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Engineering a Light Touch

Researchers have found a way to enhance the force of light on matter. Most of the time the momentum of light and the associated forces are too small to notice, but at the nanoscale the effect can be quite large, and researchers have used these forces to dynamically manipulate optical waveguides at the nanoscale. Optical forces decay significantly, however, as the distance between the waveguides increases and become too small for all-optical device actuation at larger separations.

The Golden Key

Gold atoms can be the key to making new materials with fascinating and frequently beautiful arrangements of atoms. For example, materials made from gold, sodium and gallium contain gold atoms arranged into tetrahedra, rods of hexagonal stars, or diamond-like three-dimensional frameworks.  For certain gold concentrations, gold interacts in a novel way with sodium and stabilizes the formation of icosahedra.

Magnetic Memory Moves into the Ultra-Fast Lane

Researchers have found a trick that could make writing data to a hard disk as much as a thousand times faster. Recording information in today’s magnetic memory and magneto-optical drives uses an external magnetic field and/or a laser that heats up tiny spots, one at a time, to the point where the magnetic field can switch the magnetic ordering, to store single binary digits. The speed of the magnetic switching is limited by how long it takes the laser to heat the spot close to its Curie point and the external field to reverse the magnetic region.

Cutting Biofuel Production Costs

Working to use sunlight to convert biomass to biofuels, researchers have found a pathway toward reducing the energy costs associated with making renewable biofuels. To achieve this, they designed semiconducting nanorods that act as light harvesting antennas, and attached metal nanoparticles that are activated by energy from the sun.

Tinkering with Zinc

Scientists have made air-stable compounds that should not be stable in air. Custom-designed carbon chains bonded to zinc control the rate and selectivity of reactions with oxygen and lead to the formation of novel stable zinc peroxides.

Shaken Not Stirred — A Superconducting Material also Shows Promise for Hydrogen Storage

A new recipe for storing hydrogen involves taking magnesium diboride, putting it in a container, adding some hydrogen and ball bearings, and shaking vigorously. Unlike other methods, heating the mixture is not required. Creating a room-temperature-stable, solid-stored hydrogen fuel has been described as one of the grand challenges of science. MgB2 (previously known primarily for its high-temperature superconductivity) has a hexagonal structure of boron sheets separated by layers of Mg.

Transporting Atoms a Billion at a Time

The self-organization of lead on silicon stands out for its remarkable efficiency and surprising new results suggest why. Most atoms sitting on surfaces like to go about their business by themselves. Alone they walk in random directions. Rarely do they move together, so when a billion atoms collectively decide to move 0.05 mm within 1 second below room temperature, it is exceptional. Researchers have found evidence of this 'superdiffusion' for lead on silicon using a technique known as low energy electron microscopy.

Altering Current Flow in Iron-based Superconductors

How current flows through iron-based superconductors is very sensitive to composition.  Iron-based superconductors provide a unique window into the role magnetism plays in superconductivity, because their magnetism and superconductivity coexist, whereas in conventional superconductors they do not.  Researchers studied current flow by measuring the resistivity along various directions of barium–potassium–iron–arsenide superconductors with differing amounts of potassium.

New Material with each Element Doing its own Thing

A new material made from three elements — yttrium, manganese and gold — woven together in an unusual crystalline lattice shows surprisingly diverse characteristics for each element. The manganese electrons are localized at the manganese sites, whereas the yttrium and gold electrons are delocalized. Yttrium in this rhombohedral lattice tends to give up electrons and thus be positively charged whereas the gold prefers to take on electrons. The magnetic characteristics are also unusual with electron spins strongly aligned only at the manganese sites.


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