Uses and limitations of Superconductors


  • It is no surprise that all major uses for superconductors rely on two major properties:
  • Yet their limitations are also very straightforward:
    • Low critical temperatures are difficult, expensive and energy intensive to maintain.
    • The materials are usually brittle, not ductile and hard to shape.
    • They are also chemically unstable in some environments.
    • It cannot function with AC electricity, as the switching in AC destroys Cooper pairs.
    • There is a "limit" to the current passing through the material before it loses its superconducting properties.

Power Transmission

  • The lack of resistance means it can transmit electricity without losing power in heat.
  • This allows for large current densities (up to about 5 times more) to be conducted in thin wires with no power loss.
  • This would also reduce the demand for new power stations & reduce the cost of power.
  • However the brittleness of the material in the high temperature superconductors (G2) makes superconducting wires impossible.
  • Also since only DC can be used, the voltages cannot be transformed easily.

Power Generation

  • Using the Meissner effect, a very powerful magnetic field could be generated with the use of superconductors.
  • This means a smaller magnet can be used as a rotor/stator in a motor/generator, meaning less mass has to be moved to generate the same amount of power.
  • This then leads to an increase in efficiency and thus a decrease in the amount of fossil fuels required to make electricity.

Power Storage

  • Currently, electricity cannot be stored for long periods of time.
  • However with superconductors, this becomes possible with the use of Superconducting Magnetic Energy Storage.
  • This is a system that "traps" electricity within it by forcing it to flow inside the SMES until it is necessary to be used.
  • Since it's using superconductors, no energy loss occurs during the storage.
  • Of course this is used with DC instead of AC.
  • This also opens the way to renewable energy sources such as solar power and wind energy as the energy can be stored rather than used immediately.


  • Research is still being done in this field, but there's an almost unlimited scope here.
  • In integrated circuits, further miniaturisation is prevented by generation of heat due to resistance (less area, more resistance)
  • The speed that signals can be transmitted are also limited by current standards due to resistance.
The Josephson Effect
  • It was found that if two superconducting layers are separated by an insulator, it is possible for Cooper pairs to pass the barrier without any resistance.
  • This is because of a quantum tunnelling effect, and its consequences are that:
    • a current will flow through this Josephson function without any Voltage applied
    • when a Voltage IS applied, the current oscillates at a constant frequency
  • This superconducting film has achieved extremely fast switching speeds ($9 \times 10^{-12}s$), which means that superfast computers can be created.
  • It also allows very precise measurements of magnetic flux, allowing for better magnetometers used in geological surveys.

Medical Diagnoses

  • To diagnose patients, doctors sometime perform Magnetic Resonance Imaging (MRI).
  • The process requires extremely strong magnetic fields.
  • To generate such fields without superconductors, massive solenoids and large amounts of energy are needed.
  • With the use of superconductors and the Meissner effect, the device could be smaller and much more efficient.
    • It should be noted that when the desired current level is reached in the SC, it runs in a ''persistent current mode'
    • This means it DOES NOT NEED FURTHER INPUT as electricity becomes trapped inside it, flowing with no energy loss.
  • Also the ability for it to detect magnetic flux precisely allows the electrical signals sent out by nerves to be analysed
  • This is done using a Superconducting Quantum Interference Device (SQUID) which can detect fields as small as $1 \times 10^{-13}$T.


  • Mentioned later, the Meissner effect allows for Magnetic levitation, and the ability to travel at high speeds safely due to a lack of friction.