Rectification in ac Hanle effect

In alternating current Hanle effect, the resistance of a single interface in a ferromagnet-normal metal (F/N) bilayer depends on the frequency of ac current and the applied magnetic field [1]. Here we point out that another process happens at the same time in such device. The field-induced precession of electron spins in the normal part of the structure leads to the generation of spin torque on its single F/N interface. This torque excites magnetic dynamics in the F-layer, which, in turn, provides some back-action on current propagation. We solve self-consistent equations for spin current, electric current and magnetization, coupled by the non-linear boundary conditions at the interface. The non-linearity leads to voltage rectification, much like it happens in the F/N/F spin diode [2].

[1] Ya. B. Bazaliy, “Alternating current Hanle effect as poor man’s paramagnetic resonance”, Phys. Rev. B 109, 224427 (2024).

[2] A. A. Tulapurkar, Y. Suzuki, A. Fukushima, H. Kubota, H. Maehara, K. Tsunekawa, D. D. Djayaprawira, N. Watanabe, and S. Yuasa, “Spin-torque diode effect in magnetic tunnel junctions”, Nature 438, 339 (2005).