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At the Institute of Molecular Chemistry and Materials of Orsay (CNRS / Université Paris Sud 11) (1), the researchers synthesized magnetic nanoparticles consist of a heart and crown. The growth is controllable crowns at the nanometer scale and can stack multiple crowns whose chemical composition is different. Their magnetic properties then act in synergy. Other properties, including optical and electrical, are accessible through this route of synthesis, which allows of applications of these nano-objects to carry out various tasks in miniaturized devices.

Researchers from the Institute of Molecular Chemistry Orsay working on compounds of the family of Prussian blue. At the heart of these compounds are transition metal (2), responsible for their color (blue intense in the case of Prussian blue), which can also cause other optical, electrical and magnetic. In recent years, researchers are preparing nano-particles of these magnetic compounds, using the fact that, under certain conditions, they spontaneously assembled in an orderly manner to form networks of nanotechnology.

Today, they have managed to stack multiple magnetic networks, forming successive crowns around a heart, each crown was different chemical nature and thus provide a different physical property. They hope so, by combining several physical properties, creating nano-objects capable of performing various tasks in miniaturized devices, such as information storage, signal processing, processing of a signal into another form signal so.

To understand this progress, we must return to the compound structure of the family of Prussian blue: they are transition metal, surrounded by clusters linked to them (the "ligands"), all forming a network of Coordination. From a nano-particle coordination network, chemists have made a second network grow. They proceeded solution (in water), adding drip Constituents additional network and ensuring that never reach the level above which the new Constitution could aggregate them. They made such an object consisting of a heart from 9 nanometers in diameter based nickel and chromium (3) surrounded by a crown made of cobalt and chromium (4) 1.5 nm thick . This object has a bi magnetic necessary condition for magnetic storage of information. Chemists have repeated the operation by adding a third network. In addition, the thickness of each network is fully controllable at the nanometer scale.
With this process, they intend to synthesize nano-objects combining magnetic properties adjustable by the electric field, temperature, light and pressure. They also believe in nano-objects electrochromic (which change color depending on the electric current through them), to manufacture sensors or biological labels. In another sense, they could, causing the breakdown of their nano-objects, metal alloys obtain otherwise inaccessible, to produce catalysts for example, or computer memories very high density.

Notes:

1) In collaboration with the Laboratory of Physics of Solids (CNRS / Université Paris Sud 11) and the Institute of Physics and Chemistry of Materials Strasbourg (CNRS / University of Strasbourg 1)
2) A metal category classification Mendeleyev who have special electronic properties
3) CsNiCr (CN) 6
4) CsCoCr (CN) 6
References:

Core-Multishell Coordination Magnetic Nanoparticles: Toward Multifunctionality on the Nanoscale, Laure Catala, Daniela Brinzei, Yoann Prado, Alexandre Glot, Odile Stephan, Guillaume Rogez, Talal Mallah, Angewandte Chemie, DOI 10.1002/anie.200804238 edition of 22 December 2008.