Topological Hall-like magnetoresistance humps in anomalous Hall loops caused by planar Hall effect

Achievement of various topological spin textures, such as magnetic skyrmion and chiral domain walls, in heavy-metal/ferromagnet (FM) multilayer films with interfacial Dzyaloshinskii-Moriya interaction have attracted enormous attention owing to their topological nature, emergent electromagnetic properties, and potential applications in spintronics. The topological Hall effect (THE), an indicator to distinguish spin textures with nontrivial topology from the trivial collinear magnetic configurations, is usually characterized by the dome shaped peak in anomalous Hall resistivity (AHR) loops. However, several other magnetoresistance effects could also cause this aberrant hump in AHR curves. Here, we systematically study the AHR loops with these aberrant humps under the coercivity mu 0Hc as a function of the orientation of the magnetic field to the film plane in several Pt/FM/Pt films. Combining the simulation model of AHR and planar Hall magnetoresistance (PHMR), we demonstrate that this THE-like hump originates from the PHMR of the in-plane magnetization component due to magnetization is not saturated below saturation field in the out-of-plane AHR loop measurements. Our results indicate that the origin of these dome-shaped anomalous in transport measurements is manifold and should be examined carefully.

Automated summary

Achievement of topological spin textures in heavy-metal/ferromagnet multilayer films has attracted attention for their topological nature, emergent electromagnetic properties, and potential spintronics applications. However, the origin of the dome-shaped anomalous humps in anomalous Hall resistivity curves is manifold and needs to be carefully examined.