Unexpected superconductor

The helical magnetic structure of manganese phosphide.

RESEARCHERS have discovered the first manganese-based superconductor, a compound whose strong magnetism was thought to prevent superconductivity. In traditional superconductors, magnetism and superconductivity are mutually exclusive, but some of the most important classes of superconductors discovered in the past few decades (such as organic superconductors, iron-based superconductors or cuprates) are also magnetic. Researchers in China have now discovered that manganese phosphide (MnP) can be made superconducting by application of a large pressure. Superconductivity in MnP seems to be related to its exotic magnetic structure, based on a “helical” arrangement of spins. The material is superconducting only at very low temperatures and under pressure, but its discovery suggests higher-temperature superconductivity could be found in other helical magnets. The work has been published in the latest issue of “Physical Review Letters”.

Stories compiled by R. Ramachandran