Correlation between magneto-transport and magnetization reversal in CoFeB/Pt bilayers

Hall effect measurements on out-of-plane magnetized materials provide means to study the magnetization reversal process by analogy with, e.g., magneto-optical Kerr effect (MOKE) magnetometry. Chiral non-collinear spin textures may contribute to the so-called topological Hall effect as the difference between ordinary plus anomalous Hall effect and M(H) curves. In this talk, I will present results for soft-magnetic CoFeB/Pt bilayer films with perpendicular magnetic anisotropy and compare as-grown with annealed films. The differing behavior of MOKE and magneto-transport for hysteresis loops, first-order reversal curves, and angle-dependent relaxation indicates the presence of a strong topological effect, a rationale corroborated by structural characterizations and magnetic imaging.