Spin-Charge Conversion in Fe/Au/Sb2Te3 Heterostructures as Probed By Spin Pumping Ferromagnetic Resonance

Large-area antimony telluride (Sb₂Te₃) thin films are grown by a metal organic chemical vapor deposition technique on 4” Si(111) substrates, and their topological character probed by magnetoconductance measurements. When interfaced with Fe thin films, broadband ferromagnetic resonance spectroscopy (BFMR) shows a clear increase of the damping parameter in Fe/Sb₂Te₃ when compared to a reference Fe layer, which may suggest the occurrence of spin pumping (SP) into Sb₂Te₃. Simultaneously, X-ray reflectivity and conversion electron Mossbauer spectroscopy evidence the development of a chemically and magnetically pure Fe/Sb₂Te₃ interface. However, by conducting SP-FMR, it is shown that no spin-to-charge conversion (S2C) occurs in Fe/Sb₂Te₃, while a clear SP signal develops by introducing a 5 nm Au interlayer between Fe and Sb₂Te₃, with a measured inverse Edelstein effect conversion efficiency of λ_IEE = 0.27 nm. The results shed some light on the correlation among the chemical-structural-magnetic properties of the Fe/Sb₂Te₃ interface, the broadening of the magnetic damping parameter as detected by BFMR, and the occurrence of S2C, as probed by SP-FMR.