Hf thickness dependence of spin-orbit torques in Hf/CoFeB/MgO heterostructures
Abstract
We have studied the spin-orbit torques in perpendicularly magnetized Hf/CoFeB/MgO system, by systematically varying the thickness of Hf underlayer. We have observed a sign change of effective fields between Hf thicknesses of 1.75 and 2 nm, indicating that competing mechanisms, such as the Rashba and spin Hall effects, contribute to spin-orbit torques in our system. For larger Hf thicknesses (>2 nm), both the components of spin-orbit torques arise predominantly from the bulk spin Hall effect. We have also confirmed these results using spin-orbit torque induced magnetization switching measurements. Our results could be helpful in designing Hf based SOT devices.
Publication Title
Applied Physics Letters
Recommended Citation
Ramaswamy, R., Qiu, X., Dutta, T., Pollard, S., & Yang, H. (2016). Hf thickness dependence of spin-orbit torques in Hf/CoFeB/MgO heterostructures. Applied Physics Letters, 108 (20) https://doi.org/10.1063/1.4951674
