Superconductor classification

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Superconductors can be classified in accordance with several criteria that depend on our interest in their physical properties, on the understanding we have about them, on how expensive is cooling them or on the material they are made of.

By their magnetic properties[edit]

By the understanding we have about them[edit]

This criterion is important, as the BCS theory is explaining the properties of conventional superconductors since 1957, but on the other hand there have been no satisfactory theory to explain fully unconventional superconductors. In most of cases type I superconductors are conventional, but there are several exceptions as niobium, which is both conventional and type II.

By their critical temperature[edit]

Some now use 77 K as the split to emphasize whether or not we can cool the sample with liquid nitrogen (whose boiling point is 77K), which is much more feasible than liquid helium (the alternative to achieve the temperatures needed to get low-temperature superconductors).

By material[edit]

Most superconductors made of pure elements are type I (except niobium, technetium, vanadium, silicon, and the abovementioned Carbon allotropes)
eg the "metallic" compounds Hg
3
NbF
6
and Hg
3
TaF
6
are both superconductors below 7 K (−266.15 °C; −447.07 °F).[2]

See also[edit]

References[edit]

  1. ^ Jun Nagamatsu, Norimasa Nakagawa, Takahiro Muranaka, Yuji Zenitani and Jun Akimitsu (1 Mar 2001). "Superconductivity at 39 K in magnesium diboride". Nature (letter). 410 (6824): 63–64. Bibcode:2001Natur.410...63N. PMID 11242039. doi:10.1038/35065039. 
  2. ^ W.R. Datars, K.R. Morgan and R.J. Gillespie (1983). "Superconductivity of Hg3NbF6 and Hg3TaF6". Phys. Rev. B 28, 5049-5052. doi:10.1103/PhysRevB.28.5049.