A process that is too fast to be measured and analyzed. Yet a group of international scientists did not lose heart and conceived a sort of highly sophisticated moviola film-editing system, which allowed them to observe - for the first time in a direct manner - an effect underlying high-temperature conductivity. The results of their work have been published in Nature Physics on March 9, 2015.
Superconductors have properties that make them potentially very interesting for technology (examples of application include magnetic levitation trains). The road to a true application of the extraordinary properties of these superconductors is, however, blocked by the fact that the "classic" ones work at extremely low temperatures close to absolute zero, and therefore impracticable. Copper oxide-based superconductors, thanks to a higher working temperature, are more promising but the possibility of synthesizing superconductors at ambient temperature remains a distant goal. The main barrier is the lack of understanding of the mechanism enabling copper oxides to turn into superconductors.
One of the main problems is understanding whether the electron interactions inside the material are direct and instantaneous or mediated by some "delayed" interaction. To answer this question, we need to look at the process "in real life", but given its unusual rapidity, this is far from easy. "The solution we devised is based on the use of ultrafast light pulses, lasting 10 femtoseconds, that is, 10 million billionths of a second", explains Claudio Giannetti, of the Catholic University of the Sacred Heart, who coordinated the research. "To be able to carry out these measurements our laboratories developed a unique experimental apparatus capable of producing, utilizing and measuring light pulses of different colours that last less than 10 femtoseconds", adds Giulio Cerullo, head of the ultrafast spectroscopy laboratories of the Department of Physics of Milan Polytechnic.
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