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Author Liao, Z.; Gauquelin, N.; Green, R.J.; Macke, S.; Gonnissen, J.; Thomas, S.; Zhong, Z.; Li, L.; Si, L.; Van Aert, S.; Hansmann, P.; Held, K.; Xia, J.; Verbeeck, J.; Van Tendeloo, G.; Sawatzky, G.A.; Koster, G.; Huijben, M.; Rijnders, G.
Title Thickness dependent properties in oxide heterostructures driven by structurally induced metal-oxygen hybridization variations Type A1 Journal article
Year 2017 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater
Volume 27 Issue 17 Pages 1606717
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Thickness-driven electronic phase transitions are broadly observed in different types of functional perovskite heterostructures. However, uncertainty remains whether these effects are solely due to spatial confinement, broken symmetry, or rather to a change of structure with varying film thickness. Here, this study presents direct evidence for the relaxation of oxygen-2p and Mn-3d orbital (p-d) hybridization coupled to the layer-dependent octahedral tilts within a La2/3Sr1/3MnO3 film driven by interfacial octahedral coupling. An enhanced Curie temperature is achieved by reducing the octahedral tilting via interface structure engineering. Atomically resolved lattice, electronic, and magnetic structures together with X-ray absorption spectroscopy demonstrate the central role of thickness-dependent p-d hybridization in the widely observed dimensionality effects present in correlated oxide heterostructures.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000400449200011 Publication Date (up) 2017-03-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1616-301x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 55 Open Access
Notes M.H., G.K., and G.R. acknowledge funding from DESCO program of the Dutch Foundation for Fundamental Research on Matter (FOM) with financial support from the Netherlands Organization for Scientific Research (NWO). This work was funded by the European Union Council under the 7th Framework Program (FP7) Grant No. NMP3-LA-2010-246102 IFOX. J.V. and S.V.A. acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (Grant Nos. G.0044.13N, G.0374.13N, G.0368.15N, and G.0369.15N). The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. N.G. acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 278510 VORTEX. N.G., J.G., S.V.A., and J.V. acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative (Reference No. 312483-ESTEEM2). The Canadian work was supported by NSERC and the Max Planck-UBC Centre for Quantum Materials. Some experiments for this work were performed at the Canadian Light Source, which was funded by the Canada Foundation for Innovation, NSERC, the National Research Council of Canada, the Canadian Institutes of Health Research, the Government of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan. Approved Most recent IF: 12.124
Call Number UA @ admin @ c:irua:152640 Serial 5367
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Author Guzzinati, G.; Béché, A.; Lourenço-Martins, H.; Martin, J.; Kociak, M.; Verbeeck, J.
Title Probing the symmetry of the potential of localized surface plasmon resonances with phase-shaped electron beams Type A1 Journal article
Year 2017 Publication Nature communications Abbreviated Journal Nat Commun
Volume 8 Issue 8 Pages 14999
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Plasmonics, the science and technology of the interaction of light with metallic objects, is fundamentally changing the way we can detect, generate and manipulate light. Although the field is progressing swiftly, thanks to the availability of nanoscale manufacturing and analysis methods, fundamental properties such as the plasmonic excitations’ symmetries cannot be accessed directly, leading to a partial, sometimes incorrect, understanding of their properties. Here we overcome this limitation by deliberately shaping the wave function of an electron beam to match a plasmonic excitations’ symmetry in a modified transmission electron microscope. We show experimentally and theoretically that this offers selective detection of specific plasmon modes within metallic nanoparticles, while excluding modes with other symmetries. This method resembles the widespread use of polarized light for the selective excitation of plasmon modes with the advantage of locally probing the response of individual plasmonic objects and a far wider range of symmetry selection criteria.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000399084300001 Publication Date (up) 2017-04-12
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 84 Open Access OpenAccess
Notes ; We thank F.J. Garcia de Abajo and D.M. Ugarte for interesting and fruitful discussion. This work was supported by funding from the European Research Council under the 7th Framework Program (FP7) ERC Starting Grant 278510 VORTEX. Financial support from the European Union under the Framework 7 program under a contract for an Integrated Infrastructure Initiative (Reference number 312483 ESTEEM2) is also gratefully acknowledged. Aluminum nanostructures were fabricated using the Nanomat nanofabrication facility. ; Approved Most recent IF: 12.124
Call Number EMAT @ emat @ c:irua:142205UA @ admin @ c:irua:142205 Serial 4548
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Author Smolin, S.Y.; Choquette, A.K.; Wilks, R.G.; Gauquelin, N.; Félix, R.; Gerlach, D.; Ueda, S.; Krick, A.L.; Verbeeck, J.; Bär, M.; Baxter, J.B.; May, S.J.
Title Energy Level Alignment and Cation Charge States at the LaFeO3/LaMnO3(001) Heterointerface Type A1 Journal article
Year 2017 Publication Advanced Materials Interfaces Abbreviated Journal Adv Mater Interfaces
Volume 4 Issue 4 Pages 1700183
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The electronic properties of LaFeO 3 /LaMnO 3 epitaxial heterojunctions are investigated to determine the valence and conduction band offsets and the nominal Mn and Fe valence states at the interface. Studying a systematic series of (LaFeO 3 ) n /(LaMnO 3 ) m bilayers (m ≈ 50) epitaxially grown in the (001) orientation using molecular beam epitaxy, layer-resolved electron energy loss spectroscopy reveals a lack of significant interfacial charge transfer, with a nominal 3+ valence state observed for both Mn and Fe across the interface. Through a combination of variable angle spectroscopic ellipsometry and hard X-ray photoelectron spectroscopy, type I energy level alignments are obtained at the LaFeO 3 /LaMnO 3 interface with positive valence and conduction band offsets of (1.20 ± 0.07) eV and (0.5–0.7 ± 0.3) eV, respectively, with minimal band bending. Variable temperature resistivity measurements reveal that the bilayers remain insulating and that the presence of the heterojunction does not result in a conducting interface.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000406068400011 Publication Date (up) 2017-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2196-7350 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.279 Times cited 14 Open Access Not_Open_Access
Notes The authors thank Dmytro Nykypanchuk for assistance with the near- infrared ellipsometry measurement of the LaMnO 3 film. S.Y.S., A.K.C., J.B.B, and S.J.M. acknowledge funding from the National Science Foundation under grant number ECCS-1201957. S.Y.S. acknowledges additional funding from the German Academic Exchange Service (DAAD) through the Research Internships in Science and Engineering (RISE) professional program 2015 ID 5708457. A.L.K. was funded by the National Science Foundation under grant number DMR-1151649. J.V. and N.G. acknowledge funding through the GOA project “Solarpaint” of the University of Antwerp and from the FWO project G.0044.13N (Charge ordering). The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. Ellipsometry measurements of the LaMnO 3 film were carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-ACO2-98CH10886. S.U. would like to thank the staff of HiSOR, Hiroshima University, and JAEA/Spring-8 for the development of HAXPES at BL15XU of SPring-8. The HAXPES measurements were performed with approval of NIMS Synchrotron X-ray Station (Proposal No. 2015B4601), and were partly supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The authors also thank HZB for the allocation of synchrotron radiation beamtime for HAXPES/XANES measurements. R.G.W., R.F, and M.B. are grateful to the Impuls- und Vernetzungsfonds of the Helmholtz Association (VH-NG-423).; National Science Foundation, ECCS-1201957 DMR-1151649 ; Deutscher Akademischer Austauschdienst, 2015 ID 5708457 ; GOA project; Fonds Wetenschappelijk Onderzoek, G.0044.13N ; Flemish Government; U.S. Department of Energy, DE-ACO2-98CH10886 ; Vernetzungsfonds of the Helmholtz Association, VH-NG-423 ; Approved Most recent IF: 4.279
Call Number EMAT @ emat @ c:irua:142346UA @ admin @ c:irua:142346 Serial 4553
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Author Kleibert, A.; Balan, A.; Yanes, R.; Derlet, P.M.; Vaz, C.A.F.; Timm, M.; Fraile Rodríguez, A.; Béché, A.; Verbeeck, J.; Dhaka, R.S.; Radovic, M.; Nowak, U.; Nolting, F.
Title Direct observation of enhanced magnetism in individual size- and shape-selected 3d transition metal nanoparticles Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 95 Issue 95 Pages 195404
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Magnetic nanoparticles are critical building blocks for future technologies ranging from nanomedicine to spintronics. Many related applications require nanoparticles with tailored magnetic properties. However, despite significant efforts undertaken towards this goal, a broad and poorly understood dispersion of magnetic properties is reported, even within monodisperse samples of the canonical ferromagnetic 3d transition metals. We address this issue by investigating the magnetism of a large number of size- and shape-selected, individual nanoparticles of Fe, Co, and Ni using a unique set of complementary characterization techniques. At room temperature, only superparamagnetic behavior is observed in our experiments for all Ni nanoparticles within the investigated sizes, which range from 8 to 20 nm. However, Fe and Co nanoparticles can exist in two distinct magnetic states at any size in this range: (i) a superparamagnetic state, as expected from the bulk and surface anisotropies known for the respective materials and as observed for Ni, and (ii) a state with unexpected stable magnetization at room temperature. This striking state is assigned to significant modifications of the magnetic properties arising from metastable lattice defects in the core of the nanoparticles, as concluded by calculations and atomic structural characterization. Also related with the structural defects, we find that the magnetic state of Fe and Co nanoparticles can be tuned by thermal treatment enabling one to tailor their magnetic properties for applications. This paper demonstrates the importance of complementary single particle investigations for a better understanding of nanoparticle magnetism and for full exploration of their potential for applications.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000400665300002 Publication Date (up) 2017-05-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 21 Open Access OpenAccess
Notes We thank A. Weber, R. Schelldorfer, and J. Krbanjevic (Paul Scherrer Institut) for technical assistance. This paper was supported by the Swiss Nanoscience Institute, University of Basel. A.F.R. acknowledges support from the MICIIN “Ramón y Cajal” Programme. A.B. and J.V. acknowledge funding from the European Union under the European Research Council (ERC) Starting Grant No. 278510 VORTEX and under a contract for Integrated Infrastructure Initiative ESTEEM2 No. 312483. R.Y. and U.N. thank the Deutsche Forschungsgemeinschaft for financial support via Sonderforschungsbereich 1214. Part of this work was performed at the Surface/Interface: Microscopy (SIM) beamline of the Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland. Approved Most recent IF: 3.836
Call Number EMAT @ emat @ c:irua:143634UA @ admin @ c:irua:143634 Serial 4575
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Author Pullini, D.; Sgroi, M.; Mahmoud, A.; Gauquelin, N.; Maschio, L.; Lorenzo-Ferrari, A.M.; Groenen, R.; Damen, C.; Rijnders, G.; van den Bos, K.H.W.; Van Aert, S.; Verbeeck, J.
Title One step toward a new generation of C-MOS compatible oxide p-n junctions: Structure of the LSMO/ZnO interface elucidated by an experimental and theoretical synergic work Type A1 Journal article
Year 2017 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
Volume 9 Issue 9 Pages 20974-20980
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Heterostructures formed by La0.7Sr0.3MnO3/ZnO (LSMO/ZnO) interfaces exhibit extremely interesting electronic properties making them promising candidates for novel oxide p–n junctions, with multifunctional features. In this work, the structure of the interface is studied through a combined experimental/theoretical approach. Heterostructures were grown epitaxially and homogeneously on 4″ silicon wafers, characterized by advanced electron microscopy imaging and spectroscopy and simulated by ab initio density functional theory calculations. The simulation results suggest that the most stable interface configuration is composed of the (001) face of LSMO, with the LaO planes exposed, in contact with the (112̅0) face of ZnO. The ab initio predictions agree well with experimental high-angle annular dark field scanning transmission electron microscopy images and confirm the validity of the suggested structural model. Electron energy loss spectroscopy confirms the atomic sharpness of the interface. From statistical parameter estimation theory, it has been found that the distances between the interfacial planes are displaced from the respective ones of the bulk material. This can be ascribed to the strain induced by the mismatch between the lattices of the two materials employed
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000404090000079 Publication Date (up) 2017-05-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1944-8244 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.504 Times cited 4 Open Access OpenAccess
Notes Financial support is acknowledged from the European Commission – DG research and innovation to the collaborative research project named Interfacing oxides (IFOX, Contract No. NMP3-LA-2010-246102). N.G. and J.V. acknowledge the European Union (EU) Council under the 7th Framework Program (FP7) ERC Starting Grant 278510 VORTEX for support. S.V.A. and K.H.W.B. acknowledge financial support from the Research Foundation Flanders through project fundings (G.0374.13N , G.0368.15N, and G.0369.15N) and a Ph.D. research grant to K.H.W.B. The microscope was partly funded by the Hercules Fund from the Flemish Government. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. CINECA is acknowledged for computational facilities (Iscra project HP10CMO1UP). Approved Most recent IF: 7.504
Call Number EMAT @ emat @ c:irua:144431UA @ admin @ c:irua:144431 Serial 4621
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Author Bliokh, K.Y.; Ivanov, I.P.; Guzzinati, G.; Clark, L.; Van Boxem, R.; Béché, A.; Juchtmans, R.; Alonso, M.A.; Schattschneider, P.; Nori, F.; Verbeeck, J.
Title Theory and applications of free-electron vortex states Type A1 Journal article
Year 2017 Publication Physics reports Abbreviated Journal Phys Rep
Volume 690 Issue 690 Pages 1-70
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Both classical and quantum waves can form vortices: with helical phase fronts and azimuthal current densities. These features determine the intrinsic orbital angular momentum carried by localized vortex states. In the past 25 years, optical vortex beams have become an inherent part of modern optics, with many remarkable achievements and applications. In the past decade, it has been realized and demonstrated that such vortex beams or wavepackets can also appear in free electron waves, in particular, in electron microscopy. Interest in free-electron vortex states quickly spread over different areas of physics: from basic aspects of quantum mechanics, via applications for fine probing of matter (including individual atoms), to high-energy particle collision and radiation processes. Here we provide a comprehensive review of theoretical and experimental studies in this emerging field of research. We describe the main properties of electron vortex states, experimental achievements and possible applications within transmission electron microscopy, as well as the possible role of vortex electrons in relativistic and high-energy processes. We aim to provide a balanced description including a pedagogical introduction, solid theoretical basis, and a wide range of practical details. Special attention is paid to translate theoretical insights into suggestions for future experiments, in electron microscopy and beyond, in any situation where free electrons occur.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000406169900001 Publication Date (up) 2017-05-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1573 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 17.425 Times cited 210 Open Access OpenAccess
Notes AFOSR, FA9550-14-1-0040 ; CREST, JPMJCR1676 ; Portuguese Fundação para a Ciência e a Tecnologia (FCT), IF/00989/2014/CP1214/CT0004 ; Austrian Science Fund, I543-N20 ; ERC, 278510 VORTEX ; We acknowledge discussions with Mark R. Dennis and Andrei Afanasev. This work was supported by the RIKEN Interdisciplinary Theoretical Science Research Group (iTHES) Project, the Multi-University Research Initiative (MURI) Center for Dynamic Magneto-Optics via the Air Force Office of Scientific Research (AFOSR) (Grant No. FA9550-14-1-0040), Grant-in-Aid for Scientific Research (A), Core Research for Evolutionary Science and Technology (CREST), the John Templeton Foundation, the Australian Research Council, the Portuguese Funda¸c˜ao para a Ciˆencia e a Tecnologia (FCT) (contract IF/00989/2014/CP1214/CT0004 under the IF2014 Program), contracts UID/FIS/00777/2013 and CERN/FIS-NUC/0010/2015 (partially funded through POCTI, COMPETE, QREN, and the European Union), Austrian Science Fund Grant No. I543-N20, the European Research Council under the 7th Framework Program (FP7) (ERC Starting Grant No. 278510 VORTEX), and FWO PhD Fellowship grants (Aspirant Fonds Wetenschappelijk OnderzoekVlaanderen). Approved Most recent IF: 17.425
Call Number EMAT @ emat @ c:irua:143262 Serial 4574
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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.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000411170800022 Publication Date (up) 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
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Author Ramaneti, R.; Sankaran, K.J.; Korneychuk, S.; Yeh, C.J.; Degutis, G.; Leou, K.C.; Verbeeck, J.; Van Bael, M.K.; Lin, I.N.; Haenen, K.
Title Vertically aligned diamond-graphite hybrid nanorod arrays with superior field electron emission properties Type A1 Journal article
Year 2017 Publication APL materials Abbreviated Journal Apl Mater
Volume 5 Issue 6 Pages 066102
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract A “patterned-seeding technique” in combination with a “nanodiamond masked reactive ion etching process” is demonstrated for fabricating vertically aligned diamond-graphite hybrid (DGH) nanorod arrays. The DGH nanorod arrays possess superior field electron emission (FEE) behavior with a low turn-on field, long lifetime stability, and large field enhancement factor. Such an enhanced FEE is attributed to the nanocomposite nature of theDGHnanorods, which contain sp(2)-graphitic phases in the boundaries of nano-sized diamond grains. The simplicity in the nanorod fabrication process renders the DGH nanorods of greater potential for the applications as cathodes in field emission displays and microplasma display devices. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000404623000002 Publication Date (up) 2017-06-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2166-532x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.335 Times cited 16 Open Access
Notes The authors would like to thank the Methusalem “NANO” network for financial support and Mr. B. Ruttens and Professor Jan D'Haen for technical and experimental assistance. K.J. Sankaran is a Postdoctoral Fellow of the Research Foundation-Flanders (FWO). Approved Most recent IF: 4.335
Call Number UA @ admin @ c:irua:152633 Serial 5369
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Author Vatanparast, M.; Egoavil, R.; Reenaas, T.W.; Verbeeck, J.; Holmestad, R.; Vullum, P.E.
Title Bandgap measurement of high refractive index materials by off-axis EELS Type A1 Journal article
Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 182 Issue Pages 92-98
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In the present work Cs aberration corrected and monochromated scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) has been used to explore experimental setups that allow bandgaps of high refractive index materials to be determined. Semi-convergence and collection angles in the mu rad range were combined with off-axis or dark field EELS to avoid relativistic losses and guided light modes in the low loss range to contribute to the acquired EEL spectra. Off-axis EELS further supressed the zero loss peak and the tail of the zero loss peak. The bandgap of several GaAs-based materials were successfully determined by simple regression analyses of the background subtracted EEL spectra. The presented set-up does not require that the acceleration voltage is set to below the. Cerenkov limit and can be applied over the entire acceleration voltage range of modern TEMs and for a wide range of specimen thicknesses. (C) 2017 Elsevier B.V. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000413436500013 Publication Date (up) 2017-06-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 3 Open Access Not_Open_Access
Notes ; The authors would like to thank Professor Shu Min Wang and Mahdad Sadeghi at the Nanofabrication Laboratory at Chalmers University, Sweden for providing the samples. The Norwegian Research Council is acknowledged for funding the HighQ-IB project under contract no. 10415201. M.V. and T.W.R. acknowledge funding from the EEA Financial Mechanism 2009-2014 under the project contract no 23SEE/30.06.2014. 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) through the system of transnational access. R.E. and J.V. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp. ; Approved Most recent IF: 2.843
Call Number UA @ lucian @ c:irua:146639UA @ admin @ c:irua:146639 Serial 4778
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Author Drijkoningen, S.; Pobedinskas, P.; Korneychuk, S.; Momot, A.; Balasubramaniam, Y.; Van Bael, M.K.; Turner, S.; Verbeeck, J.; Nesladekt, M.; Haenen, K.
Title On the Origin of Diamond Plates Deposited at Low Temperature Type A1 Journal article
Year 2017 Publication Crystal growth & design Abbreviated Journal Cryst Growth Des
Volume 17 Issue 8 Pages 4306-4314
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The crucial requirement for diamond growth at low temperatures, enabling a wide range of new applications, is a high plasma density at a low gas pressure, which leads to a low thermal load onto sensitive substrate materials. While these conditions are not within reach for resonance cavity plasma systems, linear antenna microwave delivery systems allow the deposition of high quality diamond films at temperatures around 400 degrees C and at pressures below 1 mbar. In this work the codeposition of high quality plates and octahedral diamond grains in nanocrystalline films is reported. In contrast to previous reports claiming the need for high temperatures (T >= 850 degrees C), low temperatures (320 degrees C <= T <= 410 degrees C) were sufficient to deposit diamond plate structures. Cross-sectional high resolution transmission electron microscopy studies show that these plates are faulty cubic diamond terminated by large {111} surface facets with very little sp(2) bonded carbon in the grain boundaries. Raman and electron energy loss spectroscopy studies confirm a high diamond quality, above 93% sp(3) carbon content. Three potential mechanisms, that can account for the initial development of the observed plates rich with stacking faults, and are based on the presence of impurities, are proposed.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000407089600031 Publication Date (up) 2017-06-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1528-7483 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.055 Times cited 23 Open Access Not_Open_Access
Notes ; The Research Foundation – Flanders (FWO) is gratefully acknowledged for financial support in the form of the Postdoctoral Fellowships of P.P. and S.T., contract G.0044.13N “Charge ordering” (S.K., J.V.), the Methusalem “Nano” network, and the Hercules-linear antenna and Raman equipment. ; Approved Most recent IF: 4.055
Call Number UA @ lucian @ c:irua:145735UA @ admin @ c:irua:145735 Serial 4746
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Author Zhou, Y.; Ramaneti, R.; Anaya, J.; Korneychuk, S.; Derluyn, J.; Sun, H.; Pomeroy, J.; Verbeeck, J.; Haenen, K.; Kuball, M.
Title Thermal characterization of polycrystalline diamond thin film heat spreaders grown on GaN HEMTs Type A1 Journal article
Year 2017 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 111 Issue 4 Pages 041901
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Polycrystalline diamond (PCD) was grown onto high-k dielectric passivated AlGaN/GaN-on-Si high electron mobility transistor (HEMT) structures, with film thicknesses ranging from 155 to 1000 nm. Transient thermoreflectance results were combined with device thermal simulations to investigate the heat spreading benefit of the diamond layer. The observed thermal conductivity (k(Dia)) of PCD films is one-to-two orders of magnitude lower than that of bulk PCD and exhibits a strong layer thickness dependence, which is attributed to the grain size evolution. The films exhibit a weak temperature dependence of k(Dia) in the measured 25-225 degrees C range. Device simulation using the experimental jDia and thermal boundary resistance values predicts at best a 15% reduction in peak temperature when the source-drain opening of a passivated AlGaN/GaN-on-Si HEMT is overgrown with PCD. Published by AIP Publishing.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000406779700008 Publication Date (up) 2017-07-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; 1077-3118 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 78 Open Access Not_Open_Access
Notes ; The authors are grateful to Professor Michael Uren and Dr. Roland B. Simon (University of Bristol) for helpful discussions and to Dr. Sien Drijkoningen (Hasselt University) for taking the SEM micrographs. This work was in part supported by DARPA under Contract No. FA8650-15-C-7517, monitored by Dr. Avram Bar Cohen and Dr. John Blevins, and supported by Dr. Joseph Maurer and Dr. Abirami Sivananthan. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of DARPA. Y.Z. acknowledges China Scholarship Council for the financial support. S.K. and J.V. acknowledge the FWO-Vlaanderen for financial support under contract G.0044.13N “Charge ordering.” ; Approved Most recent IF: 3.411
Call Number UA @ lucian @ c:irua:145203 Serial 4728
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Author Li, L.; Liao, Z.; Gauquelin, N.; Minh Duc Nguyen; Hueting, R.J.E.; Gravesteijn, D.J.; Lobato, I.; Houwman, E.P.; Lazar, S.; Verbeeck, J.; Koster, G.; Rijnders, G.
Title Epitaxial stress-free growth of high crystallinity ferroelectric PbZr0.52Ti0.48O3 on GaN/AlGaN/Si(111) substrate Type A1 Journal article
Year 2018 Publication Advanced Materials Interfaces Abbreviated Journal Adv Mater Interfaces
Volume 5 Issue 2 Pages 1700921
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract <script type='text/javascript'>document.write(unpmarked('Due to its physical properties gallium-nitride (GaN) is gaining a lot of attention as an emerging semiconductor material in the field of high-power and high-frequency electronics applications. Therefore, the improvement in the performance and/or perhaps even extension in functionality of GaN based devices would be highly desirable. The integration of ferroelectric materials such as lead-zirconate-titanate (PbZrxTi1-xO3) with GaN has a strong potential to offer such an improvement. However, the large lattice mismatch between PZT and GaN makes the epitaxial growth of Pb(Zr1-xTix)O-3 on GaN a formidable challenge. This work discusses a novel strain relaxation mechanism observed when MgO is used as a buffer layer, with thicknesses down to a single unit cell, inducing epitaxial growth of high crystallinity Pb(Zr0.52Ti0.48)O-3 (PZT) thin films. The epitaxial PZT films exhibit good ferroelectric properties, showing great promise for future GaN device applications.'));
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000423173800005 Publication Date (up) 2017-11-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2196-7350 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.279 Times cited 15 Open Access Not_Open_Access
Notes ; L.L., Z.L.L., and N.G. contributed equally to this work. L.L. acknowledges financial support from Nano Next NL (Grant no. 7B 04). The authors acknowledge NXP for providing the GaN/AlGaN/Si (111) wafer. N.G. acknowledges funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and J.V. acknowledges funding from the Research Foundation Flanders (FWO, Belgium) project 42/FA070100/6088 “nieuwe eigenschappen in complexe Oxides.” N.G. acknowledges the EUROTAPES project (FP7-NMP.2011.2.2-1 Grant no. 280432) which partly funded this study. ; Approved Most recent IF: 4.279
Call Number UA @ lucian @ c:irua:148427UA @ admin @ c:irua:148427 Serial 4872
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Author Groenendijk, D.J.; Autieri, C.; Girovsky, J.; Martinez-Velarte, M.C.; Manca, N.; Mattoni, G.; Monteiro, A.M.R.V.L.; Gauquelin, N.; Verbeeck, J.; Otte, A.F.; Gabay, M.; Picozzi, S.; Caviglia, A.D.
Title Spin-orbit semimetal SrIrO3 in the two-dimensional limit Type A1 Journal article
Year 2017 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 119 Issue 25 Pages 256403
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract <script type='text/javascript'>document.write(unpmarked('We investigate the thickness-dependent electronic properties of ultrathin SrIrO3 and discover a transition from a semimetallic to a correlated insulating state below 4 unit cells. Low-temperature magnetoconductance measurements show that spin fluctuations in the semimetallic state are significantly enhanced while approaching the transition point. The electronic properties are further studied by scanning tunneling spectroscopy, showing that 4 unit cell SrIrO(3)d is on the verge of a gap opening. Our density functional theory calculations reproduce the critical thickness of the transition and show that the opening of a gap in ultrathin SrIrO3 requires antiferromagnetic order.'));
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000418619100014 Publication Date (up) 2017-12-22
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 79 Open Access OpenAccess
Notes ; This work was supported by The Netherlands Organisation for Scientific Research (NWO/OCW) as part of the Frontiers of Nanoscience program (NanoFront), by the Dutch Foundation for Fundamental Research on Matter (FOM), and by the European Research Council under the European Union's H2020 programme/ERC Grant Agreement No. [677458]. The authors thank R. Claessen, P. Schutz, D. Di Sante, G. Sangiovanni, and A. Santander Syro for useful discussions. M. G. gratefully acknowledges support from the French National Research Agency (ANR) (Project LACUNES No. ANR-13-BS04-0006-01). C. A. and S. P. acknowledge financial support from Fondazione Cariplo via the project Magister (Project No. 2013-0726) and from CNR-SPIN via the Seed Project “CAMEO”. N. G. and J. V. acknowledge support from the GOA project “Solarpaint” of the University of Antwerp. The Qu-AntEM microscope was partly funded by the Hercules fund from the Flemish Government. ; Approved Most recent IF: 8.462
Call Number UA @ lucian @ c:irua:148510 Serial 4897
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Author Schattschneider, P.; Schachinger, T.; Verbeeck, J.
Title Ein Whirlpool aus Elektronen: Transmissions-Elektronenmikroskopie mit Elektronenwirbeln Type A1 Journal article
Year 2018 Publication Physik in unserer Zeit Abbreviated Journal Phys. Unserer Zeit
Volume 49 Issue 1 Pages 22-28
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Elektronen bewegen sich im feldfreien Raum immer gleichförmig geradlinig, so steht es in den Lehrbüchern. Falsch, sagen wir. Elektronen lassen sich zu Tornados formen, die theoretisch Nanopartikel zerreißen können. In der Elektronenmikroskopie eingesetzt, versprechen sie neue Erkenntnisse in der Festkörperphysik.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date (up) 2018-01-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9252 ISBN Additional Links UA library record
Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @c:irua:148159 Serial 4806
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Author Deshmukh, S.; Sankaran, K.J.; Srinivasu, K.; Korneychuk, S.; Banerjee, D.; Barman, A.; Bhattacharya, G.; Phase, D.M.; Gupta, M.; Verbeeck, J.; Leou, K.C.; Lin, I.N.; Haenen, K.; Roy, S.S.
Title Local probing of the enhanced field electron emission of vertically aligned nitrogen-doped diamond nanorods and their plasma illumination properties Type A1 Journal article
Year 2018 Publication Diamond and related materials Abbreviated Journal Diam Relat Mater
Volume 83 Issue 83 Pages 118-125
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A detailed conductive atomic force microscopic investigation is carried out to directly image the electron emission behavior for nitrogen-doped diamond nanorods (N-DNRs). Localized emission measurements illustrate uniform distribution of high-density electron emission sites from N-DNRs. Emission sites coupled to nano graphitic phases at the grain boundaries facilitate electron transport and thereby enhance field electron emission from N-DNRs, resulting in a device operation at low turn-on fields of 6.23 V/mu m, a high current density of 1.94 mA/cm(2) (at an applied field of 11.8 V/mu m) and a large field enhancement factor of 3320 with a long lifetime stability of 980 min. Moreover, using N-DNRs as cathodes, a microplasma device that can ignite a plasma at a low threshold field of 390 V/mm achieving a high plasma illumination current density of 3.95 mA/cm2 at an applied voltage of 550 V and a plasma life-time stability for a duration of 433 min was demonstrated.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000430767200017 Publication Date (up) 2018-02-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0925-9635 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.561 Times cited 9 Open Access Not_Open_Access
Notes ; S. Deshmulch, D. Banerjee and G. Bhattacharya are indebted to Shiv Nadar University for providing Ph.D. scholarships. K.J. Sankaran and K. Haenen like to thank the financial support of the Research Foundation Flanders (FWO) via Research Grant 12I8416N and Research Project 1519817N, and the Methusalem “NANO” network. K.J. Sankaran is a Postdoctoral Fellow of the Research Foundation-Flanders (FWO). The Qu-Ant-EM microscope used for the TEM experiments was partly funded by the Hercules fund from the Flemish Government. S. Korneychuk and J. Verbeeck acknowledge funding from GOA project “Solarpaint” of the University of Antwerp. ; Approved Most recent IF: 2.561
Call Number UA @ lucian @ c:irua:151609UA @ admin @ c:irua:151609 Serial 5030
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Author Korneychuk, S.; Partoens, B.; Guzzinati, G.; Ramaneti, R.; Derluyn, J.; Haenen, K.; Verbeeck, J.
Title Exploring possibilities of band gap measurement with off-axis EELS in TEM Type A1 Journal article
Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 189 Issue 189 Pages 76-84
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract A technique to measure the band gap of dielectric materials with high refractive index by means of energy electron loss spectroscopy (EELS) is presented. The technique relies on the use of a circular (Bessel) aperture and suppresses Cherenkov losses and surface-guided light modes by enforcing a momentum transfer selection. The technique also strongly suppresses the elastic zero loss peak, making the acquisition, interpretation and signal to noise ratio of low loss spectra considerably better, especially for excitations in the first few eV of the EELS spectrum. Simulations of the low loss inelastic electron scattering probabilities demonstrate the beneficial influence of the Bessel aperture in this setup even for high accelerating voltages. The importance of selecting the optimal experimental convergence and collection angles is highlighted. The effect of the created off-axis acquisition conditions on the selection of the transitions from valence to conduction bands is discussed in detail on a simplified isotropic two band model. This opens the opportunity for deliberately selecting certain transitions by carefully tuning the microscope parameters. The suggested approach is experimentally demonstrated and provides good signal to noise ratio and interpretable band gap signals on reference samples of diamond, GaN and AlN while offering spatial resolution in the nm range. (C) 2018 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000432868500008 Publication Date (up) 2018-03-29
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 7 Open Access OpenAccess
Notes ; S.K., B.P. and J.V. acknowledge funding from the “Geconcentreerde Onderzoekacties” (GOA) project “Solarpaint” of the University of Antwerp. S.K. and J.V. also acknowledge the FWO-Vlaanderen for financial support under contract G.0044.13N 'Charge ordering'. Financial support via the Methusalem “NANO” network is acknowledged. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek-Vlaanderen (FWO). ; Approved Most recent IF: 2.843
Call Number UA @ lucian @ c:irua:151472UA @ admin @ c:irua:151472 Serial 5026
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Author Verbeeck, J.; Béché, A.; Müller-Caspary, K.; Guzzinati, G.; Luong, M.A.; Den Hertog, M.
Title Demonstration of a 2 × 2 programmable phase plate for electrons Type A1 Journal article
Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 190 Issue Pages 58-65
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract First results on the experimental realisation of a 2 × 2 programmable phase plate for electrons are presented. The design consists of an array of electrostatic elements that influence the phase of electron waves passing through 4 separately controllable aperture holes. This functionality is demonstrated in a conventional transmission electron microscope operating at 300 kV and results are in very close agreement with theoretical predictions. The dynamic creation of a set of electron probes with different phase symmetry is demonstrated, thereby bringing adaptive optics in TEM one step closer to reality. The limitations of the current design and how to overcome these in the future are discussed. Simulations show how further evolved versions of the current proof of concept might open new and exciting application prospects for beam shaping and aberration correction.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000432868800007 Publication Date (up) 2018-04-18
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 73 Open Access Not_Open_Access: Available from 19.04.2020
Notes J.V. and A.B. acknowledge funding from the Fund for Scientific Research Flanders FWO project G093417N and the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX and ERC proof of concept project DLV-789598 ADAPTEM. The Qu-Ant-EM microscope used in this work was partly funded by the Hercules fund from the Flemish Government. MdH acknowledges financial support from the ANRCOSMOS (ANR-12-JS10-0002). MdH and ML acknowledge funding from the Laboratoire d’excellence LANEF in Grenoble (ANR-10-LABX-51-01). Approved Most recent IF: 2.843
Call Number EMAT @ emat @c:irua:150459UA @ admin @ c:irua:150459 Serial 4920
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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 (up) 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
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Author Deshmukh, S.; Sankaran, K.J.; Korneychuk, S.; Verbeeck, J.; Mclaughlin, J.; Haenen, K.; Roy, S.S.
Title Nanostructured nitrogen doped diamond for the detection of toxic metal ions Type A1 Journal article
Year 2018 Publication Electrochimica acta Abbreviated Journal Electrochim Acta
Volume 283 Issue 283 Pages 1871-1878
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract This work demonstrates the applicability of one-dimensional nitrogen-doped diamond nanorods (N-DNRs) for the simultaneous electrochemical (EC) detection of Pb2+ and Cd2+ ions in an electrolyte solution. Well separated voltammetric peaks are observed for Pb2+ and Cd2+ ions using N-DNRs as a working electrode in square wave anodic stripping voltammetry measurements. Moreover, the cyclic voltammetry response of N-DNR electrodes towards the Fe(CN)(6)(/4-)/Fe(CN)(6)(/3-) redox reaction is better as compared to undoped DNR electrodes. This enhancement of EC performance in N-DNR electrodes is accounted by the increased amount of sp(2) bonded nanographitic phases, enhancing the electrical conductivity at the grain boundary (GB) regions. These findings are supported by transmission electron microscopy and electron energy loss spectroscopy studies. Consequently, the GB defect induced N-DNRs exhibit better adsorption of metal ions, which makes such samples promising candidates for next generation EC sensing devices. (C) 2018 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000441077900203 Publication Date (up) 2018-07-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-4686 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.798 Times cited 22 Open Access
Notes Sujit Deshmukh indebted to Shiv Nadar University for providing Ph. D. scholarship. The FEI Quanta SEM and Qu-Ant-EM microscope used for the TEM experiments was partly funded by the Hercules fund from the Flemish Government. S. K. and J. V. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp. Kamatchi Jothiramalingam Sankaran is a Postdoctoral Fellow of the Research Foundation-Flanders (FWO). Prof. Ken Haenen acknowledges the Methusalem “NANO” network for financial support. Approved Most recent IF: 4.798
Call Number UA @ admin @ c:irua:153072 Serial 5366
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Author Guzzinati, G.; Altantzis, T.; Batuk, M.; De Backer, A.; Lumbeeck, G.; Samaee, V.; Batuk, D.; Idrissi, H.; Hadermann, J.; Van Aert, S.; Schryvers, D.; Verbeeck, J.; Bals, S.
Title Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp Type A1 Journal article
Year 2018 Publication Materials Abbreviated Journal Materials
Volume 11 Issue 11 Pages 1304
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000444112800041 Publication Date (up) 2018-07-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1996-1944 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.654 Times cited 15 Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, G.0502.18N, G.0267.18N, G.0120.12N, G.0365.15N, G.0934.17N, S.0100.18N AUHA13009 ; European Research Council, COLOURATOM 335078 ; Universiteit Antwerpen, GOA Solarpaint ; G. Guzzinati, T. Altantzis and A. De Backer have been supported by postdoctoral fellowship grants from the Research Foundation Flanders (FWO). Funding was also received from the European Research Council (starting grant no. COLOURATOM 335078), the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 770887), the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0502.18N, G.0267.18N, G.0120.12N, G.0365.15N, G.0934.17N, S.0100.18N, G.0401.16N) and from the University of Antwerp through GOA project Solarpaint. Funding for the TopSPIN precession system under grant AUHA13009, as well as for the Qu-Ant-EM microscope, is acknowledged from the HERCULES Foundation. H. Idrissi is mandated by the Belgian National Fund for Scientific Research (F.R.S.-FNRS). (ROMEO:green; preprint:; postprint:can ; pdfversion:can); saraecas; ECAS_Sara; Approved Most recent IF: 2.654
Call Number EMAT @ emat @c:irua:153737UA @ admin @ c:irua:153737 Serial 5064
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Author Korneychuk, S.; Guzzinati, G.; Verbeeck, J.
Title Measurement of the Indirect Band Gap of Diamond with EELS in STEM Type A1 Journal article
Year 2018 Publication Physica status solidi : A : applications and materials science Abbreviated Journal Phys Status Solidi A
Volume 215 Issue 22 Pages 1800318
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In this work, a simple method to measure the indirect band gap of diamond with electron energy loss spectroscopy (EELS) in transmission electron microscopy (TEM) is showed. The authors discuss the momentum space resolution achievable with EELS and the possibility of deliberately selecting specific transitions of interest. Based on a simple 2 parabolic band model of the band structure, the authors extend our predictions from the direct band gap case discussed in previous work, to the case of an indirect band gap. Finally, the authors point out the emerging possibility to partly reconstruct the band structure with EELS exploiting our simplified model of inelastic scattering and support it with experiments on diamond.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000450818100004 Publication Date (up) 2018-07-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1862-6300 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.775 Times cited 6 Open Access Not_Open_Access
Notes S.K. and J.V. acknowledge funding from the “Geconcentreerde Onderzoekacties” (GOA) project “Solarpaint” of the University of Antwerp. Financial support via the Methusalem “NANO” network is acknowledged. G.G. acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek-Vlaanderen (FWO). The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. “Geconcentreerde Onderzoekacties” (GOA) project “Solarpaint”; Methusalem “NANO” network; Fonds Wetenschappelijk Onderzoek-Vlaanderen (FWO); Hercules fund from the Flemish Government; Approved Most recent IF: 1.775
Call Number EMAT @ emat @UA @ admin @ c:irua:155402 Serial 5138
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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.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000449125600004 Publication Date (up) 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
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Author Sankaran, K.J.; Deshmukh, S.; Korneychuk, S.; Yeh, C.-J.; Thomas, J.P.; Drijkoningen, S.; Pobedinskas, P.; Van Bael, M.K.; Verbeeck, J.; Leou, K.-C.; Leung, K.-T.; Roy, S.S.; Lin, I.-N.; Haenen, K.
Title Fabrication, microstructure, and enhanced thermionic electron emission properties of vertically aligned nitrogen-doped nanocrystalline diamond nanorods Type A1 Journal article
Year 2018 Publication MRS communications Abbreviated Journal Mrs Commun
Volume 8 Issue 3 Pages 1311-1320
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Vertically aligned nitrogen-doped nanocrystalline diamond nanorods are fabricated from nitrogen-doped nanocrystalline diamond films using reactive ion etching in oxygen plasma. These nanorods show enhanced thermionic electron emission (TEE) characteristics, viz.. a high current density of 12.0 mA/cm(2) and a work function value of 4.5 eV with an applied voltage of 3 Vat 923 K. The enhanced TEE characteristics of these nanorods are ascribed to the induction of nanographitic phases at the grain boundaries and the field penetration effect through the local field enhancement from nanorods owing to a high aspect ratio and an excellent field enhancement factor.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000448887900089 Publication Date (up) 2018-08-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2159-6859; 2159-6867 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.01 Times cited 1 Open Access
Notes The authors thank the financial support of the Research Foundation Flanders (FWO) via Research Grant 12I8416N and Research Project 1519817N, and the Methusalem “NANO” network. The Hercules Foundation Flanders is acknowledged for financial support of the Raman equipment. The Qu-Ant-EM microscope used for the TEM experiments was partly funded by the Hercules fund from the Flemish Government. S.K. and J.V. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp. K.J. Sankaran and P. Pobedinskas are Postdoctoral Fellows of FWO. Approved Most recent IF: 3.01
Call Number UA @ admin @ c:irua:155521 Serial 5364
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Author Liao, Z.; Gauquelin, N.; Green, R.J.; Müller-Caspary, K.; Lobato, I.; Li, L.; Van Aert, S.; Verbeeck, J.; Huijben, M.; Grisolia, M.N.; Rouco, V.; El Hage, R.; Villegas, J.E.; Mercy, A.; Bibes, M.; Ghosez, P.; Sawatzky, G.A.; Rijnders, G.; Koster, G.
Title Metal–insulator-transition engineering by modulation tilt-control in perovskite nickelates for room temperature optical switching Type A1 Journal article
Year 2018 Publication America Abbreviated Journal P Natl Acad Sci Usa
Volume 115 Issue 38 Pages 9515-9520
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract In transition metal perovskites ABO3 the physical properties are largely driven by the rotations of the BO6 octahedra, which can be tuned in thin films through strain and dimensionality control. However, both approaches have fundamental and practical limitations due to discrete and indirect variations in bond angles, bond lengths and film symmetry by using commercially available substrates. Here, we introduce modulation tilt control as a new approach to tune the ground state of perovskite oxide thin films by acting explicitly on the oxygen octahedra rotation modes, i.e. directly on the bond angles. By intercalating the prototype SmNiO3 target material with a tilt-control layer, we cause the system to change the natural amplitude of a given rotation mode without affecting the interactions. In contrast to strain and dimensionality engineering, our method enables a continuous fine-tuning of the materials properties. This is achieved through two independent adjustable parameters: the nature of the tilt-control material (through its symmetry, elastic constants and oxygen rotation angles) and the relative thicknesses of the target and tilt-control materials. As a result, a magnetic and electronic phase diagram can be obtained, normally only accessible by A-site element substitution, within the single SmNiO3 compound. With this unique approach, we successfully adjusted the metal-insulator transition (MIT) to room temperature to fulfill the desired conditions for optical switching applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000447224900057 Publication Date (up) 2018-09-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0027-8424 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.661 Times cited 50 Open Access OpenAccess
Notes We would like to acknowledge Prof. Z. Zhong for stimulated discussion. M.H., G.K. and G.R. acknowledge funding from DESCO program of the Dutch Foundation for Fundamental Research on Matter (FOM) with financial support from the Netherlands Organization for Scientific Research (NWO). This work was funded by the European Union Council under the 7th Framework Program (FP7) grant nr NMP3-LA-2010-246102 IFOX. J.V., S.V.A, N.G. and K.M.C. acknowledge funding from FWO projects G.0044.13N, G.0374.13N, G. 0368.15N, and G.0369.15N. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. N.G. acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. N.G. and J.V. acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative (Reference No. 312483- ESTEEM2). The Canadian work was supported by NSERC and the Max Planck-UBC Centre for Quantum Materials. Some experiments for this work were performed at the Canadian Light Source, which is funded by the Canada Foundation for Innovation, NSERC, the National Research Council of Canada, the Canadian Institutes of Health Research, the Government of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan. MB acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC CoG grant MINT #615759. A.M. and Ph.G. were supported by the ARC project AIMED and F.R.S-FNRS PDR project HiT4FiT and acknowledge access to Céci computing facilities funded by F.R.S-FNRS (Grant No 2.5020.1), Tier-1 supercomputer of the Fédération Wallonie-Bruxelles funded by the Walloon Region (Grant No 1117545) and HPC resources from the PRACE project Megapasta. Approved Most recent IF: 9.661
Call Number EMAT @ emat @c:irua:154784UA @ admin @ c:irua:154784 Serial 5059
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Author Krehl, J.; Guzzinati, G.; Schultz, J.; Potapov, P.; Pohl, D.; Martin, J.; Verbeeck, J.; Fery, A.; Büchner, B.; Lubk, A.
Title Spectral field mapping in plasmonic nanostructures with nanometer resolution Type A1 Journal article
Year 2018 Publication Nature communications Abbreviated Journal Nat Commun
Volume 9 Issue 1 Pages 4207
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Plasmonic nanostructures and -devices are rapidly transforming light manipulation technology by allowing to modify and enhance optical fields on sub-wavelength scales. Advances in this field rely heavily on the development of new characterization methods for the fundamental nanoscale interactions. However, the direct and quantitative mapping of transient electric and magnetic fields characterizing the plasmonic coupling has been proven elusive to date. Here we demonstrate how to directly measure the inelastic momentum transfer of surface plasmon modes via the energy-loss filtered deflection of a focused electron beam in a transmission electron microscope. By scanning the beam over the sample we obtain a spatially and spectrally resolved deflection map and we further show how this deflection is related quantitatively to the spectral component of the induced electric and magnetic fields pertaining to the mode. In some regards this technique is an extension to the established differential phase contrast into the dynamic regime.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000447074200005 Publication Date (up) 2018-10-11
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 15 Open Access OpenAccess
Notes G.G. acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoke-Vlaanderen (FWO). A.L. and J.K. have received funding from the European Research Council (ERC) under the Horizon 2020 research and innovation program of the European Union (grant agreement no. 715620). Approved Most recent IF: 12.124
Call Number EMAT @ emat @c:irua:154355 Serial 5058
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Author Hasanli, N.; Gauquelin, N.; Verbeeck, J.; Hadermann, J.; Hayward, M.A.
Title Small-moment paramagnetism and extensive twinning in the topochemically reduced phase Sr2ReLiO5.5 Type A1 Journal article
Year 2018 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal Dalton T
Volume 47 Issue 44 Pages 15783-15790
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Reaction of the cation-ordered double perovskite Sr2ReLiO6 with dilute hydrogen at 475 degrees C leads to the topochemical deintercalation of oxide ions from the host lattice and the formation of a phase of composition Sr2ReLiO5.5, as confirmed by thermogravimetric and EELS data. A combination of neutron and electron diffraction data reveals the reduction process converts the -Sr2O2-ReLiO4-Sr2O2-ReLiO4- stacking sequence of the parent phase into a -Sr2O2-ReLiO3-Sr2O2-ReLiO4-, partially anion-vacant ordered sequence. Furthermore a combination of electron diffraction and imaging reveals Sr2ReLiO5.5 exhibits extensive twinning – a feature which can be attributed to the large, anisotropic volume expansion of the material on reduction. Magnetisation data reveal a strongly reduced moment of (eff) = 0.505(B) for the d(1) Re6+ centres in the phase, suggesting there remains a large orbital component to the magnetism of the rhenium centres, despite their location in low symmetry coordination environments.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000450208000019 Publication Date (up) 2018-10-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1477-9226 ISBN Additional Links UA library record; WoS full record
Impact Factor 4.029 Times cited Open Access Not_Open_Access
Notes Experiments at the Diamond Light Source were performed as part of the Block Allocation Group award “Oxford Solid State Chemistry BAG to probe composition-structure-property relationships in solids” (EE13284). Experiments at the ISIS pulsed neutron facility were supported by a beam time allocation from the STFC. NH acknowledges funding from the “State Programme on Education of Azerbaijani Youth Abroad in 2007-2015” by the Ministry of Education of Azerbaijan. J. V. and N. G. acknowledge funding through the GOA project “Solarpaint” of the University of Antwerp. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. Approved Most recent IF: 4.029
Call Number EMAT @ emat @c:irua:155771 Serial 5137
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Author Conings, B.; Babayigit, A.; Klug, M.; Bai, S.; Gauquelin, N.; Sakai, N.; Wang, J.T.-W.; Verbeeck, J.; Boyen, H.-G.; Snaith, H.
Title Getting rid of anti-solvents: gas quenching for high performance perovskite solar cells Type P1 Proceeding
Year 2018 Publication 2018 Ieee 7th World Conference On Photovoltaic Energy Conversion (wcpec)(a Joint Conference Of 45th Ieee Pvsc, 28th Pvsec & 34th Eu Pvsec) Abbreviated Journal
Volume Issue Pages
Keywords P1 Proceeding; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract As the field of perovskite optoelectronics developed, a plethora of strategies has arisen to control their electronic and morphological characteristics for the purpose of producing high efficiency devices. Unfortunately, despite this wealth of deposition approaches, the community experiences a great deal of irreproducibility between different laboratories, batches and preparation methods. Aiming to address this issue, we developed a simple deposition method based on gas quenching that yields smooth films for a wide range of perovskite compositions, in single, double, triple and quadruple cation varieties, and produces planar heterojunction devices with competitive efficiencies, so far up to 20%.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000469200401163 Publication Date (up) 2018-12-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-5386-8529-7 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:160468 Serial 5365
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Author Kuo, C.-T.; Lin, S.-C.; Ghiringhelli, G.; Peng, Y.; De Luca, G.M.; Di Castro, D.; Betto, D.; Gehlmann, M.; Wijnands, T.; Huijben, M.; Meyer-Ilse, J.; Gullikson, E.; Kortright, J.B.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Gerber, T.; Balestrino, G.; Brookes, N.B.; Braicovich, L.; Fadley, C.S.
Title Depth-resolved resonant inelastic x-ray scattering at a superconductor/half-metallic-ferromagnet interface through standing wave excitation Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 98 Issue 23 Pages 235146
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We demonstrate that combining standing wave (SW) excitation with resonant inelastic x-ray scattering (RIXS) can lead to depth resolution and interface sensitivity for studying orbital and magnetic excitations in correlated oxide heterostructures. SW-RIXS has been applied to multilayer heterostructures consisting of a superconductor La1.85Sr0.15CuO4 (LSCO) and a half-metallic ferromagnet La0.67Sr0.33MnO3 (LSMO). Easily observable SW effects on the RIXS excitations were found in these LSCO/LSMO multilayers. In addition, we observe different depth distribution of the RIXS excitations. The magnetic excitations are found to arise from the LSCO/LSMO interfaces, and there is also a suggestion that one of the dd excitations comes from the interfaces. SW-RIXS measurements of correlated-oxide and other multilayer heterostructures should provide unique layer-resolved insights concerning their orbital and magnetic excitations, as well as a challenge for RIXS theory to specifically deal with interface effects.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000454160800004 Publication Date (up) 2018-12-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 5 Open Access
Notes J.V. and N.G. acknowledge ˝ funding through the GOA project “Solarpaint” of the University of Antwerp. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:156784 Serial 5363
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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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000465021000013 Publication Date (up) 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 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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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000460329300004 Publication Date (up) 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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