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In the same experiment, he also observed the superfluid transition of helium at 2.2 K, without recognizing its significance. The precise date and circumstances of the discovery were only reconstructed a century later, when Onnes's notebook was found. [10] In subsequent decades, superconductivity was observed in several other materials.
The next year, Onnes published more articles about the phenomenon. Initially, Onnes called the phenomenon "supraconductivity" (1913) and, only later, adopted the term "superconductivity." For his research, he was awarded the Nobel Prize in Physics in 1913. Onnes conducted an experiment, in 1912, on the usability of superconductivity.
This effect suggests that superconductivity is related to vibrations of the lattice. This is incorporated into BCS theory, where lattice vibrations yield the binding energy of electrons in a Cooper pair. Little–Parks experiment [15] - One of the first [citation needed] indications to the importance of the Cooper-pairing principle.
Heike Kamerlingh Onnes (Dutch: [ˈɦɛikə ˈkaːmərlɪŋ ˈɔnəs]; 21 September 1853 – 21 February 1926) was a Dutch physicist.After studying in Groningen and Heidelberg, he became professor of experimental physics at the University of Leiden where he taught from 1882 to 1923.
The experiment demonstrated for the first time that superconductors were more than just perfect conductors and provided a uniquely defining property of the superconductor state. The ability for the expulsion effect is determined by the nature of equilibrium formed by the neutralization within the unit cell of a superconductor.
Schematic image of the Little–Parks experiment. The Little–Parks effect consists in a periodic variation of the T c with the magnetic flux, which is the product of the magnetic field (coaxial) and the cross sectional area of the cylinder. T c depends on the kinetic energy of the superconducting electrons.
In superconductors, charge can flow without any resistance.It is possible to make pieces of superconductor with a large built-in persistent current, either by creating the superconducting state (cooling the material) while charge is flowing through it, or by changing the magnetic field around the superconductor after creating the superconducting state. [1]
If a BCS superconductor with a ground state consisting of Cooper pair singlets (and center-of-mass momentum q = 0) is subjected to an applied magnetic field, then the spin structure is not affected until the Zeeman energy is strong enough to flip one spin of the singlet and break the Cooper pair, thus destroying superconductivity (paramagnetic or Pauli pair breaking).