In a superconductor the resistance goes to to zero when the conductor goes to superconducting phase. The current keeps flowing even when the power source is removed. But the difference between an ideal conductor and a superconductor is that a superconductor shows Meissner effect. Suppose a conductor is placed in a magnetic field, the magnetic line of force pass within the conductor also. When the conductor is made to pass over to superconducting phase, by cooling it below its critical temperature, the magnetic field is expelled from within the conductor.
This is Meissner effect. Electrical Resistivity Normal conductors have some resistance that depends on its length, width, and material.
Superconductors have no electrical resistance below critical temperature. Energy consumption Due to resistance, the conductor consumes energy in the form of heat.
There is no energy loss or consumption in superconductors. Independently, the superconductivity phenomenon was explained by Nikolay Bogolyubov. This BCS theory explained the superconducting current as a superfluid of Cooper pairs, pairs of electrons interacting through the exchange of phonons. For this work, the authors were awarded the Nobel Prize in The BCS theory was set on a firmer footing in , when Bogoliubov showed that the BCS wavefunction, which had originally been derived from a variational argument, could be obtained using a canonical transformation of the electronic Hamiltonian.
In , the first commercial superconducting wire, a niobium-titanium alloy, was developed by researchers at Westinghouse. In the same year, Josephson made the important theoretical prediction that a supercurrent can flow between two pieces of superconductor separated by a thin layer of insulator. It is used in the most accurate available measurements of the magnetic flux quantum , and thus coupled with the quantum Hall resistivity for Planck's constant h.
Josephson was awarded the Nobel Prize for this work in Until , physicists had believed that BCS theory forbade superconductivity at temperatures above about 30 K. It was shortly found by Paul C. Chu of the University of Houston and M. Wu at the University of Alabama in Huntsville [1] that replacing the lanthanum with yttrium , i. This is important commercially because liquid nitrogen can be produced cheaply on-site with no raw materials, and is not prone to some of the problems solid air plugs, et cetera of helium in piping.
Many other cuprate superconductors have since been discovered, and the theory of superconductivity in these materials is one of the major outstanding challenges of theoretical condensed matter physics. Superconducting magnets are some of the most powerful electromagnets known.
They can also be used for magnetic separation, where weakly magnetic particles are extracted from a background of less or non-magnetic particles, as in the pigment industries. Superconductors have also been used to make digital circuits e. Superconductors are used to build Josephson junctions which are the building blocks of SQUIDs superconducting quantum interference devices , the most sensitive magnetometers known.
Series of Josephson devices are used to define the SI volt. Depending on the particular mode of operation, a Josephson junction can be used as photon detector or as mixer. The large resistance change at the transition from the normal- to the superconducting state is used to build thermometers in cryogenic micro-calorimeter photon detectors. Other early markets are arising where the relative efficiency, size and weight advantages of devices based on HTS outweigh the additional costs involved.
Promising future applications include high-performance transformers, power storage devices , electric power transmission, electric motors e. However superconductivity is sensitive to moving magnetic fields so applications that use alternating current e.
Category : Superconductivity. Read what you need to know about our industry portal chemeurope. My watch list my. My watch list My saved searches My saved topics My newsletter Register free of charge. Keep logged in. Cookies deactivated. To use all functions of this page, please activate cookies in your browser. Login Register. Home Encyclopedia Superconductivity Superconductivity. Additional recommended knowledge.
Main article: History of superconductivity. Main article: Technological applications of superconductivity. Tinkham, Michael Introduction to Superconductivity , 2 nd ed.
ISBN Paperback. Tipler, Paul; Llewellyn, Ralph Modern Physics , 4 th ed. ISBN Onnes Leiden 12 : A superconductor is a material that exhibits zero electrical resistance i. The resistance causes loss of energy in the form of heat but since there is no resistance so there is no loss of energy inside a superconductor. The resistance is directly proportional to the temperature. But unlike normal conductors whose resistance decreases slowly, the resistance of superconductors falls to zero below a fixed temperature known as critical temperature.
There is absolutely no resistance. The superconductivity is a quantum phenomenon that occurs in some special conductors only below the critical temperature. The superconductor experiences quantum locking or levitation inside a magnetic field where it locks its position hovering inside a magnetic field known as magnetic levitation. Superconductor Examples :.
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Show More. Related Articles. It doesn't. Superconductors have no virtually no losses, they are purely inductive. This has no bearing on how current flows.
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