Antisymmetric planar Hall effect in Ta/Py bilayers—Evidence for perpendicular interfacial magnetization tuned by in-plane bulk magnetization

Abstract

Antisymmetric planar Hall effect (APHE) is observed in Ta/Py bilayers, which exhibits a sinusoidal dependence on the in-plane magnetization orientation. The APHE resistance is independent of both the amplitude and direction of the applied current, excluding contributions from Joule heating and spin–orbit torque effects. Additionally, the effect is insensitive to the magnitude of the in-plane magnetic field once the magnetization is practically saturated. The APHE amplitude and phase vary with the choice of seed layer and with post-deposition annealing, suggesting involvement of strain. Results suggest the presence of strain-modulated interfacial Dzyaloshinskii–Moriya interaction, which couples the bulk and interfacial spins and induces perpendicular magnetization at the Ta/Py interface tuned by the orientation of the in-plane bulk magnetization: a miter-gear-like combination. This mechanism offers a plausible explanation for the antisymmetric Hall response and points to a new pathway for inducing and manipulating perpendicular interfacial magnetization, with potential implications for novel spintronic devices.