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Author Castelano, L.K.; Hai, G.Q.; Partoens, B.; Peeters, F.M.
  Title Artificial molecular quantum rings under magnetic field influence Type A1 Journal article
  Year 2009 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 106 Issue 7 Pages 073702,1-073702,8
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The ground states of a few electrons confined in two vertically coupled quantum rings in the presence of an external magnetic field are studied systematically within the current spin-density functional theory. Electron-electron interactions combined with inter-ring tunneling affect the electronic structure and the persistent current. For small values of the external magnetic field, we recover the zero magnetic field molecular quantum ring ground state configurations. Increasing the magnetic field many angular momentum, spin, and isospin transitions are predicted to occur in the ground state. We show that these transitions follow certain rules, which are governed by the parity of the number of electrons, the single-particle picture, Hunds rules, and many-body effects.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000270915600047 Publication Date 2009-10-03
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0021-8979; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 5 Open Access
  Notes Approved Most recent IF: 2.068; 2009 IF: 2.072
  Call Number UA @ lucian @ c:irua:86926 Serial 155
Permanent link to this record
 

 
Author Ao, Z.M.; Hernández-Nieves, A.D.; Peeters, F.M.; Li, S.
  Title Enhanced stability of hydrogen atoms at the graphene/graphane interface of nanoribbons Type A1 Journal article
  Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 97 Issue 23 Pages 233109,1-233109,3
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The thermal stability of graphene/graphane nanoribbons (GGNRs) is investigated using density functional theory. It is found that the energy barriers for the diffusion of hydrogen atoms on the zigzag and armchair interfaces of GGNRs are 2.86 and 3.17 eV, respectively, while the diffusion barrier of an isolated H atom on pristine graphene was only ∼ 0.3 eV. These results unambiguously demonstrate that the thermal stability of GGNRs can be enhanced significantly by increasing the hydrogen diffusion barriers through graphene/graphane interface engineering. This may provide new insights for viable applications of GGNRs.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000285364000067 Publication Date 2010-12-11
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0003-6951; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 3.411 Times cited 43 Open Access
  Notes ; The financial supports by the Vice-Chancellor's Postdoctoral Research Fellowship Program of the University of New South Wales (SIR50/PS19184), the Flemish Science Foundation (FWO-VI), and the Belgian Science Policy (IAP) are acknowledged. A.D.H. acknowledges also support from ANPCyT (Grant No. PICT2008-2236) and the collaborative project FWO-MINCyT (FW/08/01). ; Approved Most recent IF: 3.411; 2010 IF: 3.841
  Call Number UA @ lucian @ c:irua:86972 Serial 1056
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Author Fang, C.M.; van Huis, M.A.; Zandbergen, H.W.
  Title Stability and structures of the \epsilon-phases of iron nitrides and iron carbides from first principles Type A1 Journal article
  Year 2011 Publication Scripta materialia Abbreviated Journal Scripta Mater
  Volume 64 Issue 3 Pages 296-299
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract First-principles calculations were performed for the ε-phases and other iron carbides/nitrides with hexagonal close-packed Fe sublattices. Although these nitrides/carbides have similar crystal structures, they exhibit different chemical and physical properties. Relative to α-Fe, graphite and N2, all the ε-type nitrides are stable, while all the carbides are metastable. The lattice parameters of the ε-iron nitrides vary differently from those of the ε-carbides, as a function of the concentration of X (Xdouble bond; length as m-dashN, C). The structural relationships of ε-Fe2X with η-Fe2X and ζ-Fe2X are discussed.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000285323300022 Publication Date 2010-09-02
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1359-6462; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 3.747 Times cited 29 Open Access
  Notes Approved Most recent IF: 3.747; 2011 IF: 2.699
  Call Number UA @ lucian @ c:irua:86974 Serial 3120
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Author Yusupov, M.; Bultinck, E.; Depla, D.; Bogaerts, A.
  Title Behavior of electrons in a dual-magnetron sputter deposition system : a Monte Carlo model Type A1 Journal article
  Year 2011 Publication New journal of physics Abbreviated Journal New J Phys
  Volume 13 Issue Pages 033018-033018,17
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract A Monte Carlo model has been developed for investigating the electron behavior in a dual-magnetron sputter deposition system. To describe the three-dimensional (3D) geometry, different reference frames, i.e. a local and a global coordinate system, were used. In this study, the influence of both closed and mirror magnetic field configurations on the plasma properties is investigated. In the case of a closed magnetic field configuration, the calculated electron trajectories show that if an electron is emitted in (or near) the center of the cathode, where the influence of the magnetic field is low, it is able to travel from one magnetron to the other. On the other hand, when an electron is created at the race track area, it is more or less trapped in the strong magnetic field and cannot easily escape to the second magnetron region. In the case of a mirror magnetic field configuration, irrespective of where the electron is emitted from the cathode, it cannot travel from one magnetron to the other because the magnetic field lines guide the electron to the substrate. Moreover, the electron density and electron impact ionization rate have been calculated and studied in detail for both configurations.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Bristol Editor
  Language Wos 000289064600001 Publication Date 2011-03-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1367-2630; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 3.786 Times cited 12 Open Access
  Notes Approved Most recent IF: 3.786; 2011 IF: 4.177
  Call Number UA @ lucian @ c:irua:87544 Serial 224
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Author Bals, S.; Kabius, B.; Haider, M.; Radmilovic, V.; Kisielowski, C.
  Title Annular dark field imaging in a TEM Type A1 Journal article
  Year 2004 Publication Solid state communications Abbreviated Journal Solid State Commun
  Volume 130 Issue 10 Pages 675-680
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Annular objective apertures are fabricated for a CM300 transmission electron microscope using a focused ion beam system. A central beam stop in the back focal plane of the objective lens of the microscope blocks all electrons scattered up to a semi-angle of approximately 20 mrad. In this manner, contributions to the image from Bragg scattering are largely reduced and the image contrast is sensitive to the atomic number Z. Experimentally, we find that single atom scattering cross sections measured with this technique are close to Rutherford scattering values. A comparison between this new method and STEM-HAADF shows that both techniques result in qualitatively similar images although the resolution of ADF-TEM is limited by contrast delocalization caused by the spherical aberration of the objective lens. This problem can be overcome by using an aberration corrected microscope.
  Address
  Corporate Author Thesis
  Publisher Place of Publication New York, N.Y. Editor
  Language Wos 000221489300007 Publication Date 2004-04-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0038-1098; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 1.554 Times cited 43 Open Access
  Notes Approved Most recent IF: 1.554; 2004 IF: 1.523
  Call Number UA @ lucian @ c:irua:87584 Serial 132
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Author Salluzzo, M.; Aruta, C.; Maggio-Aprile, I.; Fischer, Ø.; Bals, S.; Zegenhagen, J.
  Title Growth of R1+xBa2-xCu3O7-\delta epitaxial films investigated by in situ scanning tunneling microscopy Type A1 Journal article
  Year 2001 Publication Physica status solidi: A: applied research Abbreviated Journal Phys Status Solidi A
  Volume 186 Issue 3 Pages 339-364
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The problem of the epitaxial growth of the high temperature superconducting R1+xBa2xCu3O7δ (R = Y or rare earth except Ce and Tb) films has been addressed. Using in situ ultra high vacuum Scanning Tunneling Microscopy (UHV-STM) we have studied the role of cationic substitution and substrate mismatch on the growth mode of stoichiometric and Nd-rich Nd1+xBa2xCu3O7δ thin films. The results are compared to the growth of Y1Ba2Cu3O7δ, Dy1Ba2Cu3O7δ and Gd1Ba2Cu3O7δ epitaxial films. Two main phenomena are investigated: a) the first stage of the direct nucleation on the substrate and b) the crossover between 2D and 3D growth upon increasing the film thickness. At the first stage of the growth, pseudo-cubic perovskite (Re,Ba)CuO3 nuclei are formed. While they disappear after the growth of a few nm in stoichiometric films, they persist on the surface of Nd-rich films of up to 110 nm thickness. Stoichiometric R1+xBa2xCu3O7δ films exhibit a rough morphology with increasing thickness due to island growth mode, whereas Nd-rich films remain smooth and continue to grow layer by layer. It is proposed that linear defects (like anti-phase boundaries), which are formed due to the misalignment of growth fronts, are the source of screw dislocations in stoichiometric films. In Nd-rich films, linear defects are eliminated through the insertion of (Nd,Ba)CuO3 extra layers without introduction of any screw dislocations.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Berlin Editor
  Language Wos 000170844500002 Publication Date 2004-11-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0031-8965;1521-396X; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 17 Open Access
  Notes Approved Most recent IF: NA
  Call Number UA @ lucian @ c:irua:87587 Serial 1398
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Author Lubyshev, D.; Fastenau, J.M.; Fang, X.-M.; Wu, Y.; Doss, C.; Snyder, A.; Liu, W.K.; Lamb, M.S.M.; Bals, S.; Song, C.
  Title Comparison of As- and P-based metamorphic buffers for high performance InP heterojunction bipolar transistor and high electron mobility transistor applications Type A1 Journal article
  Year 2004 Publication Journal of vacuum science & technology. B. Microelectronics and nanometer structures. Processing, measurement and phenomena Abbreviated Journal
  Volume 22 Issue 3 Pages 1565-1569
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Metamorphic buffers (M-buffers) consisting of graded InAlAs or bulk InP were employed for the production of InP-based epiwafers on GaAs substrates by molecular-beam epitaxy. The graded InAlAs is the standard for production metamorphic high electron mobility transistors (M-HEMTs), while the bulk InP offers superior thermal properties for higher current density circuits. The surface morphology and crystal structure of the two M-buffers showed different relaxation mechanisms. The graded InAlAs gave a cross-hatched pattern with nearly full relaxation and very effective dislocation filtering, while the bulk InP had a uniform isotropic surface with dislocations propagating further up towards the active layers. Both types of M-buffers had atomic force microscopy root-mean-square roughness values around 2030 Å. The Hall transport properties of high electron mobility transistors (HEMTs) grown on the InAlAs M-buffer, and a baseline HEMT grown lattice matched on InP, both had room-temperature mobilities >10 000 cm2/V s, while the M-HEMT on the InP M-buffer showed a decrease to 9000 cm2/V  s. Similarly, the dc parameters of a double heterojunction bipolar transistor (DHBT) grown on the InAlAs M-buffer were much closer to the baseline heterojunction bipolar transistor than a DHBT grown on the InP M-buffer. A high breakdown voltage of 11.3 V was achieved on an M-DHBT with the InAlAs M-buffer. We speculate that the degradation in device characteristics on the InP M-buffer was related to the incomplete dislocation filtering.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Woodbury, N.Y. Editor
  Language Wos 000222481400141 Publication Date 2004-07-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0734-211X; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 25 Open Access
  Notes Approved Most recent IF: NA
  Call Number UA @ lucian @ c:irua:87596 Serial 427
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Author Croitoru, M.D.; van Dyck, D.; Van Aert, S.; Bals, S.; Verbeeck, J.
  Title An efficient way of including thermal diffuse scattering in simulation of scanning transmission electron microscopic images Type A1 Journal article
  Year 2006 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
  Volume 106 Issue 10 Pages 933-940
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Vision lab
  Abstract We propose an improved image simulation procedure for atomic-resolution annular dark-field scanning transmission electron microscopy (STEM) based on the multislice formulation, which takes thermal diffuse scattering fully into account. The improvement with regard to the classical frozen phonon approach is realized by separating the lattice configuration statistics from the dynamical scattering so as to avoid repetitive calculations. As an example, the influence of phonon scattering on the image contrast is calculated and investigated. STEM image simulation of crystals can be applied with reasonable computing times to problems involving a large number of atoms and thick or large supercells.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Amsterdam Editor
  Language Wos 000240397200006 Publication Date 2006-05-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0304-3991; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.843 Times cited 18 Open Access
  Notes Fwo; Fwo-V Approved Most recent IF: 2.843; 2006 IF: 1.706
  Call Number UA @ lucian @ c:irua:87604UA @ admin @ c:irua:87604 Serial 876
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Author Eckert, M.; Mortet, V.; Zhang, L.; Neyts, E.; Verbeeck, J.; Haenen, ken; Bogaerts, A.
  Title Theoretical investigation of grain size tuning during prolonged bias-enhanced nucleation Type A1 Journal article
  Year 2011 Publication Chemistry of materials Abbreviated Journal Chem Mater
  Volume 23 Issue 6 Pages 1414-1423
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract In this paper, the effects of prolonged bias-enhanced nucleation (prolonged BEN) on the growth mechanisms of diamond are investigated by molecular dynamics (MD) and combined MD-Metropolis Monte Carlo (MD-MMC) simulations. First, cumulative impacts of CxHy+ and Hx+ on an a-C:H/nanodiamond composite were simulated; second, nonconsecutive impacts of the dominant ions were simulated in order to understand the observed phenomena in more detail. As stated in the existing literature, the growth of diamond structures during prolonged BEN is a process that takes place below the surface of the growing film. The investigation of the penetration behavior of CxHy+ and Hx+ species shows that the carbon-containing ions remain trapped within this amorphous phase where they dominate mechanisms like precipitation of sp3 carbon clusters. The H+ ions, however, penetrate into the crystalline phase at high bias voltages (>100 V), destroying the perfect diamond structure. The experimentally measured reduction of grain sizes at high bias voltage, reported in the literature, might thus be related to penetrating H+ ions. Furthermore, the CxHy+ ions are found to be the most efficient sputtering agents, preventing the build up of defective material.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Washington, D.C. Editor
  Language Wos 000288291400011 Publication Date 2011-02-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0897-4756;1520-5002; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 9.466 Times cited 9 Open Access
  Notes Iwt; Fwo; Esteem 026019; Iap Approved Most recent IF: 9.466; 2011 IF: 7.286
  Call Number UA @ lucian @ c:irua:87642 Serial 3605
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Author Yusupov, M.; Bultinck, E.; Depla, D.; Bogaerts, A.
  Title Elucidating the asymmetric behavior of the discharge in a dual magnetron sputter deposition system Type A1 Journal article
  Year 2011 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 98 Issue 13 Pages 131502-131502,3
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract A magnetron discharge is characterized by drifts of the charged particles guiding center, caused by the magnetic field, in contrast to unmagnetized discharges. Because of these drifts, a pronounced asymmetry of the discharge can be observed in a dual magnetron setup. In this work, it is found that the shape of the discharge in a dual magnetron configuration depends on the magnetic field configuration. In a closed configuration, strong drifts were observed in one preferential direction, whereas in a mirror configuration the deflection of the discharge was not so pronounced. Our calculations confirm experimental observations.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000289153600017 Publication Date 2011-04-01
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0003-6951; ISBN Additional Links (up) 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; 2011 IF: 3.844
  Call Number UA @ lucian @ c:irua:87867 Serial 1026
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Author Salluzzo, M.; Aruta, C.; Ausanio, G.; Bals, S.; d' Agostino, A.; Maglione, M.G.
  Title Role of Nd/Ba substitution on the growth mode and on the structural properties of Nd-rich Re1(NdxBa2-x)Cu3O7-\delta (Re=Nd, Y) thin films Type A1 Journal article
  Year 2002 Publication Physica: C : superconductivity Abbreviated Journal Physica C
  Volume 372-376 Issue 2 Pages 675-678
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Thin films of the superconducting Nd1+xBa2−xCu3O7−δ (NBCO) and Y1(NdxBa2−x)Cu3O7−δ (YNBCO) compounds have been deposited by dc magnetron sputtering and diode high pressure oxygen sputtering. Different techniques, including scanning tunneling microscopy, atomic force microscopy, X-ray diffraction and transmission electron microscopy (TEM) have been used to study the film microstructures and the surface morphology. It is shown that the Nd/Ba exchange promotes a 2D heteroepitaxial growth in the case of the NBCO films deposited on (1 0 0) SrTiO3 substrates, with a suppression of the characteristic 3D spirals structures. On the contrary in YNBCO the Nd/Ba exchange does not provide a driving force for the suppression of screw-dislocations, since spirals or towers originated by screw and half loop dislocations are observed on the surface. TEM reveals that anti-phase boundaries are eliminated during the growth of NBCO films thanks to the Nd/Ba exchange while this mechanism is not operating in the case of YNBCO films.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Amsterdam Editor
  Language Wos 000178018800024 Publication Date 2002-08-26
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0921-4534; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 1.404 Times cited 5 Open Access
  Notes Approved Most recent IF: 1.404; 2002 IF: 0.912
  Call Number UA @ lucian @ c:irua:87909 Serial 2917
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Author Shanenko, A.A.; Milošević, M.V.; Peeters, F.M.
  Title Extended Ginzburg-Landau formalism for two-band superconductors Type A1 Journal article
  Year 2011 Publication Physical review letters Abbreviated Journal Phys Rev Lett
  Volume 106 Issue 4 Pages 047005-047005,4
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Recent observation of unusual vortex patterns in MgB2 single crystals raised speculations about possible type-1.5 superconductivity in two-band materials, mixing the properties of both type-I and type-II superconductors. However, the strict application of the standard two-band Ginzburg-Landau (GL) theory results in simply proportional order parameters of the two bandsand does not support the type-1.5 behavior. Here we derive the extended GL formalism (accounting all terms of the next order over the small τ=1-T/Tc parameter) for a two-band clean s-wave superconductor and show that the two condensates generally have different spatial scales, with the difference disappearing only in the limit T→Tc. The extended version of the two-band GL formalism improves the validity of GL theory below Tc and suggests revisiting the earlier calculations based on the standard model.
  Address
  Corporate Author Thesis
  Publisher Place of Publication New York, N.Y. Editor
  Language Wos 000286734100010 Publication Date 2011-01-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0031-9007;1079-7114; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 8.462 Times cited 84 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-INSTANS network. Discussions with M. D. Croitoru are gratefully acknowledged. ; Approved Most recent IF: 8.462; 2011 IF: 7.370
  Call Number UA @ lucian @ c:irua:88038 Serial 1154
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Author Xu, B.; Milošević, M.V.; Peeters, F.M.
  Title Second-order multiple-quanta flux entry into a perforated spherical mesoscopic superconductor Type A1 Journal article
  Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
  Volume 82 Issue 21 Pages 214501-214501,7
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Flux entry in type-II superconductors without prominent symmetry is a first-order phase transition, where flux enters conventionally gradual in units of a flux quantum. Here we show that neither is necessarily the case in a mesoscopic superconducting sphere with a perforation. In axially applied magnetic field, vortices initially occupy the hole, and can oppose further flux entry in the sample. As a result, multiple-quanta flux entry is found at significantly higher field, and it can manifest as a second-order transition due to suppressed geometric barrier at the equatorial belt of the sample. At high fields a new state is found, with gradually destroyed condensate from the equator inwards, the exact opposite of surface superconductivity.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000286737800007 Publication Date 2010-12-02
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1098-0121;1550-235X; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 3.836 Times cited 2 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-V1), the Belgian Science Policy (IAP), and the ESF “Nanoscience and Engineering in Superconductivity” program. ; Approved Most recent IF: 3.836; 2010 IF: 3.774
  Call Number UA @ lucian @ c:irua:88039 Serial 2957
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Author Neek-Amal, M.; Peeters, F.M.
  Title Buckled circular monolayer graphene : a graphene nano-bowl Type A1 Journal article
  Year 2011 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
  Volume 23 Issue 4 Pages 045002-045002,8
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We investigate the stability of circular monolayer graphene subjected to a radial load using non-equilibrium molecular dynamics simulations. When monolayer graphene is radially stressed, after some small circular strain (~0.4%) it buckles and bends into a new bowl-like shape. Young's modulus is calculated from the linear relation between stress and strain before the buckling threshold, which is in agreement with experimental results. The prediction of elasticity theory for the buckling threshold of a radially stressed plate is presented and its results are compared to the one of our atomistic simulation. The Jarzynski equality is used to estimate the difference between the free energy of the non-compressed states and the buckled states. From a calculation of the free energy we obtain the optimum radius for which the system feels the minimum boundary stress.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000286142800003 Publication Date 2010-12-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0953-8984;1361-648X; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.649 Times cited 27 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). ; Approved Most recent IF: 2.649; 2011 IF: 2.546
  Call Number UA @ lucian @ c:irua:88043 Serial 259
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Author Connolly, M.R.; Bemding, S.J.; Milošević, M.V.; Clem, J.R.; Tamegai, T.
  Title Continuum versus discrete flux behaviour in large mesoscopic Bi2Sr2CaCu2O8+\delta disks Type A1 Journal article
  Year 2010 Publication Physica: C : superconductivity Abbreviated Journal Physica C
  Volume 470 Issue S:1 Pages S896-S897
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We have used scanning Hall probe and local Hall magnetometry measurements to map flux profiles in superconducting Bi2Sr2CaCu2O8+δ disks whose diameters span the crossover between the bulk and mesoscopic vortex regimes. The behaviour of large disks (greater-or-equal, slanted20 μm diameter) is well described by analytic models that assume a continuous distribution of flux in the sample. Small disks (less-than-or-equals, slant10 μm diameter), on the other hand, exhibit clear signatures of the underlying discrete vortex structure as well as competition between triangular Abrikosov ordering and the formation of shell structures driven by interactions with circulating edge currents. At low fields we are able to directly observe the characteristic mesoscopic compression of vortex clusters which is linked to oscillations in the diameter of the vortex dome in increasing magnetic fields. At higher fields, where single vortex resolution is lost, we are still able to track configurational changes in the vortex patterns, since competing vortex orders impose unmistakable signatures on local magnetisation curves. Our observations are in excellent agreement with molecular-dynamics numerical simulations which lead us to a natural definition of the lengthscale for the crossover between discrete and continuum behaviour in our system.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Amsterdam Editor
  Language Wos 000286075700384 Publication Date 2009-11-20
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0921-4534; ISBN Additional Links (up) UA library record; WoS full record
  Impact Factor 1.404 Times cited Open Access
  Notes ; ; Approved Most recent IF: 1.404; 2010 IF: 1.415
  Call Number UA @ lucian @ c:irua:88069 Serial 494
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Author Abakumov, A.M.; d' Hondt, H.; Rossell, M.D.; Tsirlin, A.A.; Gutnikova, O.; Filimonov, D.S.; Schnelle, W.; Rosner, H.; Hadermann, J.; Van Tendeloo, G.; Antipov, E.V.
  Title Coupled anion and cation ordering in Sr3RFe4O10.5 (R=Y, Ho, Dy) anion-deficientperovskites Type A1 Journal article
  Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
  Volume 183 Issue 12 Pages 2845-2854
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The Sr3RFe4O10.5 (R=Y, Ho, Dy) anion-deficient perovskites were prepared using a solid-state reaction in evacuated sealed silica tubes. Transmission electron microscopy and 57Fe Mössbauer spectroscopy evidenced a complete A-cations and oxygen vacancies ordering. The structure model was further refined by ab initio structure relaxation, based on density functional theory calculations. The compounds crystallize in a tetragonal a≈2√2ap≈11.3 Å, с≈4сp≈16 Å unit cell (ap: parameter of the perovskite subcell) with the P42/mnm space group. Oxygen vacancies reside in the (FeO5/4□3/4) layers, comprising corner-sharing FeO4 tetrahedra and FeO5 tetragonal pyramids, which are sandwiched between the layers of the FeO6 octahedra. Smaller R atoms occupy the 9-fold coordinated position, whereas the 10-fold coordinated positions are occupied by larger Sr atoms. The Fe sublattice is ordered aniferromagnetically up to at least 500 K, while the rare-earth sublattice remains disordered down to 2 K.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000285431100014 Publication Date 2010-10-02
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0022-4596; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.299 Times cited 8 Open Access
  Notes Approved Most recent IF: 2.299; 2010 IF: 2.261
  Call Number UA @ lucian @ c:irua:88071 Serial 533
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Author Bogaerts, A.; Aghaei, M.; Autrique, D.; Lindner, H.; Chen, Z.; Wendelen, W.
  Title Computer simulations of laser ablation, plume expansion and plasma formation Type H1 Book chapter
  Year 2011 Publication Abbreviated Journal
  Volume Issue Pages 1-10
  Keywords H1 Book chapter; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract
  Address
  Corporate Author Thesis
  Publisher Trans Tech Place of Publication Aedermannsdorf Editor
  Language Wos 000292658900001 Publication Date 2011-04-20
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1662-8985; ISBN 978-3-03785-081-7 Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 8 Open Access
  Notes Approved Most recent IF: NA
  Call Number UA @ lucian @ c:irua:88340 Serial 470
Permanent link to this record
 

 
Author Bogaerts, A.; Eckert, M.; Mao, M.; Neyts, E.
  Title Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials Type A1 Journal article
  Year 2011 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
  Volume 44 Issue 17 Pages 174030-174030,16
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract In this review paper, an overview is given of different modelling efforts for plasmas used for the formation and growth of nanostructured materials. This includes both the plasma chemistry, providing information on the precursors for nanostructure formation, as well as the growth processes itself. We limit ourselves to carbon (and silicon) nanostructures. Examples of the plasma modelling comprise nanoparticle formation in silane and hydrocarbon plasmas, as well as the plasma chemistry giving rise to carbon nanostructure formation, such as (ultra)nanocrystalline diamond ((U)NCD) and carbon nanotubes (CNTs). The second part of the paper deals with the simulation of the (plasma-based) growth mechanisms of the same carbon nanostructures, i.e. (U)NCD and CNTs, both by mechanistic modelling and detailed atomistic simulations.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000289512700030 Publication Date 2011-04-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0022-3727;1361-6463; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.588 Times cited 25 Open Access
  Notes Approved Most recent IF: 2.588; 2011 IF: 2.544
  Call Number UA @ lucian @ c:irua:88364 Serial 463
Permanent link to this record
 

 
Author Mao, M.; Bogaerts, A.
  Title Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma-enhanced CVD system : the effect of processing parameters Type A1 Journal article
  Year 2010 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
  Volume 43 Issue 31 Pages 315203-315203,15
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract A parameter study is carried out for an inductively coupled plasma used for the synthesis of carbon nanotubes or carbon nanofibres (CNTs/CNFs), by means of the Hybrid Plasma Equipment Model. The influence of processing parameters including gas ratio for four different gas mixtures typically used for CNT/CNF growth (i.e. CH4/H2, CH4/NH3, C2H2/H2 and C2H2/NH3), inductively coupled plasma (ICP) power (501000 W), operating pressure (10 mTorr1 Torr), bias power (01000 W) and temperature of the substrate (01000 °C) on the plasma chemistry is investigated and the optimized conditions for CNT/CNF growth are analysed. Summarized, our calculations suggest that a lower fraction of hydrocarbon gases (CH4 or C2H2, i.e. below 20%) and hence a higher fraction of etchant gases (H2 or NH3) in the gas mixture result in more 'clean' conditions for controlled CNT/CNF growth. The same applies to a higher ICP power, a moderate ICP gas pressure above 100 mTorr (at least for single-walled carbon nanotubes), a high bias power (for aligned CNTs) and an intermediate substrate temperature.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000280275200007 Publication Date 2010-07-17
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0022-3727;1361-6463; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.588 Times cited 17 Open Access
  Notes Approved Most recent IF: 2.588; 2010 IF: 2.109
  Call Number UA @ lucian @ c:irua:88365 Serial 1724
Permanent link to this record
 

 
Author Vernimmen, J.; Guidotti, M.; Silvestre-Albero, J.; Jardim, E.O.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Psaro, R.; Rodríguez-Reinoso, F.; Meynen, V.; Cool, P.
  Title Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene Type A1 Journal article
  Year 2011 Publication Langmuir: the ACS journal of surfaces and colloids Abbreviated Journal Langmuir
  Volume 27 Issue 7 Pages 3618-3625
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
  Abstract Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Washington, D.C. Editor
  Language Wos 000288970900054 Publication Date 2011-02-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0743-7463;1520-5827; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 3.833 Times cited 19 Open Access
  Notes Approved Most recent IF: 3.833; 2011 IF: 4.186
  Call Number UA @ lucian @ c:irua:88366 Serial 1557
Permanent link to this record
 

 
Author Vernimmen, J.; Meynen, V.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Cool, P.
  Title Formation of a Ti-siliceous trimodal material with macroholes, mesopores and zeolitic features via a one-pot templating synthesis Type A1 Journal article
  Year 2012 Publication Journal of porous materials Abbreviated Journal J Porous Mat
  Volume 19 Issue 2 Pages 153-160
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
  Abstract Based on a facile one-pot templating synthesis, using a TS-1 zeolite recipe whereby part of the zeolite structure directing agent is replaced by a mesopore templating agent, a trimodal material is formed. The resulting meso-TSM material combines mesoporosity (Ti-MCM-41) with zeolitic features (TS-1) and a unique sheet-like morphology with uniform macroporous voids (macroholes). Moreover, the macrohole formation, mesoporosity and zeolitic properties of the meso-TSM material can be controlled in a straightforward way by adjusting the length of the hydrothermal treatment. This newly developed material may imply great potential for catalytic redox applications and diffusion limitated processes because of its highly tunable character in all three dimensions (micro-, meso- and macroporous scale).
  Address
  Corporate Author Thesis
  Publisher Kluwer Academic Place of Publication Boston, Mass. Editor
  Language Wos 000301187600002 Publication Date 2011-03-28
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1380-2224;1573-4854; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 1.624 Times cited 2 Open Access
  Notes Fwo; Goa Approved Most recent IF: 1.624; 2012 IF: 1.348
  Call Number UA @ lucian @ c:irua:88367 Serial 1257
Permanent link to this record
 

 
Author Canioni, R.; Roch-Marchal, C.; Sécheresse, F.; Horcajada, P.; Serre, C.; Hardi-Dan, M.; Férey, G.; Grenèche, J.-M.; Lefebvre, F.; Chang, J.-S.; Hwang, Y.-K.; Lebedev, O.; Turner, S.; Van Tendeloo, G.
  Title Stable polyoxometalate insertion within the mesoporous metal organic framework MIL-100(Fe) Type A1 Journal article
  Year 2011 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
  Volume 21 Issue 4 Pages 1226-1233
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Successful encapsulation of polyoxometalate (POM) within the framework of a mesoporous iron trimesate MIL-100(Fe) sample has been achieved by direct hydrothermal synthesis in the absence of fluorine. XRPD, 31P MAS NMR, IR, EELS, TEM and 57Fe Mössbauer spectrometry corroborate the insertion of POM within the cavities of the MOF. The experimental Mo/Fe ratio is 0.95, in agreement with the maximum theoretical amount of POM loaded within the pores of MIL-100(Fe), based on steric hindrance considerations. The POM-MIL-100(Fe) sample exhibits a pore volume of 0.373 cm3 g−1 and a BET surface area close to 1000 m2 g−1, indicating that small gas molecules can easily diffuse inside the cavities despite the presence of heavy phosphomolybdates. These latter contribute to the decrease in the overall surface area, due to the increase in molar weight, by 65%. Moreover, the resulting Keggin containing MIL-100(Fe) solid is stable in aqueous solution with no POM leaching even after more than 2 months. In addition, no exchange of the Keggin anions by tetrabutylammonium perchlorate in organic media has been observed.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Cambridge Editor
  Language Wos 000286110400042 Publication Date 2010-11-25
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0959-9428;1364-5501; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 158 Open Access
  Notes Approved Most recent IF: NA
  Call Number UA @ lucian @ c:irua:88642 Serial 3145
Permanent link to this record
 

 
Author Müller, M.; Turner, S.; Lebedev, O.I.; Wang, Y.; Van Tendeloo, G.; Fischer, R.A.
  Title Au@MOF-5 and Au/Mox@MOF-5 (M = Zn, Ti; x = 1, 2) : preparation and microstructural characterisation Type A1 Journal article
  Year 2011 Publication European journal of inorganic chemistry Abbreviated Journal Eur J Inorg Chem
  Volume Issue 12 Pages 1876-1887
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The Zn-carboxylate-based porous coordination polymer MOF-5 [Zn4O(bdc)3] and the metal oxide loaded materials ZnO@MOF-5 and TiO2@MOF-5 were loaded in a second step with the precursor [ClAuCO] to yield intermediate materials denoted as [ClAuCO]@MOF-5, [ClAuCO]/ZnO@MOF-5 and [ClAuCO]/TiO2@MOF-5. These composites were decomposed to Au@MOF-5, Au/ZnO@MOF-5 and Au/TiO2@MOF-5 under hydrogen at 100 °C. The nanoparticle-loaded hybrid materials were characterised by powder X-ray diffraction (PXRD), IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and N2 sorption measurements, which reveal an intact MOF-5 structure that maintains a high specific surface area. For Au@MOF-5, crystalline Au nanoparticles were distributed over the MOF matrix in a homogeneous fashion with a size of ca. 13 nm, evidenced by high resolution transmission electron microscopy. In the case of Au/ZnO@MOF-5, the Au and metal oxide particles of a few nm in size were coexistent in a given volume of the MOF-5 matrix and were not separated in different crystalline MOF particles. For the TiO2 loaded materials the oxide is preferentially located near the outer surface of the MOF particles, leading to an increase of larger exterior Au particles in comparison to very small interior Au particles as observed for the other materials. Au@MOF-5, Au/ZnO@MOF-5 and Au/TiO2@MOF-5 were tested in liquid-phase oxidation of alcohols. Preliminary results show a high activity for the Au loaded materials in this reaction. This observation is attributed to the microstructure of the composites with very small Au particles distributed homogeneously over the MOF matrix.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Weinheim Editor
  Language Wos 000289644300004 Publication Date 2011-03-09
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1434-1948; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.444 Times cited 75 Open Access
  Notes Fwo; Esteem 026019 Approved Most recent IF: 2.444; 2011 IF: 3.049
  Call Number UA @ lucian @ c:irua:88644 Serial 205
Permanent link to this record
 

 
Author Martens, J.A.; Thybaut, J.W.; Denayer, J.F.M.; Sree, S.P.; Aerts, A.; Reyniers, M.-F.; van Speybroeck, V.; Waroquier, M.; Buekenhoudt, A.; Vankelecom, I.; Buijs, W.; Persoons, J.; Baron, G.V.; Bals, S.; Van Tendeloo, G.; Marin, G.B.; Jacobs, P.A.; Kirschhock, C.E.A.
  Title Catalytic and molecular separation properties of Zeogrids and Zeotiles Type A1 Journal article
  Year 2011 Publication Catalysis today Abbreviated Journal Catal Today
  Volume 168 Issue 1 Pages 17-27
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Zeogrids and Zeotiles are hierarchical materials built from assembled MFI zeolite precursor units. Permanent secondary porosity in these materials is obtained through self assembly of nanoparticles encountered in MFI zeolite synthesis in the presence of supramolecular templates. Hereon, the aggregated species are termed nanoslabs. Zeogrids are layered materials with lateral spacings between nanoslabs creating galleries qualifying as supermicropores. Zeotiles present a diversity of tridimensional nanoslab assemblies with mesopores. Zeotile-1, -4 and -6 are hexagonal mesostructures. Zeotile-1 has triangular and hexagonal channels; Zeotile-4 has hexagonal channels interconnected via slits. Zeotile-2 has a cubic structure with gyroid type mesoporosity. The behavior of Zeogrids and Zeotiles in adsorption, membrane and chromatographic separation and catalysis has been characterized and compared with zeolites and mesoporous materials derived from unstructured silica sources. Shape selectivity was detected via adsorption of n- and iso-alkanes. The mesoporosity of Zeotiles can be exploited in chromatographic separation of biomolecules. Zeotiles present attractive separation properties relevant to CO2 sequestration. Because of its facile synthesis procedure without hydrothermal steps Zeogrid is convenient for membrane synthesis. The performance of Zeogrid membrane in gas separation, nanofiltration and pervaporation is reported. In the Beckmann rearrangement of cyclohexanone oxime Zeogrids and Zeotiles display a catalytic activity characteristic of silicalite-1 zeolites. Introduction of acidity and redox catalytic activity can be achieved via incorporation of Al and Ti atoms in the nanoslabs during synthesis. Zeogrids are active in hydrocracking, catalytic cracking, alkylation and epoxidation reactions. Zeogrids and Zeotiles often behave differently from ordered mesoporous materials as well as from zeolites and present a valuable extension of the family of hierarchical silicate based materials.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Amsterdam Editor
  Language Wos 000291033300003 Publication Date 2011-03-09
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0920-5861; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 4.636 Times cited 13 Open Access
  Notes Fwo; Iap Sbo Approved Most recent IF: 4.636; 2011 IF: 3.407
  Call Number UA @ lucian @ c:irua:88647 Serial 290
Permanent link to this record
 

 
Author Rusakov, D.; Abakumov, A.M.; Yamaura, K.; Belik, A.A.; Van Tendeloo, G.; Takayama-Muromachi, E.
  Title Structural evolution of the BiFeO3-LaFeO3 system Type A1 Journal article
  Year 2011 Publication Chemistry of materials Abbreviated Journal Chem Mater
  Volume 23 Issue 2 Pages 285-292
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The (1 − x)BiFeO3−xLaFeO3 system has been investigated and characterized by room-temperature and high-temperature laboratory and synchrotron powder X-ray diffraction, electron diffraction, high-resolution transmission electron microscopy, differential scanning calorimetry, and magnetization measurements. At room temperature, the ferroelectric R3c phase is observed for 0.0 ≤ x ≤ 0.10. The PbZrO3-related √2ap × 2√2ap × 4ap superstructure (where ap is the parameter of the cubic perovskite subcell) is observed for Bi0.82La0.18FeO3, while an incommensurately modulated phase is formed for 0.19 ≤ x ≤ 0.30 with the √2ap × 2ap × √2ap basic unit cell. The GdFeO3-type phase with space group Pnma (√2ap × 2ap × √2ap) is stable at 0.50 ≤ x ≤ 1. Bi0.82La0.18FeO3 has no detectable homogeneity range (space group Pnam, a = 5.6004(1) Å, b = 11.2493(3) Å, c = 15.6179(3) Å). The incommensurately modulated Bi0.75La0.25FeO3 structure was solved from synchrotron X-ray powder diffraction data (Imma(00γ)s00 superspace group, a = 5.5956(1) Å, b = 7.8171(1) Å, c = 5.62055(8) Å, q = 0.4855(4)c*, RP = 0.023, RwP = 0.033). In this structure, cooperative displacements of the Bi and O atoms occur, which order within the (AO) (where A = Bi, La) layers, resulting in an antipolar structure. Local fluctuations of the intralayer antipolar ordering are compensated by an interaction with the neighboring (AO) layers. A coupling of the antipolar displacements with the cooperative tilting distortion of the perovskite octahedral framework is proposed as the origin of the incommensurability. All the phases transform to the GdFeO3-type structure at high temperatures. Bi0.82La0.18FeO3 shows an intermediate PbZrO3-type phase with √2ap × 2√2ap × 2ap (space group Pbam; a = 5.6154(2) Å, b = 11.2710(4) Å, and c = 7.8248(2) Å at 570 K). The compounds in the compositional range of 0.18 ≤ x ≤ 0.95 are canted antiferromagnets.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Washington, D.C. Editor
  Language Wos 000286160800021 Publication Date 2010-12-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0897-4756;1520-5002; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 9.466 Times cited 133 Open Access
  Notes Approved Most recent IF: 9.466; 2011 IF: 7.286
  Call Number UA @ lucian @ c:irua:88650 Serial 3236
Permanent link to this record
 

 
Author Abakumov, A.M.; Batuk, D.; Hadermann, J.; Rozova, M.G.; Sheptyakov, D.V.; Tsirlin, A.A.; Niermann, D.; Waschowski, F.; Hemberger, J.; Van Tendeloo, G.; Antipov, E.V.
  Title Antiferroelectric (Pb,Bi)1-xFe1+xO3-y perovskites modulated by crystallographic shear planes Type A1 Journal article
  Year 2011 Publication Chemistry of materials Abbreviated Journal Chem Mater
  Volume 23 Issue 2 Pages 255-265
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract We demonstrate for the first time a possibility to vary the anion content in perovskites over a wide range through a long-range-ordered arrangement of crystallographic shear (CS) planes. Anion-deficient perovskites (Pb,Bi)1−xFe1+xO3−y with incommensurately modulated structures were prepared as single phases in the compositional range from Pb0.857Bi0.094Fe1.049O2.572 to Pb0.409Bi0.567Fe1.025O2.796. Using a combination of electron diffraction and high-resolution scanning transmission electron microscopy, we constructed a superspace model describing a periodic arrangement of the CS planes. The model was verified by refinement of the Pb0.64Bi0.32Fe1.04O2.675 crystal structure from neutron powder diffraction data ((3 + 1)D S.G. X2/m(α0γ), X = [1/2,1/2,1/2,1/2], a = 3.9082(1) Å, b = 3.90333(8) Å, c = 4.0900(1) Å, β = 91.936(2)°, q = 0.05013(4)a* + 0.09170(3)c* at T = 700 K, RP = 0.036, RwP = 0.048). The (Pb,Bi)1−xFe1+xO3−y structures consist of perovskite blocks separated by CS planes confined to nearly the (509)p perovskite plane. Along the CS planes, the perovskite blocks are shifted with respect to each other over the 1/2[110]p vector that transforms the corner-sharing connectivity of the FeO6 octahedra in the perovskite framework to an edge-sharing connectivity of the FeO5 pyramids at the CS plane, thus reducing the oxygen content. Variation of the chemical composition in the (Pb,Bi)1−xFe1+xO3−y series occurs mainly because of a changing thickness of the perovskite block between the interfaces, that can be expressed through the components of the q vector as Pb6γ+2αBi1−7γ−αFe1+γ−αO3−3γ−α. The Pb, Bi, and Fe atoms are subjected to strong displacements occurring in antiparallel directions on both sides of the perovskite blocks, resulting in an antiferroelectric-type structure. This is corroborated by the temperature-, frequency-, and field-dependent complex permittivity measurements. Pb0.64Bi0.32Fe1.04O2.675 demonstrates a remarkably high resistivity >0.1 T Ω cm at room temperature and orders antiferromagnetically below TN = 608(10) K.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Washington, D.C. Editor
  Language Wos 000286160800018 Publication Date 2010-12-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0897-4756;1520-5002; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 9.466 Times cited 29 Open Access
  Notes Approved Most recent IF: 9.466; 2011 IF: 7.286
  Call Number UA @ lucian @ c:irua:88651 Serial 136
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Author Yan, L.; Niu, H.J.; Duong, G.V.; Suchomel, M.R.; Bacsa, J.; Chalker, P.R.; Hadermann, J.; Van Tendeloo, G.; Rosseinsky, M.J.
  Title Cation ordering within the perovskite block of a six-layer Ruddlesden-Popper oxide from layer-by-layer growth artificial interfaces in complex unit cells Type A1 Journal article
  Year 2011 Publication Chemical science Abbreviated Journal Chem Sci
  Volume 2 Issue 2 Pages 261-272
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The (AO)(ABO3)n Ruddlesden-Popper structure is an archetypal complex oxide consisting of two distinct structural units, an (AO) rock salt layer separating an n-octahedra thick perovskite block. Conventional high-temperature oxide synthesis methods cannot access members with n > 3, but low-temperature layer-by-layer thin film methods allow the preparation of materials with thicker perovskite blocks, exploiting high surface mobility and lattice matching with the substrate. This paper describes the growth of an n = 6 member CaO[(CSMO)2(LCMO)2 (CSMO)2] in which the six unit cell perovskite block is sub-divided into two central La0.67Ca0.33MnO3 (LCMO) and two terminal Ca0.85Sm0.15MnO3 (CSMO) layers to allow stabilization of the rock salt layer and variation of the transition metal charge.
  Address
  Corporate Author Thesis
  Publisher Royal Society of Chemistry Place of Publication Cambridge Editor
  Language Wos 000286327600010 Publication Date 2010-11-06
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2041-6520;2041-6539; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 8.668 Times cited 16 Open Access
  Notes Approved Most recent IF: 8.668; 2011 IF: 7.525
  Call Number UA @ lucian @ c:irua:88652 Serial 300
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Author Paul, M.; Kufer, D.; Müller, A.; Brück, S.; Goering, E.; Kamp, M.; Verbeeck, J.; Tian, H.; Van Tendeloo, G.; Ingle, N.J.C.; Sing, M.; Claessen, R.
  Title Fe3O4/ZnO : a high-quality magnetic oxide-semiconductor heterostructure by reactive deposition Type A1 Journal article
  Year 2011 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 98 Issue 1 Pages 012512,1-012512,3
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract We demonstrate the epitaxial growth of Fe<sub>3</sub>O<sub>4</sub> films on ZnO by a simple reactive deposition procedure using molecular oxygen as an oxidizing agent. X-ray photoelectron spectroscopy results evidence that the iron-oxide surface is nearly stoichiometric magnetite. X-ray diffraction results indicate monocrystalline epitaxy and almost complete structural relaxation. Scanning transmission electron micrographs reveal that the microstructure consists of domains which are separated by antiphase boundaries or twin boundaries. The magnetite films show rather slow magnetization behavior in comparison with bulk crystals probably due to reduced magnetization at antiphase boundaries in small applied fields.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000286009800055 Publication Date 2011-01-07
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0003-6951; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 3.411 Times cited 27 Open Access
  Notes The authors acknowledge financial support by DFG through Forschergruppe FOR 1162. Approved Most recent IF: 3.411; 2011 IF: 3.844
  Call Number UA @ lucian @ c:irua:88653 Serial 3532
Permanent link to this record
 

 
Author Mishra, V.K.; Dons, E.; Panis, L.I.; Frijns, E.; van Poppel, M.; Berghmans, P.; Bleux, N.; Wuyts, K.; Samson, R.
  Title Understanding ultrafine particles dynamics within a one km urban grid Type P3 Proceeding
  Year 2010 Publication Abbreviated Journal
  Volume Issue Pages
  Keywords P3 Proceeding; Sustainable Energy, Air and Water Technology (DuEL)
  Abstract
  Address
  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 ISBN Additional Links (up) UA library record
  Impact Factor Times cited Open Access
  Notes Approved no
  Call Number UA @ admin @ c:irua:88671 Serial 8709
Permanent link to this record
 

 
Author Milošević, M.V.; Peeters, F.M.; Jankó, B.
  Title Vortex manipulation in superconducting films with tunable magnetic topology Type A1 Journal article
  Year 2011 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
  Volume 24 Issue 2 Pages 024001-024001,6
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Using a combination of the phenomenological GinzburgLandau theory and micromagnetic simulations, we study properties of a superconducting film with an array of soft magnetic dots on top. An external in-plane magnetic field gradually drives the magnets from an out-of-plane or magnetic vortex state to an in-plane single-domain state, which changes spatially the distribution of the superconducting condensate. If induced by the magnets, the vortexantivortex molecules exhibit rich transitions as a function of the applied in-plane field. At the same time, we show how the magnetic dots act as very effective dynamic pinning centers for vortices in an applied perpendicular magnetic field.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Bristol Editor
  Language Wos 000286379900002 Publication Date 2011-01-20
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0953-2048;1361-6668; ISBN Additional Links (up) UA library record; WoS full record; WoS citing articles
  Impact Factor 2.878 Times cited 8 Open Access
  Notes ; This research was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the JSPS/ESF-NES program, the bilateral project between Flanders and the USA, NSF NIRT, ECS-0609249, and the Institute for Theoretical Sciences. ; Approved Most recent IF: 2.878; 2011 IF: 2.662
  Call Number UA @ lucian @ c:irua:88731 Serial 3870
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