Ceramic Superconductor Single Crystal

Superconductivity is a phenomenon characterized by the disappearance of electrical resistance in various metals, alloys, and compounds when they are cooled below a certain level, usually termed the critical temperature (Tc). The phenomenon was first observed in 1911 by Heike Kamerlingh Onnes, who noted that the resistance of a frozen mercury rod abruptly dropped to zero when cooled to the boiling point of helium (4.2 Kelvin). Onnes is also credited with realizing that a material in a superconducting state can be returned to its standard, nonsuperconducting condition through exposure to a strong magnetic field of a certain critical value or by passing a large current through it. For his significant findings, Onnes was awarded the 1913 Nobel Prize for Physics. Yet, another 20 years would pass before any other major discoveries regarding superconductors would be unearthed, scientists believing for many years that other than their intriguing lack of resistance, superconductors acted as other materials. In 1933, however, Walter Meissner and Robert Ochsenfeld discovered that superconducting materials displayed an unusually high level of diamagnetism (the ability to repel magnetic fields completely). Now known as the Meissner effect, this property of superconductors is often demonstrated experimentally by the levitation of a magnet over a superconducting material.

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