Superconductivity: No Vortices in Ceramics?

Superconducting materials levitating into strong magnetic field probably stand for the first image to come to mind when mentioning superconductivity and magnetism. No wonder! In all likelihood, it is the effect that has the longest list of possible applications.

The superconductivity phenomenon involves cooling materials to critical temperatures, when their electrical resistance drops nearly to zero. It was first discovered almost a century ago, during an experiment which used mercury cooled to extremely low temperatures, in order to observe its behavior when an electrical current was being applied. The levitating effect, or the Meisser effect, involves deploying a superconductive material into a magnetic field. The interaction between the magnetic field and the material determines the induction of a series of rotating electric currents in the former, which, in turn, generates a second magnetic field.

The interactions between the two separate magnetic fields cause the superconducting object to levitate. The phenomenon was first described in a model by Alexei Abrikosov and Vitaly Ginsburg, who eventually were awarded the Nobel prize for physics in 2003. Their model shows that the magnetic field generates so-called 'vortices' in the superconducting material, which are confined in tubes of magnetic fluxes.

However, the phenomenon is restricted to a certain class of superconductors. Superconducting materials, as the alloys of CeCoIn5 with transition temperatures of only 2.3 Kelvin, do not share the same characteristics like the Abrikosov-Ginzburg-Landau model. The results were published as a consequence of a new experiment led by Morten Ring Eskildsen from the University of Notre Dame, which involved neutrons scattering techniques.

Although Eskildsen's experiment poses no technological applications due to the extremely low transition temperatures (2.3 Kelvin), he proved that the CeCoIn5 alloy behaves much in the same way as the ceramic materials which have high transition temperatures. Such materials require temperatures of only 140 Kelvin to become superconductors and may have future use for a broad range of applications as the electric power transmission, magnetically levitating vehicles or high speed communication.