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97 results on '"Majimel, Jérôme"'

5. Versatile template-directed synthesis of gold nanocages with a predefined number of windows

Author

Hubert, Céline, primary, Chomette, Cyril, additional, Désert, Anthony, additional, Madeira, Alexandra, additional, Perro, Adeline, additional, Florea, Ileana, additional, Ihiawakrim, Dris, additional, Ersen, Ovidiu, additional, Lombardi, Anna, additional, Pertreux, Etienne, additional, Vialla, Fabien, additional, Maioli, Paolo, additional, Crut, Aurélien, additional, Del Fatti, Natalia, additional, Vallée, Fabrice, additional, Majimel, Jérôme, additional, Ravaine, Serge, additional, Duguet, Etienne, additional, and Tréguer-Delapierre, Mona, additional

Published
2021
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7. Electroceramics sintered by Spark Plasma Sintering

Author

Elissalde, Catherine, Chung Seu, U-Chan, Philippot, Gilles, Herisson de Beauvoir, Thomas, Ndayishimiye, Arnaud, Rua Taborda, Maria Isabel, Mauvy, Fabrice, Fourcade, Sébastien, Aymonier, Cyril, Mornet, Stéphane, Majimel, Jérôme, Suchomel, Matthew, Debéda, Hélène, Goglio, Graziella, Josse, Michaël, Estournès, Claude, Maglione, Mario, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)

Subjects
TheoryofComputation_MISCELLANEOUS, [SPI]Engineering Sciences [physics], [CHIM]Chemical Sciences, [CHIM.MATE]Chemical Sciences/Material chemistry, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, GeneralLiterature_MISCELLANEOUS, ComputingMilieux_MISCELLANEOUS
Abstract

Invited talk; International audience

Published
2019

8. Some strategies to (co)-sinter refractory functional oxides at low temperature by Spark Plasma Sintering

Author

ELISSALDE, Catherine, CHUNG-SEU, U-Chan, RUA TABORDA, Maria Isabel, MAGLIONE, Mario, GOGLIO, Graziella, DEBÉDA, Hélène, JOSSE, Michaël, SUCHOMEL, Matthew, MAJIMEL, Jérôme, ESTOURNES, Claude, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)

Subjects
[CHIM.MATE]Chemical Sciences/Material chemistry, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

9. Ferroelectricity in Undoped ZnO Nanorods

Author

Centre National de la Recherche Scientifique (France), Maiz, Jon, Loxq, Pauline, Fau, Pierre, Fajerwerg, Katia, Kahn, Myrtil L., Fleury, Guillalume, Hadziioannou, Georges, Guegan, Guillaume, Majimel, Jérôme, Maglione, Mario, Rodriguez, Vincent, Pavlopoulou, Eleni, Centre National de la Recherche Scientifique (France), Maiz, Jon, Loxq, Pauline, Fau, Pierre, Fajerwerg, Katia, Kahn, Myrtil L., Fleury, Guillalume, Hadziioannou, Georges, Guegan, Guillaume, Majimel, Jérôme, Maglione, Mario, Rodriguez, Vincent, and Pavlopoulou, Eleni

Abstract

The technological interest in developing novel functional nano-objects that exhibit new properties arising from their nanoscopic nature is undoubtful. Although bulk ZnO is considered to be non-ferroelectric, herein, the ferroelectric behavior of undoped and self-standing ZnO nanoparticles is reported for the first time. The nanoparticles (NPs) under study are synthesized by an organometallic approach. When dispersed in a PMMA dielectric matrix, clear polarization loops and antisymmetric switching currents are recorded for the NPs with the larger volume, in coherence with the significant polar response of these NPs in solution, measured by polarization-resolved second harmonic scattering experiments. Structural characterizations reveal that ferroelectricity is related to the appearance of a new hexagonal crystalline phase, its unit cell being swelled with respect to the well-known wurtzite ZnO cell. The volume fraction of this new phase, the polar SHS response, and the amount of ferroelectric polarization response are all linearly linked, underlining the consistency between these complementary physical characterizations.

Published
2019

10. Ferroelectricity in Undoped ZnO Nanorods

Author

Maiz, Jon, primary, Loxq, Pauline, additional, Fau, Pierre, additional, Fajerwerg, Katia, additional, Kahn, Myrtil L., additional, Fleury, Guillaume, additional, Hadziioannou, Georges, additional, Guegan, Guillaume, additional, Majimel, Jérôme, additional, Maglione, Mario, additional, Rodriguez, Vincent, additional, and Pavlopoulou, Eleni, additional

Published
2019
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13. Plasmonic nanopartices of non conventional shape

Author

Tréguer-Delapierre, Mona, Many, Véronique, Madeira, Alexandra, Chomette, Cyril, Duguet, Etienne, Majimel, Jérôme, Mornet, Stéphane, Vallée, Renaud, Crut, A., del Fatti, Natalia, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Toulin, Stéphane

Subjects
TheoryofComputation_MISCELLANEOUS, [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, GeneralLiterature_MISCELLANEOUS, ComputingMilieux_MISCELLANEOUS
Abstract

Invited talk; International audience

Published
2017

15. Nickel Oxide Selectively Deposited on the {101} Facet of Anatase TiO2 Nanocrystal Bipyramids for Enhanced Photocatalysis.

Author

Kashiwaya, Shun, Olivier, Céline, Majimel, Jérôme, Klein, Andreas, Jaegermann, Wolfram, and Toupance, Thierry

Abstract

Facet-engineered anatase TiO2 with NiO nanoparticles heterocontacts were successfully prepared by selective photodeposition of NiO nanoparticles onto the {101} facet of the top-truncated bipyramidal TiO2 anatase nanocrystals coexposed with {001} and {101} facets. The morphology and electronic properties of the resulting 0.1-10 wt % NiO-decorated TiO2 were investigated by X-ray diffraction, high-resolution electron microscopy, N2 sorption analysis, and UV-vis spectroscopy. Furthermore, a careful determination of the energy band alignment diagram was conducted by a model experiment using XPS and UPS to verify charge separation at the interface of the NiO-TiO2 heterostructure. The model experiment was performed by stepwise deposition of NiO onto oriented TiO2 substrates and in-situ photoelectron spectroscopy measurements without breaking vacuum. Core levels showed shifts of 0.58 eV toward lower binding energies, meaning an upward band bending in TiO2 at the NiO-TiO2 interface. Furthermore, 0.1 wt % NiO-TiO2 exhibited 50% higher activities than the pure TiO2 for methylene blue (MB) photodecomposition under UV irradiation. This enhanced photocatalytic activity of NiO- TiO2 nanocomposites was related to the internal electric field developed at the p-n NiO-TiO2 heterojunction, leading to vectorial charge separation. Finally, mechanistic studies conducted in the presence of carrier or radical scavengers revealed that holes dominantly contributed to the photocatalytic reactions in the case of NiO- TiO2 photocatalysts while electrons played the main role in photocatalysis for the pure TiO2 materials. [ABSTRACT FROM AUTHOR]

Published
2019
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18. Synthèse et étude d'hétérostructures diélectrique/magnétique dans des membranes d'alumine nanoporeuse

Author

UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, UCL - Ecole Polytechnique de Louvain, Piraux, Luc, Elissalde, Catherine, Maglione, Mario, Nysten, Bernard, Kiat, Jean-Michel, Temst, Kristiaan, Vignéras, Valérie, Majimel, Jérôme, Sallagoïty, David, UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, UCL - Ecole Polytechnique de Louvain, Piraux, Luc, Elissalde, Catherine, Maglione, Mario, Nysten, Bernard, Kiat, Jean-Michel, Temst, Kristiaan, Vignéras, Valérie, Majimel, Jérôme, and Sallagoïty, David

Abstract

Over the last decade, the rapid development of nanotechnology has promoted the emergence of novel miniaturized devices based on nanoobjects, leading thus to an increased demand for new nanomaterials with different structures and improved properties. In this context of integration, extensive researches are focused on multifunctional materials such as multiferroic materials and in particular, magnetoelectric heterostructures that combine both ferromagnetic and ferroelectric materials with coupled properties through interfaces and strain effects. These nanomaterials are attractive due to the possibility to generate a spontaneous polarization or magnetization by an applied magnetic and electric field respectively.They are promising candidates for applications in microwave devices, chemical sensors, high density data storage devices, light emitters, etc.. Magnetoelectric materials also provide tremendous attraction in biological and biomedical applications e.g. for hyperthermia processes used to treat cancer. Designing innovative architectures is thus a challenge in the field of magnetoelectric materials. In this thesis project, in order to promote theinterface coupling between ferroelectric and ferromagnetic phases, two strategies are followed for material design: i) 1-1 core-shell structure with ferromagnetic nanowires (1) inside ferroelectric nanotubes in a selfsupported tridimensionnal porous template (1) and ii) 1-3 structure where ferromagnetic nanowires (1) are supported on a substrate and embedded in a ferroelectric matrix (3)., (FSA - Sciences de l'ingénieur) -- UCL, 2015

Published
2015

19. Surface Plasmon Resonance of an Individual Nano-Object on an Absorbing Substrate: Quantitative Effects of Distance and 3D Orientation

Author

Pertreux, Etienne, primary, Lombardi, Anna, additional, Florea, Ileana, additional, Spuch-Calvar, Miguel, additional, Gómez-Graña, Sergio, additional, Ihiawakrim, Dris, additional, Hirlimann, Charles, additional, Ersen, Ovidiu, additional, Majimel, Jérôme, additional, Tréguer-Delapierre, Mona, additional, Hettich, Mike, additional, Maioli, Paolo, additional, Crut, Aurélien, additional, Vallée, Fabrice, additional, and Fatti, Natalia Del, additional

Published
2015
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20. Fluorination of nanosized amorphous silica derived from silicate raw materials

Author

Demyanova, Larisa P., Tressaud, Alain, Labrugère, Christine, Durand, Etienne, Majimel, Jérôme, Petsyk, P. A., Kozlov, K. G., Institute of Geology and Nature Management, Russian Academy of Sciences [Moscow] (RAS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), and Toulin, Stéphane

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, Amorphous silica, Fluorination, Silicates, [CHIM.MATE]Chemical Sciences/Material chemistry
Abstract

International audience; Surface properties of nanosized silica, synthesized using fluoridation technologies, have been modified by direct fluorination using F2-gas or by plasma radio frequency. The modifications of the physicochemical characteristics of the surface have been characterized by spectrometry of photoelectrons (XPS), infrared and high resolution transmission electronic microscopy and compared with those of pristine silica.

Published
2012

21. New highly divided Ce-Ca-based oxyfluorides with UV-Shielding properties: study of the Ce1-xCaxO2-x and Ce1-xCaxO2-x-y/2Fy series

Author

Sronek, Laetitia, Majimel, Jérôme, Kihn, Yolande, Montardi, Yvan, Tressaud, Alain, Feist, M., Legein, C., Buzaré, J.-Y., Body, M., Demourgues, Alain, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Centre de Recherches d'Aubervilliers, RHODIA, Institut für Chemie, Technische Universität Berlin (TU), Institut de recherche en ingénierie moléculaire et matériaux fonctionnels de l'université du Maine (IRIMMFUM), Centre National de la Recherche Scientifique (CNRS)-Le Mans Université (UM)-Institut de Chimie du CNRS (INC), Laboratoire des oxydes et fluorures (LdOF ), Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire de physique de l'état condensé (LPEC), Centre National de la Recherche Scientifique (CNRS)-Le Mans Université (UM), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Technical University of Berlin / Technische Universität Berlin (TU), Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
UV-Shielding properties, Oxyfluorides, Calcium, Cerium, [CHIM.MATE]Chemical Sciences/Material chemistry
Abstract

International audience; Coprecipitations of Ce(III) nitrates and Ca chlorides have been performed in basic medium at pH > 12 using NaOH, H2O2, and HF as fluorinating agent. Powders have been annealed under air at 600 C during 12 h. Oxides and oxyfluorides with Ce1-xCaxO2-x and Ce1-xCaxO2-x-y/2Fy formulas have been obtained. The Ce/Ca and F/Ca atomic ratios have been determined by elemental analysis (microprobe analysis and F titration with specific electrode), leading one to conclude that the higher is the Ca content, the higher is the F rate. The F/Ca atomic ratio is always lower than 1, but the F content strongly increases with the Ca rate, demonstrating the affinity of fluorine for Ca atoms. XRD data analysis confirmed that Ce-Ca-based oxides and oxyfluorides crystallize with the fluorite-type structure (SG: Fmm) and the a-cell parameter follows Vegard's law both for oxide and for oxyfluoride series. The solubility limit has been estimated to correspond to a Ca/Ce atomic ratio between 0.35 and 0.40 thanks to an accurate XRD analysis using monochromatic Cu K1 radiation, which allows one to detect the occurrence of CaF2 traces. Taking into account the F-Ce bond distance in tetrahedral coordination (bond valence model Ce-F = 2.50 Å; average bond distances in Ce1-xCaxO2-x-y/2Fy: Ce/Ca-O/F = 2.35 Å), the low value of the F/Ca atomic ratio is governed by steric effects and constrains present in the network...

Published
2007

22. A 2xxx aluminum alloy crept at medium temperature: role of thermal activation on dislocation mechanisms

Author

Casanove, Marie-José, Majimel, Jérôme, Casanove, M.-J, MOLENAT, G., Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Surfaces, Interfaces et Nano-Objets (CEMES-SINanO), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Elevage des ruminants en régions chaudes (UMR ERRC), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)

Subjects
Materials science, Alloy, chemistry.chemical_element, 02 engineering and technology, Activation energy, engineering.material, 01 natural sciences, Aluminium, 0103 physical sciences, General Materials Science, Composite material, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Dislocation creep, Mechanical Engineering, Metallurgy, Strain rate, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, chemistry, Creep, Mechanics of Materials, engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Dislocation, 0210 nano-technology
Abstract

Fuselage skin of the future supersonic civil transport aircraft requires a material resistant to long-term creep at temperatures ranging from 100 to 130 °C. A candidate is the 2650 aluminum alloy which presents such properties at relatively high temperatures ( 130 °C =0.43 T melting ). From an accelerated creep test conducted at 150 °C under a 280 MPa load and subsequent observations of the dislocation microstructures by transmission electron microscopy, the role of thermal activation on dislocation mechanisms is analyzed. It appears that thermal activation favors cross-slip activity and allows dislocations to glide in non-close-packed planes, namely the {0 0 1} planes. This is the first time that evidence of primary {0 0 1} glide is reported. Associated to a strain-assisted decrease of the precipitate density, thermal activation softens the material and seems to contribute to the acceleration of the strain rate (tertiary stage) by facilitating bypassing of precipitates and the production of mobile dislocations. The different creep stages are explained in terms of individual dislocation mechanisms and not by referring to the evolution of dislocation substructures.

Published
2004

25. From core–shell BaTiO3@MgO to nanostructured low dielectric loss ceramics by spark plasma sintering

Author

Berthelot, Romain, primary, Basly, Brice, additional, Buffière, Sonia, additional, Majimel, Jérôme, additional, Chevallier, Geoffroy, additional, Weibel, Alicia, additional, Veillère, Amélie, additional, Etienne, Laëtitia, additional, Chung, U-Chan, additional, Goglio, Graziella, additional, Maglione, Mario, additional, Estournès, Claude, additional, Mornet, Stéphane, additional, and Elissalde, Cathy, additional

Published
2014
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30. Surface Plasmon Resonance of an Individual Nano‐Object on an Absorbing Substrate: Quantitative Effects of Distance and 3D Orientation.

Author

Pertreux, Etienne, Lombardi, Anna, Florea, Ileana, Spuch‐Calvar, Miguel, Gómez‐Graña, Sergio, Ihiawakrim, Dris, Hirlimann, Charles, Ersen, Ovidiu, Majimel, Jérôme, Tréguer‐Delapierre, Mona, Hettich, Mike, Maioli, Paolo, Crut, Aurélien, Vallée, Fabrice, and Fatti, Natalia Del

Abstract

Modification of the plasmonic response of a metal nano‐object due to interaction with a substrate is experimentally investigated measuring the quantitative optical extinction spectra of individual nano‐objects with various elongated shapes (bipyramids and rods) deposited on a dielectric (silica) or absorbing (carbon) membrane. Apart from the expected dependence of the nanoparticle surface plasmon resonance (SPR) frequency on the nature of the substrate, large substrate and particle shape dependent modifications of its SPR width are demonstrated. These dependencies are ascribed to strong localization of the electromagnetic field associated with the longitudinal SPR of an elongated nano‐object around its tips, leading to different interaction with the substrate depending on the particle shape and 3D orientation relative to the substrate. Both parameters have been precisely determined by electron tomography, permitting excellent reproduction of the experimental data. Experiments performed on silver‐encapsulated bipyramids, whose shape evolves from a pyramidal one towards a cylindrical one, further confirm this effect. [ABSTRACT FROM AUTHOR]

Published
2016
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32. Interface Investigation in Nanostructured BaTiO3/Silica Composite Ceramics

Author

Chung, U‐Chan, primary, Elissalde, Catherine, additional, Mompiou, Frédéric, additional, Majimel, Jérôme, additional, Gomez, Sonia, additional, Estournès, Claude, additional, Marinel, Sylvain, additional, Klein, Andreas, additional, Weill, François, additional, Michau, Dominique, additional, Mornet, Stéphane, additional, and Maglione, Mario, additional

Published
2010
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34. Microwave Synthesis of an Aluminum Fluoride Hydrate with Cationic Vacancies: Structure, Thermal Stability, and Acidic Properties

Author

Dambournet, Damien, primary, Demourgues, Alain, additional, Martineau, Charlotte, additional, Durand, Etienne, additional, Majimel, Jérôme, additional, Legein, Christophe, additional, Buzaré, Jean-Yves, additional, Fayon, Franck, additional, Vimont, Alexandre, additional, Leclerc, Hervé, additional, and Tressaud, Alain, additional

Published
2008
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36. Coupling Sol-Gel Synthesis and Microwave-Assisted Techniques: A New Route from Amorphous to Crystalline High-Surface-Area Aluminium Fluoride

Author

Dambournet, Damien, primary, Eltanamy, Gehan, additional, Vimont, Alexandre, additional, Lavalley, Jean‐Claude, additional, Goupil, Jean‐Michel, additional, Demourgues, Alain, additional, Durand, Etienne, additional, Majimel, Jérôme, additional, Rudiger, Stephan, additional, Kemnitz, Erhard, additional, Winfield, John M., additional, and Tressaud, Alain, additional

Published
2008
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37. Nanostructured Aluminium Hydroxyfluorides Derived from β-AlF3

Author

Dambournet, Damien, primary, Demourgues, Alain, additional, Martineau, Charlotte, additional, Pechev, Stanislas, additional, Lhoste, Jérôme, additional, Majimel, Jérôme, additional, Vimont, Alexandre, additional, Lavalley, Jean-Claude, additional, Legein, Christophe, additional, Buzaré, Jean-Yves, additional, Fayon, Franck, additional, and Tressaud, Alain, additional

Published
2008
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38. Local organization of Fe3+ into nano-CeO2 with controlled morphologies and its impact on reducibility properties.

Author

Moog, Iona, Feral-Martin, Cédric, Duttine, Mathieu, Wattiaux, Alain, Prestipino, Carmelo, Figueroa, Santiago, Majimel, Jérôme, and Demourgues, Alain

Abstract

Ce and Fe are the main metal additives which have been tested by many laboratories for their catalytic activity at low temperature for soot oxidation in diesel engines.The key role and impact of Fe on the reducibility properties of ceria have been investigated on the basis of composition and structural features considering various synthesis routes. Two different procedures were used to prepare iron-substituted cerium dioxide Ce1−xFexO2−x/2: a classical co-precipitation route followed by annealing at T = 600 °C and an unusual microwave-assisted hydrothermal synthesis at T = 200 °C. The highest surface areas around 100 m2 g−1, have been obtained for oxides containing the largest Fe amount and prepared by the microwave-assisted route. Solid solutions were obtained up to x = 0.15 and 0.20 through microwave-assisted and co-precipitation routes, respectively. The highest decrease of the lattice parameter is observed for compounds prepared by the microwave-assisted route. The TEM analysis reveals a nano-cubic shape (with mainly {001} planes) for compounds prepared by the microwave-assisted route and containing low Fe amount. For the other compounds prepared also by the co-precipitation process, a nano-polyhedron shape corresponding to a thermodynamically stable morphology is observed. EPR (T = 5 K, very low Fe rates), Mössbauer (room temperature, x = 0.10) and XANES–EXAFS (RT and T = 20 K) spectroscopies studies showed that Fe ions adopt the trivalent state and are located in isolated distorted (orthorhombic and axial distortions) octahedra or form Fe clusters. The local organization of Fe3+ plays a key role in the oxygen vacancy distribution and consequently the reducibility properties of the Ce1−xFexO2−x/2 solid solution. For the compounds prepared by the microwave-assisted route, a large proportion of Fe3+ is located in isolated distorted octahedral sites that contribute to affect a high number of Ce4+ nearest neighbors with a high mobility of oxygen vacancies. In this case, the oxygen vacancies are well distributed around Ce4+ and Fe3+. In the case of compounds obtained by the co-precipitation route, Fe clusters abundance is higher and consequently oxygen vacancies are mainly located around Fe clusters. Such a distribution should explain the lower solubility limit and the larger variation of the cell parameter versus x Fe content in the series prepared by the microwave-assisted route. It is shown that these last compounds exhibit better reducibility properties with a doubled reduction rate (comparison between x(Fe) = 0.05 and pure CeO2) equal to 60% at T = 550 °C due to the iron local organization, a nano-cubic morphology and a higher surface area. [ABSTRACT FROM AUTHOR]

Published
2014
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42. From core–shell BaTiO3@MgO to nanostructured low dielectric loss ceramics by spark plasma sintering.

Author

Berthelot, Romain, Basly, Brice, Buffière, Sonia, Majimel, Jérôme, Chevallier, Geoffroy, Weibel, Alicia, Veillère, Amélie, Etienne, Laëtitia, Chung, U-Chan, Goglio, Graziella, Maglione, Mario, Estournès, Claude, Mornet, Stéphane, and Elissalde, Cathy

Abstract

We report a quite general way to design materials with tailored properties by combining thermolysis and fast sintering approaches. Submicrometric-sized BaTiO3 particles have been directly coated in a continuous nanocrystalline MgO shell through a thermal decomposition process. The electron microscopy study has evidenced a shell composed of randomly oriented MgO nanocrystallites. The final nanostructured composite, made of sub-micrometric MgO and BaTiO3 grains uniformly distributed, is obtained in situ during the SPS process. Such a rearrangement can be explained by the initial core–shell architecture, the weak cohesion of the MgO nanocrystallites and their soft plastic behavior under SPS conditions. The composite effect leads to significant modifications in both the dielectric properties and Curie–Weiss parameters compared to uncoated BaTiO3, especially a decrease and thermal stabilization of both the permittivity and the dielectric losses. We ascribe such changes to the stress generated during SPS through the extended interfaces between the two components. [ABSTRACT FROM AUTHOR]

Published
2014
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43. Interface Investigation in Nanostructured BaTiO3/Silica Composite Ceramics.

Author

U-Chan Chung, Elissalde, Catherine, Mompiou, Frédéric, Majimel, Jérôme, Gomez, Sonia, Estournès, Claude, Marinel, Sylvain, Klein, Andreas, Weill, François, Michau, Dominique, Mornet, Stéphane, and Maglione, Mario

Subjects
SILICA, FERROELECTRIC crystals, DIELECTRIC resonators, SUPERCAPACITORS, X-ray diffraction, X-ray photoelectron spectroscopy, SCANNING electron microscopy, SINTERING, QUANTITATIVE research
Abstract

Silica-coated ferroelectric particles are promising building blocks for functional bulk composites such as dielectric resonators, supercapacitors, or multiferroics. The ferroelectric/silica interface was fully investigated by means of high-temperature in situ X-ray diffraction, high-resolution scanning electron microscopy, and X-ray photoelectron spectroscopy. Mechanisms occurring at the interface were visualized using high-resolution postmortem and in situ transmission electron microscopy performed at different temperatures. On the light of this interface investigation, we have used advanced sintering processes such as spark plasma sintering and microwave sintering to obtain nanostructured composite ceramics and to evaluate their dielectric properties. [ABSTRACT FROM AUTHOR]

Published
2010
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44. Dual Ce4+/Fe3+Redox Phenomena into Nanocrystalline Ce1–xFexO2–x/2Solid Solution

Author

Moog, Iona, Prestipino, Carmelo, Figueroa, Santiago, Majimel, Jérôme, and Demourgues, Alain

Abstract

The Ce1–xFexO2–x/2solid solution was synthesized using a microwave-assisted hydrothermal route. The solubility limit corresponds to a Fe (x) content equal to 0.15. Our previous works showed also that isolated Fe3+distorted octahedral sites and Fe3+clusters are randomly distributed into the ceria network. Thermogravimetric analysis (TGA) under Ar/5%H2revealed a higher reduction rate for Fe-substituted ceria with changes of slope and the appearance of pseudoplateaus around 400 and 550 °C. The first Fe K-edge X-ray absorption near-edge spectroscopy (XANES) spectra recorded at several temperatures up to 700 °C shift gradually to lower energies as the temperature increases, with the formation of metallic iron starting at 550 °C, as confirmed by X-ray diffraction analysis. Moreover, on the basis of the principal component factor analysis, three K-edge structures associated with three oxidation states of iron (Fe3+, Fe2+, and Fe0) have been distinguished during this temperature-programmed reduction. The second component attributed to Fe2+is the most intense one around 500 °C. Beyond this temperature, the coexistence of the three oxidation states Fe3+/Fe2+/Fe0has to be mentioned up to 650 °C, the temperature at which metallic iron is mainly stabilized. Ce LIII-edge and Fe K-edge XANES spectra recorded in quick extended X-ray absorption fine structure mode and at various temperatures show the progressive reduction of Ce4+and Fe3+starting beyond 250 °C, which is in good agreement with the change of slope observed on the TGA curves. The Ce LIII-edge XANES spectrum of pure CeO2recorded at 700 °C under reducing atmosphere exhibits much less Ce3+stabilized into the fluorite network than Fe-substituted ceria. Fe3+ions randomly distributed into ceria strongly contribute to enhancing the Ce4+reducibility properties. The Ce4+reduction seems to appear at lower temperatures and is slower than the Fe3+reduction, whose speed decreases around 400 °C. At this temperature, the Fe2+and Fe3+components dominate and the Ce3+content remains high. However, a plateau with the stabilization of Ce4+/Ce3+mixed valences around 500 °C appears where the Fe2+contribution is also a maximum and the Fe reduction is slower. Because of the large content of either Ce3+and Fe2+, a charge-transfer equilibrium Ce4++ Fe2+⇔ Ce3++ Fe3+may occur at this temperature at which a change of slope on TGA curve also is observed with the appearance of a plateau at 550 °C associated with the Fe0demixtion phenomenon. Then, after reaching the maximum Fe2+rate, the Ce4+reduction rate increases again up to 700 °C, the temperature at which all Fe atoms have been transformed into metallic iron.

Published
2014
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45. Synthèse et étude d'hétérostructures diélectrique/magnétique dans des membranes d'alumine nanoporeuse

Author

Sallagoïty, David, UCL - SST/IMCN - Institute of Condensed Matter and Nanosciences, UCL - Ecole Polytechnique de Louvain, Piraux, Luc, Elissalde, Catherine, Maglione, Mario, Nysten, Bernard, Kiat, Jean-Michel, Temst, Kristiaan, Vignéras, Valérie, and Majimel, Jérôme

Subjects
Nanocables, Hétérostructures, Multiferroïque, Membranes d'alumine, Magnétoélectrique
Abstract

Over the last decade, the rapid development of nanotechnology has promoted the emergence of novel miniaturized devices based on nanoobjects, leading thus to an increased demand for new nanomaterials with different structures and improved properties. In this context of integration, extensive researches are focused on multifunctional materials such as multiferroic materials and in particular, magnetoelectric heterostructures that combine both ferromagnetic and ferroelectric materials with coupled properties through interfaces and strain effects. These nanomaterials are attractive due to the possibility to generate a spontaneous polarization or magnetization by an applied magnetic and electric field respectively.They are promising candidates for applications in microwave devices, chemical sensors, high density data storage devices, light emitters, etc.. Magnetoelectric materials also provide tremendous attraction in biological and biomedical applications e.g. for hyperthermia processes used to treat cancer. Designing innovative architectures is thus a challenge in the field of magnetoelectric materials. In this thesis project, in order to promote theinterface coupling between ferroelectric and ferromagnetic phases, two strategies are followed for material design: i) 1-1 core-shell structure with ferromagnetic nanowires (1) inside ferroelectric nanotubes in a selfsupported tridimensionnal porous template (1) and ii) 1-3 structure where ferromagnetic nanowires (1) are supported on a substrate and embedded in a ferroelectric matrix (3). (FSA - Sciences de l'ingénieur) -- UCL, 2015

Published
2015

46. Corrélations compositions chimiques-structures d’oxydes mixtes (Ce / Zr) à base de Pr4+ / Pr3+ et propriétés de réductibilité

Author

ABEL, Jonathan, Demourgues, Alain, Majimel, Jérôme, Delmas, Claude, Paulus, Werner, Daturi, Marco, Baca-Bellière, Virginie, Harlé, Virginie, Étourneau, Jean, and André, Gille

Subjects
Structures cristallographique, EELS, TPR, Cérium, Fluorine, Surstructures, ATG, Oxydes mixtes, Diffraction de neutrons, Propriétés de réductibilité, Mesures magnétiques, Spectroscopie d’absorption X, Zirconium, Praséodyme, Degré d’oxydation

48. Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés

Author

FERAL-MARTIN, Cédric, Demourgues, Alain, Majimel, Jérôme, Delmas, Claude, Buffat, Philippe-André, Jolivet, Jean-Pierre, Cadete Santos Aires, Francisco-José, Étourneau, Jean, and Rohart, Emmanuel

Subjects
Propriétés de surface, Propriétés interfaces, Au/CeO2, Processus germination/croissance, Met, Réactivité, Traitement hydrothermale assistée par chauffage micro-onde, Oxydes à bases de Cérium, Morphologie

49. Sur des oxydes de cérium contenant du fer nanostructurés et de morphologies contrôlées

Author

MOOG, Iona, Demourgues, Alain, Majimel, Jérôme, Thailhades, Philippe, Spalla, Olivier, Étourneau, Jean, Maglione, Mario, Farrusseng, David, Alain Demourgues, Jérôme Majimel, Mario Maglione [Président], David Farrusseng [Rapporteur], Philippe Thailhades [Rapporteur], Olivier Spalla, and Jean Étourneau

Subjects
Synthèse assistée par chauffage micro-ondes, Contrôle de morphologie, Phénomène de démixion, Solution solide Ce-Fe

50. Template-Directed Synthesis of Titania Nanocages with Four Tetrahedrally Arranged Open Windows.

Author

Cheng J, Mallet N, Baaziz W, Ersen O, Gombart E, Alard V, Majimel J, Delville MH, Tréguer-Delapierre M, and Duguet E

Abstract

Original titania nanocages are fabricated from sacrificial silica/polystyrene tetrapod-like templates. Here the template synthesis, titania deposition and nanocage development through polystyrene dissolution and subsequent silica etching are described. Discussion about the competitive deposition of titania on the biphasic templates is particularly emphasized. The morphology of the nanocages is investigated by TEM, STEM, EDX mapping and electron tomography., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2018
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