Magnetism relieves electrons of their resistance: The physicist and his colleagues have, however, looked at the magnetic moments in the superconducting version in detail. To this end, they conducted experiments at the Jülich Centre for Neutron Science at the Institut Laue-Langevin in Grenoble which involved bombarding a sample of the superconducting material with neutrons that also have a spin and therefore a magnetic moment. They thus excited the magnetic moments in the CeCu2Si2, i.e. caused them to spin around, in simplified terms. This only worked when the energy of the neutrons exceeded a certain threshold, however. It is precisely this minimum of energy which is required to break up the superconducting electron pairs.
This on its own is not enough to prove that the magnetic exchange binds the Cooper pairs together in the unconventional superconductors. "The magnetic interactions in the superconducting material release ten times more energy than the formation of the Cooper pairs, however," says Oliver Stockert: "It seems apparent that the magnetic interactions therefore make the unconventional superconductivity possible." After all, nature does everything it can to save energy. And, in this respect, the magnetic exchange seems to be particularly advantageous, especially in the superconductor.
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