Observation of nonmagnetic resonant scattering effects by tunneling in dilute Al-mn alloy superconductors

Phys Rev Lett. 2008 Feb 8;100(5):056804. doi: 10.1103/PhysRevLett.100.056804. Epub 2008 Feb 6.

Abstract

We have observed the BCS-like density of states predicted for energy-gap suppression by nonmagnetic Anderson impurities in superconductors. We show that Mn impurities in Al exhibit no magnetic character and act exclusively as strong resonant scattering sites without producing time-reverse symmetry breaking of Cooper pairs (pair breaking).