Room Temperature Super Conductors: An Innovation For Future Innovations

By Sujith Mohandas(LMB)

Arthur C. Clarke (a famous British science fiction writer) famously said that any sufficiently advanced technology is indistinguishable from magic. Advanced technology like levitating trains or bullet trains or a simple mobile phones with which almost anything cab be done never fails to amaze us. Any machine or technology which does something which people are not accustomed to or have never experienced in life, just makes people wonder how less we know about the universe. One such pending innovation in technology is Room Temperature Super Conductors.

Now before we start with Room temperature super conductors, we need to know about superconductors or superconductivity. Now generally we consider copper to be a good conductor of electricity. This means the loss of energy during the transmission of electricity through copper is less as compared to most of the materials available in nature. How about if we invent a material which offers zero resistance to the flow of current. This would mean we could transmit electricity without any losses. This is the concept of superconductivity and material which exhibit this phenomenon are called superconductors. Superconducting materials can transport electrons with no resistance, and hence release no heat, sound, or other energy forms.

Diagram explaining the Meissner effect(the expulsion of magnetic flux when a material becomes superconducting in a magnetic field)

Superconductivity was discovered on April 8, 1911 by Heike Kamerlingh Onnes, who was studying the resistance of solid mercury at cryogenic temperatures using the recently produced liquid helium as a refrigerant. At the temperature of 4.2 Kelvin (K), he observed that the resistance abruptly disappeared. The precise date and circumstances of the discovery were only reconstructed a century later, when Onnes’s notebook was found. In subsequent decades, superconductivity was observed in several other materials. In 1913, lead was found to superconduct at 7 K, and in 1941 niobium nitride was found to superconduct at 16 K.

Superconductors are among the most bizarre and exciting materials yet discovered. Its property of zero electrical resistance is more than enough to spark the imagination.  A current that could flow forever without losing any energy means transmission of power with virtually no losses in the cables. When renewable energy sources start to dominate the grid and high-voltage transmission across continents becomes important to overcome intermittency, lossless cables will result in substantial savings. What’s more, a superconducting wire carrying a current that never, ever diminishes would act as a perfect store of electrical energy. Unlike batteries, which degrade over time, if the resistance is truly zero, you could return to the superconductor in a billion years and find that same old current flowing through it. Energy could be captured and stored indefinitely!

Graph explaining zero electrical resistance below the critical temperature (Tc ) for superconductors and its comparison with normal metal

With no resistance, a huge current could be passed through the superconducting wire and, in turn, produce magnetic fields of incredible power. You could use them to levitate trains and produce astonishing accelerations, thereby revolutionizing the transport system. You could use them in power plants—replacing conventional methods which spin turbines in magnetic fields to generate electricity—and in quantum computers as the two-level system required for a “qubit,” in which the zeros and ones are replaced by current flowing clockwise or counter clockwise in a superconductor.

Superconductors can certainly seem like magical devices. So, why aren’t they busy remaking the world? There’s a problem—that critical temperature (the temperature below which they exhibit superconductivity). For all known materials, it’s hundreds of degrees below freezing.

Table representing the  critical temperature (Tc ) for various material below which they act as superconductors

Superconductors also have a critical magnetic field; beyond a certain magnetic field strength, they cease to work. There’s a trade-off: materials with an intrinsically high critical temperature can also often provide the largest magnetic fields when cooled well below that temperature. This has meant that superconductor applications so far have been limited to situations where you can afford to cool the components of your system to close to absolute zero: in particle accelerators and experimental nuclear fusion reactors, for example.

However a paper posted by Anshu Pandey and his doctoral student Dev Kumar Thapa, from the Solid State and Structural Chemistry Department of the Indian Institute of Science (IISc), Bengaluru titled ‘Evidence for Superconductivity at Ambient Temperature and Pressure in Nanostructures’ could mean a step towards room temperature superconductors. In essence, the authors made the extraordinary claim that they had discovered superconducting behaviour at room temperature and pressure in a nanostructured composite material of silver and gold – formed by embedding silver nanoparticles in a gold matrix. Nanostructured materials are those whose microstructures have a characteristic length of a few nanometres, typically 1-10 nm. One nm is a billionth of a metre. Their finding, if independently validated, would be ground-breaking. This would be the greatest discovery after Raman Effect discovered by the great Indian physicist CV Raman.

Whether the paper submitted gets validated to true or not, seem to be a question of the future. However if found true it could surely represent India on a global scale and would help India to be as future research hub in the world. Imagine an innovation which would propel millions of other innovation. Surely this would make the thin line disappear between magic and technology.

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