The TRR 227 kindly invites you to the following Colloquium.
Speaker: Prof. Dr. Xin Fan,
Department of Physics and Astronomy, University of Denver, USA
Title: Transversely-polarized spin current generation from ferromagnetic metals
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.
 A. M. Humphries, et al. "Observation of spin-orbit effects with spin rotation symmetry", Nat. Commun. 8, 911 (2017).
 W. S. Aljuaid, S. R. Allen, A. Davidson, and X. Fan, "Free-layer-thickness-dependence of the spin galvanic effect with spin rotation symmetry", Appl. Phys. Lett. 113, 122401 (2018).
 W. Wang, et al. "Anomalous spin-orbit torques in magnetic single-layer films", Nat. Nanotechnol. 14, 819 (2019).
 A. Davidson, V. P. Amin, W. S. Aljuaid, P. M. Haney, and X. Fan, "Perspectives of electrically generated spin currents in ferromagnetic materials", Phys. Lett. A 384, 126228 (2020).
 R. W. Greening and X. Fan, "Influence of nonuniform magnetization reorientation on spin-orbit torque measurements", arXiv: 2207.10349 (2022).
Time & Location
Sep 30, 2022 | 02:15 PM
Lecture Hall A (Room 1.3.14)
Physics Department - Freie Universität Berlin
Arnimallee 14, 14195 Berlin-Dahlem