Large spin Hall angle enhanced by nitrogen incorporation in Pt films

We report on the enhancement of spin Hall angle from the CoFeB/Pt interface by introducing nitrogen into the Pt thin film. Spin-torque ferromagnetic resonance measurements on the effective spin Hall angle (theta (SH)) reveal a non-monotonic variation as a function of the amount of nitrogen gas introduced, Q in the film deposition, which peaks at theta (SH)=0.16 when Q is 8%. Our analysis shows that the theta (SH) enhancement is mainly attributed to the increase in spin-dependent scattering at the interface. The effective magnetic damping decreases with increasing Q due to the reduced spin-orbit coupling. The interfacial spin transparency is also observed to show improvement after the introduction of nitrogen. Moreover, the additional damping-like torque from the interface may also lead to the enhancement of the linewidth modulation.

Automated summary

Introducing nitrogen into the Pt thin film enhances the spin Hall angle at the CoFeB/Pt interface, with a non-monotonic variation as a function of the amount of nitrogen gas introduced. The enhancement is mainly attributed to the increase in spin-dependent scattering at the interface, with a decrease in effective magnetic damping as nitrogen amount increases. Additionally, improved interfacial spin transparency and enhanced linewidth modulation are observed after the introduction of nitrogen.