Electric materials are basically divided into Conductors, Semiconductors and Insulators. They are basically divided as per their ability to resist electric current passing through them. Conductors show very low resistance and the insulators show very high resistance to electricity. But there is also another type of material called Superconductor. Superconductor can be easily described as “Super” ability to “Conduct”.
Superconductor is a perfect diamagnetic as it doesn’t let magnetism penetrate inside it. If we place a superconductor in an external magnetic field, then the current flowing on the surface of the superconductor induce a magnetic field B which cancels the original field trying to get inside that superconductor and repelling the field outside. This phenomenon is known as Meissner effect.
The superconducting material actively excludes magnetic fields from inside during its transition period from normal to a superconductor. The temperature at which the transition occurs or the temperature at which the electrical resistivity of a metal drops to zero is called Critical temperature(Tc).
Here T < Tc
For instance, if Mercury is cooled below 4.1K, it loses all of its electrical resistance.
Another effect that has a major role in superconductivity is London Effect in which magnetic field decays exponentially inside the superconductor within 20-40nm.
How Gold is Good Conductor
Gold is a very good conductor and possess little resistivity but when being applied to high temperature ,its resistance increases. Reason?
Because the application of high temperature increases the vibrations of electrons inside the crystal of Gold, hence making it difficult for the electrons to flow. So, temperature is decreased, less vibration occurs, ultimately making the flow of electrons really easy. Hence resistance changes as per temperature. Temperature is a very important factor here.
Applications of Superconductors
There are great benefits of superconductors as it’s being used to produce faster computers, floating trains (also application of Magnetic Levitation) etc. So it’s only about time we create more and more superconductors for the betterment of the world taking the fact in our minds that it will save a whole lot of time for us.
Author: Som Abhisek.
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