Coexistence of ferromagnetism and metallic conductivity in a molecule-based layered compound

Abstract

Crystal engineering--the planning and construction of crystalline supramolecular architectures from modular building blocks--permits the rational design of functional molecular materials that exhibit technologically useful behaviour such as conductivity and superconductivity, ferromagnetism and nonlinear optical properties. Because the presence of two cooperative properties in the same crystal lattice might result in new physical phenomena and novel applications, a particularly attractive goal is the design of molecular materials with two properties that are difficult or impossible to combine in a conventional inorganic solid with a continuous lattice. A promising strategy for creating this type of 'bi-functionality' targets hybrid organic/inorganic crystals comprising two functional sub-lattices exhibiting distinct properties. In this way, the organic pi-electron donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and its derivatives, which form the basis of most known molecular conductors and superconductors, have been combined with molecular magnetic anions, yielding predominantly materials with conventional semiconducting or conducting properties, but also systems that are both superconducting and paramagnetic. But interesting bulk magnetic properties fail to develop, owing to the discrete nature of the inorganic anions. Another strategy for achieving cooperative magnetism involves insertion of functional bulky cations into a polymeric magnetic anion, such as the bimetallic oxalato complex [MnIICrIII(C2O4)3]-, but only insoluble powders have been obtained in most cases. Here we report the synthesis of single crystals formed by infinite sheets of this magnetic coordination polymer interleaved with layers of conducting BEDT-TTF cations, and show that this molecule-based compound displays ferromagnetism and metallic conductivity.

Experimental and theoretical studies of hydroxyl-induced magnetism in TiO nanoclusters

“…Adsorption/ desorption of water molecules give rise to the moment variation for molecular magnets. [36][37][38][39][40][41] Both systems display intimate correlations among defect structure, humidity, conductivity, and magnetism, highlighting the crucial and promising role of defect-engineering in new material development.…”

“…[36][37][38][39][40][41] Adsorption/desorption of hydroxyls produces the moment variation for our Ti oxide clusters. Adsorption/ desorption of water molecules give rise to the moment variation for molecular magnets.…”

Synthesis of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives functionalised with two, four or eight hydroxyl groups

“…

,2R,5R,2,5, gave two separable diastereomeric thiones, which can be transformed to enantiomeric BEDT-TTF derivatives with four or eight hydroxyl groups.

…”

“…2 Particular highlights are the salts (ET) 2 (Cu(NCS) 2 ) and (ET) 2 (N(CN) 2 )X (X = Cl or Br) which become superconducting at low temperatures, 3 the paramagnetic superconducting radical salt (ET) 4 [Fe(oxalate) 3 ]·H 2 O·C 6 H 5 CN, 4 a layered salt with a mixed chromium(III) / manganese (II) oxalate network which has independent electrical and ferromagnetic properties, 5 and salts with MHg(SCN) 4 -(M = K or Tl) which form a chiral surface metal in a magnetic field. 6 The superconducting salts are of great interest to theoretical physicists since the salts are clean systems whose electrical behaviour can be modelled, and provide test beds for exploring new aspects of superconductivity.…”

Thermally-Accessible Lattice Strain and Local Pseudo Jahn-Teller Distortion in Various Dimensional CuII-MIII Bimetallic Cyanide-Bridged Assemblies

“…In particular, multi-functional cyanide-bridged molecule-based magnetic materials [3,4] such as photomagnets [5][6][7][8], chiral magnets [9][10][11][12][13], and magnetic conductors [14] have attracted much attention from potential applications functional devices. Molecular design including electronic functions of cyanide-bridged metal complexes is still challenging task in the field of crystal engineering of organic-inorganic frameworks or coordination polymers.…”