Iron-based superconductor
Iron-based superconductors (FeSC) are iron-containing chemical compounds whose superconducting properties were discovered in 2006. In 2008, led by recently discovered iron pnictide compounds (originally known as oxypnictides), they were in the first stages of experimentation and implementation. (Previously most high-temperature superconductors were cuprates and being based on layers of copper and oxygen sandwiched between other substances (La, Ba, Hg)).
This new type of superconductors is based instead on conducting layers of iron and a pnictide (chemical elements in group 15 of the periodic table, here typically arsenic (As) and phosphorus (P)) and seems to show promise as the next generation of high temperature superconductors.
Much of the interest is because the new compounds are very different from the cuprates and may help lead to a theory of non-BCS-theory superconductivity.
More recently these have been called the ferropnictides. The first ones found belong to the group of oxypnictides. Some of the compounds have been known since 1995, and their semiconductive properties have been known and patented since 2006.
It has also been found that some iron chalcogens superconduct. The undoped β-FeSe is the simplest iron-based superconductor but with the diverse properties. It has a critical temperature (Tc) of 8 K at normal pressure, and 36.7 K under high pressure and by means of intercalation. The combination of both intercalation and pressure results in re-emerging superconductivity at 48 (see and references therein).
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