South Korea superconductivity claim revived with new data

Subject : Science and Tech

SECTION: Msc

Context:

A group of scientists from China and Japan have reported findings that could indicate superconductivity in a controversial material.

About Superconductivity

Superconductivity occurs when a material offers almost zero resistance to the flow of electric current, enabling energy-efficient electrical appliances and lossless power transmission.
Superconductors also display fascinating behavior under magnetic fields, enabling technologies like MRI machines and superfast Maglev trains.

Characteristics of Material LK-99

Apatite Structure: The Korean group utilized copper-substituted lead apatite, a phosphate mineral with unique tetrahedral motifs, to create LK-99.
Superconducting Behavior: LK-99 displayed essential superconducting properties, with almost zero resistance to current flow and sudden emergence of resistance above a critical current threshold.
Magnetic Resilience: LK-99 retained superconductivity even under the presence of a magnetic field until reaching a critical threshold.

Meissner Effect: Key Indicator of Superconductivity

The Meissner effect is a phenomenon where materials expel magnetic fields from their interior upon becoming superconductors.
Observation in Study: The researchers observed this effect in copper-substituted lead apatite, suggesting potential superconductivity.

Quest for Room-Temperature Superconductors

Significance: Discovering a material that is superconducting at room temperature and pressure (RTP) has immense scientific and commercial value.
Applications: RTP superconductors could revolutionize power transmission, medical diagnostics, computing, and more, due to their ability to conduct electricity without loss.

Understanding Hysteresis in Superconductors

Meissner Effect and DC Current: The Meissner effect is observable with direct current, as alternating current would disrupt the phenomenon.
Type I and II Superconductors: The study helps distinguish between these types based on how they respond to increasing magnetic field strength.

Challenges and Limitations of the Study

Small Superconducting Portions: The material’s superconducting sections were small, leading to a low critical magnetic field strength.
Interference Issues: The presence of cuprous sulphide interfered with molecular structure analysis using X-rays.

Controversies in Superconductivity Research

Past Controversies: The field has seen several disputes, including claims by Ranga Dias and a South Korean research group, which were later contested.
Impact of Hype: The lucrative potential of RTP superconductors has sometimes led to premature claims and controversies in the scientific community.

New Study: Methodology and Findings

Approach: The team synthesized LK-99 samples using advanced techniques and tested for signs of superconductivity beyond specific claims made by previous studies.
Direct Current Measurements: They conducted hysteresis experiments, applying and removing a magnetic field to observe the material’s response at various temperatures.