Spin Pumping in NbRe-PY and Nb-Py Bilayers

Abstract

Broadband ferromagnetic resonance measurements were performed on NbRe/Py and Nb/Py bilayers of nm thickness to characterize magnetic damping and interfacial spin transport. The extracted Gilbert damping values show no significant dependence on stacking order or on the choice of normal-state superconductor. A thickness-dependent analysis of the NbRe/Py bilayer reveals a clear increase in α with the non-magnetic layer thickness, consistent with spin-pumping-induced dissipation. These results provide a concise experimental picture of damping and spin transport in FM/NM systems involving superconducting materials in their normal state