Superconductivity

Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect.) Superconductivity is a quantum-mechanical phenomenon that is different from perfect conductivity.

Related Topics:
Material - Temperature - Electrical resistance - Magnetic field - Meissner effect - Perfect conductivity

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In conventional superconductors, superconductivity is caused by a force of attraction between certain conduction electrons arising from the exchange of phonons, which causes the conduction electrons to exhibit a superfluid phase composed of correlated pairs of electrons. There also exists a class of materials, known as unconventional superconductors, that exhibit superconductivity but whose physical properties contradict the theory of conventional superconductors. In particular, the so-called high-temperature superconductors superconduct at temperatures much higher than should be possible according to the conventional theory (though still far below room temperature.) There is currently no complete theory of high-temperature superconductivity.

Related Topics:
Conventional superconductor - Force - Conduction electron - Phonon - Superfluid - Phase - Unconventional superconductor - High-temperature superconductor - Room temperature - High-temperature superconductivity

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Superconductivity occurs in a wide variety of materials, including simple elements like tin and aluminium, various metallic alloys, some heavily-doped semiconductors, and certain ceramic compounds containing planes of copper and oxygen atoms. The latter class of compounds, known as the cuprates, are high-temperature superconductors. Superconductivity does not occur in noble metals like gold and silver, nor in most ferromagnetic metals, though a number of materials displaying both superconductivity and ferromagnetism have been discovered in recent years.

Related Topics:
Tin - Aluminium - Alloy - Semiconductor - Ceramic - Copper - Oxygen - Atom - Cuprate - Noble metals - Gold - Silver - Ferromagnetic

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