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Author Verhulst, A.S.; Verreck, D.; Pourghaderi, M.A.; Van de Put, M.; Sorée, B.; Groeseneken, G.; Collaert, N.; Thean, A.V.-Y.
Title Can p-channel tunnel field-effect transistors perform as good as n-channel? Type A1 Journal article
Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 105 Issue (up) 4 Pages 043103
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We show that bulk semiconductor materials do not allow perfectly complementary p- and n-channel tunnel field-effect transistors (TFETs), due to the presence of a heavy-hole band. When tunneling in p-TFETs is oriented towards the gate-dielectric, field-induced quantum confinement results in a highest-energy subband which is heavy-hole like. In direct-bandgap IIIV materials, the most promising TFET materials, phonon-assisted tunneling to this subband degrades the subthreshold swing and leads to at least 10x smaller on-current than the desired ballistic on-current. This is demonstrated with quantum-mechanical predictions for p-TFETs with tunneling orthogonal to the gate, made out of InP, In0.53Ga0.47As, InAs, and a modified version of In0.53Ga0.47As with an artificially increased conduction-band density-of-states. We further show that even if the phonon-assisted current would be negligible, the build-up of a heavy-hole-based inversion layer prevents efficient ballistic tunneling, especially at low supply voltages. For p-TFET, a strongly confined n-i-p or n-p-i-p configuration is therefore recommended, as well as a tensily strained line-tunneling configuration. (C) 2014 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000341152600067 Publication Date 2014-07-30
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 8 Open Access
Notes ; This work was supported by imec's industrial application program. D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for Promotion of Innovation through Science and Technology in Flanders (IWT). ; Approved Most recent IF: 3.411; 2014 IF: 3.302
Call Number UA @ lucian @ c:irua:134433 Serial 4587
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Author Fernandez, M.S.; Peeters, F.M.; Neek-Amal, M.
Title Electric-field-induced structural changes in water confined between two graphene layers Type A1 Journal article
Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 94 Issue (up) 4 Pages 045436
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract An external electric field changes the physical properties of polar liquids due to the reorientation of their permanent dipoles. Using molecular dynamics simulations, we predict that an in-plane electric field applied parallel to the channel polarizes water molecules which are confined between two graphene layers, resulting in distinct ferroelectricity and electrical hysteresis. We found that electric fields alter the in-plane order of the hydrogen bonds: Reversing the electric field does not restore the system to the nonpolar initial state, instead a residual dipole moment remains in the system. The square-rhombic structure of 2D ice is transformed into two rhombic-rhombic structures. Our study provides insights into the ferroelectric state of water when confined in nanochannels and shows how this can be tuned by an electric field.
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Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000381485200005 Publication Date 2016-07-27
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 31 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:144684 Serial 4649
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Author Lu, A.K.A.; Pourtois, G.; Agarwal, T.; Afzalian, A.; Radu, I.P.; Houssa, M.
Title Origin of the performances degradation of two-dimensional-based metal-oxide-semiconductor field effect transistors in the sub-10 nm regime: A first-principles study Type A1 Journal article
Year 2016 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 108 Issue (up) 4 Pages 043504
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The impact of the scaling of the channel length on the performances of metal-oxide-semiconductor field effect transistors, based on two-dimensional (2D) channel materials, is theoretically investigated, using density functional theory combined with the non-equilibrium Green's function method. It is found that the scaling of the channel length below 10nm leads to strong device performance degradations. Our simulations reveal that this degradation is essentially due to the tunneling current flowing between the source and the drain in these aggressively scaled devices. It is shown that this electron tunneling process is modulated by the effective mass of the 2D channel material, and sets the limit of the scaling in future transistor designs. (C) 2016 AIP Publishing LLC.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000375217200061 Publication Date 2016-01-26
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 4 Open Access
Notes Approved Most recent IF: 3.411
Call Number UA @ lucian @ c:irua:144750 Serial 4677
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Author Lander, L.; Rousse, G.; Batuk, D.; Colin, C.V.; Dalla Corte, D.A.; Tarascon, J.-M.
Title Synthesis, structure, and electrochemical properties of k-based sulfates K2M2(SO4)3) with M = Fe and Cu Type A1 Journal article
Year 2017 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 56 Issue (up) 4 Pages 2013-2021
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Stabilizing new host structures through potassium extraction from K-based polyanionic materials has been proven to be an interesting approach to develop new Li+/Na+ insertion materials. Pursuing the same trend, we here report the feasibility of preparing langbeinite “Fe-2(SO4)(3)” via electrochemical and chemical oxidation of K2Fe2(SO4)(3). Additionally, we succeeded in stabilizing a new K2Cu2(SO4)(3) phase via a solid-state synthesis approach. This novel compound crystallizes in a complex orthorhombic structure that differs from that of langbeinite as deduced from synchrotron X-ray and neutron powder diffraction. Electrochemically, the performance of this new phase is limited, which we explain in terms of sluggish diffusion kinetics. We further show that K2Cu2(SO4)(3) decomposes into K2Cu3O(SO4)(3) on heating, and we report for the first time the synthesis of fedotovite K2Cu3O(SO4)(3). Finally, the fundamental attractiveness of these S = 1/2 systems for physicists is examined by neutron magnetic diffraction, which reveals the absence of a long-range ordering of Cu2+ magnetic moments down to 1.5 K.
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Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000394736600027 Publication Date 2017-01-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 13 Open Access Not_Open_Access
Notes ; We thank Matthieu Courty for performing TGA/DSC measurements. Use of the 11-BM mail service of the APS at Argonne National Laboratory was supported by the U.S. Department of Energy under Contract DE-AC02-06CH11357 and is acknowledged. The French CRG D1B is acknowledged for allocating neutron beamtime. L.L. thanks the ANR “Hipolite” for the Ph.D. funding. ; Approved Most recent IF: 4.857
Call Number UA @ lucian @ c:irua:142531 Serial 4692
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Author Sieger, M.; Pahlke, P.; Lao, M.; Eisterer, M.; Meledin, A.; Van Tendeloo, G.; Ottolinger, R.; Haenisch, J.; Holzapfel, B.; Usoskin, A.; Kursumovic, A.; MacManus-Driscoll, J.L.; Stafford, B.H.; Bauer, M.; Nielsch, K.; Schultz, L.; Huehne, R.
Title Tailoring microstructure and superconducting properties in thick BaHfO3 and Ba2YNb/Ta)O-6 doped YBCO films on technical templates Type A1 Journal article
Year 2017 Publication IEEE transactions on applied superconductivity Abbreviated Journal
Volume 27 Issue (up) 4 Pages 6601407
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The current transport capability of YBa2Cu3O7-x(YBCO) based coated conductors (CCs) is mainly limited by two features: the grain boundaries of the used textured template, which are transferred into the superconducting film through the buffer layers, and the ability to pin magnetic flux lines by incorporation of defined defects in the crystal lattice. By adjusting the deposition conditions, it is possible to tailor the pinning landscape in doped YBCO in order to meet specific working conditions (T, B) for CC applications. To study these effects, we deposited YBCO layers with a thickness of about 1-2 mu m using pulsed laser deposition on buffered rolling-assisted biaxially textured Ni-W substrates as well as on metal tapes having either an ion-beam-texturedYSZbuffer or an MgO layer textured by inclined substrate deposition. BaHfO3 and the mixed double-perovskite Ba2Y(Nb/Ta)O-6 were incorporated as artificial pinning centers in these YBCO layers. X-ray diffraction confirmed the epitaxial growth of the superconductor on these templates as well as the biaxially oriented incorporation of the secondary phase additions in the YBCO matrix. A critical current density J(c) of more than 2 MA/cm(2) was achieved at 77 K in self-field for 1-2 mu m thick films. Detailed TEM (transmission electron microscopy) studies revealed that the structure of the secondary phase can be tuned, forming c-axis aligned nanocolumns, ab-oriented platelets, or a combination of both. Transport measurements show that the J(c) anisotropy in magnetic fields is reduced by doping and the peak in the J(c) (theta) curves can be correlated to the microstructural features.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000394588100001 Publication Date 2016-12-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 12 Open Access OpenAccess
Notes ; This work was supported by EUROTAPES, a collaborative project funded by the European Commission's Seventh Framework Program (FP7/2007-2013) under Grant Agreement no. 280432. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:141961 Serial 4693
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Author Milovanović, S.P.; Tadic, M.Z.; Peeters, F.M.
Title Graphene membrane as a pressure gauge Type A1 Journal article
Year 2017 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 111 Issue (up) 4 Pages 043101
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Straining graphene results in the appearance of a pseudo-magnetic field which alters its local electronic properties. Applying a pressure difference between the two sides of the membrane causes it to bend/bulge resulting in a resistance change. We find that the resistance changes linearly with pressure for bubbles of small radius while the response becomes non-linear for bubbles that stretch almost to the edges of the sample. This is explained as due to the strong interference of propagating electronic modes inside the bubble. Our calculations show that high gauge factors can be obtained in this way which makes graphene a good candidate for pressure sensing. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000406779700035 Publication Date 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 11 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Methusalem program, the Erasmus+ programme, and the Serbian Ministry of Education, Science and Technological Development. ; Approved Most recent IF: 3.411
Call Number UA @ lucian @ c:irua:145202 Serial 4718
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Author Ata, I.; Ben Dkhil, S.; Pfannmoeller, M.; Bals, S.; Duche, D.; Simon, J.-J.; Koganezawa, T.; Yoshimoto, N.; Videlot-Ackermann, C.; Margeat, O.; Ackermann, J.; Baeuerle, P.
Title The influence of branched alkyl side chains in A-D-A oligothiophenes on the photovoltaic performance and morphology of solution-processed bulk-heterojunction solar cells Type A1 Journal article
Year 2017 Publication Organic chemistry frontiers : an international journal of organic chemistry Abbreviated Journal Org Chem Front
Volume 4 Issue (up) 4 Pages 1561-1573
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Besides providing sufficient solubility, branched alkyl chains also affect the film-forming and packing properties of organic semiconductors. In order to avoid steric hindrance as it is present in wide-spread alkyl chains comprising a branching point position at the C2-position, i.e., 2-ethylhexyl, the branching point can be moved away from the pi-conjugated backbone. In this report, we study the influence of the modification of the branching point position from the C2-position in 2-hexyldecylamine (1) to the C4-position in 4-hexyldecylamine (2) connected to the central dithieno[3,2-b: 2', 3'-d] pyrrole (DTP) moiety in a well-studied A-D-A oligothiophene on the optoelectronic properties and photovoltaic performance in solution- processed bulk heterojunction solar cells (BHJSCs) with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor material. Post-treatment of the photoactive layers is performed via solvent vapor annealing (SVA) in order to improve the film microstructure of the bulk heterojunction. The time evolution of nanoscale morphological changes is followed by combining scanning transmission electron microscopy with low-energy-loss spectroscopic imaging (STEM-SI), solid-state absorption spectroscopy, and two-dimensional grazing incidence X-ray diffraction (2D-GIXRD). Our results show an improvement of the photovoltaic performance that is dependent on the branching point position in the donor oligomer. Optical spacers are utilized to increase light absorption inside the co-oligomer 2-based BHJSCs leading to increased power conversion efficiencies (PCEs) of 8.2% when compared to the corresponding co-oligomer 1-based devices. A STEM-SI analysis of the respective device cross-sections of active layers containing 1 and 2 as donor materials indeed reveals significant differences in their respective active layer morphologies.
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Corporate Author Thesis
Publisher RSC Publishing Place of Publication London Editor
Language Wos 000406374800013 Publication Date 2017-05-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2052-4129 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.955 Times cited 24 Open Access OpenAccess
Notes ; We acknowledge financial support by the European Commission under the project “SUNFLOWER” (FP7-ICT-2011-7, grant number: 287594) and S.B. acknowledges the ERC Starting Grant Colouratoms (335078). ; Approved Most recent IF: 4.955
Call Number UA @ lucian @ c:irua:145176UA @ admin @ c:irua:145176 Serial 4727
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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 (up) 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.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000406779700008 Publication Date 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 Niu, H.; Pitcher, M.J.; Corkett, A.J.; Ling, S.; Mandal, P.; Zanella, M.; Dawson, K.; Stamenov, P.; Batuk, D.; Abakumov, A.M.; Bull, C.L.; Smith, R.I.; Murray, C.A.; Day, S.J.; Slater, B.; Cora, F.; Claridge, J.B.; Rosseinsky, M.J.
Title Room Temperature Magnetically Ordered Polar Corundum GaFeO3 Displaying Magnetoelectric Coupling Type A1 Journal article
Year 2017 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 139 Issue (up) 4 Pages 1520-1531
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The polar corundum structure type offers a route to new room temperature multiferroic materials, as the partial LiNbO3-type cation ordering that breaks inversion symmetry may be combined with long-range magnetic ordering of high spin d(5) cations above room temperature in the AFeO(3) system. We report the synthesis of a polar corundum GaFeO3 by a high-pressure, high-temperature route and demonstrate that its polarity arises from partial LiNbO3 -type cation ordering by complementary use of neutron, X-ray, and electron diffraction methods. In situ neutron diffraction shows that the polar corundum forms directly from AlFeO3-type GaFeO3 under the synthesis conditions. The A(3+)/Fe3+ cations are shown to be more ordered in polar corundum GaFeO3 than in isostructural ScFeO3. This is explained by DFT calculations which indicate that the extent of ordering is dependent on the configurational entropy available to each system at the very different synthesis temperatures required to form their corundum structures. Polar corundum GaFeO3 exhibits weak ferromagnetism at room temperature that arises from its Fe2O3-like magnetic ordering, which persists to a temperature of 408 K. We demonstrate that the polarity and magnetization are coupled in this system with a measured linear magnetoelectric coupling coefficient of 0.057 ps/m. Such coupling is a prerequisite for potential applications of polar corundum materials in multiferroic/magnetoelectric devices.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000393355600034 Publication Date 2016-12-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 12 Open Access OpenAccess
Notes This work was funded by the EPSRC under EP/N004884. We thank the STFC for provision of beam time at ISIS and Diamond Light Source. We thank the Materials Chemistry Consortium (EPSRC, EP/L000202) for access to computer time on the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk). A.M.A. is grateful to the Russian Science Foundation (Grant 14-13-00680) for financial support. MJ.R is a Royal Society Research Professor. We wish to thank Dr. Ming Li (University of Nottingham, UK) for helpful discussion and advice. Original data is available at the University of Liverpool's DataCat repository at DOI: 10.17638/datacat.liverpool.ac.uk/235. The supporting crystallographic information file may also be obtained from FIZ Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany (e-mail: crysdata@fiz-karlsruhe.de), on quoting the deposition number CSD-432419. Approved Most recent IF: 13.858
Call Number EMAT @ emat @c:irua:147507 Serial 4777
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Author Lane, T.L.M.; Andelkovic, M.; Wallbank, J.R.; Covaci, L.; Peeters, F.M.; Fal'ko, V.I.
Title Ballistic electron channels including weakly protected topological states in delaminated bilayer graphene Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 97 Issue (up) 4 Pages 045301
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract <script type='text/javascript'>document.write(unpmarked('We show that delaminations in bilayer graphene (BLG) with electrostatically induced interlayer symmetry can provide one with ballistic channels for electrons with energies inside the electrostatically induced BLG gap. These channels are formed by a combination of valley-polarized evanescent states propagating along the delamination edges (which persist in the presence of a strong magnetic field) and standing waves bouncing between them inside the delaminated region (in a strong magnetic field, these transform into Landau levels in the monolayers). For inverted stackings in BLGs on the left and right of the delamination (AB-2ML-BA or BA-2ML-AB, where 2ML indicates two decoupled monolayers of graphene), the lowest-energy ballistic channels are gapless, have linear dispersion, and appear to be weakly topologically protected. When BLG stackings on both sides of the delamination are the same (AB-2ML-AB or BA-2ML-BA), the lowest-energy ballistic channels are gapped, with a gap epsilon(g) scaling as epsilon(g) alpha W-1 with delamination width and epsilon(g) alpha delta(-1) with the on-layer energy difference in the delaminated part of the structure. Depending on the width, delaminations may also support several \u0022higher-energy\u0022 waveguide modes. Our results are based on both the analytical study of the wave matching of Dirac states and tight-binding model calculations, and we analyze in detail the dependence of the delamination spectrum on the electrostatic conditions in the structure, such as the vertical displacement field.'));
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Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000419772200005 Publication Date 2018-01-11
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 11 Open Access
Notes ; This work was funded by EPSRC via EPSRC Grand Engineering Chellenges Grant No. EP/N010345, the Manchester NOWNANO CDT EP/L-1548X, the Flemish Science Foundation (FWO-VI), the European Graphene Flagship project, ERC Synergy grant Hetero2D, and FLAG-ERA project TRANS2DTMD. The authors would like to acknowledge useful discussions with M. Zarenia, S. Slizovskiy, E. McCann, and K. Novesolov. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:148441UA @ admin @ c:irua:148441 Serial 4868
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Author Clima, S.; Belmonte, A.; Degraeve, R.; Fantini, A.; Goux, L.; Govoreanu, B.; Jurczak, M.; Ota, K.; Redolfi, A.; Kar, G.S.; Pourtois, G.
Title Kinetic and thermodynamic heterogeneity : an intrinsic source of variability in Cu-based RRAM memories Type A1 Journal article
Year 2017 Publication Journal of computational electronics Abbreviated Journal J Comput Electron
Volume 16 Issue (up) 4 Pages 1011-1016
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract <script type='text/javascript'>document.write(unpmarked('The resistive random-access memory (RRAM) device concept is close to enabling the development of a new generation of non-volatile memories, provided that their reliability issues are properly understood. The design of a RRAM operating with extrinsic defects based on metallic inclusions, also called conductive bridge RAM, allows the use of a large spectrum of solid electrolytes. However, when scaled to device dimensions that meet the requirements of the latest technological nodes, the discrete nature of the atomic structure of the materials impacts the device operation. Using density functional theory simulations, we evaluated the migration kinetics of Cu conducting species in amorphous and solid electrolyte materials, and established that atomic disorder leads to a large variability in terms of defect stability and kinetic barriers. This variability has a significant impact on the filament resistance and its dynamics, as evidenced during the formation step of the resistive filament. Also, the atomic configuration of the formed filament can age/relax to another metastable atomic configuration, and lead to a modulation of the resistivity of the filament. All these observations are qualitatively explained on the basis of the computed statistical distributions of the defect stability and on the kinetic barriers encountered in RRAM materials.'));
Address
Corporate Author Thesis
Publisher Place of Publication Place of publication unknown Editor
Language Wos 000417598100004 Publication Date 2017-08-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1569-8025 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.526 Times cited 2 Open Access Not_Open_Access
Notes Approved Most recent IF: 1.526
Call Number UA @ lucian @ c:irua:148569 Serial 4883
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Author Song, H.-D.; Wu, Y.-F.; Yang, X.; Ren, Z.; Ke, X.; Kurttepeli, M.; Tendeloo, G.V.; Liu, D.; Wu, H.-C.; Yan, B.; Wu, X.; Duan, C.-G.; Han, G.; Liao, Z.-M.; Yu, D.
Title Asymmetric Modulation on Exchange Field in a Graphene/BiFeO3Heterostructure by External Magnetic Field Type A1 Journal article
Year 2018 Publication Nano letters Abbreviated Journal Nano Lett
Volume 18 Issue (up) 4 Pages 2435-2441
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Graphene, having all atoms on its surface, is favorable to extend the functions by introducing the spin–orbit coupling and magnetism through proximity effect. Here, we report the tunable interfacial exchange field produced by proximity coupling in graphene/BiFeO3 heterostructures. The exchange field has a notable dependence with external magnetic field, and it is much larger under negative magnetic field than that under positive magnetic field. For negative external magnetic field, interfacial exchange coupling gives rise to evident spin splitting for N ≠ 0 Landau levels and a quantum Hall metal state for N = 0 Landau level. Our findings suggest graphene/BiFeO3 heterostructures are promising for spintronics.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000430155900034 Publication Date 2018-04-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.712 Times cited 9 Open Access Not_Open_Access
Notes This work was supported by National Key Research and Development Program of China (No. 2016YFA0300802) and NSFC (Nos. 11774004 and 11604004). Ministry of Science and Technology of the People's Republic of China, 2016YFA0300802 ; National Natural Science Foundation of China, 11604004 11774004 ; Approved Most recent IF: 12.712
Call Number EMAT @ lucian @c:irua:150794 Serial 4923
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Author Lombardo, J.; Jelić, Ž.L.; Baumans, X.D.A.; Scheerder, J.E.; Nacenta, J.P.; Moshchalkov, V.V.; Van de Vondel, J.; Kramer, R.B.G.; Milošević, M.V.; Silhanek, A.V.
Title In situ tailoring of superconducting junctions via electro-annealing Type A1 Journal article
Year 2018 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 10 Issue (up) 4 Pages 1987-1996
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract We demonstrate the in situ engineering of superconducting nanocircuitry by targeted modulation of material properties through high applied current densities. We show that the sequential repetition of such customized electro-annealing in a niobium (Nb) nanoconstriction can broadly tune the superconducting critical temperature T-c and the normal-state resistance R-n in the targeted area. Once a sizable R-n is reached, clear magneto-resistance oscillations are detected along with a Fraunhofer-like field dependence of the critical current, indicating the formation of a weak link but with further adjustable characteristics. Advanced Ginzburg-Landau simulations fully corroborate this picture, employing the detailed parametrization from the electrical characterization and high resolution electron microscope images of the region within the constriction where the material has undergone amorphization by electro-annealing.
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Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000423355300049 Publication Date 2017-12-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 23 Open Access
Notes ; The authors thank the Fonds de la Recherche Scientifique – FNRS, the ARC grant 13/18-08 for Concerted Research Actions, financed by the French Community of Belgium (Wallonia-Brussels Federation), the Research Foundation – Flanders (FWO-Vlaanderen) and the COST action NanoCoHybri (CA16218). The work is also suppported by Methusalem Funding by the Flemish Government. J. Lombardo acknowledges support from F. R. S.-FNRS (FRIA Research Fellowship). The LANEF framework (ANR-10-LABX-51-01) and the Nanoscience Foundation are acknowledged for their support with mutualized infrastructure. The work of A. V. Silhanek is partially supported by PDR T.0106.16 of the F. R. S.-FNRS. The authors thank the ULg Microscopy facility CAREM for part of the SEM investigations. ; Approved Most recent IF: 7.367
Call Number UA @ lucian @ c:irua:149315UA @ admin @ c:irua:149315 Serial 4937
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Author Lutz, L.; Corte, D.A.D.; Chen, Y.; Batuk, D.; Johnson, L.R.; Abakumov, A.; Yate, L.; Azaceta, E.; Bruce, P.G.; Tarascon, J.-M.; Grimaud, A.
Title The role of the electrode surface in Na-Air batteries : insights in electrochemical product formation and chemical growth of NaO2 Type A1 Journal article
Year 2018 Publication Advanced energy materials Abbreviated Journal Adv Energy Mater
Volume 8 Issue (up) 4 Pages 1701581
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The Na-air battery, because of its high energy density and low charging overpotential, is a promising candidate for low-cost energy storage, hence leading to intensive research. However, to achieve such a battery, the role of the positive electrode material in the discharge process must be understood. This issue is herein addressed by exploring the electrochemical reduction of oxygen, as well as the chemical formation and precipitation of NaO2 using different electrodes. Whereas a minor influence of the electrode surface is demonstrated on the electrochemical formation of NaO2, a strong dependence of the subsequent chemical precipitation of NaO2 is identified. In the origin, this effect stems from the surface energy and O-2/O-2(-) affinity of the electrode. The strong interaction of Au with O-2/O-2(-) increases the nucleation rate and leads to an altered growth process when compared to C surfaces. Consequently, thin (3 mu m) flakes of NaO2 are found on Au, whereas on C large cubes (10 mu m) of NaO2 are formed. This has significant impact on the cell performance and leads to four times higher capacity when C electrodes with low surface energy and O-2/O-2(-) affinity are used. It is hoped that these findings will enable the design of new positive electrode materials with optimized surfaces.
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Corporate Author Thesis
Publisher WILEY-VCH Verlag GmbH & Co. Place of Publication Weinheim Editor
Language Wos 000424152200009 Publication Date 2017-09-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1614-6832; 1614-6840 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 16.721 Times cited 13 Open Access Not_Open_Access
Notes ; L.L. thanks ALISTORE-ERI for his PhD grant. P.G.B. is indebted to the EPSRC for financial support, including the Supergen Energy Storage grant. ; Approved Most recent IF: 16.721
Call Number UA @ lucian @ c:irua:149269 Serial 4951
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Author Roxana Vlad, V.; Bartolome, E.; Vilardell, M.; Calleja, A.; Meledin, A.; Obradors, X.; Puig, T.; Ricart, S.; Van Tendeloo, G.; Usoskin, A.; Lee, S.; Petrykin, V.; Molodyk, A.
Title Inkjet printing multideposited YBCO on CGO/LMO/MgO/Y2O3/Al2O3/Hastelloy tape for 2G-coated conductors Type A1 Journal article
Year 2018 Publication IEEE transactions on applied superconductivity Abbreviated Journal
Volume 28 Issue (up) 4 Pages 6601805
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We present the preparation of a new architecture of coated conductor by Inkjet printing of low fluorine YBa2Cu3O7-x (YBCO) on top of SuperOx tape: CGO/LMO/IBAD-MgO/Y2O3/Al-2 O-3/Hastelloy. A five-layered multideposited, 475-nm-thick YBCO film was structurally and magnetically characterized. A good texture was achieved using this combination of buffer layers, requiring only a 30-nm-thin ion-beam-assisted deposition (IBAD)-MgO layer. The LF-YBCO CC reaches self-field critical current density values of J(c)(GB) similar to NJ 15.9 MA/cm(2) (5 K), similar to 1.23 MA/cm(2) (77 K) corresponding to an I-c (77 K) = 58.4 A/cm-width. Inkjet printing offers a flexible and cost effective method for YBCO deposition, allowing patterning of structures.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000429010900001 Publication Date 2018-02-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.288 Times cited 2 Open Access Not_Open_Access
Notes ; This work was performed within the framework of the EUROTAPES Project FP7-NMP.2011.2.2-1 under Grant280432, funded by the EU. ICMAB research was financed by the Ministry of Economy and Competitiveness, and FEDER funds under Projects MAT2011-28874-C02-01, MAT2014-51778-C2-1-R, ENE2014-56109-C3-3-R, and Consolider Nanoselect CSD2007-00041, and by Generalitat de Catalunya (2009 SGR 770, 2015 SGR 753, and Xarmae). ICMAB acknowledges support from Severo Ochoa Program (MINECO) under Grant SEV-2015-0496. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:150711 Serial 4971
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Author Domingos, J.L.C.; Peeters, F.M.; Ferreira, W.P.
Title Self-assembly and clustering of magnetic peapod-like rods with tunable directional interaction Type A1 Journal article
Year 2018 Publication PLoS ONE Abbreviated Journal Plos One
Volume 13 Issue (up) 4 Pages e0195552
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract Based on extensive Langevin Dynamics simulations we investigate the structural properties of a two-dimensional ensemble of magnetic rods with a peapod-like morphology, i.e, rods consisting of aligned single dipolar beads. Self-assembled configurations are studied for different directions of the dipole with respect to the rod axis. We found that with increasing misalignment of the dipole from the rod axis, the smaller the packing fraction at which the percolation transition is found. For the same density, the system exhibits different aggregation states for different misalignment. We also study the stability of the percolated structures with respect to temperature, which is found to be affected by the microstructure of the assembly of rods.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.806 Times cited Open Access
Notes Approved Most recent IF: 2.806
Call Number UA @ lucian @ c:irua:150778UA @ admin @ c:irua:150778 Serial 4977
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Author Sieger, M.; Pahlke, P.; Lao, M.; Meledin, A.; Eisterer, M.; Van Tendeloo, G.; Schultz, L.; Nielsch, K.; Huehne, R.
Title Thick secondary phase pinning-enhanced YBCO films on technical templates Type A1 Journal article
Year 2018 Publication IEEE transactions on applied superconductivity Abbreviated Journal
Volume 28 Issue (up) 4 Pages 8000505
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The critical current I-c(B) of YBa2Cu3O7-delta (YBCO) coated conductors can be increased by growing thicker superconductor layers as well as improving the critical current density J(c)(B) by the incorporation of artificial pinning centers. We studied the properties of pulsed laser deposited BaHfO3 (BHO)-doped YBCO films with thicknesses of up to 5 mu m on buffered rolling-assisted biaxially textured Ni-5 at % W tape and alternating beam assisted deposition textured Yttrium-stabilized ZrO2 layers on stainless steel. X-Ray diffraction confirms the epitaxial growth of the superconductor on the buffered metallic template. BHO additions reduce the film porosity and lower the probability to grow misoriented grains, hence preventing the J(c) decrease observed in undoped YBCO films with thicknesses > 2 mu m. Thereby, a continuous increase in I-c at 77 K is achieved. A mixed structure of secondary phase nanorods and platelets with different orientations increases J(c)(B) in the full angular range and simultaneously lowers the J(c) anisotropy compared to pristine YBCO.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000427623700001 Publication Date 2018-01-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.288 Times cited 1 Open Access Not_Open_Access
Notes ; This work was supported by EUROTAPES, a collaborative project funded by the European Commission's Seventh Framework Program (FP7 / 2007 – 2013) under Grant Agreement no. 280432. Max Sieger acknowledges funding by the Graduate Academy of the Technical University Dresden, funded by means of the Excellence Initiative by the German Federal and State Governments. ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:150712 Serial 4986
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Author Pahlke, P.; Sieger, M.; Ottolinger, R.; Lao, M.; Eisterer, M.; Meledin, A.; Van Tendeloo, G.; Haenisch, J.; Holzapfel, B.; Schultz, L.; Nielsch, K.; Huehne, R.
Title Influence of artificial pinning centers on structural and superconducting properties of thick YBCO films on ABAD-YSZ templates Type A1 Journal article
Year 2018 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 31 Issue (up) 4 Pages 044007
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Recent efforts in the development of YBa2Cu3O7-x (YBCO) coated conductors are devoted to the increase of the critical current I-c in magnetic fields. This is typically realized by growing thicker YBCO layers as well as by the incorporation of artificial pinning centers. We studied the growth of doped YBCO layers with a thickness of up to 7 mu m using pulsed laser deposition with a growth rate of about 1.2 nm s(-1). Industrially fabricated ion-beam textured YSZ templates based on metal tapes were used as substrates for this study. The incorporation of BaHfO3 (BHO) or Ba2Y(Nb0.5Ta0.5)O-6 (BYNTO) secondary phase additions leads to a denser microstructure compared to undoped films. A purely c-axis-oriented YBCO growth is preserved up to a thickness of about 4 mu m, whereas misoriented texture components were observed in thicker films. The critical temperature is slightly reduced compared to undoped films and independent of film thickness. The critical current density J(c) of the BHO- and BYNTO-doped YBCO layers is lower at 77 K and self-field compared to pure YBCO layers; however, I-c increases up to a thickness of 5 mu m. A comparison between films with a thickness of 1.3 mu m revealed that the anisotropy of the critical current density J(c)(theta) strongly depends on the incorporated pinning centers. Whereas BHO nanorods lead to a strong B vertical bar vertical bar c-axis peak, the overall anisotropy is significantly reduced by the incorporation of BYNTO forming a mixture of short c-axis-oriented nanorods and small (a-b)-oriented platelets. As a result, the J(c) values of the doped films outperform the undoped samples at higher fields and lower temperatures for most magnetic field directions.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000442196400001 Publication Date 2018-02-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.878 Times cited 9 Open Access OpenAccess
Notes ; The authors acknowledge financial support from EURO-TAPES, a collaborative project funded by the European Union's Seventh Framework Programme (FP7/ 2007-2013) under Grant Agreement no. 280432. We thank A Usoskin (Bruker HTS GmbH, Germany) for the provision of buffered templates, and M Bianchetti, A Kursumovic and J L Mac-Manus-Driscoll (University of Cambridge, UK) for the supply of BYNTO targets. The authors also gratefully acknowledge the technical assistance of J Scheiter, M Kuhnel, U Besold (IFW) and R Nast (KIT). ; Approved Most recent IF: 2.878
Call Number UA @ lucian @ c:irua:153775 Serial 5108
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Author Demiroglu, I.; Peeters, F.M.; Gulseren, O.; Cakir, D.; Sevik, C.
Title Alkali metal intercalation in MXene/graphene heterostructures : a new platform for ion battery applications Type A1 Journal article
Year 2019 Publication The journal of physical chemistry letters Abbreviated Journal J Phys Chem Lett
Volume 10 Issue (up) 4 Pages 727-734
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract The adsorption and diffusion of Na, K, and Ca atoms on MXene/graphene heterostructures of MXene systems Sc2C(OH)(2), Ti2CO2, and V2CO2 are systematically investigated by using first-principles methods. We found that alkali metal intercalation is energetically favorable and thermally stable for Ti2CO2/graphene and V2CO2/graphene heterostructures but not for Sc2C(OH)(2). Diffusion kinetics calculations showed the advantage of MXene/graphene heterostructures over sole MXene systems as the energy barriers are halved for the considered alkali metals. Low energy barriers are found for Na and K ions, which are promising for fast charge/discharge rates. Calculated voltage profiles reveal that estimated high capacities can be fully achieved for Na ion in V2CO2/graphene and Ti2CO2/graphene heterostructures. Our results indicate that Ti2CO2/graphene and V2CO2/graphene electrode materials are very promising for Na ion battery applications. The former could be exploited for low voltage applications while the latter will be more appropriate for higher voltages.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000459948800005 Publication Date 2019-01-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1948-7185 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.353 Times cited 88 Open Access
Notes ; We acknowledge the support from the TUBITAK (116F080) and the BAGEP Award of the Science Academy. Part of this work was supported by the FLAG -ERA project TRANS-2D-TMD. A part of this work was supported by University of North Dakota Early Career Award (Grant number: 20622-4000-02624). We also acknowledge financial support from ND EPSCoR through NSF grant OIA-1355466. Computational resources were provided by the High Performance and Grid Computing Center (TRGrid e-Infrastructure) of TUBITAK ULAKBIM, the National Center for High Performance Computing (UHeM) of Istanbul Technical University, and Computational Research Center (HPC Linux cluster) at the University of North Dakota. This work was performed, in part, at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under contract no. DE-AC02-06CH11357. ; Approved Most recent IF: 9.353
Call Number UA @ admin @ c:irua:158618 Serial 5194
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Author Callaert, C.; Bercx, M.; Lamoen, D.; Hadermann, J.
Title Interstitial defects in the van der Waals gap of Bi2Se3 Type A1 Journal article
Year 2019 Publication Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials (Online) Abbreviated Journal Acta Crystallogr B
Volume 75 Issue (up) 4 Pages 717-732
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Bi<sub>2</sub>Se<sub>3</sub>is a thermoelectric material and a topological insulator. It is slightly conducting in its bulk due to the presence of defects and by controlling the defects different physical properties can be fine tuned. However, studies of the defects in this material are often contradicting or inconclusive. Here, the defect structure of Bi<sub>2</sub>Se<sub>3</sub>is studied with a combination of techniques: high-resolution scanning transmission electron microscopy (HR-STEM), high-resolution energy-dispersive X-ray (HR-EDX) spectroscopy, precession electron diffraction tomography (PEDT), X-ray diffraction (XRD) and first-principles calculations using density functional theory (DFT). Based on these results, not only the observed defects are discussed, but also the discrepancies in results or possibilities across the techniques. STEM and EDX revealed interstitial defects with mainly Bi character in an octahedral coordination in the van der Waals gap, independent of the applied sample preparation method (focused ion beam milling or cryo-crushing). The inherent character of these defects is supported by their observation in the structure refinement of the EDT data. Moreover, the occupancy probability of the defects determined by EDT is inversely proportional to their corresponding DFT calculated formation energies. STEM also showed the migration of some atoms across and along the van der Waals gap. The kinetic barriers calculated using DFT suggest that some paths are possible at room temperature, while others are most probably beam induced.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000480512600024 Publication Date 2019-08-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2052-5206 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.032 Times cited Open Access
Notes University of Antwerp, 31445 ; Acknowledgements We thank Artem M. Abakumov for providing the original Bi2Se3 sample and are also very grateful to Christophe Vandevelde for trying repeatedly to get good single crystal X-ray diffraction data out of each of our failed attempts at making an undeformed single crystal. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO-Vlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 2.032
Call Number EMAT @ emat @c:irua:161847 Serial 5295
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Author Hadermann, J.; Abakumov, A.M.
Title Structure solution and refinement of metal-ion battery cathode materials using electron diffraction tomography Type A1 Journal article
Year 2019 Publication And Materials Abbreviated Journal
Volume 75 Issue (up) 4 Pages 485-494
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The applicability of electron diffraction tomography to the structure solution and refinement of charged, discharged or cycled metal-ion battery positive electrode (cathode) materials is discussed in detail. As these materials are often only available in very small amounts as powders, the possibility of obtaining single-crystal data using electron diffraction tomography (EDT) provides unique access to crucial information complementary to X-ray diffraction, neutron diffraction and high-resolution transmission electron microscopy techniques. Using several examples, the ability of EDT to be used to detect lithium and refine its atomic position and occupancy, to solve the structure of materials ex situ at different states of charge and to obtain in situ data on structural changes occurring upon electrochemical cycling in liquid electrolyte is discussed.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000480512600002 Publication Date 2019-08-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 2 Open Access
Notes ; The following funding is acknowledged: Fonds Wetenschappelijk Onderzoek (grant No. G040116N); Russian Foundation of Basic Research (grant No. 17-03-00370-a). ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:161846 Serial 5397
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Author Abdullah, H.M.; da Costa, D.R.; Bahlouli, H.; Chaves, A.; Peeters, F.M.; Van Duppen, B.
Title Electron collimation at van der Waals domain walls in bilayer graphene Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 100 Issue (up) 4 Pages 045137
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We show that a domain wall separating single-layer graphene and AA-stacked bilayer graphene (AA-BLG) can be used to generate highly collimated electron beams which can be steered by a magnetic field. Two distinct configurations are studied, namely, locally delaminated AA-BLG and terminated AA-BLG whose terminal edge types are assumed to be either zigzag or armchair. We investigate the electron scattering using semiclassical dynamics and verify the results independently with wave-packet dynamics simulations. We find that the proposed system supports two distinct types of collimated beams that correspond to the lower and upper cones in AA-BLG. Our computational results also reveal that collimation is robust against the number of layers connected to AA-BLG and terminal edges.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000477892800005 Publication Date 2019-07-29
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 12 Open Access
Notes ; H.M.A. and H.B. acknowledge the support of King Fahd University of Petroleum and Minerals under research group Project No. RG181001. D.R.C and A.C. were financially supported by the Brazilian Council for Research (CNPq) and CAPES foundation. B.V.D. is supported by a postdoctoral fellowship by the Research Foundation Flanders (FWO-Vl). ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:161887 Serial 5410
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Author Yagmurcukardes, M.; Sevik, C.; Peeters, F.M.
Title Electronic, vibrational, elastic, and piezoelectric properties of monolayer Janus MoSTe phases: A first-principles study Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 100 Issue (up) 4 Pages 045415
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract By performing density functional theory based first-principles calculations, the electronic, vibrational, elastic, and piezoelectric properties of two dynamically stable crystal phases of monolayer Janus MoSTe, namely 1H-MoSTe and 1T'-MoSTe, are investigated. Vibrational frequency analysis reveals that the other possible crystal structure, 1T-MoSTe, of this Janus monolayer does not exhibit dynamical stability. The 1H-MoSTe phase is found to be an indirect band-gap semiconductor while 1T'-MoSTe is predicted as small-gap semiconductor. Notably, in contrast to the direct band-gap nature of monolayers 1H-MoS2 and 1H-MoTe2, 1H-MoSTe is found to be an indirect gap semiconductor driven by the induced surface strains on each side of the structure. The calculated Raman spectrum of each structure shows unique character enabling us to clearly distinguish the stable crystal phases via Raman measurements. The systematic piezoelectric stress and strain coefficient analysis reveals that out-of-plane piezoelectricity appears in 1H-MoSTe and the noncentral symmetric 1T'-MoSTe has large piezoelectric coefficients. Static total-energy calculations show clearly that the formation of 1T'-MoSTe is feasible by using 1T'-MoTe2 as a basis monolayer. Therefore, we propose that the Janus MoSTe structure can be fabricated in two dynamically stable phases which possess unique electronic, dynamical, and piezoelectric properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000476687800003 Publication Date 2019-07-19
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 128 Open Access
Notes ; Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). This work was supported by the Flemish Science Foundation (FWO-Vl) by a postdoctoral fellowship (M.Y.). ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:161899 Serial 5411
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Author Van Pottelberge, R.; Moldovan, D.; Milovanović, S.P.; Peeters, F.M.
Title Molecular collapse in monolayer graphene Type A1 Journal article
Year 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue (up) 4 Pages 045047
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Atomic collapse is a phenomenon inherent to relativistic quantum mechanics where electron states dive in the positron continuum for highly charged nuclei. This phenomenon was recently observed in graphene. Here we investigate a novel collapse phenomenon when multiple sub- and supercritical charges of equal strength are put close together as in a molecule. We construct a phase diagram which consists of three distinct regions: (1) subcritical, (2) frustrated atomic collapse, and (3) molecular collapse. We show that the single impurity atomic collapse resonances rearrange themselves to form molecular collapse resonances which exhibit a distinct bonding, anti-bonding and non-bonding character. Here we limit ourselves to systems consisting of two and three charges. We show that by tuning the distance between the charges and their strength a high degree of control over the molecular collapse resonances can be achieved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000487692200003 Publication Date 2019-08-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited 10 Open Access
Notes ; We thank Matthias Van der Donck for fruitful discussions. This work was supported by the Research Foundation of Flanders (FWO-V1) through an aspirant research Grant for RVP and a postdoctoral Grant for SPM. ; Approved Most recent IF: 6.937
Call Number UA @ admin @ c:irua:163756 Serial 5422
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Author Salvant, J.; Williams, J.; Ganio, M.; Casadio, F.; Daher, C.; Sutherland, K.; Monico, L.; Vanmeert, F.; De Meyer, S.; Janssens, K.; Cartwright, C.; Walton, M.
Title A Roman Egyptian Painting Workshop : technical investigation of the portraits from Tebtunis, Egypt Type A1 Journal article
Year 2018 Publication Archaeometry Abbreviated Journal Archaeometry
Volume 60 Issue (up) 4 Pages 815-833
Keywords A1 Journal article; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Roman-period mummy portraits are considered to be ancient antecedents of modern portraiture. However, the techniques and materials used in their manufacture are not thoroughly understood. Analytical study of the pigments as well as the binding materials helps to address questions on what aspects of the painting practices originate from Pharaonic and/or Graeco-Roman traditions, and can aid in determining the provenance of the raw materials from potential locations across the ancient Mediterranean and European worlds. Here, one of the largest assemblages of mummy portraits to remain intact since their excavation from the site of Tebtunis in Egypt was examined using multiple analytical techniques to address how they were made. The archaeological evidence suggests that these portraits were products of a single workshop and, correspondingly, they are found to be made using similar techniques and materials: wax-based and lead white-rich paint combined with a variety of iron-based pigments (including hematite, goethite and jarosite), as well as Egyptian blue, minium, indigo and madder lake to create subtle variations and tones.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000438195100011 Publication Date 2017-11-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-813x; 1475-4754 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.47 Times cited 6 Open Access
Notes ; This collaborative initiative is part of NU-ACCESS's broad portfolio of activities, made possible by generous support of the Andrew W. Mellon Foundation as well as supplemental support provided by the Materials Research Center, the Office of the Vice President for Research, the McCormick School of Engineering and Applied Science and the Department of Materials Science and Engineering at Northwestern University. This work made use of the Keck-II facility of the NUANCE Center at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Part of this research was carried out at the light source PETRA III at DESY, a member of the Helmholtz Association (HGF), and at ESRF (experiment no. HG-79). We are grateful to Marine Cotte and Wout De Nolf for their support during the experiment at beamline ID21. We would like to thank Gerald Falkenberg and Jan Garrevoet for their assistance in using beamline P06. ; Approved Most recent IF: 1.47
Call Number UA @ admin @ c:irua:152396 Serial 5455
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Author Cagno, S.; Janssens, K.; Mendera, M.
Title Compositional analysis of Tuscan glass samples: in search of raw materials fingerprints Type A1 Journal article
Year 2008 Publication Analytical and bioanalytical chemistry Abbreviated Journal Anal Bioanal Chem
Volume 391 Issue (up) 4 Pages 1389-1395
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000256088700035 Publication Date 2008-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1618-2642 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.431 Times cited 26 Open Access
Notes Approved Most recent IF: 3.431; 2008 IF: 3.328
Call Number UA @ admin @ c:irua:69320 Serial 5545
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Author Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Dik, J.; Radepont, M.; Hendriks, E.; Geldof, M.; Cotte, M.
Title Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 2 : original paint layer samples Type A1 Journal article
Year 2011 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 83 Issue (up) 4 Pages 1224-1231
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The darkening of the original yellow areas painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is a phenomenon widely observed on several paintings by Vincent van Gogh, such as the famous different versions of Sunflowers. During our previous investigations on artificially aged model samples of lead chromate, we established for the first time that darkening of chrome yellow is caused by reduction of PbCrO4 to Cr2O3·2H2O (viridian green), likely accompanied by the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide]. In the second part of this work, in order to demonstrate that this reduction phenomenon effectively takes place in real paintings, we study original paint samples from two paintings of V. van Gogh. As with the model samples, in view of the thin superficial alteration layers that are present, high lateral resolution spectroscopic methods that make use of synchrotron radiation (SR), such as microscopic X-ray absorption near edge (μ-XANES) and X-ray fluorescence spectrometry (μ-XRF) were employed. Additionally, μ-Raman and mid-FTIR analyses were carried out to completely characterize the samples. On both paint microsamples, the local presence of reduced Cr was demonstrated by means of μ-XANES point measurements. The presence of Cr(III) was revealed in specific areas, in some cases correlated to the presence of Ba(sulfate) and/or to that of aluminum silicate compounds.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000287176900012 Publication Date 2011-02-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 84 Open Access
Notes ; This research was funded by grants from ESRF (experiment EC-504) and by HASYLAB (experiments 11-20080130 EC and 11-20070157 EC) and was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0103.04, G.0689.06, and G.0704.08. The staff of the Van Gogh Museum, Amsterdam, is acknowledged for their agreeable cooperation and for the authorization to publish the images of the paintings in this article. L.M. was financially supported by the Erasmus Placement in the framework of Lifelong Learning Programme (A.Y. 2009-2010). The EU Community's FP7 Research Infrastructures program under the CHARISMA Project (Grant Agreement 228330) is also acknowledged. ; Approved Most recent IF: 6.32; 2011 IF: 5.856
Call Number UA @ admin @ c:irua:88795 Serial 5571
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Author Monico, L.; Sorace, L.; Cotte, M.; de Nolf, W.; Janssens, K.; Romani, A.; Miliani, C.
Title Disclosing the binding medium effects and the pigment solubility in the (photo)reduction process of chrome yellows (PbCrO4/PbCr1-xSxO4) Type A1 Journal article
Year 2019 Publication ACS Omega Abbreviated Journal
Volume 4 Issue (up) 4 Pages 6607-6619
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The darkening due to chemical alteration of chrome yellows (PbCrO4/PbCr1-xSxO4) is a phenomenon threatening a large number of 19th-20th century paintings, including the Amsterdam Sunflowers by Vincent van Gogh. Our earlier studies have proven that the alteration is due to a Cr(VI) -> Cr(III) reduction with Cr(V)-species that are formed as long-lived intermediates and that bCr(1-x)S(x)O(4) (0 < x <= 0.8) types undergo reduction more readily than monoclinic, S-free, PbCrO4. In this context, there is still lack of knowledge about the effects of the chemical properties of the binding medium (i.e., chemical composition and drying process) and the solubility of chrome yellows on the overall reduction pathways. Here, we study a series of naturally and photochemically aged mock-up paints prepared by mixing chrome yellow powders (PbCrO4/PbCr0.2S0.8O4) with either linseed oil or a water-based acrylic emulsion as the binding medium. Equivalent paints made up of the highly soluble K2CrO4 were also investigated and used as benchmarks to provide a more in-depth understanding of the influence of the solubility on the chromate reduction pathways in the two different binders. A combination of synchrotron radiation-based Cr K-edge X-ray absorption near edge structure (XANES), electron paramagnetic resonance (EPR), and UV-Visible spectroscopy measurements shows that: (1) the Cr(VI) reduction results from the interaction between the pigment and the binder; (2) the process is more significant in oil, giving rise to Cr(V)- and Cr(III)-species as well as oxidized organic compounds; (3) the lightfastness of the chrome yellow pigment is enhanced in the acrylic binder; and (4) the tendency toward chromium reduction increases with increasing solubility of the pigment. Based on our findings, we propose a scheme for the mechanism of the (photo)reduction process of chrome yellows in the oil and acrylic binder. Overall, our results provide new insights into the factors driving the degradation of lead chromate-based paints in artworks and contribute to the development of strategies for preserving them over time.
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Publisher Place of Publication Editor
Language Wos 000466552500057 Publication Date 2019-04-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-1343 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 4 Open Access
Notes ; The research was financially supported by the European research project IPERION-CH, funded by the European Commission, H2020-INFRAIA-2014-2015 (grant agreement n. 654028), and by the project AMIS, within the program Dipartimenti di Eccellenza 2018-2022, funded by MIUR and University of Perugia. The University of Perugia is also acknowledged for financial support under the program “Ricerca di Base 2017”. L.S. acknowledges the financial support of Ente CRF. For the beamtime grants received, we thank the ESRF (experiment no. HG64 and in-house beamtimes). ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:160416 Serial 5577
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Author Amato, S.R.; Burnstock, A.; Cross, M.; Janssens, K.; Rosi, F.; Cartechini, L.; Fontana, R.; Dal Fovo, A.; Paolantoni, M.; Grazia, C.; Romani, A.; Michelin, A.; Andraud, C.; Tournie, A.; Dik, J.
Title Interpreting technical evidence from spectral imaging of paintings by Edouard Manet in the Courtauld Gallery Type A1 Journal article
Year 2019 Publication X-ray spectrometry T2 – MA-XRF Workshop on Developments and Applications of Macro-XRF in, Conservation, Art, and Archeology, SEP 24-25, 2017, Trieste, ITALY Abbreviated Journal X-Ray Spectrom
Volume 48 Issue (up) 4 Pages 282-292
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The paintings by edouard Manet in The Courtauld Gallery Dejeuner sur l'herbe (1863-68), Marguerite de Conflans en Toilette de Bal (1870-1880), Banks of the Seine at Argenteuil (1874), and A Bar at the Folies-Bergere (1882) were investigated for the first time using a range of non-invasive in situ analyses. The aims of the study were to investigate the painting techniques and materials used for this group of works and to critically evaluate the technical evidence derived from the integrated use of imaging techniques and portable spectroscopic methods in this context. The paintings were investigated by means of macro X-ray fluorescence (MA-XRF), reflection spectral imaging, portable UV-Vis-NIR spectroscopy, portable Raman spectroscopy, and reflection FTIR. MA-XRF and reflection spectral imaging allowed visualising elements in the compositions that were not visible using traditional methods of technical study. For example, MA-XRF analysis of Dejeuner sur l'herbe revealed elements of the development of the composition that provided new evidence to consider its relationship to other versions of the composition. The study also highlighted questions about the interpretation of elemental distribution maps and spectral images that did not correspond to the reworking visible in X-radiographs. For example, in A Bar at the Folies-Bergere Manet made numerous changes during painting, which were not clearly visualised with any of the techniques used. The research has wider implications for the study of Impressionist paintings, as the results will support technical studies of works by other artists of the period who used similar materials and painting methods.
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Language Wos 000472210700005 Publication Date 2018-01-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0049-8246 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.298 Times cited Open Access
Notes ; Financial support by the Access to Research Infrastructures activity in the Horizon 2020 Programme of the EU (IPERION CH Grant agreement 654028) is gratefully acknowledged. ; Approved Most recent IF: 1.298
Call Number UA @ admin @ c:irua:161296 Serial 5670
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Author Bugani, S.; Camaiti, M.; Morselli, L.; Van de Casteele, E.; Janssens, K.
Title Investigating morphological changes in treated vs. untreated stone building materials by x-ray micro-CT Type A1 Journal article
Year 2008 Publication Analytical and bioanalytical chemistry Abbreviated Journal Anal Bioanal Chem
Volume 391 Issue (up) 4 Pages 1343-1350
Keywords A1 Journal article; Vision lab; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
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Publisher Place of Publication Editor
Language Wos 000256088700030 Publication Date 2008-03-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1618-2642 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.431 Times cited 25 Open Access
Notes Approved Most recent IF: 3.431; 2008 IF: 3.328
Call Number UA @ admin @ c:irua:69319 Serial 5673
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