The discovery of and scientific investigation into the phenomenon is not exactly new. The principle has been known since 1911, although the first public scientific paper on high temperature superconductors was not published until 20 years ago. And whilst the physicists are still discussing how high temperature superconductors actually come about, industry is already carrying out further research into the conditions for commercial practability of the technology. Practical applications for high temperature superconductors could, therefore, be possible in engine construction or radio technology. It is remarkable that, even now, the basic mechanism has still not been completely revealed.
Starting from the theory of electrical resistance in conventional electrical conductors, it was discovered that in superconductors, at a transition temperature of between -120 to -140 degrees Celsius, electrical resistance vanishes. Under these physical conditions, so-called Cooper pairs are formed within the conductor, which enable a resistance free and therefore loss free passage of electric current. Although the superconductors initially discovered required an uneconomically expensive and technically complicated cooling, the superconductors made from a copper compound (cuprate) discovered after 1986 can be cooled to the transition temperature of ‑139 degrees Celsius using liquid nitrogen. This is, for example, already being used in the construction of strong magnetic coils. At the beginning of 2008, superconductors based on iron (Fe-Pnictide) were discovered – a material which up to then was assumed to prevent superconduction.
Even although superconducting technology is gradually entering industry, it is still not yet clear on which physical relationships this characteristic of some metallic and some non-metallic conductors is based. The scientists will therefore continue to develop their theories about Cooper pairs, spins and phonons, whilst the technical users are primarily interested in developing commercial applications. For the energy industry in particular, a wide range of applicability for high temperature superconductors would mean loss free electric current conduction. Whoever believes, by the way, that high temperature means heat in this case, is wrong. The cooling temperature currently in use of approximately -120 degrees Celsius is, for superconductivity and in relation to absolute low temperature, a very high temperature indeed.