Assembling Nano-Scale Electronics
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THE MAGAZINE DEVOTED TO NICKEL AND ITS APPLICATIONS |
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PURE NICKEL NANOWIRES (200 nanometres in diameter) on a silicon background are distributed randomly in
this scanning electron microscope image. |
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HERE, NICKEL NANOWIRES display a preferred orientation after a magnetic field (with a
magnetic intensity of 200 gauss) was applied as the drop of water containing the wires dried
on the silicon background. |
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Nickel nanowires prove easy to manipulate magnetically
By Virginia Heffernan
Nickel Magazine, July 2005 -- One of the main challenges of working with nano-scale structures is moving them into position so that they can fulfill their purpose. But a team of researchers at the University of Wisconsin-Madison in the U.S. has come up with a novel way to manipulate these structures, using nickel.
The researchers found they could manoeuver nanowires using magnetic fields by electroplating the wires with nickel. The original objective was to study the mechanical properties of nanowires, but the research may one day prove commercially useful in positioning wires in tiny electronic systems.
"We used nickel because it is magnetic; that allows us to use magnetic fields to move and position the nanowires," says Anne Bentley, a member of the team. "We could have used another magnetic metal, but nickel is very easy to electro-deposit."
Other methods of manipulating nanowires use electric fields or micro-fluid channels that orient the wires in the direction of the flowing solvent.
Bentley and her colleagues made the nanowires by electro-depositing a 3-micron-thick layer of nickel into the pores of an alumina membrane, followed by a 7-micron layer of bronze alloy (a mixture of tin and copper) and a final 3-micron coating of nickel. After the alumina was dissolved, the researchers were left with 200-nanometre-diameter bronze wires coated with nickel.
The nickel-copper-tin nanowires were then suspended in ethylene glycol and spun around by applying a rotating magnetic field. Bentley says this technique could be used to manipulate any kind of nanowire material that can be electro-deposited.
Pure nickel nanowires could eventually be used in magnetic data storage devices.
She believes that an increasing number of products that use nano technology (the study of materials having
at least one dimension smaller than 100 nanometre) will be brought to market over the next five to ten
years.
Virginia Heffernan is a
Toronto-based science writer.
PHOTOS: University of Wisconsin-Madison
Other stories about nickel and nano technology that have appeared recently in Nickel Magazine
include: Nano-Crystalline Nickel (July 2004) Nickel in Nanotechnology (June 2000) |
