A room-temperature superconductor is a material yet to be discovered which would be capable of exhibiting superconducting properties at operating temperatures above 0° C (273.15 K). This is not strictly speaking "room temperature" (approx. 20–25 °C), but it can be reached cheaply.
The discovery of a room temperature superconductor with a useful upper critical field and critical current density could reduce the cost (of refrigeration) of current applications of superconductors and is likely to make many more applications possible or cost-effective.
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Since the discovery of high-temperature superconductors, several materials have been reported to be room-temperature superconductors. In every case, independent investigation has quickly proven these claims false. As a result, most condensed matter physicists now treat any further claims of this nature with extreme skepticism..
In 2008 a Canadian-German team reported the discovery of superconductivity when silane (SiH4) was compressed to a solid at high pressure.[1][2] Silane was unfortunately not a room-temperature superconductor; an EE Times article grossly exaggerated this achievement and claimed that room-temperature superconductivity had been achieved. In reality, the transition temperature was 17 K at 96 and 120 GPa.
Palladium hydride: In 2003 a group of researchers published results on high-temperature superconductivity in palladium hydride (PdHx: x>1)[3] and an explanation in 2004.[4] In 2007 the same group published results suggesting a superconducting transition temperature of 260 K.[5] The superconducting critical temperature increases as the density of hydrogen inside the palladium lattice increases.
An unverified claim of 'room temperature' superconductivity was made in 2000 by J. F. Prins within a phase formed on the surface of oxygen-doped type IIa diamonds in a 10-6 mbar vacuum.[6] As of 2010[update] there is no record of any independent investigation which has either confirmed or disproved these results.
Theoretical work by Neil Ashcroft predicted that solid metallic hydrogen at extremely high pressure (~500 GPa) should become superconducting at approximately room-temperature because of its extremely high speed of sound and expected strong coupling between the conduction electrons and the lattice vibrations.[7] This prediction is yet to be experimentally verified. As yet the pressure to achieve metallic hydrogen is not known but may be of the order of 500 GPa.
Prins could not explain superconductivity on the surface of type IIa diamonds in terms of Cooper pairs, but he was able to do so in terms of a theory that he developed that uses a Wigner-type mechanism.[8][9]