Hot future for cold superconductors – research in materials science

Júlia Jareño, Alexander Stangl

Superconductivity is a highly interesting topic in physics and material science and it’s at its bottleneck between the laboratories and final applications. It’s a phase present in several different materials, which only occurs at low temperatures (below the so called critical temperature Tc~<-200°C). If a superconductor is cooled down, it can carry electric currents without any resistance and expels magnetic fields from its interior. These properties are already exploited in some fields such as medicine (RMN machines) but can still have a vast impact in new technologies for power cables, magnets and even information storage. Superconductivity might change as well how we travel with high speeds around the globe, using levitating trains.

Superconductivity is limited by current density and temperature, higher than the critical values will lead to a transition to the normal state. Many pure elements show superconductivity at almost absolute zero temperature. More complex compounds were found with much higher transition temperatures (high temperature superconductors HTS, although its still quite cold at their transition temperatures of below -200°C), as Niobium-titanium which is used in the LHC in CERN. We are working with YBa2Cu3O7, a ceramic superconductor showing excellent properties, such as very high critical currents and high critical temperature. Our research interest lays in synthesizing this material with the best possible properties and in a way which can be used by industry. Being an oxide with a layered structure means that the usual melting processes for metallic cables won’t work. Therefore, we use chemical solutions with dissolved precursors and we treat them thermally in order to achieve the material with a preferred orientation, necessary to conduct high currents without resistance.
Superconductivity can have a significant role in deregulated electricity markets and in lessening CO2 emissions and other environmental impacts, but significant market penetration of HTS devices requires HTS wires that fully exploit their fundamental current-carrying  capability.

As a chemist and physicist, working together in materials science, we will give you a quick introduction into the field of superconductivity, talk about its versatile (possible) applications and show, what needs to be done (and what we are doing) to get there.