Superconductors and Bcs Theory


BCS Theory of Superconductivity

Superconductivity is when certain metals (e.g. Mercury), alloys (e.g. (Tl5Pb2)Ba2MgCu10O17+) and ceramics (e.g. yttrium barium copper oxide ceramic) conduct electricity without resistance. Superconductivity is possible in known metals and alloys at temperatures near absolute zero where as some ceramics are able to become super conductors at temperatures as high as -148 degrees Celsius. The phenomenon of superconductivity can be explained using the BCS theory.

Developed in 1957 by American physicists, john Bardeen, Leon cooper and J. Robert Schrieffer, explains that the resistance of metal is due to collisions between free electrons and impurity atoms or imperfections in the crystal lattice. Superconductors however allow electrons to go through unimpeded. This is because of an attractive interaction between it’s electrons that allow them to form cooper pairs.
These cooper pairs are held together and flow without resistance the lattice.

Uses for Superconductors

Superconductors have a variety of uses. Some examples of these are;
    • Maglev (magnetic levitation) train: These work because the track is a superconductor with a current moving through it which produces a magnetic field that repels the magnetic field produced by an electromagnet in the train, allowing it to hover above the track. The benefits of Maglev trains in comparison to other forms of transport include:
        1. It is cheaper, faster, not congested, and has a much longer service life. They can transport tens of thousands of passengers per day along with thousands of piggyback trucks and automobiles. because there is no mechanical contact and wear, and because the weight is uniformly distributed, rather than concentrated at the wheels there is less wear and tear in need of repair. They can move at speeds around 300 mph.
        2. Better for the environment. Instead of burning fossil fuels Maglev consumes energy which can be...