Perpendicular magnetization reversal in Pt/[Co/Ni]3/Al multilayers via the spin Hall effect of Pt

Abstract

We experimentally investigate the current-induced magnetization reversal in Pt/[Co/Ni]3/Al multilayers combining the anomalous Hall effect and magneto-optical Kerr effect techniques in crossbar geometry. The magnetization reversal occurs through nucleation and propagation of a domain of opposite polarity for a current density of the order of 3 × 1011 A/m2. In these experiments, we demonstrate a full control of each stage: (i) the Ørsted field controls the domain nucleation and (ii) domain-wall propagation occurs by spin torque from the Pt spin Hall effect. This scenario requires an in-plane magnetic field to tune the domain wall center orientation along the current for efficient domain wall propagation. Indeed, as nucleated, domain walls are chiral and Neél-like due to the interfacial Dzyaloshinskii-Moriya interaction.