| | | | | | | webmail : intra-extra| Accès VPN| Accès IST| Contact
Jul 21, 2020
Premakumar Yanda, I. V. Golosovsky, I. Mirebeau, N. V. Ter-Oganessian, Juan Rodríguez-Carvajal and A. Sundaresan In most of the spin-induced multiferroics, the ferroelectricity is caused by inversion symmetry breaking by complex spin structures of the transition-metal ions. Here, we report the importance of interplay of 4 f -3d magnetic interactions in inducing ferroelectricity in the centrosymmetric (Pnma) green phase compound Gd2BaCuO5.
Jun 23, 2020
We show by X-ray and neutron small-angle scattering that gold nanoparticles with controlled sizes and morphologies can be obtained by the metallic reduction of AuCl4– ions trapped in 3D organic molds by X-ray radiolysis. The molds are spherical frozen micelles of polystyrene-b-poly(dimethylaminoethyl methacrylate) (PS-b-PDMAEMA) block copolymer in acidic aqueous solution with a PS spherical core surrounded by a corona of PDMAEMA chains in good solvent.
Apr 08, 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.
Mar 17, 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.
Feb 13, 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.
Jan 14, 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.
Dec 21, 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.
Nov 25, 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).
Oct 23, 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.
Sep 22, 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.
Aug 27, 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.
Jul 19, 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.
Jun 20, 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.
May 30, 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.
May 04, 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).
Mar 05, 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).
Mar 04, 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.
Feb 15, 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).
Jan 25, 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.
Jan 03, 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.
Dec 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).
Nov 20, 2018
Jyotsana Lal This article is dedicated to the memory of Loic Auvray The results on Winsor phases, droplet and bicontinous microemulsions phases with polymer-grafted lipids studied by Small Angle Neutron Scattering (SANS) are reported below, together with the contrast variation techniques used to characterize the average curvature in the system.
Oct 15, 2018
Raphael Dos Santos Morais, Olivier Delalande, Javier Perez, Dominique Mias-Lucquin, Melanie Lagarrigue, Anne Martel, Anne-Elisabeth Molza, Angelique Cheron, Celine Raguenes-Nicol, Thomas Chenuel, Arnaud Bondon, Marie-Sousai Appavou, Elisabeth Le Rumeur, Sophie Combet, and Jean-Francois Hubert Scaffolding proteins play important roles in supporting the plasma membrane (sarcolemma) of muscle cells.
Sep 24, 2018
Fengjiao Qian, Lars J. Bannenberg, Heribert Wilhelm, Grégory Chaboussant, Lisa M. Debeer-Schmitt, Marcus P. Schmidt, Aisha Aqeel, Thomas T. M. Palstra, Ekkes Brück, Anton J. E. Lefering, Catherine Pappas, Maxim Mostovoy, Andrey O.
Aug 29, 2018
I. Mirebeau, N. Martin, M. Deutsch, L. J. Bannenberg, C. Pappas, G. Chaboussant, R. Cubitt, C. Decorse, and A. O. Leonov Reentrant spin glasses are frustrated disordered ferromagnets developing vortexlike textures under an applied magnetic field. Our study of a Ni0.81Mn0.19Ni0.81Mn0.19 single crystal by small angle neutron scattering clarifies their internal structure and shows that these textures are randomly distributed.
Aug 09, 2018
Maelenn Chevreuil, Didier Law-Hine, Jingzhi Chen, Stéphane Bressanelli, Sophie Combet, Doru Constantin, Jéril Degrouard, Johannes Möller, Mehdi Zeghal and Guillaume Tresset The survival of viruses partly relies on their ability to self-assemble inside host cells. Although coarse-grained simulations have identified different pathways leading to assembled virions from their components, experimental evidence is severely lacking.
Jun 20, 2018
Unravelling a mechanism of action for a cecropin a‑melittin hybrid antimicrobial peptide: the induced formation of multilamellar lipid stacks T. Silva, B. Claro, B. F. B. Silva, N. Vale, P. Gomes, M.-S. Gomes, S. S. Funari, J. Teixeira, D. Uhríková, and M. Bastos, Langmuir, 2018, 34 (5), pp 2158–2170. An understanding of the mechanism of action of antimicrobial peptides is fundamental to the development of new and more active antibiotics.
May 28, 2018
Béatrice Gillon, Albert Hammerschmied, Arsen Gukasov, Alain Cousson, Thomas Cauchy, Eliseo Ruiz, John A. Schlueter, Jamie L. Manson We report neutron‐diffraction investigations of the quasi‐2D MnII(dca)2(pym)(H2O) (pym = N2C4H4) compound, where high‐spin MnII ions are bridged by dicyanamide anions, [N(CN)2]– (herein abbreviated dca). Inside the layers, Mn2+ ions are connected by single or double dca bridges.
May 04, 2018
Anne-Sophie Robbes, Fabrice Cousin , Florian Meneau, and Jacques Jestin We probe by SANS the conformation of polymer chains of the matrix in various nanocomposites based on the same building blocks, namely spherical magnetic nanoparticles of maghemite (γ-Fe2O3) as fillers and polystyrene (PS) for the matrix.
Apr 17, 2018
We report on the self-assembly behavior of poly(2-methyl-2-oxazoline)–block–poly(2-octyl-2-oxazoline) comprising different terminal perfluoroalkyl fragments in aqueous solutions. As reported previously [Kaberov et al. (2017)] such polyphiles can form a plethora of nanostructures depending of the composition and on the way of preparation.
Mar 24, 2018
Cationic thermoresponsive poly(n-vinylcaprolactam) microgels synthesized by emulsion polymerization using a reactive cationic macro-raft agent L. Etchenausia, E. Deniau, A. Brûlet, J. Forcada and M. Save,  Macromolecules  (2018) sous presse.
Feb 22, 2018
Magnetic skyrmions are topologically stable, vortex-like objects surrounded by chiral boundaries that separate a region of reversed magnetization from the surrounding magnetized material. They are closely related to nanoscopic chiral magnetic domain walls, which could be used as memory and logic elements for conventional and neuromorphic computing applications that go beyond Moore’s law.
Dec 21, 2017
D. Bounoua, R. Saint-Martin, S. Petit, P. Berthet, F. Damay, Y. Sidis, F. Bourdarot, and L. Pinsard-Gaudart, Phys. Rev. B 95, 224429 The low energy magnetic excitations spectra of the pristine and doped quasi-one-dimensional spin chains cuprates SrCuO2 have been investigated by inelastic neutron scattering.
Nov 17, 2017
A. K. Nayak, V. Kumar, T. Ma, P. Werner, E. Pippel, R. Sahoo, F. Damay, U. K. Rößler, C. Felser and S. S. P. Parkin,  Nature 548, 561–566. Magnetic skyrmions are topologically stable, vortex-like objects surrounded by chiral boundaries that separate a region of reversed magnetization from the surrounding magnetized material.
Oct 26, 2017
Raphael Dos Santos Morais, Olivier Delalande, Javier Pérez, Liza Mouret, Arnaud Bondon, Anne Martel, Marie-Sousai Appavou, Elisabeth Le Rumeur, Jean-François Hubert, and Sophie Combet Obtaining structural information on integral or peripheral membrane proteins is currently arduous due to the difficulty of their solubilization, purification, and crystallization (for X-ray crystallography (XRC) application).
Sep 06, 2017
Stehane Longeville et Laura-Roxana Stingaciu Translational diffusion of macromolecules in cell is generally assumed to be anomalous due high macromolecular crowding of the milieu. Red blood cells are a special case of cells filled quasi exclusively (95% of the dry weight of the cell) with an almost spherical protein: hemoglobin. Hemoglobin diffusion has since a long time been recognized as facilitating the rate of oxygen diffusion through a solution.
Aug 24, 2017
Crystal-electric-field excitations and spin dynamics in Ce3Co4Sn13 semimetallic chiral-lattice phase Kazuaki Iwasa, Yuka Otomo, Kazuya Suyama, Keisuke Tomiyasu, Seiko Ohira-Kawamura, Kenji Nakajima, and Jean-Michel Mignot Inelastic neutron scattering experiments have been conducted to investigate the spin dynamics and crystal-electric-field level scheme of the Ce 4f4f electrons in Ce3Co4Sn13Ce3Co4Sn13 .
Apr 07, 2016
Fractionalized excitations that emerge from a many-body system have revealed rich physics and concepts, from composite fermions in two-dimensional electron systems, revealed through the fractional quantum Hall effect, to spinons in antiferromagnetic chains and, more recently, fractionalization of Dirac electrons in graphene and magnetic monopoles in spin ice.
Mar 04, 2010
D. S. Inosov1, J. T. Park1, P. Bourges2, D. L. Sun1, Y. Sidis2, A. Schneidewind3,4, K. Hradil4,5, D.Haug1, C. T. Lin1, B. Keimer1, and V. Hinkov
1 Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany2 Laboratoire Léon Brillouin, CEA-CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France3 Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), TU München, D-85747 Garching, Germany In March 2008, superconductivity at high critical temperature (Tc> 50K) was found in iron-arsenide compounds  [1] to the surprise of the scientific community.
Jan 07, 2008
(1,2) B. Toudic, P. Garcia, C. Odin, P. Rabiller, C. Ecolivet and E. Collet,
P. Bourges3, G.J. McIntyre4, M.D. Hollingsworth5, T. Breczewski6
1 Institut de Physique de Rennes, CNRS UMR 6251, Univ. Rennes 1, 35042 Rennes, France2 CNRS, UMR 6251, IPR, 263 Avenue du Général Leclerc, 35042 Rennes Cedex, France.3 Laboratoire Léon Brillouin, CEA-CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France4 Institut Laue-Langevin, 38042 Grenoble Cedex 9, France.5 Department of Chemistry, Kansas State University, Manhattan, KS 66506, USA.6 Facultad de Ciencias, Universidad del Pais Vasco, Apdo 644, Bilbao, Spain.
Apr 11, 2007
S. Petit, F. Moussa, M. Hennion et S. Pailhès (DRECAM/LLB CEA-Saclay)
L. Pinsard-Godard, Laboratoire de Chimie du Solide, Paris XI
A. Ivanov, ILL, BP 156 F-38042 Grenoble
Multi-ferroïcs are exceptional materials whose fundamental state is both magnetic and ferro-electric [1]. Moreover, in such materials, magnetism and ferroelectricity maintains close links: as for example the manganese oxide YMnO3 [2], can see its magnetization modified by the action of an electric field, or its electric polarization by the action of a magnetic field (magnetoelectric effect).

 

Retour en haut