superconductivity
superconductivity, abnormally high electrical conductivity of certain substances. The phenomenon was discovered in 1911 by Heike Kamerlingh Onnes, who found that the resistance of mercury dropped suddenly to zero at a temperature of about 4.2°K; he received (1913) the Nobel Prize for the discovery. For the next 75 years there followed a rather steady string of announcements of new materials that become superconducting near absolute zero. A major breakthrough occurred in 1986 when Karl Alexander Müller and J. Georg Bednorz announced that they had discovered a new class of copper-oxide materials that become superconducting at temperatures exceeding 70°K. The work of Müller and Bednorz, which earned them the Nobel Prize in Physics in 1987, precipitated a host of discoveries of other high-temperature cuprate superconductors that exhibit lossless electrical flow at temperatures up to nearly 140°K. In 2008 Hideo Hosono and a Japanese team announced the discovery of a iron-arsenic high-temperature superconductor, and since then other such iron-based superconductors have been identified.
The Columbia Encyclopedia, © Columbia University Press 2013
