New Understanding of Iron-Based Superconductors
Superconductors are materials that have been baffling scientists for decades, as they have worked to discover how the materials are able to conduct electricity without resistance. The hope is to one day create materials that are superconducting at room temperatures, and could be integrated into the technologies we use and rely on each day. Researchers at Argonne National Laboratory have recently made a discovery with iron-based superconductors, which could have some powerful implications.
Iron-based superconductors are rather odd materials as at room temperatures, they are often magnetic, and magnetism is believed to counter superconductivity. Yet at low temperatures, magnetism will disappear and superconductivity will emerge. For a particular iron arsenide material, while the it cools its atomic structure changes. At first the iron atoms are arranged in a square lattice with four-fold symmetry, but as the temperature drops, the structure will change to a rectangular lattice with two-fold symmetry. This is called nematic order and it was believed that this persists as the material becomes superconducting, but the Argonne researchers have recently observed that at temperatures just above that critical point, the atomic structure changes back to the square lattice.
Currently there are two theories to explain nematic order, but only one is able to explain this observation at the moment. Potentially this discovery could afford researchers not only a greater understanding of this particular superconductor, but other iron arsenide superconductors, and even copper oxide superconductors, in which nematic disorders have been observed.
Source: Argonne National Laboratory