High-temperature superconductor
The term high-temperature superconductor was initially employed to designate the new family of cuprate-perovskite ceramic materials discovered by J.G. Bednorz and K.A. Mueller in 1986. These materials are characterized by presenting superconductivity at a higher temperature than conventional superconductors (which require temperatures a few degrees above absolute zero), and by other unconventional features. So-called high-temperature superconductors are generally considered to be those that demonstrate superconductivity at or above the temperature of liquid nitrogen, or -196 degrees C.Recently, other unconventional superconductors have been discovered. Some of them also have unusually high values of the critical temperature Tc, and hence they are sometimes also called high-temperature superconductors, although the record is still held by a cuprate perovskite material (Tc=133K, that is -140°C). Nevertheless it is widely believed that if room temperature superconductivity is ever achieved it will be in a different family of materials.
