15 janvier 2016
Structure refinement using precession electron diffraction tomography and dynamical diffraction
The method for accurate structure refinements from three-dimensional precession electron diffraction data using dynamical diffraction theory has been applied to different samples. The data were measured on different instruments and with variable precession angles. A large series of tests revealed that the method provides structure models with an average error in atomic positions typically between 0.01 and 0.02 Å compared to the reference structures. The method allows a reliable determination of site occupancies and absolute structure.
See also Closing the gap between electron and X-ray crystallography, a scientific commentary on this article.
Corresponding author : Philippe Boullay
L. Palatinus, C. A. Corrêa, G. Steciuk, D. Jacob, P. Roussel, P. Boullay, M. Klementová, M. Gemmi, J. Kopecek, M. C. Domeneghetti, F. Cámara and V. Petrícek.
Acta Cryst. B71 (2015) 740-751. DOI : 10.1107/S2052520615017023
7 janvier 2016
Advances in Magnetoelectric Materials and Their Application
The present contribution is an updated supplement to the review “Magneto- electricity” published in Chapter 3 of Volume 19 of the series Handbook of Magnetic Materials (Fuentes-Cobas et al., 2011).
The combined research area of magnetoelectric/multiferroic materials continues to show, as general tendency, an exponential growth. The basic science of magnetoelectricity is as charming as challenging. Particularly for single-phase magnetoelectric multiferroics, quantum theory has already provided answers to important questions, but several (old and new) open issues demand attention, targetted here. Magnetoelectricity has just started to show its potentialities, magnetoelectric composites for instance as materials mostly used in the real world to develop practical applications. In this aim, textured polycrystalline ME tensor modeling are described.
In the bse article (Fuentes-Cobas et al., 2011), Magnetoelectricity was represented as a young and gorgeous princess (awakening from a one-century sleep), with plenty of mysteries and promises. In 2015, our princess has grown from her teens and she is preparing herself to work as a Queen. She already visualizes her contributions in the utilization of relatively simple systems and now she feels attracted by challenges from highly complex objects. Who knows, maybe she finds her way to participate actively in the cure of some cancers
L.E. Fuentes-Cobas, J.A. Matutes-Aquino, M.E. Botello-Zubiate, A. Gonzalez-Vazquez, M.E. Fuentes-Montero and D. Chateigner
"Handbook of Magnetic Materials", Vol. 24 Edité par K.H.J. Buschow chez Elsevier, chapitre 3,pages 237-322 dédié aux matériaux magnéto-électriques :
23 novembre 2015
Interplay between 3d-3d and 3d-4f interactions at the origin of the magnetic ordering in the Ba2LnFeO5 oxides
A. K Kundu, V. Hardy, V. Caignaert, B. Raveau
J. Phys.:Condens. Matter 27, 486001 (2015)
Collaboration PSOM & NMF2
3 novembre 2015
A new active Li–Mn–O compound for high energy density Li-ion batteries
In this work, we report on a new electrochemically active compound with the ‘Li4Mn2O5’ composition, prepared by direct mechanochemical synthesis at room temperature. This rock-salt type nanostructured material shows a discharge capacity of 355 mAh/g, which is the highest one among the known lithium manganese oxide electrode materials ever reported. According to the magnetic measurements, this exceptional capacity results from the electrochemical activity of the Mn3+/Mn4+ and O2-/O- redox couples, and, importantly, of the Mn4+/Mn5+ couple also.
M. Freire, N. V. Kosova, C. Jordy, D. Chateigner, O. I. Lebedev, A. Maignan and V. Pralong*
Nature Materials Letters Vol 14, December 2015 DOI : 10.1038/NMAT4479
2 mai 2016
Prix de Thèse de l’Association Française de Cristallographie (AFC) 2016 – Mention Chimie
29 avril 2016
La journée de remise des Grands Prix, des Prix binationaux et des titres de Membre distingué 2015, de la SCF aura lieu à Caen le jeudi 26 Mai prochain.
L’entrée est libre et gratuite.