Giant anomalous Hall conductivity in the itinerant ferromagnet LaCrSb3 and the effect of f-electrons.

Itinerant ferromagnets constitute an important class of materials wherein spin-polarization can affect the electric transport properties in nontrivial ways. One such phenomenon is anomalous Hall effect which depends on the details of the band structure such as the amount of band crossings in the valence band of the ferromagnet. Here, we have found extraordinary anomalous Hall effect in an itinerant ferromagnetic metal LaCrSb3. The rather two-dimensional nature of the magnetic subunit imparts large anisotropic anomalous Hall conductivity of 1250 S/cm at 2K. Our investigations suggest that a strong Berry curvature by abundant momentum-space crossings and narrow energy-gap openings are the primary sources of the anomalous Hall conductivity. An important observation is the existence of quasi-dispersionless bands in LaCrSb3 which is now known to increase the anomalous Hall conductivity. After introducing f-electrons, anomalous Hall conductivity experiences more than two-fold increase and reaches 2900 S/cm in NdCrSb3.