Unveiling the interplay of magnetic order and electronic band structure in the evolution of the anomalous Hall effect in single crystalline MnPtGa

The recent studies on the anomalous Hall effect (AHE) have revealed an intrinsic relationship between the topological band structure and the experimentally observed transverse conductivity. Consequently, this has led to a heightened focus on examining the topological aspects of AHE. Here, an in-depth study of temperature driven sign reversal of anomalous Hall conductivity in the single crystalline MnPtGa (space group: P6₃/mmc) has been presented. From the interdependence of the linear and anomalous Hall resistivity, the origin of AHE is confirmed to be of intrinsic type. By systematically studying the electronic band structure and Berry curvature of MnPtGa using first principle calculations supported by temperature and magnetic field dependent magnetization measurements, it is concluded that the temperature dependent complex magnetic structure plays a significant role and leads to the sign reversal of anomalous Hall conductivity. Supported by the ab initio calculations, a continuous evolution of the magnetic structure is proposed, which is consistent with the experimental data. This study has established that the critical temperature (110 K), where the sign reversal appears is strongly associated with the magnetic structure and the magnitude of Mn moments.