Anatomy of the spin Hall effect in ferromagnetic metals
Fanxing Zheng, Meng Zhu, Jianting Dong, Xinlu Li, Ye Zhou, Kai Wu, Jia Zhang
Abstract
The spin Hall effect (SHE) is one of the most important spin-to-charge conversion mechanisms in spintronics and has been intensively investigated in nonmagnetic materials. However, the SHE in ferromagnetic metals has been rarely studied and remains obscure. Here, we clarify that the SHE in ferromagnetic metals can be classified into three categories including conventional-, spin anomalous-, and magnetic spin Hall effect. By using first-principles calculations, we find the above three spin Hall mechanisms do coexist in common ferromagnetic metals. Particularly, for Pt-based ferromagnetic alloys, comparable conventional and magnetic spin Hall angles have been predicted. In addition, we investigate the temperature dependence and scaling behavior of different types of spin Hall conductivity by taking into account the lattice vibration and spin disorder scattering. Finally, we argue that ferromagnetic metals with remarkable unconventional SHE may be efficient spin current sources with out-of-plane spin polarization for spin-orbit torque-induced switching and spin terahertz emission. This work provides a comprehensive understanding of the SHE in ferromagnetic metals and may pave the way for promising applications in spin-to-charge conversion spintronics devices.