Evidence of interfacial asymmetric spin scattering at ferromagnet-Pt interfaces

We measure the spin-charge interconversion by the spin Hall effect in various ferromagnetic/Pt nanodevices. The extracted effective spin Hall angles of Pt evolve drastically with the ferromagnetic (FM) materials (CoFe, Co, and NiFe), when assuming transparent interfaces and a bulk origin of the spin injection/detection by the FM elements. By carefully estimating the interface resistance, we show that it is quite large and cannot be neglected. We then evidence that the spin injection/detection at the FM/Pt interfaces are dominated by the spin polarization of the interfaces. We show that interfacial asymmetric spin scattering becomes the driving mechanism of the spin injection in our samples.

Automated summary

In this study, we measured the spin-charge interconversion using the spin Hall effect in various ferromagnetic/Pt nanodevices, and found that interface resistance and spin polarization play crucial roles in spin injection/detection. Additionally, we showed that interfacial asymmetric spin scattering becomes the dominant mechanism of spin injection in our samples.