Giant topological Hall effect in MnxGa/Pt bilayers induced by non-collinear spin textures with fixed chirality

The interaction of chiral spin textures with charge carriers will give rise to a rich variety of phenomena, such as the topological Hall effect (THE). However, the appearance of characteristic bumps or dips in the THE cannot serve as an unambiguous evidence for identifying topologically protected non-collinear spin textures. Here, we present a giant THE in MnxGa/Pt bilayers deriving from non-collinear spin textures with fixed chirality, which are similar with skyrmions clusters. During the extraction of the THE from the total Hall resistivities, we have found that the strong skew scattering should contribute a spurious THE in the low temperature limit, with the opposite sign to the chiral spin textures induced. The relations of spin textures and transport features have been further investigated through the magnetic-field-dependent magnetic force microscopy in the low temperature limit. In general, the extracted Hall signals with bump/dip features in MnxGa/Pt bilayers can be separated into two contributions: i) the THE due to chiral spin textures; ii) the AHE due to skew scattering of non-magnetic impurities.