We report systematic measurements of anomalous Hall effect (AHE) in $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}/\mathrm{Ta}$ and $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}/\mathrm{Pt}$ bilayers modified by strong spin-orbit coupling (SOC) of the heavy metals. The results are compared with the AHE in $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}/\mathrm{Cu}$ with weak SOC. We have used a scaling involving multiple competing scattering mechanisms to distinguish different contributions to the modified AHE. The scaling analysis reveals that the origin of the modified AHE in $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}/\mathrm{Cu}$ is different from those in $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}/\mathrm{Ta}$ and $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}/\mathrm{Pt}$. The direct observation of spin-orbit torque induced magnetization switching confirms that the result is a combination of the AHE of $\mathrm{M}{\mathrm{n}}_{1.5}\mathrm{Ga}$ and spin Hall effect of the heavy metals.

• Received 3 November 2015
• Revised 18 January 2016

DOI:https://doi.org/10.1103/PhysRevB.93.060406