Super Conductivity

Super Conductivity

A substance is said to be superconducting when it offers no resistance to the flow of electricity. Electrical resistance decreases with decreases in temperature and becomes almost zero near the absolute zero. The phenomenon was first discovered by Kammerlingh Onnes in 1913 when he found that mercury becomes superconducting at 4 K. The temperature at which a substance starts behaving as super conductor is called transition temperature. Most metals have transition temperatures between 2K -5K. Certain organic compounds also becomes superconducting below 5K. Such low temperature can be attained only with liquid helium which is very expensive.

Certain alloys of niobium have been found to be superconducting at temperature as high as 23 K. Since 1987, many complex metal oxides have been found to possess super conductivity at some what higher temperature e.g.

Super conductivity materials have great technical potentials. They can be used in electronics in building magnets, in power transmission and levitation transportation (trains which move in air without rails).

Further Reading

• Classification of Material in Terms of Conductivity
• Interstitial Voids