Electrical detection of magnetic domain walls by inverse and direct spin Hall effect

Abstract

Domain wall (DW) detection is a prerequisite to perform current-induced DW motion. In this letter, we demonstrate a detection method, based on the ability for a ferromagnetic nanowire, in which a DW is pinned, to inject or detect a pure spin current. The device consists of such a ferromagnetic nanowire in contact with an orthogonal spin Hall effect (SHE) nanowire. When a current flows along the ferromagnetic nanowire, and provided a DW is pinned, the pure spin current is transformed into a transverse voltage by inverse spin Hall effect (ISHE). In the reciprocal configuration, the pure spin current created by the direct SHE, generates a transverse voltage along the ferromagnetic wire. Finite element method (FEM) simulations allow estimating the Pt spin Hall angle (SHA) (7.5 ± 0.5%). This technique provides an electrical way to study the DW motion, a device akin to the ferromagnetic/spin Hall effect bilayers typically used for spin-orbit torques experiments.