A nanoscale molecular switch can be used to store information in a single molecule. Although the switching process can be detected electrically in the form of a change in the molecule′s conductance, adding spin functionality to molecular switches is a key concept for realizing molecular spintronic devices. Here we show that iron-based spin-crossover molecules can be individually and reproducibly switched between a combined high-spin, high-conduction state and a low-spin, low-conduction state, provided the individual molecule is decoupled from a metallic substrate by a thin insulating layer. These results represent a step to achieving combined spin and conduction switching functionality on the level of individual molecules.

Magnetite particles with an average size of 39 nm and good monodispersity have been synthesized by coprecipitation at 70 °C from ferrous Fe2+ and ferric Fe3+ ions by a (N(CH3)4OH) solution, followed by hydrothermal treatment at 250 °C. The magnetite nanoparticles before the hydrothermal step display an average size of 12 nm and are highly oxidized when they are in contact with air. Complementary microstructural and magnetic characterizations of nanoparticles after hydrothermal treatment show unambiguously that they consist of magnetite with only a slight deviation from stoichiometry (δ ≈ 0.05), leading to Fe2.95O4.

Today, seeking new materials for tailor-made applications and new devices leads to explore the potential offered by various kinds of functional building blocks. Hence, it concerns not only solid-state chemists, physicists or materials engineers, but also the area of (supra)molecular chemistry, and biochemistry as well. This is especially clear in the field of hybrid multifunctional materials. Indeed, their design requires investigating new concepts derived from principles developed in these different disciplines. The aim of this critical review is to present the last achievements concerning transition metal hydroxide hybrids, their synthesis, flexibility and functional properties. They often provide nice model systems for understanding the correlation between structure and physical properties brought by the molecular moieties grafted onto the metal hydroxide basis layers. The contribution of the atomic scale modelling to the electronic structure calculations and structural optimization is also reported (216 references).

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We report on the growth by evaporation under high vacuum of high-quality thin films of Fe(phen)2(NCS)2 (phen=1,10-phenanthroline) that maintain the expected electronic structure down to a thickness of 10 nm and that exhibit a temperature-driven spin transition. We have investigated the current-voltage characteristics of a device based on such films. From the space charge-limited current regime, we deduce a mobility of 6.5x10-6 cm2/V?s that is similar to the low-range mobility measured on the widely studied tris(8-hydroxyquinoline)aluminium organic semiconductor. This work paves the way for multifunctional molecular devices based on spin-crossover complexes

hydrogen bonds · magnetic properties · metalorganic frameworks · multiferroic compounds · solid-state structuresThe realization of ever smaller tunable devices is a major challenge in nanoelectronics; as a result, considerable efforts have been devoted to multifunctional materials in the last few years. Multiferroic compounds in which magnetic and electric properties coexist have received much attention. The observation of combined weak ferromagnetism and antiferroelectric order in a metal-organic framework (MOF) from Jain et al. illustrates a new route towards multiferroic systems that significantly differs from usually reported studies. [1] Multiferroic materials present at least two coexisting orders among the electric, magnetic and/or elastic ones. The most appealing combination to date involves electric and magnetic orders, as it opens great perspectives in terms of applications, especially in the field of spintronics.[2] A clear distinction has to be made between systems exhibiting independent electric and magnetic orders and those featuring a magneto-electric coupling, both of which are promising in terms of applications. The former allows, for example, the conception of a four-state memory, [3] but the greatest promise is likely to be held by magneto-electric compounds, for they give access to a new type of control of magnetization by an electric field in spintronics devices. [4] The heart of the problem currently is to find examples of multiferroic/magnetoelectric materials. One option is, of course, to combine the properties of two separate materials, one being ferromagnetic, the other ferroelectric, in a nanostructured composite material.[5] The coupling between both, which allows their mutual control, is usually carried out indirectly through strain by magneto-and electro-striction, which results in slow switching and fatigue phenomena. Intrinsic multiferroics are thus highly desirable, although, as mentioned by Jain et al., electric and magnetic orders tend to be mutually exclusive. Indeed, the presence of d electrons of transition metal ions, which are required to stabilize ferromagnetism, inhibits hybridization with the p orbitals of the surrounding oxygen anions, and thus displacement of the cations necessary for the establishment of a ferroelectric order. [6] Intrinsic multiferroic materials, which are scarce, are generally classified according to the mechanism responsible for ferroelectricity: in proper ferroelectrics, spontaneous polarization appears as being itself the order parameter, whereas in improper ferroelectrics, it only appears as a by product in a phase transition governed by another order parameter. [7] For the former, the magnetic and electric orders are usually due to distinct cations, and the magnetoelectric coupling is generally weak. The prototypical compound is BiFeO 3 (BFO), in which 3d electrons of the iron(III) cations are responsible for magnetization, whereas ferroelectricity originates from a structural instability caused by the hybridization between the oxygen 2p and th...

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