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5 December 2013 11:26 am ,
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At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Superconductor Sets Record for Metal Compounds
16 February 2001 7:00 pm
A new discovery has the superconductivity community abuzz: A boron-containing metal compound that superconducts at 39 K, nearly twice the temperature of the previous metallic record holder. Although some ceramics can superconduct at temperatures up to 96 degrees higher, most metallic compounds make better wires for magnetic resonance imaging (MRI) machines and other applications.
Researchers have spent decades looking at boron-containing compounds for hints of superconductivity, because theory suggests they should have a relatively high superconducting temperature. Some do. But magnesium diboride (MgB2) beats them hands down, as physicist Jun Akimitsu of Aoyama Gakuin University in Tokyo reported at the Symposium on Transition Metal Oxides, held in Sendai, Japan, on 10 January. The result has already been replicated by other teams, and now physicists are racing to make sense of MgB2's abnormally high superconducting temperature.
Materials superconduct when electrons inside overcome their usual repulsion and pair up; that allows them to surf through a material's crystalline lattice without banging into atoms that would slow their progress. But in most metallic superconductors these pairs break apart when the temperature rises much above 20 K. So figuring out what is keeping electron pairs together at nearly 40 K in MgB2 has become the latest contest in the most competitive area of materials physics. "I can't sleep," says Jorge Hirsch, a superconductivity theorist at the University of California, San Diego. "It's extremely exciting." Hirsch's insomnia may be short lived. A series of papers posted to the Los Alamos physics preprint server this month report that MgB2's behavior strongly resembles that of its closest metallic cousins.
No matter what the mechanism, MgB2 could generate an even greater buzz in the real world. Despite the hype that accompanied the earlier high-temperature superconductors, low-temperature metallic superconductors continue to dominate the applications arena, because these materials can be fashioned into wires that carry large currents. Yesterday, a team led by Iowa State University physicist Paul Canfield reported on the Los Alamos site that they've already made superconducting MgB2 wires. Because magnesium and boron are cheap compared to other metallic superconductors, MgB2 could be in store for a powerful future.
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