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23-05-2020
Au sein d'un échantillon solide, réduire la température des spins est une bonne méthode pour améliorer le signal de RMN ou de RPE, puisque cela favorise leur polarisation selon la direction imposée par le champ externe appliqué.
09-05-2020
Andrew M. Jimenez, Dan Zhao, Kyle Misquitta, Jacques Jestin and Sanat K. Kumar Understanding the structure and dynamics of the bound polymer layer (BL) that forms on favorably interacting nanoparticles (NPs) is critical to revealing the mechanisms responsible for material property enhancements in polymer nanocomposites (PNCs).
28-04-2020
Black phosphorus (BP) is a stack of monoatomic layers of phosphorus, bound together by Van der Waals forces. This 2d material is today attracting a great interest due to its widely tunable band gap, depending on the thickness of the material, the very high mobility of its carriers, for its application in field effect transistors (FETs), and the possible emergence of topologically protected states.
09-04-2020
  Dans une nanostructure ferromagnétique, la dynamique de l’aimantation peut rester cohérente à des angles de précession remarquablement élevés, ce qui constitue un élément important pour un contrôle fiable des dispositifs nanomagnétiques.
08-04-2020
Aline Maire du Poset, Mikaela Börjesson, Céline Rameau, Claire Madeleine-Perdrillat, Adrien Lerbret, Camille Loupiac, Fabrice Cousin, Ali Assifaoui We show here how the structure of polygalacturonate (polyGalA) hydrogels cross-linked by Ca2+ cations via external gelation controls the loading and release rate of beta-lactoglobulin (BLG), a globular protein.
17-03-2020
A. C. Ferreira, S. Paofai, A. Létoublon, J. Ollivier, S. Raymond, B. Hehlen, B. Rufflé, S. Cordier, C. Katan, J. Even & P. Bourges   Hybrid organolead perovskites (HOP) have started to establish themselves in the field of photovoltaics, mainly due to their great optoelectronic properties and steadily improving solar cell efficiency. Study of the lattice dynamics is key in understanding the electron-phonon interactions at play, responsible for such properties.
13-02-2020
de Oliveira-Silva, Rodrigo; Bélime, Agathe; Le Coeur, Clémence; Chennevière, Alexis; Helary, Arnaud; Cousin, Fabrice; Judeinstein, Patrick; Sakellariou, Dimitrios; Zanotti, Jean-Marc In soft condensed matter, Small Angle Neutron Scattering (SANS) is a central tool to probe structures with characteristic sizes ranging from 1 to 100 nm. However, when used as a standalone technique, the dynamic properties of the sample are not accessible.
14-01-2020
N. Martin, M. Deutsch, T. C. Hansen, M. T. Fernandez-Diaz, L. N. Fomicheva, A. V. Tsvyashchenko, and I. Mirebeau In the MnGe chiral magnet, the helimagnetic order and local moment collapse in two steps, showing the succession of high spin (HS) and low spin (LS) states as pressure increases. Here, we use high-pressure neutron diffraction to study the doped compounds Mn0.86Co0.14Ge and Mn0.9Rh0.1Ge, and show that the evolution of their microscopic magnetic properties is instead continuous.
21-12-2019
M. Ruminy, S. Guitteny, J. Robert, L.-P. Regnault, M. Boehm, P. Steffens, H. Mutka, J. Ollivier, U. Stuhr, J. S. White, B. Roessli, L. Bovo, C. Decorse, M. K. Haas, R. J. Cava, I. Mirebeau, M. Kenzelmann, S. Petit, and T. Fennell Tb2Ti2O7 presents an ongoing conundrum in the study of rare-earth pyrochlores.
13-12-2019
La ténacité d’un matériau définit sa résistance à rupture. Si on sait la mesurer expérimentalement de manière précise, on ne sait pas, à l’heure actuelle, prévoir sa valeur à partir de la structure atomistique du matériau considéré, même dans les cas les plus simples.
25-11-2019
A. S. Sukhanov, Praveen Vir, A. S. Cameron, H. C. Wu, N. Martin, S. Mühlbauer, A. Heinemann, H. D. Yang, C. Felser, and D. S. Inosov The cubic chiral helimagnets with the P213 space group represent a group of compounds in which the stable skyrmion-lattice state is experimentally observed. The key parameter that controls the energy landscape of such systems and determines the emergence of a topologically nontrivial magnetic structure is the Dzyaloshinskii-Moriya interaction (DMI).
23-10-2019
N. Martin, I. Mirebeau, C. Franz, G. Chaboussant, L. N. Fomicheva, and A. V. Tsvyashchenko We study the helimagnetic ground state of the MnGe cubic alloy using small-angle neutron scattering and a high-resolution method, the so-called MIEZE spectroscopy. Upon cooling below the Néel temperature TN = 170(5) K, we observe the proliferation of long-wavelength gapless spin fluctuations, concomitant with a continuous evolution of the helical correlation length.
22-09-2019
Daniela Russo, Maya Dimova Lambreva, Christiane Alba Simionesco, Pierre Sebban,and Giuseppina Rea Studies on the dynamical properties of photosynthetic membranes of land plants and purple bacteria have been previously performed by neutron spectroscopy, revealing a tight coupling between specific photochemical reactions and macromolecular dynamics.
11-09-2019
La réduction catalytique de composés organiques comportant des liaisons C=O suscite de nombreuses études en chimie fine pour former des molécules d’intérêt (éthers, alcools…), mais l’obtention sélective d’un produit de réaction est parfois difficile. Le choix du catalyseur et du réducteur joue ici un rôle essentiel.
27-08-2019
D. Russo, A. De Angelis, A. Paciaroni, B. Frick, N. de Sousa, F. R. Wurm, and J. Teixeira We investigate the relaxation dynamics of protein−polymer conjugates by neutron scattering spectroscopy to understand to which extent the coating of a protein by a polymer can replace water in promoting thermal structural fluctuations.
19-07-2019
The response of a position-sensitive Li-glass scintillator detector to alpha-particles from a collimated 241Am source scanned across the face of the detector has been measured. Scintillation light was read out by an 8x8 pixel multi-anode photomultiplier and the signal amplitude for each pixel has been recorded for every position on a scan. The pixel signal is strongly dependent on position and in general several pixels will register a signal (a hit) above a given threshold.
11-07-2019
La métrologie (spectroscopie, mesures de temps ou de distances) ou encore la réalisation de réseaux optiques quantiques nécessitent des sources de photons uniques efficaces. Une équipe du SPEC à Saclay, en collaboration avec l'IQST d'Ulm en Allemagne, propose une voie originale pour obtenir une source de photons microondes uniques, simple, efficace et brillante.
20-06-2019
A. Theodoratou, L.-T. Lee, J. Oberdisse and A. Aubert-Pouëssel, Langmuir 35(20) (2019) 6620. Abstract : Nanofilms of about 2 nm thickness have been formed at the air–water interface using functionalized castor oil (ICO) with cross-linkable silylated groups.
30-05-2019
"Dynamics properties of photosynthetic microorganisms probed by incoherent neutron scattering" Daniela Russo, Maya Dimova Lambreva, Christiane Alba Simionesco, Pierre Sebban, and Giuseppina Rea Biophysical Journal, 116 (9) (2019) 1759-1768 Studies on the dynamical properties of photosynthetic membranes of land plants and purple bacteria have been previously performed by neutron spectroscopy, revealing a tight coupling between specific photochemical reactions and macromolecular dynamics.
04-05-2019
B. Annighöfer , A. Hélary, A. Brulet, A. Colas de la Noue, C. Loupiac and S. Combet Review of Scientific Instruments 90 (2019) 025106 Abstract : We report on a high pressure (HP) cell designed for the determination of the structure of molecular solutions by small-angle neutron scattering (SANS). The HP cell is fitted up with two thick metallic windows that make the device very resistant under hydrostatic pressures up to 600 MPa (or 6 kbar).
01-04-2019
Andrés Marcoleta, Frank Wien, Véronique Arluison, Rosalba Lagos, Rafael Giraldo Bacterial Amyloids (2019) Amyloids are supramolecular protein assemblies based on fibrillar arrangements of β‐sheets that were first found as linked to neurodegenerative and systemic human diseases. However, there is now overwhelming evidence on alternative roles of amyloids as functional assemblies and as epigenetic determinants of beneficial traits, both in Fungi and Metazoa.
11-03-2019
La métrologie (spectroscopie, mesures de temps ou de distances) ou encore la réalisation de réseaux optiques quantiques nécessitent des sources de photons uniques efficaces. Une équipe du SPEC à Saclay, en collaboration avec l'IQST d'Ulm en Allemagne, démontre expérimentalement une voie originale pour obtenir une source de photons microonde uniques, simple, efficace et brillante.
05-03-2019
Annelies Sels, Giovanni Salassa, Fabrice Cousin, Lay-Theng Lee, Thomas Bürgi, Nanoscale 26 (2018) 12754. Aromatic dithiol linkers were used to prepare aggregates of Au25(SR)18 clusters (SR: thiolate) via ligand exchange reactions. Fractions of different aggregate sizes were separated by size exclusion chromatography (SEC).
04-03-2019
Marguerite Léang, Didier Lairez, Fabrice Cousin, Frédérique Giorgiutti-Dauphiné, Ludovic Pauchard, Lay-Theng Lee During evaporative drying of a colloidal dispersion, the structural behavior at the air-dispersion interface is of particular relevance to the understanding of the consolidation mechanism and the final structural and mechanical properties of the porous media.
15-02-2019
Burkhard Annighöfer, Arnaud Hélary, Annie Brûlet, Alexandre Colas de la Noue, Camille Loupiac, and Sophie Combet We report on a high pressure (HP) cell designed for the determination of the structure of molecular solutions by small-angle neutron scattering (SANS). The HP cell is fitted up with two thick metallic windows that make the device very resistant under hydrostatic pressures up to 600 MPa (or 6 kbar).
25-01-2019
M. Deutsch, W. Peng, P. Foury-Leylekian, V. Balédent, S. Chattopadhyay, M. T. Fernandez-Diaz, T. C. Hansen, A. Forget, D. Colson, M. Greenblatt, M.-B. Lepetit, S. Petit, and I. Mirebeau The magnetic structure of TbMn2O5 and DyMn2O5 multiferroics has been studied by high-pressure neutron diffraction in a large pressure range up to 6.6 GPa.
17-01-2019
The electron is an elementary particle carrying the elementary charge "e" that is a fundamental constant of physics. However, in a 2-dimensional confined conductor within an intense magnetic field (~ 10 T), the electrons can be organized into a new topologically correlated quantum state so that the electric current can be transported by fractional charges: e / 3, e / 4, e / 5 ....
10-01-2019
L’avènement des lasers femtosecondes (1fs = 10-18s) de puissance avec la technique "Chirped Pulse Amplification" (CPA) [1] permet aujourd’hui de délivrer des intensités lumineuses gigantesques (> 1021 W.cm-2) associées à des champs électriques ultra-intenses de l’ordre de 1013 V.m-1.
03-01-2019
Sophie Combet, Fabrice Cousin, Human Rezaei, Sylvie Noinville Soluble oligomers of prion proteins (PrP), produced during amyloid aggregation, have emerged as the primary neurotoxic species, instead of the fibrillar end-products, in transmissible spongiform encephalopathies. However, whether the membrane is among their direct targets, that mediate the downstream adverse effects, remains a question of debate.
12-12-2018
Souha Ben Mahmoud, Wafa Essafi, Annie Brûlet and François Boué The chain conformation in sulfonated polystyrene PSSNa of a degree of sulfonation 0.34 ≤ f ≤ 1, i.e., of various hydrophobicity, is followed in mixtures of water and increasing content of tetrahydrofuran (THF), a good solvent of the hydrophobic polystyrene moieties (which improves the solvent quality of the mixture).

 

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