*NEWS*NANOTECHNOLOGY & INKJET PRINTERS

[Anonymous]

In solution, tiny magnetic wires scatter light

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 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.”

[Author]

March 17, 2005 at 10:55 AM