The Superconducting Phenomenon
Superconductors are remarkable materials that conduct electricity without any resistance. They perform far better than everyday conductors like the copper wire inside electrical cables and the tungsten filament inside light bulbs. Many scientists are studying superconductors to learn how they can improve many familiar devices and services.
What can they be used for?
Superconducting materials have an almost unlimited number of potential uses, such as:
o Electric cables: Making electric cables with superconducting wire could drastically reduce the amount of cable needed to power cities and regions. It could also reduce the size of power plant generators, cutting costs for the consumer.
o Medical imaging: Medical imaging techniques like magnetic resonance imaging (MRI) scanners use superconducting magnets to produce sharper, more detailed images of the body.
o Computers and electronics: Superconductors may lead to smaller, faster computer chips and ultra-fast computers. Other electronic devices like cellular phones can be improved by making circuits with superconducting materials.
o Transportation: Superconducting magnets may enable systems of levitating trains that are fast, quiet, and efficient. This technology, known as Maglev, was developed in the 1960s by Brookhaven scientists, and is being tested in Japan, Germany, and China.
How do they work?
To understand superconductors, it is first necessary to understand conventional conductors.
Inside a conductor, many electrons are not attached to any particular atom. Instead, these “free electrons” scatter about as they are repelled by the bound electrons and drawn to the atoms’ positive nuclei. But constantly changing direction prevents the electrons from gaining momentum.Inside a hot conductor, the atoms begin to vibrate, further hindering the free electrons’ motion. For this reason, conductors perform better at colder temperatures.
To conduct electrons with no resistance, superconducting materials must be cooled to extremely low temperatures — approaching the coldest temperature possible, called “absolute zero,” which is equal to about minus 460 degrees Fahrenheit (°F), or zero Kelvin (K). When a super-conducting material is very cold, its atoms barely vibrate and its electrons behave as if they no longer repel each other. As a result, masses of electrons flow without any obstacles. This happens at a different temperature for each superconductor.
Where is superconductor research headed?
Currently, many superconductors must be cooled to nearly zero Kelvin
using complicated cryogenic systems. Scientists are studying materials
that exhibit superconductivity around 100K, or about -280° F, but this
is still a very cold temperature to achieve. Scientists are hoping to
discover materials that perform as superconductors at “room-temperature”
and could be integrated into our everyday lives.