Detection of Spin-orbit Torque with Spin Rotation Symmetry

It has been recently demonstrated that spin–orbit coupling in ferromagnetic metals can generate spin current with symmetries different from the conventional spin Hall effect in nonmagnetic metals. The generated spin current can induce a spin–orbit torque on a neighboring magnetic layer with spin rotation symmetry. In this paper, we introduce a set of tools to measure this effect in a perpendicularly magnetized film, by using the second-order planar Hall effect method and spin-torque ferromagnetic resonance spectroscopy. These results are comparable to those detected by the polar magneto-optic Kerr effect technique