Nickel on Lead, Magnetically Dead or Alive?

TL;DR

This study investigates the magnetic properties of nickel layers on lead films, revealing that the reduction in superconducting transition temperature is not caused by magnetic moments but likely due to non-magnetic effects, using weak localization measurements.

Contribution

The paper demonstrates that nickel layers on lead do not produce magnetic pair-breaking effects, challenging previous assumptions based on anomalous Hall effect measurements.

Findings

Ni layers do not cause significant electron dephasing

Superconducting T_c reduction is not due to magnetic moments

Weak localization measurements show minimal magnetic scattering

Abstract

Two atomic layers of Ni condensed onto Pb films behave, according to anomalous Hall effect measurements, as magnetic dead layers. However, the Ni lowers the superconducting T_{c} of the Pb film. This has lead to the conclusion that the Ni layers are still very weakly magnetic. In the present paper the electron dephasing due to the Ni has been measured by weak localization. The dephasing is smaller by a factor 100 than the pair-breaking. This proves that the T_{c}-reduction in the PbNi films is not due magnetic Ni moments.