124 research outputs found
Revised French guidelines for the diagnosis and management of migraine in adults and children.
International audience: N/A
Adjusting the cation and anion nature in ionic liquids used for the growth control of nanoparticles of organic conductors
Ionic liquids are used for controlling the growth of organic conductors as nanoparticles. We review the conditions of preparation of nanoparticles of conductors derived from tetrathiafulvalene (TTF), tetramethyltetraselenafulvalene (TMTSF) and bis-ethylenedithiotetrathiafulvalene (BEDT-TTF). They are prepared by electrocrystallization using an ionic liquid supporting electrolyte in which the cation plays the role of growth controller and the anion enters the composition of the expected organic conductor. Stable suspensions of nanoparticles are obtained in one case, a valuable characteristic for potential applications in electronic devices
Superconductivity in TTF[Ni(dmit)2]2 films
We report on the observation of a superconducting transition in a fiber-like film of the TTF[Ni(dmit)2]2 phase electrodeposited on silicon substrates. Superconductivity is evidenced by a broad drop of the resistance below 0.8K under the application of a hydrostatic pressure of 7.7 kbar. Zero resistance is not reached due to the contribution of inter-fiber resistance. Superconductivity is confirmed by the application of a magnetic field perpendicular to the plane of the film. The critical field determined on the film is in agreement with that obtained in bulk single crystals
Framing education on headache disorders into the Global Burden of Disease Study 2010 : the European Headache Federation stands ready
Framing education on headache disorders into the Global Burden of Disease Study 2010. The European Headache Federation stands ready
Spin density wave and superconducting properties of nanoparticle organic conductor assemblies
Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).-- et al.The magnetic susceptibilities of nanoparticle assemblies of two Bechgaard salts (TMTSF)2PF6 and (TMTSF)2ClO4, have been studied vs temperature and magnetic field. In the bulk these materials exhibit a spin density wave formation (TSDW=12K) and superconductivity (Tc=1.2K), respectively. We show from inductive (susceptibility) measurements that the nanoparticle assemblies exhibit ground-state phase transitions similar to those of randomly oriented polycrystalline samples of the parent materials. Resistivity and diamagnetic shielding measurements yield additional information on the functional nanoparticle structure in terms of stoichiometric and nonstoichiometric composition.This work was supported by NSF-DMR Grants No. 1005293 and No. 1309146, and the NHMFL is supported by NSF Cooperative Agreement No. DMR-1157490, the State of Florida, and the U.S. Department of Energy. I.C. thanks the French Ministére de l’Enseignement Supérieur et de la Recherche (MESR) for a Ph.D. grant.Peer Reviewe
Facile synthesis of nanoparticles of the molecule-based superconductor Îş-(BEDT-TTF)2Cu(NCS)2
Well-dispersed roughly spherical nano-objects of the molecule-based superconductor κ-(BEDT-TTF)2Cu(NCS)2 have been prepared in an organic solution by using an easy synthetic route. Long alkyl-chain aconitate esters have been used as growth controlling agents. Nano-objects exhibiting sizes in the 35–120 nm range are made of aggregated individual smaller nanoparticles ranging from 3 to 10 nm. Nanoparticle powders have been studied by X-ray diffraction, high resolution electron microscopy and atomic force microscopy in the conductivity mode.
Résumé :
Des nano-objets sphériques et bien dispersés du supraconducteur moléculaire κ-(BEDT-TTF)2Cu(NCS)2 ont été préparés en solution organique à l'aide d'une méthode de synthèse relativement aisée. Des aconitates à longue chaîne alkyle ont été utilisés comme régulateurs de croissance. Ces nano-objets de taille comprise entre 35 et 120 nm sont constitués de petites particules dont le diamètre individuel est de l'ordre de 3 à 10 nm. Les poudres nanoparticulaires ont été étudiées par diffraction des rayons X, par microscopie électronique à haute résolution et enfin par microscopie à force atomique en mode conducteur
Spin density wave and superconducting properties of nanoparticle organic conductor assemblies
The magnetic susceptibilities of nanoparticle assemblies of two Bechgaard salts (TMTSF)2PF6 and (TMTSF)2ClO4, have been studied vs temperature and magnetic field. In the bulk these materials exhibit a spin density wave formation (TSDW=12K) and superconductivity (Tc=1.2K), respectively. We show from inductive (susceptibility) measurements that the nanoparticle assemblies exhibit ground-state phase transitions similar to those of randomly oriented polycrystalline samples of the parent materials. Resistivity and diamagnetic shielding measurements yield additional information on the functional nanoparticle structure in terms of stoichiometric and nonstoichiometric composition
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