In order to make practical use of any type of electricity conduit, including superconductors, you have to be able to control how the electricity flows. Researchers from Lucent Technologies' Bell Labs have made a tunable circuit that allows them to modulate the flow of electricity through organic superconductors like polymers and fullerenes. Fullerenes, or buckyballs, are made entirely of carbon and resemble molecular-scale soccer balls.
Polymers are long strings of molecules.
The circuit is a type of Josephson junction, which is a superconductor ring with a gap in it. The gap is spanned by a thinner piece of superconductor that causes electricity to flow more slowly than if the ring were unbroken. The researchers tuned the device by changing the voltage of current flowing through an electrode at the gap. This voltage change affected the electrical field surrounding the connecting piece of organic material, which in turn changed its properties from insulating to superconducting. Insulators slow or block electricity flow and superconductors allow electricity to flow with perfect efficiency.