Controlling superconducting regions within an exotic metal

Researchers at EPFL have created a metallic microdevice in which they can define and tune patterns of superconductivity. Their discovery, which holds great promise for quantum technologies of the future, has just been published ...

Simple materials offer a peek into the quantum realm

As reported in Nature Physics, a Berkeley Lab-led team of physicists and materials scientists was the first to unambiguously observe and document the unique optical phenomena that occur in certain types of synthetic materials ...

Finding the 'magic angle' to create a new superconductor

Researchers at The Ohio State University, in collaboration with scientists around the world, have made a discovery that could provide new insights into how superconductors might move energy more efficiently to power homes, ...

One step closer future to quantum computers

Physicists at Uppsala University in Sweden have identified how to distinguish between true and 'fake' Majorana states in one of the most commonly used experimental setups, by means of supercurrent measurements. This theoretical ...

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Superconductivity

Superconductivity is a phenomenon occurring in certain materials generally at very low temperatures, characterized by exactly zero electrical resistance and the exclusion of the 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.

The electrical resistivity of a metallic conductor decreases gradually as the temperature is lowered. However, in ordinary conductors such as copper and silver, impurities and other defects impose a lower limit. Even near absolute zero a real sample of copper shows a non-zero resistance. The resistance of a superconductor, despite these imperfections, drops abruptly to zero when the material is cooled below its "critical temperature". An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source.

Superconductivity occurs in a wide variety of materials, including simple elements like tin and aluminium, various metallic alloys and some heavily-doped semiconductors. Superconductivity does not occur in noble metals like gold and silver, nor in pure samples of ferromagnetic metals.

In 1986 the discovery of a family of cuprate-perovskite ceramic materials known as high-temperature superconductors, with critical temperatures in excess of 90 kelvin, spurred renewed interest and research in superconductivity for several reasons. As a topic of pure research, these materials represented a new phenomenon not explained by the current theory. In addition, because the superconducting state persists up to more manageable temperatures, past the economically-important boiling point of liquid nitrogen (77 kelvin), more commercial applications are feasible, especially if materials with even higher critical temperatures could be discovered.

See also the history of superconductivity.

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