My Transversely-Polarized Spin Current Generation from Ferromagnetic Metals

Xin Fan, University of Denver

The anomalous Hall effect, discovered by Edwin Hall in 1880, describes a phenomenon that an electric current perpendicular to magnetization of a magnetic material can produce a charge accumulation in the direction orthogonal to both electric current and magnetization. Through century-long theoretical and experimental efforts, it is now understood that the anomalous Hall effect arises from the spin-orbit coupling.

The understanding of the anomalous Hall effect has also led to the discovery of new spin-orbit effects, such as the spin Hall effect, where an electric current generates spin accumulations in nonmagnetic materials. The spin Hall effect also exists in ferromagnetic materials, in a more complicated and interesting way. There exist a group of spin-orbit effects associated with transverse spins – spins polarized perpendicular to the magnetization, which we refer to this group of spin-orbit effects as transverse-spin-orbit effects in magnetic materials.

In my talk, I will present our experimental observations of two unique transverse spin-orbit effects: (1) spin-to-charge interconversion with unconventional spin rotation symmetry and (2) the generation of anomalous spin-orbit torque in a single-layer magnetic film – a hidden counterpart to the anomalous Hall effect. I will also discuss the impact of these effects on the understanding of general spin-charge conversion phenomena.