Stacking order dependence of inverse spin Hall effect and anomalous Hall effect in spin pumping experiments

Abstract

The dependence of the measured DC voltage on the non-magnetic material (NM) in NM/CoFeB and CoFeB/NM bilayers is studied under ferromagnetic resonance conditions in a TE011 resonant cavity. The directional change of the inverse spin Hall effect (ISHE) voltage V-ISHE for the stacking order of the bilayer can separate the pure VISHE and the anomalous Hall effect (AHE) voltage V-AHE utilizing the method of addition and subtraction. The Ta and Ti NMs show a broad deviation of the spin Hall angle theta(ISH), which originates from the AHE in accordance with the high resistivity of NMs. However, the Pt and Pd NMs show that the kinds of NMs with low resistivity are consistent with the previously reported theta(ISH) values. Therefore, the characteristics that NM should simultaneously satisfy to obtain a reasonable VISHE value in bilayer systems are large theta(ISH) and low resistivity.