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Author (up) Missault, N.; Vasilopoulos, P.; Vargiamidis, V.; Peeters, F.M.; Van Duppen, B.
Title Spin- and valley-dependent transport through arrays of ferromagnetic silicene junctions Type A1 Journal article
Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 92 Issue 92 Pages 195423
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study ballistic transport of Dirac fermions in silicene through arrays of barriers, of width d, in the presence of an exchange field M and a tunable potential of height U or depth-U. The spin-and valley-resolved conductances as functions of U or M, exhibit resonances away from the Dirac point (DP) and close to it a pronounced dip that becomes a gap when a critical electric field E-z is applied. This gap widens by increasing the number of barriers and can be used to realize electric field-controlled switching of the current. The spin p(s) and valley p(v) polarizations of the current near the DP increase with Ez or M and can reach 100% for certain of their values. These field ranges widen significantly by increasing the number of barriers. Also, ps and pv oscillate nearly periodically with the separation between barriers or wells and can be inverted by reversing M.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000364998100006 Publication Date 2015-11-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121; 1550-235x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 54 Open Access
Notes ; This work was supported by the Canadian NSERC Grant No. OGP0121756 (P.V.) and by the Flemish Science Foundation (FWO-Vl) with a Ph.D. research grant (B.V.D.). ; Approved Most recent IF: 3.836; 2015 IF: 3.736
Call Number UA @ lucian @ c:irua:130264 Serial 4247
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Author (up) Missen, O.P.; Mills, S.J.; Canossa, S.; Hadermann, J.; Nenert, G.; Weil, M.; Libowitzky, E.; Housley, R.M.; Artner, W.; Kampf, A.R.; Rumsey, M.S.; Spratt, J.; Momma, K.; Dunstan, M.A.
Title Polytypism in mcalpineite : a study of natural and synthetic Cu₃TeO₆ Type A1 Journal article
Year 2022 Publication Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials (Online) Abbreviated Journal Acta Crystallogr B
Volume 78 Issue 1 Pages
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Synthetic and naturally occurring forms of tricopper orthotellurate, (Cu3TeO6)-Te-II-O-IV (the mineral mcalpineite) have been investigated by 3D electron diffraction (3D ED), X-ray powder diffraction (XRPD), Raman and infrared (IR) spectroscopic measurements. As a result of the diffraction analyses, (Cu3TeO6)-Te-II-O-IV is shown to occur in two polytypes. The higher-symmetric (Cu3TeO6)-Te-II-O-IV-1C polytype is cubic, space group 1a (3) over bar, with a = 9.537 (1) angstrom and V = 867.4 (3) angstrom(3) as reported in previous studies. The 1C polytype is a well characterized structure consisting of alternating layers of (CuO6)-O-II octahedra and both (CuO6)-O-II and (TeO6)-O-VI octahedra in a patchwork arrangement. The structure of the lower-symmetric orthorhombic (Cu3TeO6)-Te-II-O-IV-2O polytype was determined for the first time in this study by 3D ED and verified by Rietveld refinement. The 2O polytype crystallizes in space group Pcca, with a = 9.745 (3) angstrom, b = 9.749 (2) angstrom, c = 9.771 (2) angstrom and V = 928.3 (4) angstrom(3) . High-precision XRPD data were also collected on (Cu3TeO6)-Te-II-O-IV-2O to verify the lower-symmetric structure by performing a Rietveld refinement. The resultant structure is identical to that determined by 3D ED, with unit-cell parameters a = 9.56157 (19) angstrom, b = 9.55853 (11) angstrom, c = 9.62891 (15) angstrom and V = 880.03 (2) angstrom(3) . The lower symmetry of the 2O polytype is a consequence of a different cation ordering arrangement, which involves the movement of every second (CuO6)-O-II and (TeO6)-O-VI octahedral layer by (1/4, 1/4, 0), leading to an offset of (TeO6)-O-VI and (CuO6)-O-II octahedra in every second layer giving an ABAB* stacking arrangement. Syntheses of (Cu3TeO6)-Te-II-O-IV showed that low-temperature (473 K) hydrothermal conditions generally produce the 2O polytype. XRPD measurements in combination with Raman spectroscopic analysis showed that most natural mcalpineite is the orthorhombic 2O polytype. Both XRPD and Raman spectroscopy measurements may be used to differentiate between the two polytypes of (Cu3TeO6)-Te-II-O-IV. In Raman spectroscopy, (Cu3TeO6)-Te-II-O-IV-1C has a single strong band around 730 cm(-1), whereas (Cu3TeO6)-Te-II-O-IV-2O shows a broad double maximum with bands centred around 692 and 742 cm(-1).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000752899700003 Publication Date 2022-01-18
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 1.9 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 1.9
Call Number UA @ admin @ c:irua:186529 Serial 6962
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Author (up) Mlinar, V.; Peeters, F.M.
Title A three-dimensional model for artificial atoms and molecules: influence of substrate orientation and magnetic field dependence Type A1 Journal article
Year 2007 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
Volume 17 Issue 35 Pages 3687-3695
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000249080100013 Publication Date 2007-07-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 7 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:66124 Serial 3653
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Author (up) Mlinar, V.; Schliwa, A.; Bimberg, D.; Peeters, F.M.
Title Theoretical study of electronic and optical properties of inverted GaAs/AlxGa1-xAs quantum dots with smoothed interfaces in an external magnetic field Type A1 Journal article
Year 2007 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 75 Issue Pages 205308,1-9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000246890900065 Publication Date 2007-09-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 14 Open Access
Notes Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:69652 Serial 3610
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Author (up) Mlinar, V.; Tadić, M.; Partoens, B.; Peeters, F.M.
Title Nonsymmetrized Hamiltonian for semiconducting nanostructures in a magnetic field Type A1 Journal article
Year 2005 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 71 Issue Pages 205305,1-12
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000230244300054 Publication Date 2005-05-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 37 Open Access
Notes Approved Most recent IF: 3.836; 2005 IF: 3.185
Call Number UA @ lucian @ c:irua:62436 Serial 2363
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Author (up) Mlinar, V.; Tadić, M.; Peeters, F.M.
Title Hole and exciton energy levels in InP/InxGa1-xP quantum dot molecules: influence of geometry and magnetic field dependence Type A1 Journal article
Year 2006 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 73 Issue 23 Pages 235336,1-10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000238696600104 Publication Date 2006-06-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 16 Open Access
Notes Approved Most recent IF: 3.836; 2006 IF: 3.107
Call Number UA @ lucian @ c:irua:59708 Serial 1474
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Author (up) Mobaraki, A.; Kandemir, A.; Yapicioglu, H.; Gulseren, O.; Sevik, C.
Title Validation of inter-atomic potential for WS2 and WSe2 crystals through assessment of thermal transport properties Type A1 Journal article
Year 2018 Publication Computational materials science Abbreviated Journal
Volume 144 Issue Pages 92-98
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In recent years, transition metal dichalcogenides (TMDs) displaying astonishing properties are emerged as a new class of two-dimensional layered materials. The understanding and characterization of thermal transport in these materials are crucial for efficient engineering of 2D TMD materials for applications such as thermoelectric devices or overcoming general overheating issues. In this work, we obtain accurate Stillinger-Weber type empirical potential parameter sets for single-layer WS2 and WSe2 crystals by utilizing particle swarm optimization, a stochastic search algorithm. For both systems, our results are quite consistent with first-principles calculations in terms of bond distances, lattice parameters, elastic constants and vibrational properties. Using the generated potentials, we investigate the effect of temperature on phonon energies and phonon linewidth by employing spectral energy density analysis. We compare the calculated frequency shift with respect to temperature with corresponding experimental data, clearly demonstrating the accuracy of the generated inter-atomic potentials in this study. Also, we evaluate the lattice thermal conductivities of these materials by means of classical molecular dynamics simulations. The predicted thermal properties are in very good agreement with the ones calculated from first-principles. (C) 2017 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000424902300013 Publication Date 2017-12-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0927-0256 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:193774 Serial 8729
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Author (up) Moldovan, D.; Masir, M.R.; Covaci, L.; Peeters, F.M.
Title Resonant valley filtering of massive Dirac electrons Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 11 Pages 115431
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Electrons in graphene, in addition to their spin, have two pseudospin degrees of freedom: sublattice and valley pseudospin. Valleytronics uses the valley degree of freedom as a carrier of information similarly to the way spintronics uses electron spin. We show how a double-barrier structure consisting of electric and vector potentials can be used to filter massive Dirac electrons based on their valley index. We study the resonant transmission through a finite number of barriers and we obtain the energy spectrum of a superlattice consisting of electric and vector potentials. When a mass term is included, the energy bands and energy gaps at the K and K′ points are different and they can be tuned by changing the potential.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000309173300004 Publication Date 2012-09-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 55 Open Access
Notes This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro- GRAPHENE within the project CONGRAN, and the Flemish Science Foundation (FWO-Vl). Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101835 Serial 2896
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Author (up) Moldovan, D.; Masir, M.R.; Peeters, F.M.
Title Electronic states in a graphene flake strained by a Gaussian bump Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 3 Pages 035446-35447
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The effect of strain in graphene is usually modeled by a pseudomagnetic vector potential which is, however, derived in the limit of small strain. In realistic cases deviations are expected in view of graphene's very high strain tolerance, which can be up to 25%. Here we investigate the pseudomagnetic field generated by a Gaussian bump and we show that it exhibits significant differences with numerical tight-binding results. Furthermore, we calculate the electronic states in the strained region for a hexagon shaped flake with armchair edges. We find that the sixfold symmetry of the wave functions inside the Gaussian bump is directly related to the different effects of strain along the fundamental directions of graphene: zigzag and armchair. Low energy electrons are strongly confined in the armchair directions and are localized on the carbon atoms of a single sublattice.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000322587500003 Publication Date 2013-07-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 50 Open Access
Notes ; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem Funding of the Flemish Government. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:109800 Serial 1007
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Author (up) Moldovan, D.; Masir, M.R.; Peeters, F.M.
Title Magnetic field dependence of the atomic collapse state in graphene Type A1 Journal article
Year 2018 Publication 2D materials Abbreviated Journal 2D Mater
Volume 5 Issue 1 Pages 015017
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract <script type='text/javascript'>document.write(unpmarked('Quantum electrodynamics predicts that heavy atoms (Z \u003E Z(c) approximate to 170) will undergo the process of atomic collapse where electrons sink into the positron continuum and a new family of so-called collapsing states emerges. The relativistic electrons in graphene exhibit the same physics but at a much lower critical charge (Z(c) approximate to 1) which has made it possible to confirm this phenomenon experimentally. However, there exist conflicting predictions on the effect of a magnetic field on atomic collapse. These theoretical predictions are based on the continuum Dirac-Weyl equation, which does not have an exact analytical solution for the interplay of a supercritical Coulomb potential and the magnetic field. Approximative solutions have been proposed, but because the two effects compete on similar energy scales, the theoretical treatment varies depending on the regime which is being considered. These limitations are overcome here by starting from a tight-binding approach and computing exact numerical results. By avoiding special limit cases, we found a smooth evolution between the different regimes. We predict that the atomic collapse effect persists even after the magnetic field is activated and that the critical charge remains unchanged. We show that the atomic collapse regime is characterized: (1) by a series of Landau level anticrossings and (2) by the absence of root B scaling of the Landau levels with regard to magnetic field strength.'));
Address
Corporate Author Thesis
Publisher IOP Publishing Place of Publication Bristol Editor
Language Wos 000415015000001 Publication Date 2017-10-26
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 13 Open Access
Notes ; We thank Eva Andrei, Jinhai Mao and Yuhang Jiang for insightful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Funding of the Flemish Government. ; Approved Most recent IF: 6.937
Call Number UA @ lucian @ c:irua:147361UA @ admin @ c:irua:147361 Serial 4884
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Author (up) Moldovan, D.; Peeters, F.M.
Title Atomic Collapse in Graphene Type P1 Proceeding
Year 2016 Publication Nanomaterials For Security Abbreviated Journal
Volume Issue Pages 3-17
Keywords P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract When the charge Z of an atom exceeds the critical value of 170, it will undergo a process called atomic collapse which triggers the spontaneous creation of electron-positron pairs. The high charge requirements have prevented the observation of this phenomenon with real atomic nuclei. However, thanks to the relativistic nature of the carriers in graphene, the same physics is accessible at a much lower scale. The atomic collapse analogue in graphene is realized using artificial nuclei which can be created via the deposition of impurities on the surface of graphene or using charged vacancies. These supercritically charged artificial nuclei trap electrons in a sequence of quasi-bound states which can be observed experimentally as resonances in the local density of states.
Address
Corporate Author Thesis
Publisher Springer Place of Publication Dordrecht Editor
Language Wos 000386506200001 Publication Date 2016-07-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-94-017-7593-9; 978-94-017-7591-5 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 3 Open Access
Notes ; ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:138237 Serial 4348
Permanent link to this record
 
 
Author (up) Molnár, B.; Peeters, F.M.; Vasilopoulos, P.
Title Spin-dependent magnetotransport through a ring due to spin-orbit interaction Type A1 Journal article
Year 2004 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 69 Issue Pages 155335,1-11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000221426800104 Publication Date 2004-04-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 199 Open Access
Notes Approved Most recent IF: 3.836; 2004 IF: 3.075
Call Number UA @ lucian @ c:irua:69385 Serial 3083
Permanent link to this record
 
 
Author (up) Molnár, B.; Vasilopoulos, P.; Peeters, F.M.
Title Magnetoconductance through a chain of rings with or without periodically modulated spin-orbit interaction strength and magnetic field Type A1 Journal article
Year 2005 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 72 Issue Pages 075330,1-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000231564500117 Publication Date 2005-08-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 52 Open Access
Notes Approved Most recent IF: 3.836; 2005 IF: 3.185
Call Number UA @ lucian @ c:irua:69414 Serial 1915
Permanent link to this record
 
 
Author (up) Monarkha, Y.P.; Shirahama, K.; Kono, K.; Peeters, F.M.
Title Nonlinear quantum magnetotransport in a strongly correlated two-dimensional electron liquid Type A1 Journal article
Year 1998 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 58 Issue Pages 3762-3776
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000075616800057 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 4 Open Access
Notes Approved Most recent IF: 3.836; 1998 IF: NA
Call Number UA @ lucian @ c:irua:24163 Serial 2354
Permanent link to this record
 
 
Author (up) Monico, L.; d'Acapito, F.; Cotte, M.; Janssens, K.; Romani, A.; Ricci, G.; Miliani, C.; Cartechini, L.
Title Total electron yield (TEY) detection mode Cr K-edge XANES spectroscopy as a direct method to probe the composition of the surface of darkened chrome yellow (PbCr1-xSxO4) and potassium chromate paints Type A1 Journal article
Year 2023 Publication Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms Abbreviated Journal
Volume 539 Issue Pages 141-147
Keywords A1 Journal article; Engineering sciences. Technology; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Abstract The darkening of chromate-pigments, including chrome yellows (PbCr1-xSxO4), is a surface phenomenon affecting late 19th-early 20th c. paintings, such as those by Van Gogh. Exploring analytical strategies that contribute to a deep understanding of darkening is therefore significant for the long-term conservation of unique masterpieces. Here, we examined the capabilities of Cr K-edge XANES spectroscopy collected at the same time in X-ray fluorescence yield (XFY) and total electron yield (TEY) detection modes to selectively study the surface composition of darkened oil paint mock-ups composed of chrome yellow (PbCr0.2S0.8O4) or potassium chromate. By discussing advantages and drawbacks in using XFY/TEY modes in relation to XFY & mu;-XANES analysis from sectioned samples, we aim at assessing if TEY-XANES spectroscopy: (i) is a selective surface method to determine the abundance of different Cr-species from paint fragments; (ii) can contribute to optimize the analytical strategy by limiting time consuming sample preparation procedures; (iii) can decrease the probability of radiation damage.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001041485400001 Publication Date 2023-04-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-583x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.3 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 1.3; 2023 IF: 1.109
Call Number UA @ admin @ c:irua:198427 Serial 8944
Permanent link to this record
 
 
Author (up) Montero-Sistiaga, M.L.; Pourbabak, S.; Van Humbeeck, J.; Schryvers, D.; Vanmeensel, K.
Title Microstructure and mechanical properties of Hastelloy X produced by HP-SLM (high power selective laser melting) Type A1 Journal article
Year 2019 Publication Materials & design Abbreviated Journal Mater Design
Volume 165 Issue Pages 107598
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In order to increase the production rate during selective laser melting (SLM), a high power laser with a large beam diameter is used to build fully dense Hastelloy X parts. Compared to SLM with a low power and small diameter beam, the productivity was increased from 6 mm3/s to 16 mm3/s, i.e. 2.6 times faster. Besides the productivity benefit, the influence of the use of a high power laser on the rapid solidification microstructure and concomitant material properties is highlighted. The current paper compares the microstructure and tensile properties of Hastelloy X built with low and high power lasers. The use of a high power laser results in wider and shallower melt pools inducing an enhanced morphological and crystallographic texture along the building direction (BD). In addition, the increased heat input results in coarser sub-grains or high density dislocation walls for samples processed with a high power laser. Additionally, the influence of hot isostatic pressing (HIP) as a post-processing technique was evaluated. After HIP, the tensile fracture strain increased as compared to the strain in the as-built state and helped in obtaining competitive mechanical properties as compared to conventionally processed Hastelloy X parts.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000458259300020 Publication Date 2019-01-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-1275 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.364 Times cited 15 Open Access OpenAccess
Notes This research was supported by the ENGIE Research and Technology Division. The authors acknowledge ENGIE Research and Technology Division for the use of the SLM280HL machine. S.P. likes to thank the Flemish Science Foundation FWO for financial support under Project G.0366.15N. Approved Most recent IF: 4.364
Call Number EMAT @ emat @UA @ admin @ c:irua:157469 Serial 5176
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Author (up) Monticelli, O.; Musina, Z.; Russo, S.; Bals, S.
Title On the use of TEM in the characterization of nanocomposites Type A1 Journal article
Year 2007 Publication Materials letters Abbreviated Journal Mater Lett
Volume 61 Issue 16 Pages 3446-3450
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Both an organically modified commercial clay of montmorillonite type (MMT) and its nanocomposites, based either on polyamide 6 (PA6) or an epoxy resin, as matrix polymer, have been characterized by transmission electron microscopy (TEM). Sample micrographs, taken at increasing exposure times (t(e)), have shown the gradual disappearance of clay layers, because of an amorphisation of the MMT crystalline structures caused by prolonged sample exposure to electron beam. Indeed, the above phenomenon, which is mostly evident in the case of intercalated nanocomposites, makes the detection of the layered silicate dispersion in the polymer matrix rather difficult and compels to perform TEM measurements using very short exposure times. Moreover, the microscopy accelerating voltage has turned out to affect sample stability; namely, when decreasing the above parameter, the disappearance of clay structure occurs at lower exposure times. (C) 2006 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000247146100034 Publication Date 2006-12-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0167-577X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.572 Times cited 28 Open Access
Notes Approved Most recent IF: 2.572; 2007 IF: 1.625
Call Number UA @ lucian @ c:irua:64757 Serial 2460
Permanent link to this record
 
 
Author (up) Moors, K.; Contino, A.; Van de Put, M.L.; Vandenberghe, W.G.; Fischetti, M., V; Magnus, W.; Sorée, B.
Title Theoretical study of scattering in graphene ribbons in the presence of structural and atomistic edge roughness Type A1 Journal article
Year 2019 Publication Physical review materials Abbreviated Journal
Volume 3 Issue 2 Pages 024001
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We investigate the diffusive electron-transport properties of charge-doped graphene ribbons and nanoribbons with imperfect edges. We consider different regimes of edge scattering, ranging from wide graphene ribbons with (partially) diffusive edge scattering to ribbons with large width variations and nanoribbons with atomistic edge roughness. For the latter, we introduce an approach based on pseudopotentials, allowing for an atomistic treatment of the band structure and the scattering potential, on the self-consistent solution of the Boltzmann transport equation within the relaxation-time approximation and taking into account the edge-roughness properties and statistics. The resulting resistivity depends strongly on the ribbon orientation, with zigzag (armchair) ribbons showing the smallest (largest) resistivity and intermediate ribbon orientations exhibiting intermediate resistivity values. The results also show clear resistivity peaks, corresponding to peaks in the density of states due to the confinement-induced subband quantization, except for armchair-edge ribbons that show a very strong width dependence because of their claromatic behavior. Furthermore, we identify a strong interplay between the relative position of the two valleys of graphene along the transport direction, the correlation profile of the atomistic edge roughness, and the chiral valley modes, leading to a peculiar strongly suppressed resistivity regime, most pronounced for the zigzag orientation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000458161800001 Publication Date 2019-02-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 4 Open Access
Notes ; We acknowledge the Research Foundation – Flanders (FWO) for supporting K.M.'s research visit at the University of Texas at Dallas, as well as the support by the National Research Fund Luxembourg (FNR) with ATTRACT Grant No. 7556175. ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:157499 Serial 5235
Permanent link to this record
 
 
Author (up) Morozov, V.; Deyneko, D.; Basoyich, O.; Khaikina, E.G.; Spassky, D.; Morozov, A.; Chernyshev, V.; Abakumov, A.; Hadermann, J.
Title Incommensurately modulated structures and luminescence properties of the AgxSm(2-x)/3WO4 (x=0.286, 0.2) scheelites as thermographic phosphors Type A1 Journal article
Year 2018 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 30 Issue 14 Pages 4788-4798
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Ag+ for Sm3+ substitution in the scheelite-type AgxSm(2-x)/3 square(1-2x)/3WO4 tungstates has been investigated for its influence on the cation-vacancy ordering and luminescence properties. A solid state method was used to synthesize the x = 0.286 and x = 0.2 compounds, which exhibited (3 + 1)D incommensurately modulated structures in the transmission electron microscopy study. Their structures were refined using high resolution synchrotron powder X-ray diffraction data. Under near-ultraviolet light, both compounds show the characteristic emission lines for (4)G(5/2) -> H-6(J) (J = 5/2, 7/2, 9/2, and 11/2) transitions of the Sm3+ ions in the range 550-720 nm, with the J = 9/2 transition at the similar to 648 nm region being dominant for all photoluminescence spectra. The intensities of the (4)G(5/2) -> H-6(9/2) and (4)G(5/2) -> H-6(7/2) bands have different temperature dependencies. The emission intensity ratios (R) for these bands vary reproducibly with temperature, allowing the use of these materials as thermographic phosphors.
Address
Corporate Author Thesis
Publisher American Chemical Society Place of Publication Washington, D.C Editor
Language Wos 000440105500037 Publication Date 2018-06-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 2 Open Access Not_Open_Access
Notes ; This research was supported by FWO (Project G039211N), Flanders Research Foundation. The research was carried out within the state assignment of FASO of Russia (Themes No. 0339-2016-0007). V.M. thanks the Russian Foundation for Basic Research (Grant 18-03-00611) for financial support. E.G.K. and O.B. acknowledge financial support from the Russian Foundation for Basic Research (Grant 16-03-00510). D.D. thanks the Foundation of the Russian Federation President (Grant MK-3502.2018.5) for financial support. We are grateful to the ESRF for granting the beamtime. V.C. is grateful for the financial support of the Russian Ministry of Science and Education (Project No. RFMEFI61616X0069). We are grateful to the ESRF for the access to ID22 station (experiment MA-3313). ; Approved Most recent IF: 9.466
Call Number UA @ lucian @ c:irua:153156 Serial 5107
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Author (up) Morozov, V.A.; Arakcheeva, A.V.; Chapuis, G.; Guiblin, N.; Rossell, M.D.; Van Tendeloo, G.
Title KNd(MoO4)2: a new incommensurate modulated structure in the scheelite family Type A1 Journal article
Year 2006 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 18 Issue 17 Pages 4075-4082
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000239758300022 Publication Date 2006-07-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 46 Open Access
Notes Iap V-1 Approved Most recent IF: 9.466; 2006 IF: 5.104
Call Number UA @ lucian @ c:irua:60688 Serial 3538
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Author (up) Morozov, V.A.; Arakcheeva, A.V.; Pattison, P.; Meert, K.W.; Smet, P.F.; Poelman, D.; Gauquelin, N.; Verbeeck, J.; Abakumov, A.M.; Hadermann, J.
Title KEu(MoO4)2 : polymorphism, structures, and luminescent properties Type A1 Journal article
Year 2015 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 27 Issue 27 Pages 5519-5530
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In this paper, with the example of two different polymorphs of KEu(MoO4)2, the influence of the ordering of the A-cations on the luminescent properties in scheelite related compounds (A′,A″)n[(B′,B″)O4]m is investigated. The polymorphs were synthesized using a solid state method. The study confirmed the existence of only two polymorphic forms at annealing temperature range 9231203 K and ambient pressure: a low temperature anorthic α-phase and a monoclinic high temperature β-phase with an incommensurately modulated structure. The structures of both polymorphs were solved using transmission electron microscopy and refined from synchrotron powder X-ray diffraction data. The monoclinic β-KEu(MoO4)2 has a (3+1)-dimensional incommensurately modulated structure (superspace group I2/b(αβ0)00, a = 5.52645(4) Å, b = 5.28277(4) Å, c = 11.73797(8) Å, γ = 91.2189(4)o, q = 0.56821(2)a*0.12388(3)b*), whereas the anorthic α-phase is (3+1)-dimensional commensurately modulated (superspace group I1̅(αβγ)0, a = 5.58727(22) Å, b = 5.29188(18)Å, c = 11.7120(4) Å, α = 90.485(3)o, β = 88.074(3)o, γ = 91.0270(23)o, q = 1/2a* + 1/2c*). In both cases the modulation arises due to Eu/K cation ordering at the A site: the formation of a 2-dimensional Eu3+ network is characteristic for the α-phase, while a 3-dimensional Eu3+-framework is observed for the β-phase structure. The luminescent properties of KEu(MoO4)2 samples prepared under different annealing conditions were measured, and the relation between their optical properties and their structures is discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000360323700011 Publication Date 2015-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 26 Open Access
Notes 278510 Vortex; Fwo G039211n; G004413n ECASJO_; Approved Most recent IF: 9.466; 2015 IF: 8.354
Call Number c:irua:127244 Serial 3537
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Author (up) Morozov, V.A.; Batuk, D.; Batuk, M.; Basovich, O.M.; Khaikina, E.G.; Deyneko, D.V.; Lazoryak, B.I.; Leonidov, I.I.; Abakumov, A.M.; Hadermann, J.
Title Luminescence Property Upgrading via the Structure and Cation Changing in AgxEu(2–x)/3WO4and AgxGd(2–x)/3–0.3Eu0.3WO4 Type A1 Journal article
Year 2017 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 29 Issue 20 Pages 8811-8823
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The creation and ordering of A-cation vacancies and the effect of cation substitutions in the scheelite-type framework are investigated as a factor for controlling the scheelite-type structure and luminescence properties. AgxEu3+(2−x)/3□(1−2x)/3WO4 and AgxGd(2−x)/3−0.3Eu3+0.3□(1−2x)/3WO4 (x = 0.5−0) scheelite-type phases were synthesized by a solid state method, and their structures were investigated using a combination of transmission electron microscopy techniques and powder synchrotron X-ray diffraction. Transmission electron microscopy also revealed the (3 + 1)D incommensurately modulated character of AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.286, 0.2) phases. The crystal structures of the scheelite-based AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.5, 0.286, 0.2) red phosphors have been refined from high resolution synchrotron powder X-ray diffraction data. The luminescence properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.5, 0.286,0.2) phosphors show the strongest absorption at 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The excitation spectra of the Eu2/3□1/3WO4 and Gd0.367Eu0.30□1/3WO4 phases exhibit the highest contribution of the charge transfer band at 250 nm and thus the most efficient energy transfer mechanism between the host and the luminescent ion as compared to direct excitation. The emission spectra of all samples indicate an intense red emission due to the 5D0 → 7F2 transition of Eu3+. Concentration dependence of the 5D0 → 7F2 emission for AgxEu(2−x)/3□(1−2x)/3WO4 samples differs from the same dependence for the earlier studied NaxEu3+(2−x)/3□(1−2x)/3MoO4 (0 ≤ x ≤ 0.5) phases. The intensity of the 5D0 → 7F2 emission is reduced almost 7 times with decreasing x from 0.5 to 0, but it practically does not change in the range from x = 0.286 to x = 0.200. The emission spectra of Gd-containing samples show a completely different trend as compared to only Eu-containing samples. The Eu3+ emission under excitation of Eu3+(5L6) level (λex = 395 nm) increases more than 2.5 times with the increasing Gd3+ concentration from 0.2 (x = 0.5) to 0.3 (x = 0.2) in the AgxGd(2−x)/3−0.3Eu3+0.3□(1−2x)/3WO4, after which it remains almost constant for higher Gd3+ concentrations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000413884900028 Publication Date 2017-10-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 7 Open Access Not_Open_Access
Notes This research was supported by FWO (project G039211N), Flanders Research Foundation. V.A.M. is grateful for financial support of the Russian Foundation for Basic Research (Grant 15-03-07741). E.G.K. and O.M.B. are grateful for financial support of the Russian Foundation for Basic Research (Grants 13-03-01020 and 16-03-00510). D.V.D. is grateful for financial support of the Russian Foundation for Basic Research (Grant 16-33-00197) and the Foundation of the President of the Russian Federation (Grant MK-7926.2016.5.). We are grateful to the ESRF for granting the beamtime. Experimental support of Andy Fitch at the ID31 beamline of ESRF is kindly acknowledged. Approved Most recent IF: 9.466
Call Number EMAT @ emat @c:irua:147241 Serial 4768
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Author (up) Morozov, V.A.; Lazoryak, B.I.; Shmurak, S.Z.; Kiselev, A.P.; Lebedev, O.I.; Gauquelin, N.; Verbeeck, J.; Hadermann, J.; Van Tendeloo, G.
Title Influence of the structure on the properties of NaxEuy(MoO4)z red phosphors Type A1 Journal article
Year 2014 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 26 Issue 10 Pages 3238-3248
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Scheelite related compounds (A',A '')(n)[(B',B '')O-4](m) with B', B '' = W and/or Mo are promising new materials for red phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. Cation substitution in CaMoO4 of Ca2+ by the combination of Na+ and Eu3+, with the creation of A cation vacancies, has been investigated as a factor for controlling the scheelite-type structure and the luminescent properties. Na5Eu(MoO4)(4) and NaxEu(2-x)/33+square(2-x)/3MoO4 (0.138 <= x <= 0.5) phases with a scheelite-type structure were synthesized by the solid state method; their structural characteristics were investigated using transmission electron microscopy. Contrary to powder synchrotron X-ray diffraction before, the study by electron diffraction and high resolution transmission electron microscopy in this paper revealed that Na0.286Eu0.571MoO4 has a (3 + 2)D incommensurately modulated structure and that (3 + 2)D incommensurately modulated domains are present in Na0.200Eu0.600MoO4. It also confirmed the (3 + 1)D incommensurately modulated character of Na(0.138)Eu(0.621)Mo04. The luminescent properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of these phosphors show the strongest absorption at about 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The emission spectra indicate an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with local minima in the intensity at Na0.286Eu0.571MoO4 and Na0.200Eu0.600MoO4 for similar to 613 nm and similar to 616 nm bands. The phosphor Na5Eu(MoO4)(4) shows the brightest red light emission among the phosphors in the Na2MoO4-Eu2/3MoO4 system and the maximum luminescence intensity of Na5Eu(MoO4)(4) (lambda(ex) = 395 nm) in the D-5(0) -> F-7(2) transition region is close to that of the commercially used red phosphor YVO4:Eu3+ (lambda(ex) = 326 nm). Electron energy loss spectroscopy measurements revealed the influence of the structure and Na/Eu cation distribution on the number and positions of bands in the UV-optical-infrared regions of the EELS spectrum.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000336637000028 Publication Date 2014-05-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 53 Open Access
Notes Fwo G039211n; Fwo G004413n; 278510 Vortex ECASJO_; Approved Most recent IF: 9.466; 2014 IF: 8.354
Call Number UA @ lucian @ c:irua:117765UA @ admin @ c:irua:117765 Serial 1652
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Author (up) Morsdorf, L.; Kashiwar, A.; Kübel, C.; Tasan, C.C.
Title Carbon segregation and cementite precipitation at grain boundaries in quenched and tempered lath martensite Type A1 Journal article
Year 2023 Publication Materials science and engineering: part A: structural materials: properties, microstructure and processing Abbreviated Journal
Volume 862 Issue Pages 144369-21
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Tempering is widely applied to make carbon atoms beneficially rearrange in high strength steel microstructures after quenching; though the nano-scale interaction of carbon atoms with crystallographic defects is hard to experimentally observe. To improve, we investigate the redistribution of carbon atoms along martensite grain boundaries in a quenched and tempered low carbon steel. We observe the tempering-induced microstructural evolution by in-situ heating in a transmission electron microscope (TEM) and by compositional analysis through atom probe tomography (APT). Probe volumes for APT originate from a single martensite packet but in different tempering conditions, which is achieved via a sequential lift-out with in-between tempering treatments. The complementary use of TEM and APT provides crystallographic as well as chemical information on carbon segregation and subsequent carbide precipitation at martensite grain boundaries. The results show that the amount of carbon segregation to martensite grain boundaries is influenced by the boundary type, e.g. low-angle lath or high-angle block boundaries. Also, the growth behavior of cementite precipitates from grain boundary nucleation sites into neighboring martensite grains differs at low- and high-angle grain boundaries. This is due to the crystallographic constraints arising from the semi-coherent orientation relationship between cementite and adjacent martensite. We also show that slower quenching stabilizes thin retained austenite films between martensite grains because of enhanced carbon segregation during cooling. Finally, we demonstrate the effect of carbon redistribution along martensite grain boundaries on the mechanical properties. Here, we compare micro-scale Vickers hardness results from boundary-containing probe volumes to nanoindentation results from pure bulk martensite (boundary-free) probe volumes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000905165700001 Publication Date 2022-12-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-5093 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.4 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 6.4; 2023 IF: 3.094
Call Number UA @ admin @ c:irua:192279 Serial 7285
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Author (up) Mortazavi, B.; Bafekry, A.; Shahrokhi, M.; Rabczuk, T.; Zhuang, X.
Title ZnN and ZnP as novel graphene-like materials with high Li-ion storage capacities Type A1 Journal article
Year 2020 Publication Materials today energy Abbreviated Journal
Volume 16 Issue Pages Unsp 100392-8
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract In this work, we employed first-principles density functional theory (DFT) calculations to investigate the dynamical and thermal stability of graphene-like ZnX (X = N, P, As) nanosheets. We moreover analyzed the electronic, mechanical and optical properties of these novel two-dimensional (2D) systems. Acquired phonon dispersion relations reveal the absence of imaginary frequencies and thus confirming the dynamical stability of predicted monolayers. According to ab-initio molecular dynamics results however only ZnN and ZnP exhibit the required thermally stability. The elastic modulus of ZnN, ZnP and ZnAs are estimated to be 31, 21 and 17 N/m, respectively, and the corresponding tensile strengths values are 6.0, 4.9 and 4.0 N/m, respectively. Electronic band structure analysis confirms the metallic electronic character for the predicted monolayers. Results for the optical characteristics also indicate a reflectivity of 100% at extremely low energy levels, which is desirable for photonic and optoelectronic applications. According to our results, graphene-like ZnN and ZnP nanosheets can yield high capacities of 675 and 556 mAh/g for Li-ion storage, respectively. Acquired results confirm the stability and acceptable strength of ZnN and ZnP nanosheets and highlight their attractive application prospects in optical and energy storage systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000539083500049 Publication Date 2020-02-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2468-6069 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.3 Times cited 13 Open Access
Notes ; B. M. and X. Z. appreciate the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). ; Approved Most recent IF: 9.3; 2020 IF: NA
Call Number UA @ admin @ c:irua:169752 Serial 6655
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Author (up) Mortet, V.; Zhang, L.; Echert, M.; Soltani, A.; d' Haen, J.; Douheret, O.; Moreau, M.; Osswald, S.; Neyts, E.; Troadec, D.; Wagner, P.; Bogaerts, A.; Van Tendeloo, G.; Haenen, K.
Title Characterization of nano-crystalline diamond films grown under continuous DC bias during plasma enhanced chemical vapor deposition Type A3 Journal article
Year 2009 Publication Materials Research Society symposium proceedings Abbreviated Journal
Volume Issue 1203 Pages
Keywords A3 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Nanocrystalline diamond films have generated much interested due to their diamond-like properties and low surface roughness. Several techniques have been used to obtain a high re-nucleation rate, such as hydrogen poor or high methane concentration plasmas. In this work, the properties of nano-diamond films grown on silicon substrates using a continuous DC bias voltage during the complete duration of growth are studied. Subsequently, the layers were characterised by several morphological, structural and optical techniques. Besides a thorough investigation of the surface structure, using SEM and AFM, special attention was paid to the bulk structure of the films. The application of FTIR, XRD, multi wavelength Raman spectroscopy, TEM and EELS yielded a detailed insight in important properties such as the amount of crystallinity, the hydrogen content and grain size. Although these films are smooth, they are under a considerable compressive stress. FTIR spectroscopy points to a high hydrogen content in the films, while Raman and EELS indicate a high concentration of sp2 carbon. TEM and EELS show that these films consist of diamond nano-grains mixed with an amorphous sp2 bonded carbon, these results are consistent with the XRD and UV Raman spectroscopy data.
Address
Corporate Author Thesis
Publisher Place of Publication Wuhan Editor
Language Wos Publication Date 2010-03-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1946-4274; ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:81646 Serial 327
Permanent link to this record
 
 
Author (up) Mortet, V.; Zhang, L.; Eckert, M.; D'Haen, J.; Soltani, A.; Moreau, M.; Troadec, D.; Neyts, E.; De Jaeger, J.C.; Verbeeck, J.; Bogaerts, A.; Van Tendeloo, G.; Haenen, K.; Wagner, P.
Title Grain size tuning of nanocrystalline chemical vapor deposited diamond by continuous electrical bias growth : experimental and theoretical study Type A1 Journal article
Year 2012 Publication Physica status solidi : A : applications and materials science Abbreviated Journal Phys Status Solidi A
Volume 209 Issue 9 Pages 1675-1682
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this work, a detailed structural and spectroscopic study of nanocrystalline diamond (NCD) thin films grown by a continuous bias assisted CVD growth technique is reported. This technique allows the tuning of grain size and phase purity in the deposited material. The crystalline properties of the films are characterized by SEM, TEM, EELS, and Raman spectroscopy. A clear improvement of the crystalline structure of the nanograined diamond film is observed for low negative bias voltages, while high bias voltages lead to thin films consisting of diamond grains of only ∼10 nm nanometer in size, showing remarkable similarities with so-called ultrananocrystalline diamond. These layers arecharacterized by an increasing amount of sp2-bonded carbon content of the matrix in which the diamond grains are embedded. Classical molecular dynamics simulations support the observed experimental data, giving insight in the underlying mechanism for the observed increase in deposition rate with bias voltage. Furthermore, a high atomic concentration of hydrogen has been determined in these films. Finally, Raman scattering analyses confirm that the Raman line observed at ∼1150 cm−1 cannot be attributed to trans-poly-acetylene, which continues to be reported in literature, reassigning it to a deformation mode of CHx bonds in NCD.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000308942100009 Publication Date 2012-09-04
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 31 Open Access
Notes M.E. and E.N. acknowledge financial support from, respectively, the Institute for Promotion of Innovation through Science and Technology in Flanders (IWT), and the Research Foundation-Flanders (FWO). J.V. gratefully acknowledges financial support from the GOA project “XANES meets ELNES” of the research fund of the University of Antwerp. Calculation support was provided by the University of Antwerp through the core facility CALCUA. G.V.T. acknowledges the ERC grant COUNTATOMS. The work was also financially supported by the joint UAUHasseltMethusalem “NANO” network, the Research Programs G.0068.07 and G.0555.10N of the Research Foundation-Flanders (FWO), the IAP-P6/42 project “Quantum Effects in Clusters and Nanowires”, and by the EU FP7 through the Integrated Infrastructure Initiative “ESMI” (No. 262348), the Marie Curie ITN “MATCON” (PITN-GA-2009-238201), and the Collaborative Project “DINAMO” (No. 245122). Approved Most recent IF: 1.775; 2012 IF: 1.469
Call Number UA @ lucian @ c:irua:101516UA @ admin @ c:irua:101516 Serial 1364
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Author (up) Moshnyaga, V.; Damaschke, B.; Shapoval, O.; Belenchuk, A.; Faupel, J.; Lebedev, O.I.; Verbeeck, J.; Van Tendeloo, G.; Mücksch, M.; Tsurkan, V.; Tidecks, R.; Samwer, K.
Title Corrigendum: Structural phase transition at the percolation threshold in epitaxial (La0.7Ca0.3MnO3)1-x:(MgO)x nanocomposite films Type A1 Journal article
Year 2005 Publication Nature materials Abbreviated Journal Nat Mater
Volume 4 Issue Pages 104
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1476-1122 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 39.737 Times cited Open Access
Notes Approved Most recent IF: 39.737; 2005 IF: 15.941
Call Number UA @ lucian @ c:irua:54856 Serial 530
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Author (up) Moshnyaga, V.; Damaschke, B.; Shapoval, O.; Belenchuk, A.; Faupel, J.; Lebedev, O.I.; Verbeeck, J.; Van Tendeloo, G.; Mücksch, M.; Tsurkan, V.; Tidecks, R.; Samwer, K.
Title Structural phase transition at the percolation threshold in epitaxial (La0.7Ca0.3MnO3)1-x:(MgO)x nanocomposite films Type A1 Journal article
Year 2003 Publication Nature materials Abbreviated Journal Nat Mater
Volume 2 Issue 4 Pages 247-252
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract 'Colossal magnetoresistance' in perovskite manganites such as La0.7Ca0.3MnO3 (LCMO), is caused by the interplay of ferro-paramagnetic, metal-insulator and structural phase transitions. Moreover, different electronic phases can coexist on a very fine scale resulting in percolative electron transport. Here we report on (LCMO)(1-x):(MgO)(x) (0 < x less than or equal to 0.8) epitaxial nano-composite films in which the structure and magnetotransport properties of the manganite nanoclusters can be tuned by the tensile stress originating from the MgO second phase. With increasing x, the lattice of LCMO was found to expand, yielding a bulk tensile strain. The largest colossal magnetoresistance of 10(5)% was observed at the percolation threshold in the conductivity at x(c) approximate to 0.3, which is coupled to a structural phase transition from orthorhombic (0 < x less than or equal to 0.1) to rhombohedral R (3) over barc structure (0.33 less than or equal to x less than or equal to 0.8). An increase of the Curie temperature for the R (3) over barc phase was observed. These results may provide a general method for controlling the magnetotransport properties of manganite-based composite films by appropriate choice of the second phase.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000182052700022 Publication Date 2003-03-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1476-1122;1476-4660; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 39.737 Times cited 177 Open Access
Notes Approved Most recent IF: 39.737; 2003 IF: 10.778
Call Number UA @ lucian @ c:irua:54855 Serial 3247
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Author (up) Mudronja, D.; Vanmeert, F.; Hellemans, K.; Fazinic, S.; Janssens, K.; Tibljas, D.; Rogosic, M.; Jakovljevic, S.
Title Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods Type A1 Journal article
Year 2013 Publication Applied physics A : materials science & processing Abbreviated Journal Appl Phys A-Mater
Volume 111 Issue 1 Pages 109-119
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Samples of cretaceous limestone have been treated with three application methods (poultice, immersion and brushing) using different concentrations of ammonium oxalate solution (AmOx) and varying treatment time in order to test the efficiency of surface and in-depth formation of a protective layer of calcium oxalate (CaOx). Synchrotron-based microanalytical techniques (SR-mu XRD with 12.5 mu mx7.5 mu m (HxV) probe size, SR-mu FTIR with 10 mu mx10 mu m and 8 mu mx20 mu m probe sizes) and laboratory mu FTIR, XRD and SEM have been employed for analysis of the treated samples. Synchrotron-based techniques showed variations in the CaOx distribution along the surface on a micrometer scale. All treatments resulted in the development of a CaOx layer with a maximum thickness of approximately 40 mu m. Application by the brushing method with 10 1-min applications with 5-min breaks during one hour showed a development of the calcium oxalate layer equivalent to the poultice treatment taking 10 h. This treatment could be preferred for large marble or limestone surfaces where poultice usage is economically not feasible.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316075700014 Publication Date 2012-10-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-8396 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.455 Times cited 13 Open Access
Notes ; This research 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.0704.08 and G.01769.09. The research leading to these results has received financial support by the Access to Research Infrastructures activity in the 7th Framework Programme of the EU (CHARISMA Grant Agreement No. 228330). ; Approved Most recent IF: 1.455; 2013 IF: 1.694
Call Number UA @ admin @ c:irua:108262 Serial 5584
Permanent link to this record