Properties of Super Conductors

Zero resistance and therefore infinite conductivity

Since the resistance of the superconductors is zero that means that the energy loss incurred by the movement of charges from one place to another is zero hence it gives rise to infinite conductivity

Expulsion of Magnetic field

The superconductors expel the magnetic fields and doesn’t allow magnetic fields to penetrate inside it. This is also called the Meissner effect.

Transition Temperature/Critical Temperature

The temperature at which a material changes its behavior from normal state to a superconducting state is called the transition temperature or the critical temperature, note that this transition is fast and sudden.

Critical Magnetic Field

The magnetic field where material moves away from super conducting to behaving as a normal conductor is known as the critical Magnetic Field. This is because when the magnetic field increase above a certain value the transition said above may take place, this may be either produced by the current flowing or externally produced.

Persistent Current

A ring made of superconductor material is placed in a magnetic field above its critical temperature.

Let’s say that the ring is now cooled below its critical temperature, now the material is in its super conducting mode.

Now if the magnetic field is removed now a current is induced in the ring due to the induced self-inductance.

Since the material now is super conducting the current induced will continue to flow through. This current is called the Persistent Current.

The magnetic flux produced through this current is constant through the ring.

Josephson Current

When two superconductors are separated by a thin insulating filament, there forms a low resistant junction, it is found that the cooper pairs explained above can tunnel from one side to another, the current induced due to the flow of these cooper pares is called the Josephson current.

Critical Current

When current is passed through a conductor under super conducting state a magnetic field is induced. If the current is increased till a state where the magnetic field increases so that the material loses its super conducting state, this current is known as the critical current.