Events at Physics
The Spin-orbit interaction is a relativistic effect describing the coupling between a particleaEuroTMs spin and motion. It lifts the spin-dependent degeneracy of electronaEuroTMs motion in a solid. The related phenomena have been intensively studied in semiconductors over the past decades. Very recently, it has been shown that the spin-orbit interaction in metals can be orders stronger than that in conventional semiconductors. It is demonstrated that an electric current through a heavy metal/ferromagnetic metal bilayer can efficiently control the magnetization of the ferromagnetic layer.
Although the phenomena have been successfully demonstrated, the microscopic detail of the spin-orbit interaction in the metallic bilayer is still unclear. The major question is whether the dominating spin-orbit interaction is from the spin Hall effect in the heavy metal itself (bulk effect) or the Rashba effect at the interface (interface effect). In this talk, I will firstly introduce both electrical and optical methods that I developed to determine the magnetic torques generated from the spin-orbit interaction. Then I will show the co-existence of interface and bulk contributions in the samples under study. The result suggests that both the selection of the heavy metal and the engineering of the interface are crucial for the control of the magnetization. In the end, I will discuss the challenges and potential researches in this area.