Superconductivity 

05 Aug 2023 Superconductivity 

This article covers “Daily Current Affairs” and the topic details “Superconductivity”. The topic “Superconductivity” has relevance in the “Science and Technology” section of the UPSC CSE exam.

For Prelims:

What is Superconductivity?

For Mains:

GS3:  Science and Technology- advancements, their effects in everyday life 

Why in the news?

South Korean researchers posted papers on the internet about lead-based compound’s superconducting properties at room temperature. Discovery of a room temperature superconductor generates excitement and scepticism. Potential for Nobel Prize and revolutionising technology, but past claims have been elusive.

Superconductivity 

Superconductivity is a state in which a material exhibits almost no resistance to the flow of electric current. Electric current involves the movement of charged particles, usually electrons, which interact with atoms in the material as they move.

Resistance: 

• The property of a conductor by virtue of which it opposes the flow of electric current through it is called resistance.
• Resistance in electric current leads to energy loss, primarily in the form of heat. This phenomenon is why devices like electrical appliances become hot during operation.

Potential Benefits of Superconductivity:

• Improved power transmission: Superconducting wires can carry much higher currents than conventional wires without losing any energy due to resistance. This could lead to significant reductions in energy losses in the power grid, which could save billions of dollars per year.
• More efficient motors and generators: Superconducting motors and generators could be much more efficient than conventional motors and generators, leading to significant reductions in energy consumption.
• Maglev transportation: Superconducting magnets could be used to levitate trains, which would eliminate friction and allow for much faster and more efficient transportation.
• MRI and NMR imaging: Superconducting magnets are used in MRI and NMR imaging devices, which are essential for medical diagnosis.
• Cryogenics: Superconducting materials can be used to create and maintain cryogenic temperatures, which are essential for a variety of applications, such as research in quantum physics and the development of new medical treatments.
• Critical roles of superconductors extend to various fields beyond these examples.

Challenges in Achieving Superconductivity:

• High temperatures: Many superconducting materials require extremely low temperatures to exhibit their properties, which makes them difficult to use in everyday applications.
• Material synthesis: Some superconducting materials can be difficult to synthesise with the necessary crystalline structure and purity.
• Stability and sensitivity: Superconductors can be sensitive to external factors such as magnetic fields, pressure, and mechanical stress, which can disrupt their superconducting properties.
• Critical current density: In practical applications, it’s important for a superconducting material to carry a high current density while maintaining its superconducting state.
• Anisotropy: Many superconductors exhibit anisotropic behavior, meaning their superconducting properties vary with direction.
• Losses at interfaces: Interfaces between different materials, such as superconductors and normal conductors, can lead to energy losses and reduce the efficiency of superconducting devices.

Search for Room-Temperature Superconductors:

• Current Limitations: Even so-called “high-temperature” superconductors function well below -150 degrees Celsius. Claims of higher-temperature superconductivity often require extreme pressures or face skepticism.
• Quest for Room Temperature: Scientists aim to discover materials displaying superconductivity at or near room temperature (20-25 degrees Celsius) and under normal pressure. The term “room temperature” refers to conditions that are relatively easy to create, such as slightly above or below typical room temperatures.

Related Terms:

Critical Temperature (Tc)

• The critical temperature is the point at which a superconductor transitions between normal and superconducting behaviour.

The Meissner Effect

• The Meissner effect is the expulsion of a magnetic field from the interior of a superconductor during its transition to the superconducting state when it is cooled below the critical temperature. This expulsion will repel a nearby magnet.
• Above Tc, a superconductor doesn’t react significantly to a magnetic field – the field passes through unhindered. However, below Tc, the applied magnetic field is pushed out from inside the superconductor and curved around it. 
• This happens due to the development of surface currents within the superconductor when influenced by a magnetic field. These currents create magnetization that counters the magnetic field, effectively neutralising it inside the superconductor. 
• This results in strong diamagnetism, where the superconductor is repelled by the magnetic field.

Levitation Phenomenon

• The repelling force between the superconductor and the magnetic field can be powerful enough to make a magnet levitate above the superconductor. 
• This levitation isn’t completely stable, allowing the magnet some rotational freedom as it orients its magnetic poles. If the superconductor warms above Tc or the magnetic field is removed, the magnet loses its levitation ability.

What is the news? 

• South Korean researchers recently published two papers online, describing the development of a new material called LK-99. According to their findings, LK-99 can exhibit superconductivity at room temperatures. 
• The researchers claim that LK-99 can be created by baking a combination of minerals, specifically lanarkite (Pb2SO4) and copper phosphide. 
• Remarkably, this material shows key superconducting properties even under normal air pressure and at temperatures as high as 127 degrees Celsius. 
• The researchers have proposed a possible explanation for how LK-99 achieves room-temperature superconductivity, but they haven’t yet presented solid experimental proof to substantiate their assertions.

The search for materials exhibiting room-temperature superconductivity holds immense significance, offering potential for groundbreaking advancements in technology and energy efficiency. Despite challenges, the scientific community remains focused on realizing this elusive goal.

Sources: 

Why room temperature superconductivity remains science’s elusive Holy Grail | Explained News – The Indian Express

Yojna daily current affairs eng med 5th August 2023

Q1. With reference Superconductors, consider the following statements: 

1. Superconductivity is a state in which a material exhibits almost no resistance to the flow of electric current.
2. Many superconducting materials require extremely low temperatures to exhibit their properties, which makes them difficult to use in everyday applications.
3. Superconducting magnets are used in X-ray imaging devices, which are essential for medical diagnosis.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 2 and 3 only

(c) 3 only 

(d) None 

Answer: (a) 

Q2. Consider the following statements: 

Statement-I: High-temperature superconductors function above 150 degrees Celsius. 

Statement-II: Claims of higher-temperature superconductivity often require extreme pressures or face skepticism.

Which one of the following is correct in respect of the above statements? 

(a) Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I 

(b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I
(c) Statement-I is correct but Statement-II is incorrect
(d) Statement-I is incorrect but Statement-II is correct

Answer: (d) 

Q3. What is superconductivity, and how does it relate to the meissner effect? Explain its potential benefits in terms of applications for human advancement.

Gaurav N