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Abstract

Disorder, in general, should rapidly destroy the superconductivity that is produced by fluctuating magnetism. Scientists at Los Alamos National Lab have discovered a superconducting material (CeCoIn5) with incredibly high purity (electrons can travel past thousands of atoms before colliding with an impurity), making it an ideal system to investigate the relationship among magnetism, superconductivity and disorder. At the verge of static magnetism, as is the case in CeCoIn5, magnetic fluctuations proliferate, and it is these fluctuations that are believed to be responsible for generating superconductivity. By intentionally creating disorder in CeCoIn5, Los Alamos researchers have shown that the proliferation of the lowest energy magnetic fluctuations, present in the pure system, disappeared when chemical impurities were added to this material; however, the transition temperature into the superconducting state remained nearly unaffected. This suggests why other superconductors, which require chemical disorder to suppress the static magnetic order and generate magnetic fluctuations, still possess very high superconducting transition temperatures.