Roller coaster superconductivity discovered
Superconductors are more than 150 times more efficient at carrying electricity than copper wires. However, to attain the superconducting state, these materials have to be cooled below an extremely low, so-called transition temperature, at which point normal electrical resistance disappears. Developing superconductors with higher transition temperatures is one of physics' greatest quests. Now, researchers at the Carnegie Institution's Geophysical Laboratory, with colleagues, have unexpectedly found that the transition temperature can be induced under two different intense pressures in a three-layered bismuth oxide crystal referred to as 'Bi2223.' The higher pressure produces the higher transition temperature. They believe this unusual two-step phenomena comes from competition of electronic behaviour in different kinds of copper-oxygen layers in the crystal. The work is published in the August 19, 2010, issue of Nature...