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IN SOLUTION, TINY MAGNETIC WIRES SCATTER LIGHT
13 March 2005 - University of Wisconsin-Madison
| Manoeuvring 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 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
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About: University of Wisconsin-Madison
In achievement and prestige, the University of Wisconsin-Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW-Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Many of its programs are hailed as world leaders in instruction, research and public service.The university traces its roots to a clause in the Wisconsin Constitution, which decreed that the state should have a prominent public university. In 1848, Nelson Dewey, Wisconsin’s first governor, signed the act that formally created the university, and its first class, with 17 students, met in a Madison school building on February 5, 1849. From those humble beginnings, the university has grown into a large, diverse community, with about 40,000 students enrolled each year. These students represent every state in the nation, as well as countries from around the globe, making for a truly international population. UW-Madison is the oldest and largest campus in the University of Wisconsin System, a statewide network of 13 comprehensive universities, 13 freshman-sophomore transfer colleges and an extension service. One of two doctorate-granting universities in the system, UW-Madison’s specific mission is to provide "a learning environment in which faculty, staff and students can discover, examine critically, preserve and transmit the knowledge, wisdom and values that will help insure the survival of this and future generations and improve the quality of life for all." The university achieves these ends through innovative programs of research, teaching and public service. Throughout its history, UW-Madison has sought to bring the power of learning into the daily lives of its students through innovations such as residential learning communities and service-learning opportunities. Students also participate freely in research, which has led to life-improving inventions from more fuel-efficient engines to cutting-edge genetic therapies. Students, faculty and staff are motivated by a tradition known as the "Wisconsin Idea," described by UW President Charles Van Hise in 1904 as the compelling need to carry "the beneficent influence of the university ... to every home in the state." The Wisconsin Idea permeates the university’s work and helps forge close working relationships among university faculty and students and the state’s industries and government. |
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