HIGH TEMPERATURE SUPERCONDUCTORS

vIn this post i will talk about high-temperature superconductivity. For those of you who don't know what superconductivity is the superconductivity is phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials that are subjected to temperatures below the critical temperature.  The phenomenon of superconductivity was discovered by Kamerlingh Onnes in 1911, in metallic mercury below 4 K (−269.15 °C). For seventy-five years after that, researchers attempted to observe superconductivity at higher and higher temperatures. In the late 1970s, superconductivity was observed in certain metal oxides at temperatures as high as 13 K (−260.2 °C), which were much higher than those for elemental metals.

High-temperature superconductors are materials that behave as superconductors at usually high temperatures. Until 1986 scientist believed that BCS theory forbade superconductivity at temperatures above 30K. That year the IBM researchers Karl Müller and Johannes Bednorz discovered the first high superconductor. Ordinary superconductors or metallic superconductors usually have transition below 30K or -242.2 C. HTC have been observed with transition temperatures as high as 138 K or -135 C.  Until 2008 only certain compounds of copper and oxygen were believed to have HTS properties, and the term high-temperature superconductor was used interchangeably with capture superconductor for compounds such as bismuth strontium calcium copper oxide or BSCCO and yttrium barium copper oxide or YBCO. However, several iron-based compounds are now known to be superconducting at high temperatures.