Superconductivity

What it is ?Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature.

 It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 8,1911 in  Leiden.

How does Superconductivity work?In practical terms, a computer processor or electric train track equipped with a superconductor would use very little electricity to perform its functions.

Lead

Niobium

Titanium

Types of SuperconductorsA superconductor with little or no magnetic field within it is

said to be in the Meissner state. The Meissner state breaks down when the applied magnetic field is too large. Superconductors can be divided into two classes according to how this breakdown occurs.

Type IThere are thirty pure metals which exhibit

zero resistivity at low temperatures and have the property of excluding magnetic fields from the interior of the superconductor. They are called Type I superconductors.

Eg.:- Tantarium(Ta), Lead(Pb), Lanthanium(La)

Type IISuperconductors made from alloys are called

Type II superconductors. Besides being mechanically harder than Type I superconductors, they exhibit much higher critical magnetic fields. Type II superconductors such as niobium-titanium (NbTi) are used in the construction of high field superconducting magnets.

.Eg.:- NbTi(Niobium-titanium), PbMoS(Lead-

molybdenum)

The trick for creating a practical superconductor lies in finding a material which becomes superconductive at room temperature.

So far, researchers have not discovered any metal or composite material which loses all of its electrical resistance at high temperatures.

Superconductivity in Applications

1. Superconducting MagnetA superconducting magnet is

an electromagnet made from coils of superconducting wire. They must be cooled to cryogenic temperatures during operation.

Superconducting

Magnet

YAMANASHI MAGLEV TRAIN

2.Superconducting Radio Frequency

Superconducting radio frequency (SRF) science and technology involves the application of electrical superconductors to radio frequency devices. The ultra-low electrical resistivity of a superconducting material allows an RF resonator to obtain an extremely high quality factor, Q.

NMR SPECTROMETERS

Advantages Of Superconductivity

The resistance of Superconductivity is so low, there is no current wastage when they are used to conduct electricity.

When used in the process of Magnetic Levitation, no Kinetic energy is wasted due to friction from contact with the ground.

The power and cost efficiency happens due to the negligible energy losses that occur in Superconductors.

It helps reduce the size and weight of motors, generators and supporting equipment.

Conclusion• Superconductivity is a quantum mechanical

phenomenon.• In these materials, the characteristics of

superconductivity appear when the temperature T is lowered below a critical temperature Tc.

• The value of this critical temperature varies from material to material

• These magnets are some of the most powerful electromagnets known.