Superconductors

• A superconductor is a substance that conducts electricity without resistance when it becomes colder than a “critical temperature.” At this temperature, electrons can move freely through the material.
• The critical temperature for superconductors is the temperature at which the electrical resistivity of a metal drops to zero.
• Another property of a superconductor is that it will exclude magnetic fields, a phenomenon called the Meissner effect.

Uses of superconductivity

• Maglev (magnetic levitation) trains. These work because a superconductor repels a magnetic field so a magnet will float above a superconductor – this virtually eliminates the friction between the train and the track.
• Large hadron collider or particle accelerator.
• SQUIDs (Superconducting QUantum Interference Devices) are used to detect even the weakest magnetic field. They are used in mine detection equipment to help in the removal of landmines.
• Superconductors also makes electricity generation more efficient
• Very fast computing.
• Superconducting magnets have become the natural choice for any application where strong magnetic fields are needed – for magnetic resonance imaging (MRI) in hospitals, for example, or for magnetic separation of minerals in industry.

Why in News?

• A group of researchers in the U.S. have created a material composed of carbon, hydrogen and sulphur that is superconducting at 15 degrees Celsius. That is, it shows zero resistance to the flow of electricity through it.
• That’s a new record for superconductivity, a phenomenon usually associated with very cold temperatures. 
• Common superconductors work at atmospheric pressures, but only if they are kept very cold. Even the most sophisticated ones — copper oxide-based ceramic materials — work only below 133 kelvin (−140 °C). 
• Superconductors that work at room temperature could have a big technological impact, for example in electronics that run faster without overheating.
• The only caveat is that it needs ultrahigh pressure of about 2 million atmospheres to achieve this transition, putting off any thoughts of application to the future. 

Reference:

1. https://www.thehindu.com/sci-tech/science/room-temperature-superconductivity-possible-but-under-severe-pressure/article32937247.ece