7.7 Applications

Expulsion of magnetic field by superconductors in superconducting state is useful in a variety of applications such as magnetically levitated trains, called as Maglevs (shown below), which are operational in a few countries and can achieve very high speeds because of no friction which is present between normal train’s wheels and the tracks. Here, the huge magnetic field that can be sustained by the superconductors is used to levitate and propel the trains.

Another application is magnetic resonance imaging (MRI). In this a strong superconductor-derived magnetic field is applied to the body such that water borne hydrogen atoms and fat molecules in the body are forced to pick the energy from the magnetic field. These species then release this energy at a certain frequency which can be detected and displayed in the form of an image by a computer.

Zero resistance is potentially a fantastic property to have for conductors but since transition temperatures are below RT, the commercial applications are not financially viable. At the same time, wires of only YBCO would be very brittle given that it is a ceramic material. However, a few firms in US are trying to make taped wires where YBCO is grown on top of a nickel tape which provides it the strength without compromising on the T_C and current carrying capacity. However, any commercial products are yet to be witnessed.