|
Bulk spin Hall effects are well know to provide spin orbit torques, which can be used to drive magnetization dynamics [1]. But one of the reoccurring questions is to what extend spin orbit torques may also originate at the interface between materials with strong spin orbit coupling and the ferromagnets. Using spin torque driven ferromagnetic resonance we show for two systems, where interfacial torques dominate, that they can be large enough to be practically useful. First, we show spin transfer torque driven magnetization dynamics based on Rashba-Edelstein effects at the Bi/Ag interface [2]. Second, we will show that combining permalloy with monolayer MoS2 gives rise to sizable spin-orbit torques. Given the monolayer nature of MoS2 it is clear that bilk spin Hall effects are negligible and therefore the spin transfer torques are completely interfacial in nature. Interestingly the spin orbit torques with MoS2 show a distinct dependence on the orientation of the magnetization in the permalloy, and become strongly enhanced, when the magnetization is pointing perpendicular to the interfacial plane.
This work was supported by the U.S. Department of Energy, Office of Science, Materials Science and Engineering Division.
[1] A. Hoffmann, IEEE Trans. Mag. 49, 5172 (2013).
[2] W. Zhang et al., J. Appl. Phys. 117, 17C727 (2015).
[3] M. B. Jungfleisch et al., arXiv:1508.01410.
|
