It has been a century since the discovery of Superconductors. The discovery was made by Heike Onnes on April 8th, 1911 at the Leiden Cryogenic Laboratory in Netherlands. The first experiment involved the immersing of a mercury capillary in liquid helium. In this experiment, Heike Onnes noticed the resistance of the mercury dropping to zero as soon as the temperature reaches 3 Kelvinâ€™s or 3 degrees above absolute zero temperature. This was the first phenomenon which clearly showed superconductivity. But, the reason behind the phenomenon could not be explained then. The theory of quantum physics was not yet developed then. Later, researchers developed the basics of quantum physics and explained the reason behind Heike Onnes discovery.
There may still be people who are unaware of what superconductivity actually is. It is explained below.
We all know that in conductors, the resistance decreases as the temperature of the conductor decreases. But, in common conductors like Copper and Silver, the decrease in resistance will be limited to a certain extent even if the temperature is decreased. Even, if the temperature is brought to absolute zero, the copper conductor will show some resistance.Â But, this characteristic is not seen in a superconductor. When the temperature is dropped down below its critical temperature, the resistance tends to jump to zero.
Thus Superconductivity can be defined as the sudden dropping of the electrical resistance to zero as soon as the temperature is lowered below its critical temperature. The phenomenon is characterized by an effect called the Meissner Effect. According to this theory, the principle of superconductivity cannot be understood through the principles of conductivity in classical physics. The theory also led to the discovery of better superconducting materials like â€œBalmyâ€ which has a superconducting temperature of 138 Kelvinâ€™s.
The principle of Superconductivity is so accurate that it has been proved that when a superconducting material placed in a closed loop, carrying an electric current will persist indefinitely even without an external power source.
Since then, researchers have discovered new families of materials that superconduct at higher and higher temperatures: the current record-holder works at a balmy 138 K.
What happened after 100 years?
The applications of such a great discovery still remain limited.
Some high end concepts like MAGLEV Trains, high speed, high efficiency super computers were all promised for future. But they have not been fully materialized.
In the MAGLEV train concept, the trains will levitate over magnetic fields and thus enable faster and highly efficient trains. The super computer technology will run at terra hertz speed without any heat loss.
The existing application of Superconductors includes strong magnets that power magnetic resonance imaging machines and also in advanced experimentation. Some of the most correct measurements in science are done through superconducting quantum interference devices [SQUIDs].
One recent application includes the use of electrical transmission lines using superconductors. These wires are made from high temperature superconducting materials like liquid nitrogenâ€“based cryogenics. This transmission facility is being used by many for high end applications. A South Korean utility plans to install them on a large scale. There are also plans for constructing and designing a national superconducting supergrid instead of using the conventional high-voltage system.