The Theory of Superconductivity Cooper Pairs

In the late 1950s, more than 40 years after its discovery, Bardeen, Cooper, and Schrieffer (BCS) provided a theory to explain superconductivity. Their BCS theory postulated that electrons travel through a material in pairs, in spite of their mutual electrostatic 

3 High-Temperature Superconductors YBajCUjOy and Related Compounds 

7-4-3 HIGH-TEMPERATURE SUPERCONDUCTORS (YBa2Cu307 AND RELATED COMPOUNDS) 

FIGURE 7-20 Two Views of Orthorhombic YBa2Cu307. (a) The unit cell. The Y atom in the middle is in a reflection plane. (Adapted from C. P. Poole, Jr., H. A. Farach, and R. J. Creswick, Superconductivity, Academic Press, San Diego, 1995, p. 181, with permission.) (b) Stacking of copper oxide units. (Adapted from C. P. Poole, Jr., T. Datta, and H. A. Farach, Copper Oxide Superconductors, John Wiley Sons, New York, 1988, p. 100. John Wiley Sons, used by permission.) 

The understanding of superconductivity in the high-temperature superconductors is incomplete, but at this point an extension of the BCS theory seems to fit much of the known data. The mechanism of electron pairing and the details of the behavior of the electron pairs are less clear. Other theories have been proposed, but none has gained general acceptance yet. 

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