos | 000577126100001 | Publication Date | 2020-09-28 | |
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Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4 | Times cited | 8 | Open Access | OpenAccess |
Notes | Nederlandse Organisatie voor Wetenschappelijk Onderzoek, 13HTSM01 ; | Approved | Most recent IF: 4; 2020 IF: 3.411 | ||
Call Number | EMAT @ emat @c:irua:172461 | Serial | 6415 | ||
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Author | Jovanović, Z.; Gauquelin, N.; Koster, G.; Rubio-Zuazo, J.; Ghosez, P.; Verbeeck, J.; Suvorov, D.; Spreitzer, M. | ||||
Title | Simultaneous heteroepitaxial growth of SrO (001) and SrO (111) during strontium-assisted deoxidation of the Si (001) surface | Type | A1 Journal article | ||
Year | 2020 | Publication | Rsc Advances | Abbreviated Journal | Rsc Adv |
Volume | 10 | Issue | 52 | Pages | 31261-31270 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Epitaxial integration of transition-metal oxides with silicon brings a variety of functional properties to the well-established platform of electronic components. In this process, deoxidation and passivation of the silicon surface are one of the most important steps, which in our study were controlled by an ultra-thin layer of SrO and monitored by using transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), synchrotron X-ray diffraction (XRD) and reflection high energy electron diffraction (RHEED) methods. Results revealed that an insufficient amount of SrO leads to uneven deoxidation of the silicon surface<italic>i.e.</italic>formation of pits and islands, whereas the composition of the as-formed heterostructure gradually changes from strontium silicide at the interface with silicon, to strontium silicate and SrO in the topmost layer. Epitaxial ordering of SrO, occurring simultaneously with silicon deoxidation, was observed. RHEED analysis has identified that SrO is epitaxially aligned with the (001) Si substrate both with SrO (001) and SrO (111) out-of-plane directions. This observation was discussed from the point of view of SrO desorption, SrO-induced deoxidation of the Si (001) surface and other interfacial reactions as well as structural ordering of deposited SrO. Results of the study present an important milestone in understanding subsequent epitaxial integration of functional oxides with silicon using SrO. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000566579400025 | Publication Date | 2020-08-24 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2046-2069 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.9 | Times cited | 1 | Open Access | OpenAccess |
Notes | Vlaamse regering, Hercules Fund ; Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja, III 45006 ; Javna Agencija za Raziskovalno Dejavnost RS, J2-9237 P2-0091 ; Fonds Wetenschappelijk Onderzoek, G.0044.13N ; Ministerio de Ciencia, Innovación y Universidades; Universiteit Antwerpen, GOA project Solarpaint ; F.R.S.-FNRS, PDR project PROMOSPAN ; Consejo Superior de Investigaciones Cientificas; University of Liège, ARC project AIMED ; Ministry of Education, Science and Sport, M.ERA-NET project SIOX ; | Approved | Most recent IF: 3.9; 2020 IF: 3.108 | ||
Call Number | EMAT @ emat @c:irua:172059 | Serial | 6416 | ||
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Author | Bigiani, L.; Gasparotto, A.; Andreu, T.; Verbeeck, J.; Sada, C.; Modin, E.; Lebedev, O.I.; Morante, J.R.; Barreca, D.; Maccato, C. | ||||
Title | Au-manganese oxide nanostructures by a plasma-assisted process as electrocatalysts for oxygen evolution : a chemico-physical investigation | Type | A1 Journal article | ||
Year | 2020 | Publication | Advanced sustainable systems | Abbreviated Journal | |
Volume | Issue | Pages | 2000177-11 | ||
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Earth-abundant and eco-friendly manganese oxides are promising platforms for the oxygen evolution reaction (OER) in water electrolysis. Herein, a versatile and potentially scalable route to gold-decorated manganese oxide-based OER electrocatalysts is reported. In particular, MnxOy(MnO2, Mn2O3) host matrices are grown on conductive glasses by plasma assisted-chemical vapor deposition (PA-CVD), and subsequently functionalized with gold nanoparticles (guest) as OER activators by radio frequency (RF)-sputtering. The final selective obtainment of MnO2- or Mn2O3-based systems is then enabled by annealing under oxidizing or inert atmosphere, respectively. A detailed material characterization evidences the formation of high-purity Mn(x)O(y)dendritic nanostructures with an open morphology and an efficient guest dispersion into the host matrices. The tailoring of Mn(x)O(y)phase composition and host-guest interactions has a remarkable influence on OER activity yielding, for the best performing Au/Mn(2)O(3)system, a current density of approximate to 5 mA cm(-2)at 1.65 V versus the reversible hydrogen electrode (RHE) and an overpotential close to 300 mV at 1 mA cm(-2). Such results, comparing favorably with literature data on manganese oxide-based materials, highlight the importance of compositional control, as well as of surface and interface engineering, to develop low-cost and efficient anode nanocatalysts for water splitting applications. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000572376000001 | Publication Date | 2020-09-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2366-7486 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 7.1 | Times cited | 4 | Open Access | Not_Open_Access |
Notes | ; Padova University (DOR 2017-2019 and P-DiSC #03BIRD2018-UNIPD OXYGENA projects), as well as the INSTM Consortium (INSTMPD004 – NETTUNO project) and AMGA Foundation (Mn4Energy project), are gratefully acknowledged for financial support. The Qu-Ant-EM microscope was partially funded by the Hercules fund from the Flemish Government. J.V. acknowledges funding from a GOA project “Solarpaint” from the University of Antwerp and from EU H2020 823717 ESTEEM3 project. The authors thank Dr. Daniele Valbusa, Dr. Gianluca Corr, Dr. Andrea Gallo, and Dr. Dileep Khrishnan for helpful experimental assistance. ; esteem3TA; esteem3reported | Approved | Most recent IF: 7.1; 2020 IF: NA | ||
Call Number | UA @ admin @ c:irua:171937 | Serial | 6457 | ||
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Author | Bigiani, L.; Gasparotto, A.; Maccato, C.; Sada, C.; Verbeeck, J.; Andreu, T.; Morante, J.R.; Barreca, D. | ||||
Title | Dual improvement of beta-MnO₂ oxygen evolution electrocatalysts via combined substrate control and surface engineering | Type | A1 Journal article | ||
Year | 2020 | Publication | Chemcatchem | Abbreviated Journal | Chemcatchem |
Volume | Issue | Pages | 1-10 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The development of catalysts with high intrinsic activity towards the oxygen evolution reaction (OER) plays a critical role in sustainable energy conversion and storage. Herein, we report on the development of efficient (photo)electrocatalysts based on functionalized MnO(2)systems. Specifically,beta-MnO(2)nanostructures grown by plasma enhanced-chemical vapor deposition on fluorine-doped tin oxide (FTO) or Ni foams were decorated with Co(3)O(4)or Fe(2)O(3)nanoparticles by radio frequency sputtering. Upon functionalization, FTO-supported materials yielded a performance increase with respect to bare MnO2, with current densities at 1.65 Vvs. the reversible hydrogen electrode (RHE) up to 3.0 and 3.5 mA/cm(2)in the dark and under simulated sunlight, respectively. On the other hand, the use of highly porous and conductive Ni foam substrates enabled to maximize cooperative interfacial effects between catalyst components. The best performing Fe2O3/MnO(2)system provided a current density of 17.9 mA/cm(2)at 1.65 Vvs. RHE, an overpotential as low as 390 mV, and a Tafel slope of 69 mV/decade under dark conditions, comparing favorably with IrO(2)and RuO(2)benchmarks. Overall, the control of beta-MnO2/substrate interactions and the simultaneous surface property engineering pave the way to an efficient energy generation from abundant natural resources. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000571229000001 | Publication Date | 2020-09-18 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1867-3880; 1867-3899 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.5 | Times cited | 5 | Open Access | Not_Open_Access |
Notes | ; This work has been financially supported by Padova University DOR 2017-2019, P-DiSC #03BIRD2016-UNIPD and #03BIRD2018-UNIPD projects. A.G. acknowledges AMGA Foundation and INSTM Consortium. J.V. gratefully acknowledges funding from the GOA project “Solarpaint” of the University of Antwerp and the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717-ESTEEM3. ; esteem3TA; esteem3reported | Approved | Most recent IF: 4.5; 2020 IF: 4.803 | ||
Call Number | UA @ admin @ c:irua:171949 | Serial | 6493 | ||
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Author | Bigiani, L.; Andreu, T.; Maccato, C.; Fois, E.; Gasparotto, A.; Sada, C.; Tabacchi, G.; Krishnan, D.; Verbeeck, J.; Ramon Morante, J.; Barreca, D. | ||||
Title | Engineering Au/MnO₂ hierarchical nanoarchitectures for ethanol electrochemical valorization | Type | A1 Journal article | ||
Year | 2020 | Publication | Journal Of Materials Chemistry A | Abbreviated Journal | J Mater Chem A |
Volume | 8 | Issue | 33 | Pages | 16902-16907 |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | The design of eco-friendly electrocatalysts for ethanol valorization is an open challenge towards sustainable hydrogen production. Herein we present an original fabrication route to effective electrocatalysts for the ethanol oxidation reaction (EOR). In particular, hierarchical MnO(2)nanostructures are grown on high-area nickel foam scaffolds by a plasma-assisted strategy and functionalized with low amounts of optimally dispersed Au nanoparticles. This strategy leads to catalysts with a unique morphology, designed to enhance reactant-surface contacts and maximize active site utilization. The developed nanoarchitectures show superior performances for ethanol oxidation in alkaline media. We reveal that Au decoration boosts MnO(2)catalytic activity by inducing pre-dissociation and pre-oxidation of the adsorbed ethanol molecules. This evidence validates our strategy as an effective route for the development of green electrocatalysts for efficient electrical-to-chemical energy conversion. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000562931300008 | Publication Date | 2020-07-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2050-7488; 2050-7496 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 11.9 | Times cited | 16 | Open Access | OpenAccess |
Notes | ; This work was financially supported by Padova University DOR 2016-2019 and P-DiSC #03BIRD2018-UNIPD OXYGENA projects, as well as by the INSTM Consortium (INSTMPD004 – NETTUNO), AMGA Foundation Mn4Energy project and Insubria University FAR2018. J. V. and D. K. acknowledge funding from the Flemish Government (Hercules), GOA project “Solarpaint” (Antwerp University) and European Union's H2020 programme under grant agreement no. 823717 ESTEEM3. The authors are grateful to Dr Gianluca Corr for skillful technical support. ; esteem3TA; esteem3reported | Approved | Most recent IF: 11.9; 2020 IF: 8.867 | ||
Call Number | UA @ admin @ c:irua:171989 | Serial | 6506 | ||
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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. | ||||
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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 | ||
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Author | Chen, B.; Gauquelin, N.; Jannis, D.; Cunha, D.M.; Halisdemir, U.; Piamonteze, C.; Lee, J.H.; Belhadi, J.; Eltes, F.; Abel, S.; Jovanovic, Z.; Spreitzer, M.; Fompeyrine, J.; Verbeeck, J.; Bibes, M.; Huijben, M.; Rijnders, G.; Koster, G. | ||||
Title | Strain-engineered metal-to-insulator transition and orbital polarization in nickelate superlattices integrated on silicon | Type | A1 Journal article | ||
Year | 2020 | Publication | Advanced Materials | Abbreviated Journal | Adv Mater |
Volume | Issue | Pages | 2004995 | ||
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Epitaxial growth of SrTiO3 (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO3/LaFeO3 SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy. Both sets of SLs show a similar thickness-driven metal-to-insulator transition, albeit with resistivity and transition temperature modified by the different amounts of strain. In particular, the large tensile strain promotes a pronounced Ni 3dx2-y2 orbital polarization for the SL grown on Si/STO, comparable to that reported for LaNiO3 SL epitaxially strained to DyScO3 substrate. Those results illustrate the ability to integrate oxide SLs on silicon with structure and property approaching their counterparts grown on STO single crystal, and also open up new prospects of strain engineering in functional oxides based on the Si platform. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000588146500001 | Publication Date | 2020-11-11 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0935-9648 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 29.4 | Times cited | 18 | Open Access | OpenAccess |
Notes | ; This work is supported by the international M-ERA.NET project SIOX (project 4288) and H2020 project ULPEC (project 732642). M.S. acknowledges funding from Slovenian Research Agency (Grants No. J2-9237 and No. P2-0091). This work received support from the ERC CoG MINT (#615759) and from a PHC Van Gogh grant. M.B. thanks the French Academy of Science and the Royal Netherlands Academy of Arts and Sciences for supporting his stays in the Netherlands. This project has received funding as a transnational access project from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. N.G. and J.V. acknowledge GOA project “Solarpaint” of the University of Antwerp. ; esteem3TA; esteem3reported | Approved | Most recent IF: 29.4; 2020 IF: 19.791 | ||
Call Number | UA @ admin @ c:irua:173516 | Serial | 6617 | ||
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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. | ||||
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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 | ||
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Author | Savchenko, T.M.; Buzzi, M.; Howald, L.; Ruta, S.; Vijayakumar, J.; Timm, M.; Bracher, D.; Saha, S.; Derlet, P.M.; Béché, A.; Verbeeck, J.; Chantrell, R.W.; Vaz, C.A.F.; Nolting, F.; Kleibert, A. | ||||
Title | Single femtosecond laser pulse excitation of individual cobalt nanoparticles | Type | A1 Journal article | ||
Year | 2020 | Publication | Physical Review B | Abbreviated Journal | Phys Rev B |
Volume | 102 | Issue | 20 | Pages | 205418 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Laser-induced manipulation of magnetism at the nanoscale is a rapidly growing research topic with potential for applications in spintronics. In this work, we address the role of the scattering cross section, thermal effects, and laser fluence on the magnetic, structural, and chemical stability of individual magnetic nanoparticles excited by single femtosecond laser pulses. We find that the energy transfer from the fs laser pulse to the nanoparticles is limited by the Rayleigh scattering cross section, which in combination with the light absorption of the supporting substrate and protective layers determines the increase in the nanoparticle temperature. We investigate individual Co nanoparticles (8 to 20 nm in size) as a prototypical model system, using x-ray photoemission electron microscopy and scanning electron microscopy upon excitation with single femtosecond laser pulses of varying intensity and polarization. In agreement with calculations, we find no deterministic or stochastic reversal of the magnetization in the nanoparticles up to intensities where ultrafast demagnetization or all-optical switching is typically reported in thin films. Instead, at higher fluences, the laser pulse excitation leads to photo-chemical reactions of the nanoparticles with the protective layer, which results in an irreversible change in the magnetic properties. Based on our findings, we discuss the conditions required for achieving laser-induced switching in isolated nanomagnets. | ||||
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Language | Wos | 000589602000005 | Publication Date | 2020-11-16 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2469-9950 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 3.7 | Times cited | 1 | Open Access | OpenAccess |
Notes | This work received funding by the Swiss National Foundation (SNF) (Grants No. 200021160186 and No. 2002153540), the Swiss Nanoscience Institute (SNI) (Grant No. SNI P1502), the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 737093 (FEMTOTERABYTE), and the COST Action CA17123 (MAGNETOFON). Part of this work was performed at the SIM beamline of the Swiss Light Source (SLS), Paul Scherrer Institut, Villigen, Switzerland. Part of the simulations were undertaken on the VIKING cluster, which is a high-performance compute facility provided by the University of York. We kindly acknowledge Anja Weber from PSI for preparation of substrates with marker structures. A.B. and Jo Verbeeck acknowledge funding through FWO Project No. G093417N (“Compressed sensing enabling low dose imaging in transmission electron microscopy”) from the Flanders Research Fund. Jo Verbeeck acknowledges funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 823717 – ESTEEM3. S.S. acknowledges ETH Zurich Post-Doctoral fellowship and Marie Curie actions for people COFUND program.; esteem3JRA; esteem3reported | Approved | Most recent IF: 3.7; 2020 IF: 3.836 | ||
Call Number | EMAT @ emat @c:irua:174273 | Serial | 6669 | ||
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Author | Van Dijck, J.G.; Mampuys, P.; Ching, H.Y.V.; Krishnan, D.; Baert, K.; Hauffman, T.; Verbeeck, J.; Van Doorslaer, S.; Maes, B.U.W.; Dorbec, M.; Buekenhoudt, A.; Meynen, V. | ||||
Title | Synthesis – properties correlation and the unexpected role of the titania support on the Grignard surface modification | Type | A1 Journal article | ||
Year | 2020 | Publication | Applied Surface Science | Abbreviated Journal | Appl Surf Sci |
Volume | 527 | Issue | Pages | 146851-17 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY); Applied Electrochemistry & Catalysis (ELCAT) | ||||
Abstract | While the impact of reaction conditions on surface modification with Grignard reactants has been studied for silica supports, such information is absent for metal oxides like titania. Differences between modified titania and silica are observed, making it paramount to explore the reaction mechanism. A detailed study on the impact of the reaction conditions is reported, with a focus on the chain length of the alkyl Grignard reactant, its concentration, the reaction time and temperature, and the type of titania support. While the increase in the chain length reduces the amount of organic groups on the surface, the concentration, time and temperature show little/no influence on the modification degree. However, the type of titania support used and the percentage of amorphous phase present has a significant impact on the amount of grafted groups. Even though the temperature and concentration show no clear impact on the modification degree, they can cause changes in the surface hydroxyl population, which are thus not linked to the modification degree. Furthermore, the titania support is reduced during functionalization. This reduction dependents on the reaction temperature, the titania support and the chain length of the Grignard reactant. Similarly, this reduction is not linked to the modification degree. | ||||
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Language | Wos | 000564205300003 | Publication Date | 2020-06-03 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0169-4332 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 6.7 | Times cited | 5 | Open Access | OpenAccess |
Notes | ; The FWO (Fonds Wetenschappelijk Onderzoek) is gratefully acknowledged for the VITO-FWO grant of fellow Jeroen G. Van Dijck (11W9416N) and the financial support granted in project GO12712N. The E.U. is acknowledged for H.Y. Vincent Ching's H2020-MSCA-IF (grant number 792946, iSPY). Dileep Krishnan and Johan Verbeeck acknowledge funding from GOA project “solarpaint” of the University of Antwerp. ; | Approved | Most recent IF: 6.7; 2020 IF: 3.387 | ||
Call Number | UA @ admin @ c:irua:169722 | Serial | 6712 | ||
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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. | ||||
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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 | ||
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Author | Guzzinati, G.; Das, P.P.; Zompra, A., A.; Nicopoulos, S.; Verbeeck, J. | ||||
Title | Electron energy loss spectra of several organic compounds | Type | Dataset | ||
Year | 2020 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | |||
Keywords | Dataset; Electron microscopy for materials research (EMAT) | ||||
Abstract | We placed crystals of different compounds to explore the possibility of fingerprinting them through EELS. Here are representative datasets of 7 different compounds: b-cyclodextrin hexacarboxy cyclohexane tannin TH-15 peptide TH-27 peptide two different forms of piroxicam The datasets were collected at EMAT, using a monochromated FEI Titan3 TEM, within the scope of an EUSMI request. More information as well as analysis methodologies adopted for the data are detailed in the paper: Das et al. “Reliable Characterization of Organic & Pharmaceutical Compounds with High Resolution Monochromated EEL Spectroscopy”, Polymers 2020, 12(7), 1434. | ||||
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ISSN | ISBN | Additional Links | UA library record | ||
Impact Factor | Times cited | Open Access | |||
Notes | Approved | Most recent IF: NA | |||
Call Number | UA @ admin @ c:irua:180654 | Serial | 6866 | ||
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Author | Müller-Caspary, K.; Grieb, T.; Müßener, J.; Gauquelin, N.; Hille, P.; Schörmann, J.; Verbeeck, J.; Van Aert, S.; Eickhoff, M.; Rosenauer, A. | ||||
Title | Electrical Polarization in AlN/GaN Nanodisks Measured by Momentum-Resolved 4D Scanning Transmission Electron Microscopy | Type | A1 Journal article | ||
Year | 2019 | Publication | Physical review letters | Abbreviated Journal | Phys Rev Lett |
Volume | 122 | Issue | 10 | Pages | 106102 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | We report the mapping of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures at unit cell resolution as a key for the correlation of optical and structural phenomena in semiconductor optoelectronics. Momentum-resolved aberration-corrected scanning transmission electron microscopy is employed as a new imaging mode that simultaneously provides four-dimensional data in real and reciprocal space. We demonstrate how internal mesoscale and atomic electric fields can be separated in an experiment, which is verified by comprehensive dynamical simulations of multiple electron scattering. A mean difference of 5.3 +- 1.5 MV/cm is found for the polarization-induced electric fields in AlN and GaN, being in accordance with dedicated simulations and photoluminescence measurements in previous publications. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000461067700007 | Publication Date | 2019-03-11 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0031-9007 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 8.462 | Times cited | 26 | Open Access | OpenAccess |
Notes | The authors gratefully acknowledge the help of Natalie Claes for analyzing the EDX data. K. M.-C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association within the Helmholtz Young Investigator Group moreSTEM under Contract No. VHNG- 1317 at Forschungszentrum Jülich in Germany. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. N. G. and J. V. acknowledge funding from the Geconcentreerde Onderzoekacties project Solarpaint of the University of Antwerp. T. G. and A. R. acknowledge support from the Deutsche Forschungsgemeinschaft (Germany) under Contract No. RO2057/8-3. This work also received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (Contract No. 770887). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project funding (G.0368.15N).; Helmholtz Association, VH-NG-1317 ; Forschungszentrum Jülich; Flemish Government; Universiteit Antwerpen; Deutsche Forschungsgemeinschaft, RO2057/8-3 ; H2020 European Research Council, 770887 ; Fonds Wetenschappelijk Onderzoek, G.0368.15N ; | Approved | Most recent IF: 8.462 | ||
Call Number | UA @ lucian @UA @ admin @ c:irua:158120 | Serial | 5157 | ||
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Author | Jannis, D.; Müller-Caspary, K.; Béché, A.; Oelsner, A.; Verbeeck, J. | ||||
Title | Spectroscopic coincidence experiments in transmission electron microscopy | Type | A1 Journal article | ||
Year | 2019 | Publication | Applied physics letters | Abbreviated Journal | Appl Phys Lett |
Volume | 114 | Issue | 14 | Pages | 143101 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | We demonstrate the feasibility of coincidence measurements on a conventional transmission electron microscope, revealing the temporal correlation between electron energy loss spectroscopy (EELS) and energy dispersive X-ray (EDX) spectroscopy events. We make use of a delay line detector with ps-range time resolution attached to a modified EELS spectrometer. We demonstrate that coincidence between both events, related to the excitation and deexcitation of atoms in a crystal, provides added information not present in the individual EELS or EDX spectra. In particular, the method provides EELS with a significantly suppressed or even removed background, overcoming the many difficulties with conventional parametric background fitting as it uses no assumptions on the shape of the background, requires no user input and does not suffer from counting noise originating from the background signal. This is highly attractive, especially when low concentrations of elements need to be detected in a matrix of other elements. |
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000464450200022 | Publication Date | 2019-04-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.411 | Times cited | 18 | Open Access | OpenAccess |
Notes | Fonds Wetenschappelijk Onderzoek, G093417 ; Horizon 2020 Framework Programme, 823717 ESTEEM3 ; Helmholtz Association, VH-NG-1327 ; | Approved | Most recent IF: 3.411 | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:159155 | Serial | 5168 | ||
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Author | Vanrompay, H.; Béché, A.; Verbeeck, J.; Bals, S. | ||||
Title | Experimental Evaluation of Undersampling Schemes for Electron Tomography of Nanoparticles | Type | A1 Journal article | ||
Year | 2019 | Publication | Particle and particle systems characterization | Abbreviated Journal | Part Part Syst Char |
Volume | 36 | Issue | 36 | Pages | 1900096 |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | One of the emerging challenges in the field of 3D characterization of nanoparticles by electron tomography is to avoid degradation and deformation of the samples during the acquisition of a tilt series. In order to reduce the required electron dose, various undersampling approaches have been proposed. These methods include lowering the number of 2D projection images, reducing the probe current during the acquisition, and scanning a smaller number of pixels in the 2D images. A comparison is made between these approaches based on tilt series acquired for a gold nanoparticle. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000477679400014 | Publication Date | 2019-05-29 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0934-0866 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 4.474 | Times cited | 12 | Open Access | Not_Open_Access |
Notes | H.V. acknowledges financial support by the Research Foundation Flanders (FWO Grant No. 1S32617N). A.B. and J.V. acknowledge FWO project 6093417N “Compressed sensing enabling low dose imaging in STEM.” The authors thank G. González-Rubio, A. Sánchez-Iglesias, and L.M. Liz-Marzán for provision of the samples. | Approved | Most recent IF: 4.474 | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:159986 | Serial | 5175 | ||
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Author | Guzzinati, G.; Ghielens, W.; Mahr, C.; Béché, A.; Rosenauer, A.; Calders, T.; Verbeeck, J. | ||||
Title | Electron Bessel beam diffraction for precise and accurate nanoscale strain mapping | Type | A1 Journal article | ||
Year | 2019 | Publication | Applied physics letters | Abbreviated Journal | Appl Phys Lett |
Volume | 114 | Issue | 24 | Pages | 243501 |
Keywords | A1 Journal article; ADReM Data Lab (ADReM); Electron microscopy for materials research (EMAT) | ||||
Abstract | Strain has a strong effect on the properties of materials and the performance of electronic devices. Their ever shrinking size translates into a constant demand for accurate and precise measurement methods with a very high spatial resolution. In this regard, transmission electron microscopes are key instruments thanks to their ability to map strain with a subnanometer resolution. Here, we present a method to measure strain at the nanometer scale based on the diffraction of electron Bessel beams. We demonstrate that our method offers a strain sensitivity better than 2.5 × 10−4 and an accuracy of 1.5 × 10−3, competing with, or outperforming, the best existing methods with a simple and easy to use experimental setup. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000472599100019 | Publication Date | 2019-06-17 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0003-6951 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.411 | Times cited | 17 | Open Access | OpenAccess |
Notes | Deutsche Forschungsgemeinschaft, RO2057/12-2 ; Fonds Wetenschappelijk Onderzoek, G.0934.17N ; | Approved | Most recent IF: 3.411 | ||
Call Number | EMAT @ emat @UA @ admin @ c:irua:160119 | Serial | 5181 | ||
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Author | Becker, M.; Guzzinati, G.; Béché, A.; Verbeeck, J.; Batelaan, H. | ||||
Title | Asymmetry and non-dispersivity in the Aharonov-Bohm effect | Type | A1 Journal article | ||
Year | 2019 | Publication | Nature communications | Abbreviated Journal | Nat Commun |
Volume | 10 | Issue | 10 | Pages | 1700 |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Decades ago, Aharonov and Bohm showed that electrons are affected by electromagnetic potentials in the absence of forces due to fields. Zeilinger's theorem describes this absence of classical force in quantum terms as the “dispersionless” nature of the Aharonov-Bohm effect. Shelankov predicted the presence of a quantum “force” for the same Aharonov-Bohm physical system as elucidated by Berry. Here, we report an experiment designed to test Shelankov's prediction and we provide a theoretical analysis that is intended to elucidate the relation between Shelankov's prediction and Zeilinger's theorem. The experiment consists of the Aharonov-Bohm physical system; free electrons pass a magnetized nanorod and far-field electron diffraction is observed. The diffraction pattern is asymmetric confirming one of Shelankov's predictions and giving indirect experimental evidence for the presence of a quantum “force”. Our theoretical analysis shows that Zeilinger's theorem and Shelankov's result are both special cases of one theorem. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000464338100011 | Publication Date | 2019-04-12 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2041-1723 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 12.124 | Times cited | 12 | Open Access | OpenAccess |
Notes | ; H.B. would like to thank Michael Berry for bringing the presence of a quantum “force” to our attention. A.B., G.G. and J.V. acknowledge support from the European Research Council under the 7th Framework Program (FP7) ERC Starting Grant 278510 VORTEX. G.G. acknowledges support from the Fonds Wetenschappelijk Onderzoek -Vlaanderen (FWO). M.B. and H.B. acknowledge support by the U.S. National Science Foundation under Grant No. 1602755. ; | Approved | Most recent IF: 12.124 | ||
Call Number | UA @ admin @ c:irua:159341 | Serial | 5241 | ||
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Author | Müller-Caspary, K.; Krause, F.F.; Winkler, F.; Béché, A.; Verbeeck, J.; Van Aert, S.; Rosenauer, A. | ||||
Title | Comparison of first moment STEM with conventional differential phase contrast and the dependence on electron dose | Type | A1 Journal article | ||
Year | 2019 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 203 | Issue | 203 | Pages | 95-104 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | This study addresses the comparison of scanning transmission electron microscopy (STEM) measurements of momentum transfers using the first moment approach and the established method that uses segmented annular detectors. Using an ultrafast pixelated detector to acquire four-dimensional, momentum-resolved STEM signals, both the first moment calculation and the calculation of the differential phase contrast (DPC) signals are done for the same experimental data. In particular, we investigate the ability to correct the segment-based signal to yield a suitable approximation of the first moment for cases beyond the weak phase object approximation. It is found that the measurement of momentum transfers using segmented detectors can approach the first moment measurement as close as 0.13 h/nm in terms of a root mean square (rms) difference in 10 nm thick SrTiO3 for a detector with 16 segments. This amounts to 35% of the rms of the momentum transfers. In addition, we present a statistical analysis of the precision of first moment STEM as a function of dose. For typical experimental settings with recent hardware such as a Medipix3 Merlin camera attached to a probe-corrected STEM, we find that the precision of the measurement of momentum transfers stagnates above certain doses. This means that other instabilities such as specimen drift or scan noise have to be taken into account seriously for measurements that target, e.g., the detection of bonding effects in the charge density. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000465021000013 | Publication Date | 2018-12-30 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 25 | Open Access | OpenAccess |
Notes | ; The direct electron detector (Medipix3 Merlin) was funded by the Hercules fund from the Flemish Government. K. Muller-Caspary acknowledges funding from the Initiative and Network Fund of the Helmholtz Association within the framework of the Helmholtz Young Investigator Group moreSTEM (VH-NG-1317) at Forschungszentrum Julich, Germany. F. F. Krause acknowledges funding from the Central Research Development Fund of the University of Bremen, Germany. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) and the Research Fund of the University of Antwerp. ; | Approved | Most recent IF: 2.843 | ||
Call Number | UA @ admin @ c:irua:160213 | Serial | 5242 | ||
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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. | ||||
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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 | ||
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Author | Gan, Y.; Christensen, D.V.; Zhang, Y.; Zhang, H.; Krishnan, D.; Zhong, Z.; Niu, W.; Carrad, D.J.; Norrman, K.; von Soosten, M.; Jespersen, T.S.; Shen, B.; Gauquelin, N.; Verbeeck, J.; Sun, J.; Pryds, N.; Chen, Y. | ||||
Title | Diluted oxide interfaces with tunable ground states | Type | A1 Journal article | ||
Year | 2019 | Publication | Advanced materials | Abbreviated Journal | Adv Mater |
Volume | 31 | Issue | 10 | Pages | 1805970 |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | The metallic interface between two oxide insulators, such as LaAlO3/SrTiO3 (LAO/STO), provides new opportunities for electronics and spintronics. However, due to the presence of multiple orbital populations, tailoring the interfacial properties such as the ground state and metal-insulator transitions remains challenging. Here, an unforeseen tunability of the phase diagram of LAO/STO is reported by alloying LAO with a ferromagnetic LaMnO3 insulator without forming lattice disorder and at the same time without changing the polarity of the system. By increasing the Mn-doping level, x, of LaAl1-xMnxO3/STO (0 <= x <= 1), the interface undergoes a Lifshitz transition at x = 0.225 across a critical carrier density of n(c) = 2.8 x 10(13) cm(-2), where a peak T-SC approximate to 255 mK of superconducting transition temperature is observed. Moreover, the LaAl1-xMnxO3 turns ferromagnetic at x >= 0.25. Remarkably, at x = 0.3, where the metallic interface is populated by only d(xy) electrons and just before it becomes insulating, a same device with both signatures of superconductivity and clear anomalous Hall effect (7.6 x 10(12) cm(-2) < n(s) <= 1.1 x 10(13) cm(-2)) is achieved reproducibly. This provides a unique and effective way to tailor oxide interfaces for designing on-demand electronic and spintronic devices. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000460329300004 | Publication Date | 2019-01-14 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0935-9648 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 19.791 | Times cited | 31 | Open Access | Not_Open_Access |
Notes | ; The authors thank the technical help from J. Geyti. J.R.S. acknowledges the support of the National Basic Research of China (2016YFA0300701, 2018YFA0305704), the National Natural Science Foundation of China (11520101002), and the Key Program of the Chinese Academy of Sciences. N.G., D.K., and J.V. acknowledge funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp, Belgium. ; | Approved | Most recent IF: 19.791 | ||
Call Number | UA @ admin @ c:irua:158553 | Serial | 5245 | ||
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