Developments to Watch
SUPERCONDUCTORS THAT WON'T GO TO PIECES
Ever since high-temperature superconductors were discovered five years ago, researchers have tried to make the brittle ceramics stronger. But so far, most of the materials they've invented aren't robust enough for commercial use.
Then, on July 22, at an international conference on superconductivity in Japan, researchers from Northwestern University and Argonne National Laboratory announced the discovery of a new family of high-temperature superconductors that are more stable than earlier materials. They think these compounds will be much easier to form into wire or cable that could conduct electricity with no resistance.
The key to these new materials is substituting gallium for other substances in the conducting material. In this new material, layers of gallium and oxygen atoms are sandwiched between layers of copper and oxygen atoms. It's the planes of copper and oxygen atoms that conduct electricity without resistance; in other materials, the copper-oxide planes are broken up by nonconducting elements. The researchers think this new structure is what makes the materials, which become superconducting at minus 328F, less brittle than other superconductors.EDITED BY EMILY T. SMITH