Anomalous Hall effect at a PtOx/Co interface

We study the anomalous Hall effect at a ${\mathrm{PtO}}_{x}/\mathrm{Co}$ interface. We extracted the intrinsic and extrinsic contributions to the anomalous Hall effect in ${\mathrm{SiO}}_{2}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ and ${\mathrm{PtO}}_{x}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ films by measuring temperature dependence of the anomalous Hall resistivity. The result shows that the intrinsic anomalous Hall effect in the ${\mathrm{PtO}}_{x}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ film is almost identical to that in the ${\mathrm{SiO}}_{2}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ film. In contrast, the extrinsic anomalous Hall effect is clearly different between the ${\mathrm{SiO}}_{2}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ and ${\mathrm{PtO}}_{x}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ films. The anomalous Hall effect for various Co-layer thicknesses $t$ at various temperatures reveals that the extrinsic anomalous Hall resistivity shows a ${t}^{\ensuremath{-}1}$ dependence in the ${\mathrm{PtO}}_{x}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ film, while it is almost independent of $t$ in the ${\mathrm{SiO}}_{2}/\mathrm{Co}/{\mathrm{SiO}}_{2}$ film. This result demonstrates the extrinsic anomalous Hall effect originating from the ${\mathrm{PtO}}_{x}/\mathrm{Co}$ interface. Our results show that both the side-jump and skew-scattering mechanisms contribute to the interfacial anomalous Hall effect, which can be attributed to the formation of Co-O bonds and electron scattering by Pt impurities at the ${\mathrm{PtO}}_{x}/\mathrm{Co}$ interface.