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  • Substituting ruthenium for iron in iron-based superconductors tunes their properties in a very unusual way. The substitution of one element for another normally changes the crystal’s electronic structure and induces superconductivity by adding charge carriers and/or altering the size of the crystal lattice. High resolution angle-resolved photoemission experiments showed neither mechanism is responsible in the case of barium–iron–ruthenium–arsenide, Ba(Fe1-xRux)2As2. The researchers speculate that ruthenium dilutes the magnetic characteristics of...

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  • Pectins have a previously unsuspected role in holding plant cells together, according to recent research.  Cell walls are made up of three major classes of polysaccharides:  cellulose, hemicellulose and pectins. The molecular interactions of these polysaccharides walls were studied for the first time within intact plant cells using multidimensional solid state NMR, a technique related to magnetic resonance imaging (MRI). Scientists were able to look at the interactions of both rigid and mobile polysaccharides using solid state NMR by studying plants grown in a solution of water...

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  • A new group of bacteria has been discovered in Death Valley’s Badwater Basin that makes nanoparticles of both magnetite (Fe3O4) and greigite (Fe3S4). Magnetotactic bacteria use these tiny magnets as part of their navigation system to align themselves along the Earth’s magnetic field. Typical magnetotactic bacteria do not make both magnetite and greigite and the discovery dispels the notion that greigite-producing bacteria live only in marine environments. The researchers found two different gene clusters related to magnet formation, suggesting...

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  • Significant LED performance improvements have been achieved by taking advantage of novel materials.  An organic light emitting diode (OLED) requires at least one transparent electrode, which is most commonly indium tin oxide (ITO).  While ITO is both transparent and a good electrical conductor, its light transmission differs from the other organic material layers used in the device, leading to internal reflections which reduce efficiency. Researchers replaced...

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  • Making superconducting nanocircuits with rounded internal corners will significantly improve performance.Scientists showed this by calculating how circuit geometry impacts current flow. The key is how geometry affects “current crowding”. Crowding can happen when electrical current travels around a sharp corner or hairpin turn much like cars racing on a tight track. The current (like cars) tends to concentrate near the inner edges of sharp turns. By rounding the corners this bottleneck is eased.This work explains reduced critical currents observed in manufactured devices and has important...

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  • Liquids and glasses are often described as having “disordered” structures, but new methods are showing that there are some significant patterns hidden in the seemingly random arrangements of atoms. When applied to a glassy copper–zirconium alloy, “order mining” has revealed an unexpected similarity between metallic glasses and quasicrystals, among other novel features. Previous methods only examined the local arrangements of closely neighbored atoms of these complex materials, but the new approach focuses on larger motifs, rather than getting bogged down in the details, much in the way...

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  • Iron and copper are both magnetic, but only iron sticks to your refrigerator. That’s because iron is ferromagnetic at room temperature, while copper is paramagnetic. For a material to have two types of magnetism simultaneously at one temperature is uncommon. To have three types simultaneously is exceedingly rare. The alloy NbFe2 is one of those rare materials: at low temperatures it is ferromagnetic, paramagnetic and antiferromagnetic.But why? Researchers have discovered that this odd behavior in a metal is actually caused by a “lucky accident”, rather than a complex...

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  • Researchers working to understand high temperature superconductivity in barium-iron-arsenide have discovered that applying pressure affects the material's magnetic and superconducting behavior just as if they had replaced some iron with a little ruthenium. To better quantify and understand the similarities of changing pressure versus ruthenium concentration, they made Ba(Fe1-xRux)2As2 with varying amounts (x) of ruthenium and studied each concentration as a function of pressure and temperature. The temperature-pressure phase diagrams showed this...

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  • Researchers have used pressure as a tool to study the magnetic behavior of a challenging series of materials, RVSb3, where R is a rare-earth.  This series offers a way to study magnetic ordering in materials with a single, unique rare-earth site and it has been studied primarily as a function of temperature. CeVSb3 is the only compound in the family that orders ferromagnetically, that is with all its unpaired electron spins parallel, at low temperatures. Even after applying pressures up to 8 GigaPascals, about 80 times the pressure at the deepest part of...

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  • Organometallc nanomaterials hold the promise for molecular hydrogen (H2) storage by providing nearly ideal binding strength to H2 for room-temperature applications. However, synthesizing such materials faces severe setbacks due to the problem of metal clustering. Inspired by a recent experimental breakthrough (J. Am. Chem. Soc. 2008, 130, 6992), which demonstrates enhanced H2 binding in Ti-grafted mesoporous silica, we propose combining the graphene oxide (GO) technique with Ti anchoring to overcome the current synthesis...

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