  The dc voltage obtained from the inverse spin Hall effect (iSHE) due to spin
pumping in ferromagnet/normal-metal (NM) bilayers can be unintentionally
superimposed with magnetoresistive rectification of ac charge currents in the
ferromagnetic layer. We introduce a geometry in which these spurious
rectification voltages vanish while the iSHE voltage is maximized. In this
geometry, a quantitative study of the dc iSHE is performed in a broad frequency
range for Permalloy/NM multilayers with NM={Pt, Ta, Cu/Au, Cu/Pt}. The
experimentally recorded voltages can be fully ascribed to the iSHE due to spin
pumping. Furthermore we measure a small iSHE voltage in single CoFe thin films.
