Jl Duvail
Université catholique de Louvain
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Featured researches published by Jl Duvail.
Synthetic Metals | 2001
S. Garreau; Jl Duvail; Guy Louarn
Abstract The in situ electrochemical doping process of the poly(3,4-ethylenedioxythiophene) (PEDT) has been studied in an aqueous micellar medium by means of optical spectroscopies. The cyclic voltammetry (CV) and optical absorption results were compared with previous ones obtained either in acetonitrile or in water without surfactant. No significant effect of the medium, water or acetonitrile, was found, but the presence or absence of surfactant in water give rise to different doping CVs, especially in the reductive part. Resonant Raman scattering experiments show a behavior of PEDT different from the one in acetonitrile. The doping mechanism we deduced from these results should imply a variation between an “intermediate” electronic conformation of the polymer in the reduced state to a predominant benzenic one during doping. The comparison with our previous results obtained in acetonitrile leads us to think that the reduced PEDT is in fact slightly oxidized by the aqueous medium.
Journal of Applied Physics | 2000
S. Pignard; G. Goglio; A. Radulescu; Luc Piraux; Sylvain Dubois; A Declemy; Jl Duvail
The magnetization reversal of Ni nanowires was studied by anisotropic magnetoresistance measurements at temperatures between 15 and 300 K. The wires, synthesized by electrodeposition in a nanoporous polycarbonate membrane, are regular cylinders 22 mu m long with a diameter of 75 or 35 nm. The nucleation field was measured on individual nanowires as a function of the angle between the applied field and the wire axis. The results are quantitatively analyzed using classical magnetization reversal theories. Measurements of the nucleation field first obtained as a function of temperature evidence an extra uniaxial anisotropy induced by the contraction of the membrane at low temperature. Combining SQUID measurements and x-ray diffractometry at different temperatures, a clear picture of the large magnetoelastic effect was obtained
Journal of Materials Research | 2002
F. Hamadache; Jl Duvail; Scheuren; Luc Piraux; Claude Poleunis; Patrick Bertrand; Belkaid
The cathodic deposition of iron-cobalt alloys inside the pores of anodically formed nanoporous silicon (PS) from p-type Si substrate is investigated with respect to the electrolyte composition. The samples were characterized by scanning electron microscopy, energy dispersive spectrometry, Auger electron spectroscopy, and Fourier transform infrared spectroscopy. Results showed that the nucleation of pure cobalt started at the bottom of the pores and the nucleation of pure iron occurred all over the pore walls, leading to a preferential deposition on top surface of the porous layer. Nevertheless, a low concentration of Co2+ ions (5 at.%) in the electrolyte drastically improved the penetration of iron into the pores. As a result, a good filling of the pores with Co metal as well as with Fe-Co alloys was achieved. It was also shown that the deposition process oxidizes the structure mainly at the pore walls. The results of our investigation indicate that the mechanisms occurring during the electrodeposition of metals on porous p-type silicon substrates are completely different depending on the kind of electrolyte used: pure iron-based electrolyte or cobalt-based solutions. A complete understanding of the deposition process requires further analyses of the carrier transport in PS and of the charge exchange at the Si/electrolyte and PS/electrolyte interfaces. These new results involving the deposition of iron-group materials into porous p-type silicon are useful for future silicon technologies.
ieee international magnetics conference | 2000
A. Radulescu; U. Ebels; Y Henry; K. Ounadjela; Jl Duvail; Luc Piraux
We report on the domain wall magnetoresistance of Co and Ni nanowires of 35 nm on diameter or less. The enhancement of the resistance due to an isolated domain wall is clearly evidenced from magnetoresistance hysteresis loops obtained under parallel and perpendicular fields. The domain walls magnetoresistance effect is by one order of magnitude smaller in Ni than in Co and it was observed only at low temperature for Ni nanowires. The formation and motion of domain walls is demonstrated by MFM experiments.
Archive | 2010
Loïk Gence; Vincent Callegari; Sorin Melinte; Sophie Demoustier-Champagne; Yun-Ze Long; A. Dinescu; Jl Duvail
This book describes nanowires fabrication and their potential applications, both as standing alone or complementing carbon nanotubes and polymers. Understanding the design and working principles of nanowires described here, requires a multidisciplinary background of physics, chemistry, materials science, electrical and optoelectronics engineering, bioengineering, etc. This book is organized in eighteen chapters. In the first chapters, some considerations concerning the preparation of metallic and semiconductor nanowires are presented. Then, combinations of nanowires and carbon nanotubes are described and their properties connected with possible applications. After that, some polymer nanowires single or complementing metallic nanowires are reported. A new family of nanowires, the photoferroelectric ones, is presented in connection with their possible applications in non-volatile memory devices. Finally, some applications of nanowires in Magnetic Resonance Imaging, photoluminescence, light sensing and field-effect transistors are described. The book offers new insights, solutions and ideas for the design of efficient nanowires and applications. While not pretending to be comprehensive, its wide coverage might be appropriate not only for researchers but also for experienced technical professionals.
Synthetic Metals | 2002
Jl Duvail; P. Retho; S. Garreau; Guy Louarn; C Godon; Sophie Demoustier-Champagne
Physical Review B | 2001
U. Ebels; Jl Duvail; Pe Wigen; Luc Piraux; Ld Buda; K. Ounadjela
Journal of Materials Research | 1999
Luc Piraux; Roger Legras; Jl Duvail; A. Radulescu; Sophie Demoustier-Champagne; Etienne Ferain
Physical Review B | 2000
Sylvain Dubois; Jean Colin; Jl Duvail; Luc Piraux
Physica Status Solidi (a) | 2003
F. Hamadache; Jl Duvail; Patrick Bertrand