Superconductivity at Higher Temperatures: Latest Experiment and Future Potential

• Zero Electrical Resistance: Superconductivity is a phenomenon where certain materials conduct electricity with zero resistance, allowing current to flow without energy loss.
• Perfect Magnetic Behaviour: Superconductors also exhibit the Meissner effect, meaning they expel magnetic fields, enabling applications like magnetic levitation.
• Extremely Low Temperature Requirement: Traditionally, superconductivity occurs only at very low temperatures close to absolute zero, requiring expensive cooling systems.

History of Superconductivity

• Discovery in 1911: Dutch physicist Heike Kamerlingh Onnes discovered superconductivity in mercury at about −269°C, marking the first observation of zero electrical resistance.
• Development of High-Temperature Superconductors (1986–87): Scientists discovered copper-oxide (cuprate) superconductors, which worked above liquid nitrogen temperature (−196°C), making research more practical.
• 1993 Temperature Record: The compound Hg1223 (mercury-based cuprate) achieved superconductivity at −140°C at normal pressure, a record that remained unbroken for decades.
• Recent High-Pressure Experiments: Some materials showed superconductivity near room temperature, but only under extreme pressures comparable to Earth’s core, limiting real-world applications.

• Retention of Electronic Properties: Because atoms cannot rearrange at very low temperatures, the material retains the electronic structure formed under pressure even after the pressure is removed.
• Stabilising Exotic Phases: This method allows scientists to stabilise unusual electronic or crystal structures that normally exist only under extreme pressure.