0000000001307986
AUTHOR
Brahim Dkhil
Multiferroics by Rational Design: Implementing Ferroelectricity in Molecule-Based Magnets
Multiferroics (MF) are materials that exhibit simultaneouslyseveral ferroic order parameters. Among the multiferroicmaterials, those combining antiferro- or ferroelectricity (FE)and antiferro-, ferri-, or ferromagnetism (FM) within thesame material are highly desirable: the coexistence of thepolar and magnetic orders paves the way towards four-levelmemories while their interactions through the magnetoelec-tric effect makes it possible to control the magnetization byelectric fields and hence to develop electronically tuneablemagnetic devices, which are an essential feature for spin-tronics.
Study of the spontaneous relaxor to normal ferroelectric phase transition in la-doped lead titanate
Abstract Highly lanthanum doped lead titanate ceramics exhibit relaxor properties and undergo on cooling a subsequent spontaneous macroscopic phase transition. The dielectric response is strongly affected by chemical (copper) doping and is found to become independent of the applied ac field for temperatures lower than the phase transition one.
High proton conduction in a chiral ferromagnetic metal-organic quartz-like framework.
A complex-as-ligand strategy to get a multifunctional molecular material led to a metal-organic framework with the formula (NH(4))(4)[MnCr(2)(ox)(6)]·4H(2)O. Single-crystal X-ray diffraction revealed that the anionic bimetallic coordination network adopts a chiral three-dimensional quartz-like architecture. It hosts ammonium cations and water molecules in functionalized channels. In addition to ferromagnetic ordering below T(C) = 3.0 K related to the host network, the material exhibits a very high proton conductivity of 1.1 × 10(-3) S cm(-1) at room temperature due to the guest molecules.
Postsynthetic Approach for the Rational Design of Chiral Ferroelectric Metal–Organic Frameworks
International audience; Ferroelectrics (FEs) are materials of paramount importance with a wide diversity of applications. Herein, we propose a postsynthetic methodology for the smart implementation of ferroelectricity in chiral metal−organic frameworks (MOFs): following a single-crystal to single-crystal cation metathesis, the Ca2+ counterions of a preformed chiral MOF of formula Ca6II{CuII24[(S,S)-hismox]12(OH2)3}·212H2O (1), where hismox is a chiral ligand derived from the natural amino acid l-histidine, are replaced by CH3NH3+. The resulting compound, (CH3NH3)12{CuII24[(S,S)-hismox]12(OH2)3}·178H2O (2), retains the polar space group of 1 and is ferroelectric below 260 K. These results op…
CCDC 1541852: Experimental Crystal Structure Determination
Related Article: Marta Mon, Jesús Ferrando-Soria, Michel Verdaguer, Cyrille Train, Charles Paillard, Brahim Dkhil, Carlo Versace, Rosaria Bruno, Donatella Armentano, Emilio Pardo|2017|J.Am.Chem.Soc.|139|8098|doi:10.1021/jacs.7b03633
CCDC 1541853: Experimental Crystal Structure Determination
Related Article: Marta Mon, Jesús Ferrando-Soria, Michel Verdaguer, Cyrille Train, Charles Paillard, Brahim Dkhil, Carlo Versace, Rosaria Bruno, Donatella Armentano, Emilio Pardo|2017|J.Am.Chem.Soc.|139|8098|doi:10.1021/jacs.7b03633