This is a classic article from 快猫短视频鈥檚 archive, republished as part of our 50th anniversary celebrations
IN THE 1980s, 鈥渉igh-temperature superconductors鈥� promised everything from magnetically levitating trains to resistance-free power lines and cheap MRI scanners. They have failed to deliver largely because they could not carry enough current. Now a material will not only conduct with zero resistance but has overtaken its rivals on the current it can carry.
The material, magnesium diboride (MgB2), sparked a huge research effort after it was shown to superconduct earlier this year. The 鈥渙ff-the-shelf鈥� chemical loses all electrical resistance below 39 kelvin. This is cold when compared with working temperatures of more than 100 kelvin reached by many chemically complex high-temperature superconductors. But it is almost double the temperature of any other simple metallic compounds.
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A key test for the material, however, is how much current it can carry. Three papers in this week鈥檚 Nature answer that question (vol 411, p 558, p 561 and p 563). One team, led by Chang-Beom Eom at the University of Wisconsin at Madison, persuaded MgB2 to carry higher currents when thin films of the material became contaminated with oxygen.
David Caplin and colleagues at Imperial College London blasted the compound with protons. At around 20 kelvin with a strong magnetic field, the material carried a current to compete with the best high-temperature superconductors. 鈥淲hat is needed now is a way, presumably chemical, of junking it up inexpensively,鈥� says Caplin.
A third group, led by Sungho Jin at Lucent Technologies鈥� Bell Labs in New Jersey, has made dense, iron-clad superconducting MgB2 wires. Paul Grant of the Electric Power Research Institute in Palo Alto, California, says these finds 鈥渕ake substantial progress towards improving the properties vital to high electric current and magnetic field applications鈥�.
This article was originally published in 快猫短视频 on 3 June 2001
50 Years of 快猫短视频: The Best Articles 鈥� find many more in our exclusive Special Report. You can also have your say on what you think was the biggest scientific advance of the last 50 years, in our
