  Recent findings of large anomalous Hall signal in nonferromagnetic and
nonferrimagnetic materials suggest that the magnetization of the system is not
a critical component for the realization of the anomalous Hall effect (AHE).
Here, we present a combined theoretical and experimental study demonstrating
the evolution of different mechanisms of AHE in a cubic Heusler system
MnPt$_{1-x}$Ir$_x$Sn. With the help of magnetization and neutron diffraction
studies, we show that the substitution of nonmagnetic Ir in place of Pt
significantly reduces the net magnetic moment from 4.17 $ \mu _B$/f.u. in
MnPtSn to 2.78 $ \mu _B$/f.u. for MnPt$_{0.5}$Ir$_{0.5}$Sn. In contrast, the
anomalous Hall resistivity is enhanced by nearly three times from 1.6 $ \mu
\Omega $ cm in MnPtSn to about 5 $ \mu \Omega $ cm for
MnPt$_{0.5}$Ir$_{0.5}$Sn. The power law analysis of the Hall resistivity data
suggests that the extrinsic contribution of AHE that dominates in the case of
the parent MnPtSn almost vanishes for MnPt$_{0.5}$Ir$_{0.5}$Sn, where the
intrinsic mechanism plays the major role. The experimental results are well
supported by our theoretical study, which shows a considerable enhancement of
the spin-orbit coupling when Ir is introduced into the system. Our finding of a
crossover of the anomalous Hall effect with chemical engineering is a major
contribution toward the recent interest in controlling the band topology of
topological materials, both in bulk and thin-film forms.
