Publications of Rudi Cloots
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See detailNanoblock coupling effect in iodine intercalated [Bi0.82CaO 2]2[CoO2]1.69 layered cobaltite
Guilmeau, E.; Pollet, M.; Grebille, D. et al

in Inorganic Chemistry (2007), 46(6), 2124-2131

We report on the structural, microstructural, and electronic properties of iodine intercalated [Bi0.82CaO2]2[CoO 2]1.69 misfit cobaltite. We first prove through a detailed and careful structural study ... [more ▼]

We report on the structural, microstructural, and electronic properties of iodine intercalated [Bi0.82CaO2]2[CoO 2]1.69 misfit cobaltite. We first prove through a detailed and careful structural study that the block layer structure can be modified in the desired way. Iodine enters the material between the [BiO] double layers, and the c-cell parameter of the pristine compound is elongated by 3.6 Å. On the basis of this result, we point out the coupling between the block-layer structure and the transport properties. Additionally, we provide in-depth commentary and discussion of some extra results, clarifying some doping effects in the quasi-2D studied phase. Finally, we also propose some expressions that might be useful to material scientists for the tuning of the properties of such compounds. © 2007 American Chemical Society. [less ▲]

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See detailDoes the orbital degeneracy play any role in the high thermopower of lamellar cobaltites?
Pollet, M.; Doumerc, J. P.; Guilmeau, E. et al

in Journal of Applied Physics (2007), 101(8),

This article investigates the role of the CoO6 octahedron distortion on the electronic properties and more particularly on the high value of the Seebeck coefficient in the BiCaCoO lamellar cobaltites. Our ... [more ▼]

This article investigates the role of the CoO6 octahedron distortion on the electronic properties and more particularly on the high value of the Seebeck coefficient in the BiCaCoO lamellar cobaltites. Our measurements provide clues indicating that the t2g orbital degeneracy lifting has to be considered to account for the observed high temperature limit of the thermopower. They also provide experimental arguments for locating the a1g and eg′ orbitals levels on the energy scale, through the compression of the octahedron. These results are in agreement with recent ab initio calculation including the electronic correlations and concluding for the inversion of these levels as compared to the expectation from the crystal field theory. © 2007 American Institute of Physics. [less ▲]

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See detailPhotodegradation of bacteria with TiO2 produced by sol-gel method
Tasseroul, Ludivine ULiege; Pàez Martinez, Carlos ULiege; Braconnier, Benoît et al

Poster (2007)

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See detailStructural and electrical properties of tellurovanadate glasses containing Li2O
Krins, Natasha ULiege; Rulmont, André ULiege; Grandjean, Jean ULiege et al

in Solid State Ionics (2006), 177(35-36 Sp. Iss. SI), 3147-3150

Glassy materials are promising intercalation compounds, due to their open network structure and absence of grain boundaries. Some glasses containing alkali ions and a high concentration of transition ... [more ▼]

Glassy materials are promising intercalation compounds, due to their open network structure and absence of grain boundaries. Some glasses containing alkali ions and a high concentration of transition metal ions can present mixed ionic-electronic conductivity and are therefore potential candidates for application as cathode material in Li-ion batteries. The present work is devoted to the ternary system xLi(2)O-(1-x)[0.3V(2)O(5)-0.7TeO(2)] with 0 <= x <= 0.4. These compounds were prepared by heat treatment in air at 800 degrees C followed by traditional quenching. Raman spectroscopy and V-51 nuclear magnetic resonance measurements were performed in order to highlight the structural short range order modifications induced by the introduction of the Li2O network modifier. These structural effects can be related to the electrical behaviour, as studied by complex impedance spectroscopy measurements. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailEffect of Ga doping on magneto-transport properties in colossal magnetoresistive La0.7Ca0.3Mn1-xGaxO3 (0 < x < 0.1)
Pekala, M.; Mucha, Jan ULiege; Vertruyen, Bénédicte ULiege et al

in Journal of Magnetism and Magnetic Materials (2006), 306(2), 181-190

Samples of La0.7Ca0.3Mn1-xGaxO3 with x = 0, 0.025, 0.05 and 0.10 were prepared by standard solid-state reaction. They were first characterized chemically, including the microstructure. The magnetic ... [more ▼]

Samples of La0.7Ca0.3Mn1-xGaxO3 with x = 0, 0.025, 0.05 and 0.10 were prepared by standard solid-state reaction. They were first characterized chemically, including the microstructure. The magnetic properties and various transport properties, i.e. the electrical resistivity, magnetoresistivity (for a field below 8 T), thermoelectric power and thermal conductivity measured each time on the same sample, are reported. The markedly different behaviour of the x = 0.1 sample from those with a smaller Ga content, is discussed. The dilution of the Mn3+/Mn4+ interactions with Ga doping considerably reduces the ferromagnetic double exchange interaction within the manganese lattice leading to a decrease of the Curie temperature. The polaron binding energy varies from 224 to 243 meV with increased Ga doping. (C) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailLiMn2-xTixO4 spinel-type compounds (x <= 1): Structural, electrical and magnetic properties
Krins, Natasha ULiege; Hatert, Frédéric ULiege; Traina, Karl ULiege et al

in Solid State Ionics (2006), 177(11-12), 1033-1040

LiMn2-xTixO4 compounds with 0.5 =<x =< 1 were prepared by solid state reaction and Pechini technique. Powder X-ray diffraction showed that all samples crystallize with the spinel crystal structure (S.G ... [more ▼]

LiMn2-xTixO4 compounds with 0.5 =<x =< 1 were prepared by solid state reaction and Pechini technique. Powder X-ray diffraction showed that all samples crystallize with the spinel crystal structure (S.G. Fd3m). The cubic unit-cell parameter increases with the Ti content. The influence of the Ti content and cationic distribution on the magnetic properties of the compounds was studied by measuring the temperature and magnetic field dependences of the magnetization: substitution by non-magnetic d(0) Ti4+ ions appeared to weaken the magnetic interactions between the manganese ions. The electrical properties of LiMnTiO4 were studied by AC impedance spectroscopy and DC polarisation measurements, which revealed the electronic character of the conduction process. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailInfluence of Na doping and sintering temperature on increasing Bi2Sr2CaCu2O8 superconducting phase content in powder-form materials
Rahier, Sébastien ULiege; Stassen, S.; Cloots, Rudi ULiege et al

in Materials Letters (2006), 60(3), 298-300

This paper proposes a systematic way to explore the effects of Na on Bi-2212 phase formation. The influence of sodium metal is correlated with the 2212 fraction formed in the sample. The effect on the ... [more ▼]

This paper proposes a systematic way to explore the effects of Na on Bi-2212 phase formation. The influence of sodium metal is correlated with the 2212 fraction formed in the sample. The effect on the sintering temperature and the importance of the substitution site is studied. Samples are characterized by X-ray diffraction analysis (XRD). Results clearly show that the 2212 phase content is enhanced and sintering temperatures can be lowered with regard to the undoped samples. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailEBSD study on YBCO textured bulk samples: correlation between crystal growth and 'microtexture'
Grossin, D.; Henrist, Catherine ULiege; Mathieu, J. P. et al

in Superconductor Science and Technology (2006), 19(2), 190-199

This work describes an electron backscattered diffraction (EBSD) study of the perovskite-derived structures YBa2Cu3O7-delta. After having pointed out the difficulties of EBSD analyses in resolving the ... [more ▼]

This work describes an electron backscattered diffraction (EBSD) study of the perovskite-derived structures YBa2Cu3O7-delta. After having pointed out the difficulties of EBSD analyses in resolving the orientations of these pseudo-cubic structures, various YBaCuO bulk samples are analysed and the correlation between the microstructure, crystal growth and global texture, determined by neutron diffraction, is carried out. Homogeneous 'microtexture' with small subdomain misorientation of 12 degrees are measured for YBCO top seeding melt textured growth (TSMTG) samples. YBCO perforated samples also exhibit misoriented subdomains, giving rise to a heterogeneous 'microtexture' correlated to the YBCO growth front and to the pattern used for the perforating. [less ▲]

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See detailChemical interactions between Bi2Sr3CaO7(Bi-2310) and Bi2Sr2Ca0.8Dy0.2Cu2O8 (Bi-2212(Dy))
Rahier, Sébastien ULiege; Lafort, Adeline ULiege; Henrist, Catherine ULiege et al

in Superconductor Science & Technology (2006), 19(1), 39-43

The chemical interactions between Bi2Sr3CaO7 (Bi-2310) and Bi2Sr2Ca0.8Dy0.2Cu2O8 (Bi-2212(Dy)) at 965 degrees C were investigated by means of: (i) an interdiffusion couple and (ii) layers deposited by dip ... [more ▼]

The chemical interactions between Bi2Sr3CaO7 (Bi-2310) and Bi2Sr2Ca0.8Dy0.2Cu2O8 (Bi-2212(Dy)) at 965 degrees C were investigated by means of: (i) an interdiffusion couple and (ii) layers deposited by dip coating on oxidized nickel Substrates. The samples were characterized by optical and electron microscopies, energy-dispersive x-ray (EDX) analysis and x-ray diffraction. It turns out that at the peritectic temperature Of Bi-2212(Dy), the Bi-2310 phase reacts with the liquid phase resulting from the peritectic decomposition of the Bi-2212(Dy) phase. Dissolution of Bi-2310 leads to an enrichment in Sr and an impoverishment in Cu of the liquid phase, resulting in a shift of the composition of the insoluble phase towards the Ca-rich end of the (Ca, Sr)O Solid Solution. [less ▲]

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See detailInfluence of the shaping effect on hardness homogeneity by Vickers indentation analysis
Guillaume, Bernard ULiege; Boschini, Frédéric ULiege; Rulmont, André ULiege et al

in Journal of the European Ceramic Society (2006), 26(15), 3191-3196

In this study, indentation technique (Vickers indentation) has been unconventionally used to evaluate the homogeneity of barium zirconate ceramic samples which have been shaped through different routes ... [more ▼]

In this study, indentation technique (Vickers indentation) has been unconventionally used to evaluate the homogeneity of barium zirconate ceramic samples which have been shaped through different routes. Statistical tools have been used to estimate the con-elation which can be established between heterogeneities within the samples and their shaping ways. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailEtude de l'appareil producteur de sons d'Ophidion barbatum
Fontenelle, Nicolas; Henrist, Catherine ULiege; Cloots, Rudi ULiege et al

Poster (2006)

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See detailCost-effective media for the rapid and high resolution of small DNA fragments using polyacrylamide-based electrophoresis
Negro, S. S.; Cloots, Rudi ULiege; Gemmell, N. J.

in Molecular Ecology Notes (2006), 6(3), 609-612

Current Tris-based solutions for DNA electrophoresis produce a positive feedback loop between current and temperature at high voltage, resulting in long running times for the separation of even small DNA ... [more ▼]

Current Tris-based solutions for DNA electrophoresis produce a positive feedback loop between current and temperature at high voltage, resulting in long running times for the separation of even small DNA fragments. We optimized the separation of small DNA fragments (90-300 bp) in polyacrylamide-based electrophoresis at high voltages (200volts/cm) by substituting Tris with low concentration alkali salts (e.g. 1 mm LiCl and CsCl). These media reduced the heat produced during electrophoresis, enhanced the DNA fragment resolution, and allowed gels to be run at higher voltages, reducing gel running times by 25%. In addition, the elimination of Tris and EDTA from the buffer reduced material costs approximately 10-fold. © 2006 The Authors. [less ▲]

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See detailStructural and electrical properties of tellurovanadate glasses containing Li2O
Krins, Natacha ULiege; Vertruyen, Bénédicte ULiege; Lepot, Laurent et al

Poster (2006)

Detailed reference viewed: 17 (2 ULiège)
See detailStructural and electrical properties of tellurovanadate glasses containing Li2O
Krins, Natacha ULiege; Vertruyen, Bénédicte ULiege; Lepot, Laurent et al

Conference (2006)

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See detailSlip casting of barium zirconate aqueous concentrated suspensions
Boschini, Frédéric ULiege; Guillaume, Bernard ULiege; Rulmont, André ULiege et al

in Journal of the European Ceramic Society (2006), 26(9), 1591-1598

The rheological behaviour of aqueous suspensions of barium zirconate was studied focusing on the effect of the Volume fraction of particles, leading to the determination of the maximum packing fraction ... [more ▼]

The rheological behaviour of aqueous suspensions of barium zirconate was studied focusing on the effect of the Volume fraction of particles, leading to the determination of the maximum packing fraction. Optimised suspensions dispersed with both polymethacrylic acid and tetramethylammonium hydroxide were slip cast on plaster Moulds to produce discs and crucibles, leading to relative green densities greater than 62% of theoretical ones. Densification was studied at temperatures ranging from 1450 to 1700 degrees C by static and dynamic sintering experiments. Scanning electron microscopy studies demonstrate that slip cast parts are dense and very homogeneous, without any significant processing-related defects or abnormal grain growth. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailPreparation of YBa2Cu3O7-x superconducting thick films by the electrophoretic deposition method
Dusoulier, Laurent; Denis, Samuel ULiege; Vanderbemden, Philippe ULiege et al

in Journal of Materials Science (2006), 41(24), 8109-8114

YBa2Cu3O7-x thick films have been realised by the Electrophoretic Deposition method (EPD). The influence of several parameters (powder and iodine concentrations in the suspension, applied voltage and ... [more ▼]

YBa2Cu3O7-x thick films have been realised by the Electrophoretic Deposition method (EPD). The influence of several parameters (powder and iodine concentrations in the suspension, applied voltage and deposition time) on the EPD process has been studied by measuring the conductivity of the suspension and the amount of YBa2Cu3O7-x particles deposited on the electrode. Superconducting coatings onto silver substrates have been produced by a multilayer process during different deposition times. The highest critical current density value of these coatings measured by the four-point probe method is about 10^3 A/cm^2 (77 K), in a suitable range for magnetic shielding applications. [less ▲]

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See detail(Micro)-structural comparison between geopolymers, alkali-activated slag cement and Portland cement
Lecomte, I.; Henrist, Catherine ULiege; Duyckaerts, Monique ULiege et al

in Journal of the European Ceramic Society (2006), 26(16), 3789-3797

Concurrently to research conducted on ordinary Portland cement (PC), new types of binders were developed during the last decades. These are formed by alkali-activation of metakaolin or ground-granulated ... [more ▼]

Concurrently to research conducted on ordinary Portland cement (PC), new types of binders were developed during the last decades. These are formed by alkali-activation of metakaolin or ground-granulated blast furnace slag (GGBFS) and are named, respectively, geopolymers (GP) or alkali-activated slag (AAS). Four different cementitious materials were synthesised: PC, AAS, GP, and a mix GP-AAS and fully compared about their compositions and (micro)-structures. X-ray diffraction has revealed the presence of semi-crystalline C-S-H gel binding phase in PC while AAS, GP and GP-AAS are nearly amorphous. Progressive structural changes have been observed between the different samples by means of infrared spectroscopy, Si-29 and At-27 magic-angle-spinning nuclear magnetic resonance spectroscopy: there is a polymerisation extent of the (alumino)-silicate framework from PC [SiQ(1) and SiQ(2) units] to AAS [SiQ(2) and SiQ(2)(1Al) units] and finally to GP [SiQ(4)(2Al) and SiQ(4)(3Al) units]. Scanning electron microscopy has shown that GP is a homogeneous matrix while the other materials are composites containing GGBFS grains surrounded by a binding matrix. Energy dispersive X-ray EDX analyses (line scans) have shown the absence of formation of any specific phase at the matrix-grains interfaces. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailYBa2Cu3O(7-delta) thick films on Ag prepared by the electrophoretic deposition technique
Dusoulier, Laurent; Denis, Samuel; Fagnard, Jean-François ULiege et al

in Journal of Physics: Conference Series (2006), 43

YBa2Cu3O7-δ thick films have been deposited onto Ag substrates by the Electrophoretic Deposition (EPD) technique. Different microstructures and electrical behaviours were observed depending on the ... [more ▼]

YBa2Cu3O7-δ thick films have been deposited onto Ag substrates by the Electrophoretic Deposition (EPD) technique. Different microstructures and electrical behaviours were observed depending on the starting powder. Coatings prepared from commercial powder displayed significant porosity and the superconducting transition width was found to be magnetic-field dependent. Films produced from home-made coprecipitated powder are denser but contain some secondary phases. No dependence of the resistive transition as a function of magnetic field (H ≤ 20 Oe) was observed in that case. [less ▲]

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See detailCharacterisation of the magnetic shielding properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates
Denis, Samuel; Grenci, G.; Dusoulier, Laurent et al

in Journal of Physics: Conference Series (2006), 43

This communication reports experimental results on the superconducting properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates. The magnetic shielding properties of ... [more ▼]

This communication reports experimental results on the superconducting properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates. The magnetic shielding properties of the coatings were characterised by various methods. First, the electrical resistance and the transport critical current density, Jc, were determined. Our coatings exhibit a superconducting transition at a temperature of 90 K. Next, shielding characterisations were carried out at 77 K for samples having either a slab or a cylindrical geometry. In both cases, the frequency of the applied magnetic field was 103 Hz; the field behind the shielding wall was measured by a pick-up coil connected to a lock-in amplifier. In the case of cylindrical samples and for an applied induction lower than 1 G, the field inside the shielding enclosure is reduced by a factor greater than 106 (i.e. 120 dB) with respect to the applied field. [less ▲]

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See detailTexturation of YBa2Cu3O7-delta thick films by electrophoretic deposition under magnetic field
Dusoulier, Laurent; Denis, Samuel ULiege; Nutal, Nicolas ULiege et al

in Key Engineering Materials [=KEM] (2006), 314

YBa2Cu3O7-delta coatings were deposited by electrophoretic deposition (EPD) onto Ni substrates. Particles of different sizes and shapes were used in order to study the influence of the powder ... [more ▼]

YBa2Cu3O7-delta coatings were deposited by electrophoretic deposition (EPD) onto Ni substrates. Particles of different sizes and shapes were used in order to study the influence of the powder microstructure on the film density. Texturation of the thick films was induced by application of a magnetic field during the electrophoretic deposition. X-ray diffraction analysis has clearly shown preferred c-axis alignment of the YBa2Cu3O7-delta films along the direction normal to the substrate surface. Scanning electron microscopy and optical polarised light microscopy were used to characterise the microstructure of the coatings, revealing a nonrandom platelets organisation. [less ▲]

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