Inverse Spin-Hall Effect Induced by Spin Pumping in Various Metals*

The inverse spin-Hall effect (ISHE), conversion of spin currents into electric voltage, was observed in Ni₈₁Fe₁₉/N (N=Pt, Pd, Ag, and Au) films using the spin pumping at room temperature. The spin pumping driven by magnetization precession in the Ni₈₁Fe₁₉ layer injects a spin current into the N layer, giving rise to an electric potential difference between the edges of the N layer via ISHE. We found resonant electromotive force signals at the ferromagnetic resonance condition in the Ni₈₁Fe₁₉/N films. The spectral shape of the electromotive force signals are well reproduced by simple Lorentz functions, which is consistent with the prediction of ISHE induced by the spin pumping. The ISHE signal was observed to typically be enhanced in the Ni₈₁Fe₁₉/Pt system, showing the crucial role of the spin-orbit interaction in ISHE induced by the spin pumping.