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Josephson Effect

Josephson EffectJosephson effect was theoretically predicted in 1962 by Josephson. It was confirmed in practice in 1963 by American physicists Philip Anderson and John Rowell. Josephson effect is a phenomenon when the electric current flows between two regions of a superconductor which are divided by a thin region of an insulator.Structurally Josephson element is represented by two intersecting tin conductors. At the intersection region they are divided by a tin oxide film which is 10 angstrom thick. At the same time such element is a highly sensitive magnetic field sensor as under the influence of magnetic fields the junction current increases sharply. You can see that on the diagram.Josephson effect has a second interesting property. When DC is applied to conductors then electromagnetic waves are emitted at the point where the tunnelling effect occurred. This radiation is explained by the absence of thermal losses in a superconductor. Thus the only way to get rid of the excess energy is to radiate a light quantum. Such radiation was initially discovered in 1965 by a group of Soviet scientists at Kharkov Physics and Technology Institute.The third interesting property of Josephson effect is that it can be used as an electromagnetic oscillation sensor. A current-voltage characteristic at Josephson junction changes under the influence of the oscillations. All this makes Josephson effect one of the most important aspects of modern cryogenic radio electronics.