Superconductors

Subject: Science and Technology

Section: Nanotechnology

Context: The Indian Institute of Science (IISc) has achieved a breakthrough what they call ‘Au-Ag Nanostructures’.

Content:

Superconducting materials work only in ultra-cold conditions. So, an engineered material called ‘Au-Ag Nanostructures’ is being developed.
Silver particles, a billionth of a metre in size, are embedded into lattice structures of gold atoms.
It shows “superconductivity-like signatures” because it offers zero resistance to the flow of electrons.
But to qualify fully as a ‘superconductor’ it would need to have a few other properties like ‘stability’. Presently, the material is “extremely unstable”, meaning it does not remain unchanged for long and it is expected that the problem can be tackled in some months.

Superconductor

Superconductors are materials that conduct electricity with no resistance. Unlike the more familiar conductors such as copper or steel, a superconductor can carry a current indefinitely without losing any energy. They also have several other very important properties, such as the fact that no magnetic field can exist within a superconductor.
Another property of a superconductor is that it will exclude magnetic fields, a phenomenon called the Meissner effect.

Advantage of superconductors:

Currently, superconductivity can only be achieved at temperatures far below zero, in processes that are too expensive for wider application.
The devices have low power dissipation, high operating speed, and extreme sensitivity.
Devices built with room temperature superconductors tend to be extremely efficient and entail large savings in both energy and costs.

Application:

Superconductors already have drastically changed the world of medicine with the advent of MRI machines, which have meant a reduction in exploratory surgery.
Power utilities, electronics companies, the military, transportation, and theoretical physics have all benefited strongly from the discovery of these materials.

Meissner effect

When a material makes the transition from the normal to the superconducting state, it actively excludes magnetic fields from its interior; this is called the Meissner effect.

Critical temperature

The critical temperature for superconductors is the temperature at which the electrical resistivity of metal drops to