Neutrons
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Les neutrons permettent de sonder la matière et leur sensibilité aux éléments légers et au magnétisme en font une sonde unique et originale. Au DRECAM, l’utilisation de la spectrométrie neutronique dans divers domaines de la recherche fondamentale et appliquée est développée autour du Laboratoire mixte CEA-CNRS Léon Brillouin autour du réacteur Orphée à Saclay. Ils sont principalement destinés à l'étude de la matière condensée. L'activité scientifique propre du laboratoire peut se regrouper en trois secteurs sensiblement d'égale importance: la physico-chimie, les études structurales et de transition de phases, le magnétisme et la supraconductivité.
Les réacteurs Orphée (LLB) et Osiris du Centre de Saclay sont aussi des sources de neutrons utilisées pour activer des échantillons qui sont ensuite analysés par spectrométrie γ (voir Analyse par Activation Neutronique Instrumentale).
maj : 12-09-2012 (110)
Voir aussi
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Reflectivity experiments have been performed on the Eros reflectometer at Saclay on very small pieces of glass. During this measurement, we did demonstrate our ability to obtain reflectivity curves down to values of 10-5 within a few hours. The curve obtain in this measurement is given ... Lire la suite » |
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 | TiNi alloy is polymorphic. It exhibits a martensitic transition near room temperature between a cubic CsCl-type (austenite) and a monoclinic TiNi-type (martensite) structure. This transformation is at the origin of its shape memory effect. In addition, TiNi has good hydrogen storage properties ... Lire la suite » |
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The improvement of the mechanical properties of polymer films by inclusion of mineral particles is a well known industrial practice used since the end of the XIX century. A classical example is the rubber industry for which the addition of carbon black as fillers permits to increase the elastic ... Lire la suite » |
 | Using conjugated polymers as the active materials in electronic and optoelectronic devices opens up the possibility of fabricating all-polymer devices using solution processing technologies. The fabrication of good quality field-effect transistors (FETs) is crucial to a number of polymer-based ... Lire la suite » |
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 | I.V. Golosovsky1, I. Mirebeau2, G. André2, D. A. Kurdyukov3, Yu. A. Kumzerov3, 1: St. Petersburg Nuclear Physics Institute, 188350, Gatchina, St. Petersburg, Russia
2: Laboratoire Léon Brillouin, CE-Saclay, F-91191, Gif-sur-Yvette, France
3: A. F. Ioffe Physico-Technical Institute, 194021, St. Petersburg, Russia
4: Rostov State University, 344090, Rostov/Don, ... Lire la suite » |
 | Les nanoaimants moléculaires forment des systèmes magnétiques discrets isolés, composés d’un nombre fini d’atomes magnétiques, qui présentent donc des effets quantiques par rapport aux systèmes classiques de dimension infinie. ... Lire la suite » |
 | The strongly interacting conduction electrons can be accurately represented as a gas of weakly interacting electron-like excitations. This description, known as Fermi liquid theory, works for many metallic systems. However, over the past two decades, new types of metallic materials with strongly ... Lire la suite » |
 | Following the synthesis by the ribosome, to carry out its biological function, a protein much fold into a single, well defined conformational state: the native state. Protein folding is thus the physico-chemical process by which a polypeptidic chain undergoes a structural change from an ensemble of ... Lire la suite » |
 | This study investigates the long term behavior of glasses used for confinement of nuclear wastes. The results have been obtained from a fruitful collaboration between different CEA laboratories (LLB, LIONS, CEA Marcoule) and the Ecole Polytechnique. The corrosion process of the glasses by water ... Lire la suite » |
 | BiFeO3 is a multiferroic materials in which ferroelectric and anti-ferromagnetic orders coexist well above room temperature (TN=643 K, TC=1093 K), with a high polarization (over 100 μC/cm2 [1]). We have shown at the LLB by neutron diffraction that these two order parameters interact and that the ... Lire la suite » |
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Les systèmes catanioniques sont des mélanges de tensioactifs cationiques et anioniques. Nous nous focalisons plus particulièrement sur les vésicules catanioniques où la bicouche est à l'état solide ("phase gel"). Elles permettent ... Lire la suite » |
 | In 1893 Sir William Armstrong reported a remarkable experiment: if a high voltage is established between two wine-glasses filled to the brim with pure water and connected by a cotton thread, a rope of water is formed and remains suspended between the lips of the two glasses. This "water ... Lire la suite » |
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In the pyrochlore compounds R2Mo2O7, both rare earth R3+ and M4+ transition metal ions form a threedimensional network of corner sharing tetrahedra. The pyrochlore lattice is geometrically frustrated both for antiferromagnetic (AF) and ferromagnetic (F) nearestneighbour exchange ... Lire la suite » |
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 | The concept of "spin ladder" originally appeared to study the theoretically still controversial antiferromagnet (AF) 2D square lattice in high temperature superconducting cuprates starting from a well understood 1D AF chain [1-2]. They can been schematized as an array of finite number of coupled ... Lire la suite » |
 | This work is part of a theoretical project which aims to unravel the mechanism at work in the high temperature cuprate superconductors. In the recent article [1] we have studied the role of spin fluctuations, and namely of the collective spin mode, for the superconducting pairing and numerous ... Lire la suite » |
 | The pseudogap region of the phase diagram is an important unsolved puzzle in the field of hightransition-temperature (Tc) superconductivity, characterized by anomalous physical properties below a certain temperature, T*[1]. In contrast to the superconducting temperature Tc which exhibits a ... Lire la suite » |
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