Anomalous Hall effect in epitaxial L10-Mn1.5Ga films with variable chemical ordering

The anomalous Hall effect (AHE) in perpendicularlymagnetized L1(0)-Mn1.5Ga epitaxial films is investigated as a function of the degree of long-range chemical ordering at different temperatures. Our results provide conclusive evidence that the only correct AHE scaling is rho(AH) = a(0)rho(xx0) + b rho(2)(xx). Based on this scaling, we unambiguously identify the pronounced influence of the chemical ordering on both the intrinsic and extrinsic contributions to the AHE, and significant suppression of the extrinsic anomalous Hall conductivity by phonon and magnon scatterings. Our results help clarify the controversy over the AHE scaling and its microscopic mechanisms in this material. The experiments also demonstrate an approach for the study of the AHE by altering the long-range chemical ordering of magnetic materials.