Electric current certain materials when cooled below a characteristic critical temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of "perfect conductivity" in classical physics. In a semiconductor it is sometimes useful to think of the current as due to the flow
Nikolai Kasterin Nikolai Kasterin Nikolai Petrovich Kasterin (1869–1947) was a Russian physicist, student of Aleksandr Stoletov. His 1903 doctoral dissertation, portions of which were published in German in the Proceedings of the Royal Academy of Sciences in Amsterdam under the sponsorship of Heike Kamerlingh Onnes, is considered to be a pivotal contribution to multiple scattering theory (MST) by such experts as Paul Peter Ewald and Jan Korringa. The MST formalism is widely used for electronic structure calculations as well as diffraction theory, and is the subject of many books. Kasterin studied at the Physical-Mathematical Faculty of Moscow University under the supervision of