High-temperature superconductors discovered: study

Washington, Apr 19 (UNI) Researchers in Japan and China have discovered high-temperature superconductors--materials that generate electricity without any resistance at inexplicably high temperatures.

Physicists around the world are hailing the discovery of the new iron-and-arsenic compounds as a major advance, as the only other high-temperature superconductors are the copper-and-oxygen compounds, or cuprates, that were discovered in 1986.

"It's possible that these materials will provide a cleaner system to work with, and suddenly [the physics of] the cuprates will become clearer," says Hai-Hu Wen, a physicist at the Institute of Physics (IoP) at the Chinese Academy of Sciences in Beijing. But Philip Anderson, a theorist at Princeton University and a Nobel Laureate, says that the new superconductors will be more important if they don't work like the old one. "If it's really a new mechanism, God knows where it will go," he says.

The first question on everyone's mind is whether the new high-temperature superconductors work the same way as the old ones.

Anderson says they cannot because the older materials evolve from a state with one electron per copper ion, whereas new materials evolve from a state with two electrons per iron ion.

But Steven Kivelson, a theorist at Stanford University in Palo Alto, California, notes that the old and new materials both have planar structures, start off as bad conductors, and exhibit a type of magnetism known as antiferromagnetism. "That's enough similarities that it's a good working hypothesis that they're parts of the same thing," he says.

All agree that the new materials will generate intense interest and that the next step is to synthesise higher quality samples consisting of a single pristine crystal.

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