Abnormal Peak Of Angular-Dependent Hall Effect As An Indicator For Skyrmion In Perpendicular Magnetic Anisotropy System

The anomalous Hall effect (AHE) has been extensively studied in terms of its diverse and profound physics, but the AHE behavior under spatially rotated external fields has not been well understood yet. Here, we selected a traditional CoFeB-based multilayer film as the platform, and by continuously tuning its magnetic anisotropy, we have observed the progressively evolved angular-dependence of the AHE, in which an abnormal turning peak emerged in the case of moderate perpendicular magnetic anisotropy (PMA). By applying comprehensive micromagnetic simulations, a general model was established that can almost fully account for the existing trend of the angular AHE. The PMA magnitude, together with the multi-to-single domain transformation, determined the final behavior of the AHE at various magnetic-field-tilt angles. Notably, we identified a close relationship between the angular-Hall anomaly and formation of magnetic skyrmions, which can possibly offer an alternative method to detect the skyrmions.