SUPER CONDUCTORS - SCIENCE AND TECHNOLOGY
News:
A clear picture of how mercury becomes a superconductor
What's in the news?
● In
1911, Dutch physicist Heike Kamerlingh
Onnes discovered superconductivity in mercury. He found that at a very low
temperature, called the threshold temperature, solid mercury offers no
resistance to the flow of electric current.
Key takeaways:
● Scientists
later classified mercury as a conventional
superconductor because its superconductivity could be explained by the
concepts of Bardeen-Cooper-Schrieffer (BCS) theory.
Bardeen-Cooper-Schrieffer (BCS) Theory:
● In
BCS superconductors, vibrational energy released by the grid of atoms
encourages electrons to pair up, forming so-called Cooper pairs.
● These
Copper pairs can move like water in a stream, facing no resistance to their
flow, below a threshold temperature.
● The
researchers accounted for the relationship between an electron’s spin and
momentum; they could explain why mercury has such a low threshold temperature
(around –270°C).
● Coulomb repulsion:
○ One electron in each pair
in mercury occupied a higher energy level than the other.
This detail reportedly lowered the Coulomb repulsion (like charges repel)
between them and nurtured superconductivity.
Super Conductors:
● Superconducting
materials show zero electrical
resistance at low temperatures, which allows them to conduct
'supercurrents' without dissipation.
● A
superconductor is a material that achieves superconductivity, which is a state
of matter that has no electrical resistance and does not allow magnetic fields
to penetrate.
● An
electric current in a superconductor can persist indefinitely.
● Superconductivity
can typically be achieved at very cold temperatures.
● Superconductors
can be metals, ceramics, organic materials, or heavily doped semiconductors -
Only criteria is that material should conduct electricity without resistance.
Popular superconductors are Lead and Mercury.
Application:
● Superconducting
electromagnets are also used in maglev
trains, experimental nuclear fusion reactors and high-energy particle
accelerator laboratories.
● Superconductors
are also used to power railguns and
coilguns, cell phone base stations, fast digital circuits and particle
detectors.
● It
is also used in quantum computers.