Vivek Amin
Ferromagnets generate spin currents under an applied electric field. For example, charge currents in ferromagnets are spin-polarized because majority and minority carriers have different conductivities. However, in the presence of spin-orbit coupling, electrons can carry a substantial spin current flowing perpendicularly to the electric field with spin directions both longitudinal and transverse to the magnetization.
In this talk, we discuss several mechanisms to electrically generate spin currents in ferromagnets. These mechanisms are closely related to the anomalous and planar Hall effects but yield spin currents with spin directions transverse to the magnetization. Such spin currents can be detected through the torques they exert at layer boundaries [1]. We present first principles transport calculations giving the strength and magnetization dependence of the electrically generated spin currents allowed by symmetry via both intrinsic [2] and extrinsic [3] mechanisms. We find that in transition metal ferromagnets, the spin currents with spin direction transverse to the magnetization can have an associated conductivity comparable to the spin Hall conductivity in Pt.
[2] V. P. Amin, J. Li, M. D. Stiles, and P. M. Haney, Intrinsic Spin Currents in Ferromagnets, Phys. Rev. B 99, 220405(R), 2019
[3] V. P. Amin, J. Zemen, and M. D. Stiles, Interface generated spin currents, Phys. Rev. Lett. 121, 136805 (2018)