“Calorimetric properties of mesoscopic superconducting disks, rings, and cylinders”. Xu B, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 81, 064501 (2010). http://doi.org/10.1103/PhysRevB.81.064501
Abstract: The thermal signatures of superconductivity in mesoscopic disks, rings and cylinders are calculated within the Ginzburg-Landau theory. In an applied perpendicular magnetic field H the heat capacity of mesoscopic samples shows a strong dependence on the realized vortex state; discontinuities are found at the critical field for different vorticities, as well as at the superconducting-to-normal state transition. The same applies to the intermediate state of type-I superconductors. Even the subtle changes in the fluxoid distribution inside the sample leave clear signatures on heat capacity, which is particularly useful for fully three-dimensional samples whose interior is often inaccessible by magnetometry. The heat-capacity jump ΔC(H) at the critical temperature exhibits quasiperiodic modulations as a function of magnetic field. In mesoscopic superconducting rings, these oscillations provide calorimetric verification of the Little-Parks effect.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.81.064501
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“Nanoindentation of a circular sheet of bilayer graphene”. Neek-Amal M, Peeters FM, Physical review : B : condensed matter and materials physics 81, 235421 (2010). http://doi.org/10.1103/PhysRevB.81.235421
Abstract: Nanoindentation of bilayer graphene is studied using molecular-dynamics simulations. We compared our simulation results with those from elasticity theory as based on the nonlinear Föppl-Hencky equations with rigid boundary condition. The force-deflection values of bilayer graphene are compared to those of monolayer graphene. Youngs modulus of bilayer graphene is estimated to be 0.8 TPa which is close to the value for graphite. Moreover, an almost flat bilayer membrane at low temperature under central load has a 14% smaller Youngs modulus as compared to the one at room temperature.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 108
DOI: 10.1103/PhysRevB.81.235421
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“Coherent level mixing in dot energy spectra measured by magnetoresonant tunneling spectroscopy of vertical quantum dot molecules”. Payette C, Amaha S, Yu G, Gupta JA, Austing DG, Nair SV, Partoens B, Tarucha S, Physical review : B : condensed matter and materials physics 81, 245310 (2010). http://doi.org/10.1103/PhysRevB.81.245310
Abstract: We study by magnetoresonant tunneling spectroscopy single-particle energy spectra of the constituent weakly coupled dots in vertical quantum dot molecules over a wide energy window. The measured energy spectra are well modeled by calculated spectra for dots with in-plane confinement potentials that are elliptical and parabolic in form. However, in the regions where two, three, or four single-particle energy levels are naively expected to cross, we observe pronounced level anticrossing behavior and strong variations in the resonant currents as a consequence of coherent mixing induced by small deviations in the nearly ideal dot confinement potentials. We present detailed analysis of the energy spectra, and focus on two examples of three-level crossings whereby the coherent mixing leads to concurrent suppression and enhancement of the resonant currents when the anticrossing levels are minimally separated. The suppression of resonant current is of particular interest since it is a signature of dark state formation due to destructive interference. We also describe in detail and compare two measurement strategies to reliably extract the resonant currents required to characterize the level mixing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.81.245310
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“Spin-orbit interaction controlled properties of two-dimensional superlattices”. Földi P, Szaszkó-Bogár V, Peeters FM, Physical review : B : condensed matter and materials physics 82, 115302 (2010). http://doi.org/10.1103/PhysRevB.82.115302
Abstract: The band structure of two-dimensional artificial superlattices in the presence of (Rashba-type) spin-orbit interaction (SOI) is presented. The position and shape of the energy bands in these spintronic crystals depend on the geometry as well as the strength of the SOI, which can be tuned by external gate voltages. For finite mesoscopic arrays, we show that their conductance properties and possible applications can be understood from these spin-dependent band diagrams.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.82.115302
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“Klein tunneling in single and multiple barriers in graphene”. Pereira JM, Peeters FM, Chaves A, Farias GA, Semiconductor science and technology 25, 033002 (2010). http://doi.org/10.1088/0268-1242/25/3/033002
Abstract: We review the transmission properties of carriers interacting with potential barriers in graphene. The tunneling of electrons and holes in quantum structures in graphene is found to display features that are in marked contrast with those of other systems. In particular, the interaction between the carriers with electrostatic potential barriers can be related to the propagation of electromagnetic waves in media with negative refraction indices, also known as metamaterials. This behavior becomes evident as one calculates the time evolution of wavepackets propagating across the barrier interface. In addition, we discuss the effect of trigonal warping on the tunneling through potential barriers.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.305
Times cited: 83
DOI: 10.1088/0268-1242/25/3/033002
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“Transport detection of quantum Hall fluctuations in graphene”. Branchaud S, Kam A, Zawadzki P, Peeters FM, Sachrajda AS, Physical review : B : condensed matter and materials physics 81, 121406 (2010). http://doi.org/10.1103/PhysRevB.81.121406
Abstract: Low-temperature magnetoconductance measurements were made in the vicinity of the charge neutrality point (CNP). Two origins for the fluctuations were identified close to the CNP. At very low magnetic fields there exist only mesoscopic magnetoconductance quantum interference features which develop rapidly as a function of density. At slightly higher fields (>0.5 T), close to the CNP, additional fluctuations track the quantum Hall (QH) sequence expected for monolayer graphene. These additional features are attributed to effects of locally charging individual QH localized states. These effects reveal a precursor to the quantum Hall effect since, unlike previous transport observations of QH dot charging effects, they occur in the absence of quantum Hall plateaus or Shubnikov-de Haas oscillations. From our transport data we are able to extract parameters that characterize the inhomogeneities in our device.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 25
DOI: 10.1103/PhysRevB.81.121406
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“Zener tunneling in semiconductors under nonuniform electric fields”. Vandenberghe W, Sorée B, Magnus W, Groeseneken G, Journal of applied physics 107, 054520 (2010). http://doi.org/10.1063/1.3311550
Abstract: Recently, a renewed interest in Zener tunneling has arisen because of its increasing impact on semiconductor device performance at nanometer dimensions. In this paper we evaluate the tunnel probability under the action of a nonuniform electric field using a two-band model and arrive at significant deviations from the commonly used Kanes model, valid for weak uniform fields only. A threshold on the junction bias where Kanes model for Zener tunneling breaks down is determined. Comparison with Kanes model particularly shows that our calculation yields a higher tunnel probability for intermediate electric fields and a lower tunnel probability for high electric fields. When performing a current calculation comparing to the WKB approximation for the case of an abrupt p-n junction significant differences concerning the shape of the I-V curve are demonstrated.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 22
DOI: 10.1063/1.3311550
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“Analytic treatment of vortex states in cylindrical superconductors in applied axial magnetic field”. Ludu A, Van Deun J, Milošević, MV, Cuyt A, Peeters FM, Journal of mathematical physics 51, 082903 (2010). http://doi.org/10.1063/1.3470767
Abstract: We solve the linear GinzburgLandau (GL) equation in the presence of a uniform magnetic field with cylindrical symmetry and we find analytic expressions for the eigenfunctions in terms of the confluent hypergeometric functions. The discrete spectrum results from an implicit equation associated to the boundary conditions and it is resolved in analytic form using the continued fractions formalism. We study the dependence of the spectrum and the eigenfunctions on the sample size and the surface conditions for solid and hollow cylindrical superconductors. Finally, the solutions of the nonlinear GL formalism are constructed as expansions in the linear GL eigenfunction basis and selected by minimization of the free energy. We present examples of vortex states and their energies for different samples in enhancing/suppressing superconductivity surroundings.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.077
Times cited: 10
DOI: 10.1063/1.3470767
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“Conditions defining the mechanisms of the formation of light gas ions in multicomponent laser-produced plasmas”. Khaydarov RT, Beisinbaeva HB, Sabitov MM, Kalal M, Berdiyorov GR, Nuclear fusion 50, 105007 (2010). http://doi.org/10.1088/0029-5515/50/10/105007
Abstract: Using the mass-spectrometric method we study the charge, energy and spatial characteristics of ions in multicomponent plasma, generated under the action of Nd : YAG laser radiation on the surface of solid targets. We focus on the effect of the entry form of light gas atoms on the parameters of ions in such laser-produced plasmas. We found that the presence of light gas atoms considerably affects the parameters (e.g. the intensity and the charge multiplicity) of the heavier ions.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.307
Times cited: 1
DOI: 10.1088/0029-5515/50/10/105007
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“Continuum versus discrete flux behaviour in large mesoscopic Bi2Sr2CaCu2O8+\delta disks”. Connolly MR, Bemding SJ, Milošević, MV, Clem JR, Tamegai T, Physica: C : superconductivity 470, S896 (2010). http://doi.org/10.1016/j.physc.2009.11.117
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.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
DOI: 10.1016/j.physc.2009.11.117
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“Dynamics of kinematic vortices in a mesoscopic superconducting loop”. Berdiyorov GR, Milošević, MV, Peeters FM, Physica: C : superconductivity 470, 946 (2010). http://doi.org/10.1016/j.physc.2010.02.028
Abstract: Using the time-dependent GinzburgLandau formalism, we study the dynamic properties of a submicron superconducting loop in applied current and in presence of a perpendicular magnetic field. The resistive state of the sample is caused by the motion of kinematic vortexantivortex pairs. Vortices and antivortices move in opposite directions to each other, perpendicularly to the applied drive, and the periodic creation and annihilation of such pairs results in periodic oscillations of the voltage across the sample. The dynamics of these kinematic pairs is strongly influenced by the applied magnetic field, which for high fields leads to the flow of just vortices. Kinematic vortices can be temporarily pinned inside the loop with observable trace in the voltage vs. time characteristics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 9
DOI: 10.1016/j.physc.2010.02.028
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“Freezing vortex rivers”. Silhanek AV, Kramer RGB, van de Vondel J, Moshchalkov VV, Milošević, MV, Berdiyorov GR, Peeters FM, Luccas RF, Puig T, Physica: C : superconductivity 470, 726 (2010). http://doi.org/10.1016/j.physc.2010.02.072
Abstract: We demonstrate experimentally and theoretically that the dissipative state at high current densities of superconducting samples with a periodic array of holes consist of flux rivers resulting from a short range attractive interaction between vortices. This dynamically induced vortexvortex attraction results from the migration of quasiparticles out of the vortex core. We have directly visualized the formation of vortex chains by scanning Hall microscopy after freezing the dynamic state by a field cooling procedure at constant bias current. Similar experiments carried out in a sample without holes show no hint of flux river formation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 4
DOI: 10.1016/j.physc.2010.02.072
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“Magnetoresistance in a hybrid ferromagnetic/semiconductor device”. Papp G, Peeters FM, Journal of applied physics 107, 063718 (2010). http://doi.org/10.1063/1.3359652
Abstract: Ballistic transport of a two-dimensional electron gas (2DEG) in a rectangle shaped wire, subjected to a local nonhomogeneous magnetic field that results from an in-plane magnetized ferromagnetic (FM) strip deposited above the 2DEG, is investigated theoretically. We found a positive magnetoresistance (MR), which exhibits hysteresis behavior with respect to the direction of the magnetic field sweep, in agreement with a recent experiment. This positive MR can be tuned by applying a gate voltage to the FM strip.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 10
DOI: 10.1063/1.3359652
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“Molecular interaction energies and optimal configuration of a cubane dimer”. Nikolaev AV, Verberck B, Ionova GV, International journal of quantum chemistry 110, 1063 (2010). http://doi.org/10.1002/qua.22073
Abstract: We have studied the dependence of the binding energy of a cubane dimer on the mutual orientation of and the distance between the composing monomers employing the second-order Møller-Plesset perturbation scheme (MP2) with the cc-pVDZ molecular basis set. We have found that the MP2 contribution from the molecular correlations is responsible for the bound state of the cubane dimer, whereas the Hartree-Fock contribution remains anti-bonding at all intermolecular distances. Starting with two molecules in the standard orientation and centers of mass at (0,0,0) and (0,0,d), respectively, the maximal binding energy is found at d = 5.125 Å and one of the monomers rotated by 45° about the z-axis. This configuration implies that the hydrogen atoms belonging to different monomers tend to repel each other. The results are in agreement with experimental data on the optimal packing of cubane molecules in the solid state.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.92
Times cited: 1
DOI: 10.1002/qua.22073
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“Phase-diagram for the magnetic states of the Mn-ion subsystem in a magnetic quantum dot”. Nguyen NTT, Peeters FM, Journal of physics : conference series
T2 –, Conference on Quantum Dots 2010 (QD2010), APR 26-30, 2010, Nottingham, ENGLAND , 012032 (2010). http://doi.org/10.1088/1742-6596/245/1/012032
Abstract: The interplay between two types of spin-spin exchange interaction (namely of the electron with the Mn-ions and the Mn-ions with each other) that are governed by the positions of the Mn-ions and the magnetic field is studied in the case of a Mn-ion doped CdTe quantum dot. We investigate the formation of different magnetic phases and the existence of frustrated magnetic states due to the dominant contribution of the Mn-Mn energy.
Keywords: P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1088/1742-6596/245/1/012032
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“Photo-excited carriers and optical conductance and transmission in graphene in the presence of phonon scattering”. Dong HM, Xu W, Zhang J, Peeters FM, Vasilopoulos P, Physica. E: Low-dimensional systems and nanostructures 42, 748 (2010). http://doi.org/10.1016/j.physe.2009.11.048
Abstract: We present a theoretical study of the optoelectronic properties of monolayer graphene. Including the effect of the electron-photon-phonon scattering, we employ the mass- and energy-balance equations derived from the Boltzmann equation to evaluate self-consistently the carrier densities, optical conductance and transmission coefficient in graphene in the presence of linearly polarized radiation field. We find that the photo-excited carrier density can be increased under infrared radiation and depend strongly on radiation intensity and frequency. For short wavelengths (lambda <3 mu m), the universal optical conductance sigma(0) = e(2)/4h is obtained and the light transmittance is about 0.97-0.98. Interestingly, there is an optical absorption window in the range 4-100 mu m which is induced by different transition energies required for inter- and intra-band optical absorption. The position and width of this absorption window depend sensitively on temperature and carrier density of the system. These results are relevant for applications of recently developed graphene devices in advanced optoelectronics such as the infrared photodetectors. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 2.221
Times cited: 7
DOI: 10.1016/j.physe.2009.11.048
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“Stacking order dependent electric field tuning of the band gap in graphene multilayers”. Avetisyan AA, Partoens B, Peeters FM, Physical review : B : condensed matter and materials physics 81, 115432 (2010). http://doi.org/10.1103/PhysRevB.81.115432
Abstract: The effect of different stacking order of graphene multilayers on the electric field induced band gap is investigated. We considered a positively charged top and a negatively charged back gate in order to independently tune the band gap and the Fermi energy of three and four layer graphene systems. A tight-binding approach within a self-consistent Hartree approximation is used to calculate the induced charges on the different graphene layers. We found that the gap for trilayer graphene with the ABC stacking is much larger than the corresponding gap for the ABA trilayer. Also we predict that for four layers of graphene the energy gap strongly depends on the choice of stacking, and we found that the gap for the different types of stacking is much larger as compared to the case of Bernal stacking. Trigonal warping changes the size of the induced electronic gap by approximately 30% for intermediate and large values of the induced electron density.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 142
DOI: 10.1103/PhysRevB.81.115432
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“The breakdown of Kohn's theorem in few-electron parabolic quantum dots doped with a single magnetic impurity Mn2+”. Nguyen NTT, Peeters FM, Journal of physics : conference series
T2 –, Conference on Quantum Dots 2010 (QD2010), APR 26-30, 2010, Nottingham, ENGLAND , 012031 (2010). http://doi.org/10.1088/1742-6596/245/1/012031
Abstract: The cyclotron resonance (CR) absorption spectrum is calculated for a II-VI parabolic quantum dot (QD) containing few electrons and a single magnetic dopant (Mn(2+)). We find that Kohn's theorem no longer holds for this system and that the CR spectrum depends on the number of electrons inside the QD. The electron-Mn-ion interaction strength can be tuned for example by the magnetic field and by moving the Mn-ion to different positions inside the QD. We demonstrate that due to the presence of the Mn-ion the relative motion of the electrons couple with their center-of-mass motion through the electron-Mn-ion spin-spin exchange term resulting in an electron-electron interaction dependence of the magneto-optical absorption spectrum. At the ferromagnetic-antiferromagnetic transition we observe significant discontinuities in the CR lines.
Keywords: P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Times cited: 1
DOI: 10.1088/1742-6596/245/1/012031
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“The Ginzburg-Landau theory in application”. Milošević, MV, Geurts R, Physica: C : superconductivity 470, 791 (2010). http://doi.org/10.1016/j.physc.2010.02.056
Abstract: A numerical approach to GinzburgLandau (GL) theory is demonstrated and we review its applications to several examples of current interest in the research on superconductivity. This analysis also shows the applicability of the two-dimensional approach to thin superconductors and the re-defined effective GL parameter κ. For two-gap superconductors, the conveniently written GL equations directly show that the magnetic behavior of the sample depends not just on the GL parameter of two bands, but also on the ratio of respective coherence lengths.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 66
DOI: 10.1016/j.physc.2010.02.056
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“The ground states of the two-component order parameter superconductor”. Doria MM, de Romaguera ARC, Peeters FM, Europhysics letters 92, 17004 (2010). http://doi.org/10.1209/0295-5075/92/17004
Abstract: We show that in presence of an applied external field the two-component order parameter superconductor falls in two categories of ground states, namely, in the traditional Abrikosov ground state or in a new ground state fitted to describe a superconducting layer with texture, that is, patched regions separated by a phase difference of pi. The existence of these two kinds of ground states follows from the sole assumption that the total supercurrent is the sum of the two individual supercurrents and is independent of any consideration about the free energy expansion. Uniquely defined relations between the current density and the superfluid density hold for these two ground states, which also determine the magnetization in terms of average values of the order parameters. Because these ground-state conditions are also Bogomolny equations we construct the free energy for the two-component superconductor which admits the Bogomolny solution at a special coupling value. Copyright (C) EPLA, 2010
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.957
Times cited: 8
DOI: 10.1209/0295-5075/92/17004
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“Transformation of C70 peapods into double walled carbon nanotubes”. Launois P, Chorro M, Verberck B, Albouy P-A, Rouzière S, Colson D, Forget A, Noé, L, Kataura H, Monthioux M, Cambedouzou J, Carbon 48, 89 (2010). http://doi.org/10.1016/j.carbon.2009.08.035
Abstract: X-ray diffraction studies comparing the transformation of C(60) and C(70) peapods into double walled carbon nanotubes are presented. The structures of the as-formed DWCNTs are strikingly similar, showing that they are not dependent on the nature of the fullerene precursor. High temperature X-ray diffraction measurements of C(70) peapods below the coalescence temperature show that confined C(70) molecules in large tubes undergo an orientational. transition to free rotations. Fast re-orientations of C(70) molecules allow cyclo-addition between adjacent fullerenes to form, in good agreement with the mechanism of coalescence proposed in the literature for C(60) molecules. (C) 2009 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 6.337
Times cited: 27
DOI: 10.1016/j.carbon.2009.08.035
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“Tunable exciton Aharonov-Bohm effect in a quantum ring”. Li B, Magnus W, Peeters FM, Journal of physics : conference series
T2 –, Proceedings of the 11th International Conference on Optics of Excitons in Confined Systems, September 7-11, 2009, Spain / Vina, L. [edit.], et al. [edit.] 210, 012030 (2010). http://doi.org/10.1088/1742-6596/210/1/012030
Abstract: We studied the optical Aharonov-Bohm effect for an exciton in a semiconductor quantum ring. A perpendicular electric field applied to a quantum ring with large height, is able to tune the exciton ground state energy such that it exhibits a weak observable Aharonov-Bohm oscillations. This Aharonov-Bohm effect is tunable in strength and period.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 3
DOI: 10.1088/1742-6596/210/1/012030
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“Unconventional dynamics of vortex shells in mesoscopic superconducting corbino disks”. Misko VR, Lin NS, Peeters FM, Physica: C : superconductivity 470, 939 (2010). http://doi.org/10.1016/j.physc.2010.02.058
Abstract: The dynamics of vortex matter in mesoscopic superconducting Corbino disk is strongly influenced by the discrete vortex structure arranged in shells. While in previous works the vortex dynamics has been studied in large (macroscopic) and in very small mesoscopic disks (containing only few shells), in the intermediate-size regime it is much more complex and unusual, due to: (i) the competition between the vortexvortex interaction and confinement and (ii) (in)commensurability among the vortex shells. We found that the interplay between these effects can result in a very unusual vortex dynamical behavior: (i) unconventional angular melting (i.e., propagating from the boundary, where the shear stress is minimum, towards the center) and (ii) unconventional dynamics of shells (i.e., the inversion of shell velocities with respect to the gradient driving force). This unusual behavior is found for different number of shells.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 3
DOI: 10.1016/j.physc.2010.02.058
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“Vortex patterns in a superconducting-ferromagnetic rod”. Romaguera AR de C, Doria MM, Peeters FM, Physica: C : superconductivity 470, 871 (2010). http://doi.org/10.1016/j.physc.2010.02.069
Abstract: A superconducting rod with a magnetic moment on top develops vortices obtained here through 3D calculations of the GinzburgLandau theory. The inhomogeneity of the applied field brings new properties to the vortex patterns that vary according to the rod thickness. We find that for thin rods (disks) the vortex patterns are similar to those obtained in presence of a homogeneous magnetic field instead because they consist of giant vortex states. For thick rods novel patterns are obtained as vortices are curve lines in space that exit through the lateral surface.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 1
DOI: 10.1016/j.physc.2010.02.069
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“A brief history of 50 years of ICXOM”. Janssens K, , 1 (2010)
Abstract: The ICXOM series of meetings began in 1956 and for over 50 years have been conferences devoted to the topic of “X-ray microanalysis”, both for those interested in developing instrumentation and methods of analysis and for scientists mainly interested in using X-ray micro-analysers for investigations of an applied nature. This contribution surveys the ICXOM series origins, its development and trends over the years.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Chemical analysis of 16th to 19th century Limoges School painted enamel objects in three museums of the Low Countries”. van der Linden V, Schalm O, Houbraken J, Thomas M, Meesdom E, Devos A, van Dooren R, Nieuwdorp H, Janssen E, Janssens K, X-ray spectrometry 39, 112 (2010). http://doi.org/10.1002/XRS.1207
Abstract: In this study, the results of analysing of a series of 16th-19th century painted enamel objects of the Limoges School currently in collections in three Dutch and Flemish museums by means of portable and micro x-ray fluorescence analysis (PXRF and µ-XRF) and electron probe micro analysis (EPMA) are presented. The aim of the investigation was the authentication of specific pieces. Therefore, the glass compositions as well as the (glass) colouring agents used by the Limoges' artists were studied as a function of the age of the objects. Due to the evolution of these properties, it is possible to approximately date these objects based on their chemical composition. The complete émail peint collection of the Museum Boijmans-Van Beuningen (Rotterdam, The Netherlands), consisting of 20 émail peint plaques, was analysed with µ-XRF. Quantitative information was obtained by EPMA analysis of 15 enamel fragments of objects from museum and private collections in the Low Countries. PXRF analyses were performed on the painted enamel collection of the Antwerp Vleeshuis Museum (13 objects) and the Mayer van den Bergh Museum (4 objects) and on a set of 18 plaques that were donated to the Boijmans-Van Beuningen Museum by a private collector. The results obtained by means of EPMA, µ-XRF and PXRF proved to be useful in the discrimination of 16th century painted enamel objects from those of the19th century. From a total of 70 objects examined, 2 objects (OM964A and OM993) featured a chemical signature that deviated from the published literature composition and pigment use consistent with its presumed period of manufacture.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.298
Times cited: 8
DOI: 10.1002/XRS.1207
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“Homogeneity, composition and deterioration of window glass fragments and paint layers from two seventeenth-century stained glass windows created by Jan de Caumont (similar to 1580-1659)”. Schalm O, Caen J, Janssens K, Studies in conservation 55, 216 (2010). http://doi.org/10.1179/SIC.2010.55.3.216
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 0.578
Times cited: 2
DOI: 10.1179/SIC.2010.55.3.216
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“The identification of chromophores in ancient glass by the use of UV-VIS-NIR spectroscopy”. Meulebroeck W, Baert K, Wouters H, Cosyns P, Ceglia A, Cagno S, Janssens K, Nys K, Terryn H, Thienpont H, Proceedings of the Society of Photo-optical Instrumentation Engineers 7726, 77260d (2010). http://doi.org/10.1117/12.853666
Abstract: In this publication optical spectroscopy is considered to be a supplementary technique to study ancient colored glass. It results from a systematic study of the UV-VIS-NIR transmission spectra of intentionally colored glass fragments from various archaeological and historical sites and dated from the Roman period to the 21th century AD. The main goal consists of defining optical sensing parameters for this type of material. The considered colorants are iron, cobalt, manganese, copper and chromium. It is proved that many cases exist where optical spectroscopy can be seen as a straightforward, non-destructive, low-cost and in-situ applicable technique in identifying authentic material or to obtain information about the origin of the material. Possible sensing parameters are defined as the absence/presence of absorption bands characteristic for a specific coloring metal oxide and the spectral position of these bands. These parameters could reveal information about the applied furnace conditions and/or to the composition of the glass matrix. It is shown that the cobalt absorption band situated around 535 nm for soda rich glasses (Roman and industrial times) is shifted towards 526 nm for potash rich glasses (medieval and post-medieval times).
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 10
DOI: 10.1117/12.853666
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“A methodology for the identification of glass panes of different origin in a single stained glass window: application on two 13th century windows”. Schalm O, de Raedt I, Caen J, Janssens K, Journal of cultural heritage 11, 487 (2010). http://doi.org/10.1016/J.CULHER.2010.05.004
Abstract: The chemical composition of 11 glass panes originating from two 13th century non-figurative windows were analyzed by means of Scanning Electron MicroscopyEnergy Dispersive X-ray system (SEM-EDX). The windows were discovered in the back-wall of the triforium during the restoration of the choir of the cathedral St. Michael and St. Gudule in Brussels (Belgium). In order to determine if these windows were fabricated with glass of different origin or not, the compositional difference between the panes were compared with the variation in composition as a result of the following causes: (1) compositional fluctuation between panes cut from the same sheet of glass, (2) compositional fluctuation caused when panes are cut from different sheets that were made with the same batch, (3) compositional fluctuation caused when the glass is made from different batches at the same production center, and (4) compositional fluctuation as a result of glass produced at different fabrication centers.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.838
Times cited: 7
DOI: 10.1016/J.CULHER.2010.05.004
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“Synchrotron-based X-ray absorption spectroscopy for art conservation: looking back and looking forward”. Cotte M, Susini J, Dik J, Janssens K, Accounts of chemical research 43, 705 (2010). http://doi.org/10.1021/AR900199M
Abstract: A variety of analytical techniques augmented by the use of synchrotron radiation (SR), such as X-ray fluorescence (SR-XRF) and X-ray diffraction (SR-XRD), are now readily available, and they differ little, conceptually, from their common laboratory counterparts. Because of numerous advantages afforded by SR-based techniques over benchtop versions, however, SR methods have become popular with archaeologists, art historians, curators, and other researchers in the field of cultural heritage (CH). Although the CH community now commonly uses both SR-XRF and SR-XRD, the use of synchrotron-based X-ray absorption spectroscopy (SR-XAS) techniques remains marginal, mostly because CH specialists rarely interact with SR physicists. In this Account, we examine the basic principles and capabilities of XAS techniques in art preservation. XAS techniques offer a combination of features particularly well-suited for the chemical analysis of works of art. The methods are noninvasive, have low detection limits, afford high lateral resolution, and provide exceptional chemical sensitivity. These characteristics are highly desirable for the chemical characterization of precious, heterogeneous, and complex materials. In particular, the chemical mapping capability, with high spatial resolution that provides information about local composition and chemical states, even for trace elements, is a unique asset. The chemistry involved in both the objects history (that is, during fabrication) and future (that is, during preservation and restoration treatments) can be addressed by XAS. On the one hand, many studies seek to explain optical effects occurring in historical glasses or ceramics by probing the molecular environment of relevant chromophores. Hence, XAS can provide insight into craft skills that were mastered years, decades, or centuries ago but were lost over the course of time. On the other hand, XAS can also be used to characterize unwanted reactions, which are then considered alteration phenomena and can dramatically alter the objects original visual properties. In such cases, the bulk elemental composition is usually unchanged. Hence, monitoring oxidation state (or, more generally, other chemical modifications) can be of great importance. Recent applications of XAS in art conservation are reviewed and new trends are discussed, highlighting the value (and future possibilities) of XAS, which remains, given its potential, underutilized in the CH community.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 20.268
Times cited: 74
DOI: 10.1021/AR900199M
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