Sharpening of the Resistive Transition of a Superconductor with the Addition of Paramagnetic Impurities

Abstract
We present evidence demonstrating that the addition of magnetic moments to a superconductor suppresses the Maki-Thompson contribution to the fluctuation conductivity. Measurements of the resistive transition of aluminum films with erbium impurities exhibit a sharpening of the transition with increasing impurity concentration which can be explained quantitatively using Thompson's scheme for regularizing the Maki-Thompson conductivity diagrams.