Superconductivity

Kyshalee Vázquez

In most futuristic movies we see objects or transportation devices that hover over the ground, such as trains, cars and even skateboards. This was thought as one of the impossible creations of science fiction; nonetheless this could be made possible through the superconductivity phenomenon. However these are not the only cases in which superconductivity can improve our daily lives. But first let us discuss what superconductivity is. 

Nobel Prize winner, Heike Kamerlingh Onnes in 1911 was first to observe the phenomenon in which the electrical resistance of numerous metals and ceramic materials dramatically drops to cero, when its temperature reaches its critical points. This phenomenon was named superconductivity, most probably for its lack of resistance to electrical conductivity. This happened when Onnes cooled mercury to the temperature of liquid helium, four degrees Kelvin, and its resistance disappeared unexpectedly.  Later in 1933, Walther Meissner along with Robert Ochsenfeld noticed that materials in their superconductive states will repel magnetic fields and thus repelling the magnet.   This effect was named the Meissner effect. Therefore the loss of all electrical resistance is not the only feature that distinguishes the phenomenon, for the Meissner effect also characterizes superconductivity. The Meissner effect happens when a material does not interact or excludes magnetic fields from its interior, behaving like a perfect diamagnet. Because of this effect, if you were to put a magnet on a material in its superconductive state, the magnet would hover over the material without falling until the material is no longer in its superconductive state. This happens because the magnetic field of the magnet is not able to interact with the inside of the material, expulsing it outward and thus making it hover. As a result from this vehicles of transportation can be optimized in ways we thought impossible or too far away from our technology, just by applying this phenomena. 

The problematic part of this wonderful discovery is that the material’s temperature has to reach its critical point, which is usually very low. This is usually achieved by the use of liquid nitrogen, which is quite accessible, but a slight disturbance of the process; clearly because it would be ideally best to reach super conductivity at room temperature.   Some critical points are extremely low temperatures such as less than 1 K and others can be as high as 125 K. Superconductors have been categorized in type I and type II, mostly depending in the critical point’s temperature of the material. Type I superconductors are pure metals characterized by no electrical resistivity, no internal magnetic fields and can be explained by the BCS theory, named after John Bardeen, Leon Cooper and Robert Schrieffer, which describes the act of electron pairs as bosons. On the other hand, type II superconductors are made from alloys, mechanically harder and depict much higher critical magnetic fields.

Many technological advances and discoveries have been made during the last century, but there is so much more left to uncover. The future of superconductivity lies in the simplification of the application of this phenomenon in our daily lives. To achieve the upmost simplification it would be ideal to find another way to cool the material or a material which can be superconductive without cooling it. If this were to happen, the electrical systems in houses and cities would be even more efficient. Our mediums of transportation could be completely revolutionized, by the decrease of our dependence of petroleum.

Bibliography

"Superconductivity." Hyper physics. Web. 15 November 2011.

"Superconductivity." The teacher’s web. Web. 20 November 2011.

"What is superconductivity?" Howstuffworks. 7 May 2009.Web. 17 November 2011.