SAN
DIEGO - Maneuvering external magnets, scientists can
command the direction in which light bounces off tiny,
magnetic wires that sway like matchsticks in thick,
slow-moving solutions.
Announcing her finding here today (March 13) at the
229th meeting of the American Chemical Society, University
of Wisconsin-Madison materials chemist Anne Bentley
described how suspended nickel wires - each 200 times
thinner than a human hair - could one day serve as magneto-optical
switches. The switches could aid in fields such as photonics,
where light, rather than electricity, relays information.
"In a broader sense, it
is also helpful to study how these wires behave in
wet situations because if they are ever medically
used, there is little inside our bodies that's dry,"
says Bentley, who suspended her wires in several types
of fluids and found that the light-directing phenomenon
was most consistent when she used "molasses-like"
liquids such as glycerol.
"Another advantage that
'magnetic fluids' may have over other light-directing
devices, such as mirrors, is that fluids can easily
take various shapes," Bentley adds.
Bentley calls her microscopic
wires "nanowires" after nanotechnology,
the booming, cutting-edge science of small. The "nano"
in nanotechnology derives from the nanometer, which
is equivalent to a billionth of one meter. Several
types of nanoparticles are already in use, in products
such as sunscreens and inkjet printer ink.
But in the fledgling realm
of nanowire research, Bentley is one of only a few
scientists worldwide who is studying the properties
of nickel nanowires. Other nano-scale structures under
investigation include, for instance, non-magnetic
carbon nanotubes.
Nanowires have not yet ventured
outside the research arena, but researchers believe
they will one day become critical components in ever-shrinking
electronic circuits. Nickel nanowires, for instance,
could play a key role in storing information, says
Bentley. In particular, scientists could use external
magnets to dictate the orientation and position of
magnetic nickel nanowires within complex and tiny
electronic systems. Without such control, says Bentley,
working with nano-scale circuit parts could be like
"trying to put Legos together with oven mitts
on."
- Paroma Basu, 608-262 9772, basu1@wisc.edu
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