Superconductivity occurs in certain materials at very low temperatures. When superconductive, a material has an electrical resistance of exactly zero and no interior magnetic field (the Meissner effect). It was discovered by Heike Kamerlingh Onnes in 1911. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It cannot be understood simply as the idealization of "perfect conductivity" in classical physics
{i} quality of nearly perfect conductivity, ability of some materials to conduct electricity with virtually no resistance when chilled to temperatures near absolute zero (Physics)
About one third of all metals loose all electrical resistance at tempertures below a critical temperature Tc Many elemental metals are superconductors Some critical temperatures are: lead Tc = 7 2 K, tin Tc = 3 7 K, niobium Tc = 9 2 K, aluminum Tc = 1 2 K, mercury Tc = 4 2 K, and vanadium Tc = 5 3 K Compounds can have even higher critical temperatures YBa2Cu3O7 has a critical temperature of Tc = 92 K and HgBa2Ca2Cu3O8 has a critical temperature of Tc = 133 K Superconducting wires can carry currents with zero losses up to very high current densities Above a critical current density Jc, superconductivity is supressed A typical critical current density is 106 A/cm2 Superconductivity is also supressed by strong magnetic fields
A phenomenon occurring in many metals and alloys If these substances are cooled below a transition temperature, Tc, close to absolute zero, the electrical resistance becomes vanishingly small (see also Meissner effect and Josephson effect )
The pairing of ELECTRONs in certain materials when cooled below a critical temperature, causing the material to lose all resistance to electricity flow Superconductors can carry electric current without any energy losses
Superconductivity is the ability of certain metals to allow electricity to pass through them without any resistance at very low temperatures. the ability of some substances to allow electricity to flow through them very easily, especially at very low temperatures. Almost total lack of electrical resistance in certain materials when they are cooled to a temperature near absolute zero. Superconducting materials allow low power dissipation, high-speed operation, and high sensitivity. They also have the ability to prevent external magnetic fields from penetrating their interiors and are perfect diamagnets (see diamagnetism). Since it was first discovered in mercury by Heike Kamerlingh Onnes in 1911, similar behaviour has been found in some 25 other chemical elements and in thousands of alloys and compounds. Superconductors have applications in medical imaging, magnetic energy-storage systems, motors, generators, transformers, computer components, and sensitive magnetic-field measuring devices
{i} substance which has almost perfect conductivity, material that conducts electricity with nearly no resistance when chilled to temperatures nearing absolute zero (Physics)
A superconductor is a metal that allows electricity to pass through it without resistance at very low temperatures. a substance that allows electricity to flow through it very easily, especially at very low temperatures