The Quest For A Room Temperature Superconductor

Relevance: GS3 - Science and Technology- developments and their applications and effects in everyday life. Prelims

(Source: The Hindu, 08/07/2023)

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Why in the news?

• Recently, scientists from South Korea have discovered a material that acted as a superconductor at room temperature and ambient pressure.
• Earlier superconductors were believed to exist only at more than -240° Celsius, which is well below the liquefaction temperature of nitrogen, -195° Celsius.
• The discovery could be beneficial for the medical and industrial sectors as superconductors can transport heavy currents without any loss.

What have the researchers discovered?

• They have discovered that a copper-doped lead apatite, a type of phosphate mineral, displays superconducting properties at room temperature and pressure.
  • Apatites are minerals with a phosphate scaffold with a tetrahedral, or pyramidal, motif i.e. one phosphorus atom surrounded by four oxygen atoms.
  • Different apatites have different properties based on which atoms sit in between these pyramids.
  • Eg: Hydroxyapatite contributes to the strength of tooth enamel and the bones of living organisms.
• The material displayed zero resistance to the flow of an electric current and a sudden resistance when the amount of current was increased beyond a threshold value (critical current) – as expected in a superconductor.

How can a superconductor be identified?

• When a material becomes a superconductor, four changes are induced in it by the superconducting state.
• Electronic effect: it will transport electric currents with zero resistance
  • It requires sophisticated equipment and is usually difficult when the quantity of material is very less.
• Magnetic effect:
  • A type 1 superconductor will display the Meissner effect, in which a magnetic field will be expelled from its body as long as the field strength is below a critical value.
  • If a magnet is placed near the material, it will be pushed away as the material transitions into a superconductor.
  • A type 2 superconductor will display the flux pinning phenomenon in which magnetic fields are prevented from moving throughout the material
  • If a flux-pinned superconductor is removed from the magnetic field and then returned, it will revert to its original relative position.
• Thermodynamic effect: The transition to the superconducting state is accompanied by a drop in its electronic-specific heat.
  • If the material is warmed to the critical temperature, the electronic-specific heat returns to the pre-super conducting state value.
• Spectroscopic effect: Electrons in the material are forbidden from attaining certain energy levels even if they were attainable when the material was not a superconductor.
  • This gap is observable when scientists create a map of all the possible energy levels in the superconductor.

Uses

• Medicine: It could be used in medical diagnostics like MRI, and mass spectrometers.
• Particle science: It can be used in nuclear plant design and the construction of particle colliders.
• Energy Transmission: Superconducting cables can transmit electricity without losses, making them ideal for long-distance power transmission.
  • Superconducting materials can also enhance the efficiency of electric motors and generators.
• Transportation: The use of superconducting magnets allows magnetic levitation (maglev) trains to float above tracks, thereby reducing friction and enabling high-speed travel.
• Quantum Computing: The ability of some superconducting materials to exhibit quantum states makes them important for quantum computing.

Conclusion

• Although superconductor research is nearly a century old, it is still difficult to understand if a material is a superconductor or not due to the small margins of error involved.
• The discovery of a superconductor at room temperature could help technological development in a wide range of sectors through improved energy efficiency and reduced power losses.

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FAQs

MCQs

Question: What is the difference between a CFL and an LED lamp?

1. To produce light, a CFL uses mercury vapor and phosphor while an LED lamp uses semi-conductor material.
2. The average lifespan of a CFL is much longer than that of an LED lamp.
3. A CFL is less energy-efficient as compared to an LED lamp.

Which of the statement(s) given above is/are correct? (UPSC CSE 2011)

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Question: Consider the following statements:

1. Superconductors generally have very little resistance at very high temperatures.
2. Superconductivity was first discovered in apatite.

Which of the above statements is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) None of the above