Superconductor classification

Summary

Superconductors can be classified in accordance with several criteria that depend on physical properties, current understanding, and the expense of cooling them or their material.

By their magnetic properties edit

By the understanding we have about them edit

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

By their critical temperature edit

77 K is used as the split to emphasize whether or not superconductivity in the materials can be achieved with liquid nitrogen (whose boiling point is 77K), which is much more feasible than liquid helium (an alternative to achieve the temperatures needed to get low-temperature superconductors).

By material constituents and structure edit

Most superconductors made of pure elements are type I (except niobium, technetium, vanadium, silicon, and the above-mentioned Carbon allotropes)
  • Alloys, such as
    • Niobium-titanium (NbTi), whose superconducting properties were discovered in 1962.
  • Ceramics (often insulators in the normal state), which include
  • Palladates – palladium compounds.[4][5]
  • other
e.g. the "metallic" compounds Hg
3
NbF
6
and Hg
3
TaF
6
are both superconductors below 7 K (−266.15 °C; −447.07 °F).[6]

See also edit

References edit

  1. ^ Li, Danfeng; Lee, Kyuho; Wang, Bai Yang; Osada, Motoki; Crossley, Samuel; Lee, Hye Ryoung; Cui, Yi; Hikita, Yasuyuki; Hwang, Harold Y. (August 2019). "Superconductivity in an infinite-layer nickelate". Nature. 572 (7771): 624–627. doi:10.1038/s41586-019-1496-5. ISSN 1476-4687.
  2. ^ Pan, Grace A.; Ferenc Segedin, Dan; LaBollita, Harrison; Song, Qi; Nica, Emilian M.; Goodge, Berit H.; Pierce, Andrew T.; Doyle, Spencer; Novakov, Steve; Córdova Carrizales, Denisse; N’Diaye, Alpha T.; Shafer, Padraic; Paik, Hanjong; Heron, John T.; Mason, Jarad A. (February 2022). "Superconductivity in a quintuple-layer square-planar nickelate". Nature Materials. 21 (2): 160–164. arXiv:2109.09726. doi:10.1038/s41563-021-01142-9. ISSN 1476-4660.
  3. ^ Jun Nagamatsu, Norimasa Nakagawa, Takahiro Muranaka, Yuji Zenitani and Jun Akimitsu (March 1, 2001). "Superconductivity at 39 K in magnesium diboride". Nature. 410 (6824): 63–64. Bibcode:2001Natur.410...63N. doi:10.1038/35065039. PMID 11242039. S2CID 4388025.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Kitatani, Motoharu; Si, Liang; Worm, Paul; Tomczak, Jan M.; Arita, Ryotaro; Held, Karsten (2023). "Optimizing Superconductivity: From Cuprates via Nickelates to Palladates". Physical Review Letters. Vol. 130, no. 16. doi:10.1103/PhysRevLett.130.166002.
  5. ^ "Palladium-based compounds may be the superconductors of the future, scientists say".
  6. ^ W.R. Datars, K.R. Morgan and R.J. Gillespie (1983). "Superconductivity of Hg3NbF6 and Hg3TaF6". Phys. Rev. B. 28 (9): 5049–5052. Bibcode:1983PhRvB..28.5049D. doi:10.1103/PhysRevB.28.5049.