ε-iron nitrides: Intrinsic anomalous Hall ferromagnets

Abstract

The anomalous Hall effect in ε-iron nitrides (ε-Fe3-xN, 0 ≤ x ≤ 1) has been systematically investigated taking advantage of the fact that the exchange splitting of ε-Fe3-xN can be continuously tuned through the nitrogen concentration. It has been found that the anomalous Hall conductivity, σ x y A H, is proportional to the saturation magnetization MS, i.e., σ x y A H = S H M S, across significant variations in the saturation magnetization (96-1146 emu/cc). This relationship is in excellent agreement with the intrinsic mechanism as well as with the unified theory of AHE. Our results also demonstrate that the anomalous Hall conductivity is sensitive to the exchange splitting of the band structure.