Superconductivity

A material that has zero bulk electrical resistance.

The phenomena by which, at sufficiently low temperatures, a conductor can conduct charge with zero resistance. The current theory for explaining superconductivity is the BCS theory. Named after J. Bardeen, L.N. Cooper and J.R. Schrieffer.

A theory put forth to explain both superconductivity and superfluidity. It suggests that in the superconducting (or superfluid) state electrons form Cooper pairs, where two electrons act as a single unit. It takes a nonzero amount of energy to break such pairs, and the imperfections in the superconducting solid (which would normally lead to resistance) are incapable of breaking the pairs, so no dissipation occurs and there is no resistance.

Historical Notes

  1. 1911 Dutch physicist Heike Kammerlingh discovered superconductivity.
  2. 1933 Meissner and Ochsenfeld discovered that superconductors expelled applied magnetic fields.
  3. 1950 Ginzburg-Landau theory of superconductivity was devised.
  4. 1954 The first practical application of superconductivity was developed with Dudley Allen Buck′s invention of the cryotron.
  5. 1957 complete microscopic theory of superconductivity was proposed by Bardeen, Cooper and Schrieffer. Independently, the superconductivity phenomenon was explained by Nikolay Bogolyubov.
  6. 1962 first commercial superconducting wire, a niobium-titanium alloy, was developed by researchers at Westinghouse.
  7. 1986 Bednorz and Müller discovered superconductivity in a lanthanum-based cuprate perovskite material.

See also: Josephson Effects, Meissner Effect, Resistance.

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Subjects: Electronics Physics