Noncollinear ferrimagnetism and anomalous Hall effects in Mn4N thin films

The magnetic structure of thin films of ferrimagnetic metallic Mn${}_{4}$N differs from the triangular ferrimagnetism of the bulk. Based on distance-dependence of Mn-Mn exchange and magnetic structures of other Mn${}_{3}$$X$N perovskites, a topological noncollinear spin structure is proposed for [001] Mn${}_{4}$N films with perpendicular anisotropy, which is confirmed by temperature-independent anomalous Hall conductivity coexisting with a normal temperature-dependent contribution. The study shows how a small symmetry change in the spin structure can influence magnetotransport properties of frustrated ferrimagnetic films.