Scaling of the anomalous Hall effect in lower conductivity regimes

The scaling of the anomalous Hall effect (AHE) was investigated using amorphous and epitaxial Fe_xSi_1-x (0.43 < x < 0.71) magnetic thin films by varying the longitudinal conductivity using two different approaches: modifying the carrier mean free path with chemical or structural disorder while holding the carrier concentration constant or varying n _h and keeping l constant. The anomalous Hall conductivity , when suitably normalized by magnetization and n _h, is shown to be independent of for all samples. This observation suggests a primary dependence on an intrinsic mechanism, unsurprising for the epitaxial high conductivity films where the Berry phase curvature mechanism is expected, but remarkable for the amorphous samples. That the amorphous samples show this scaling indicates a local atomic level description of a Berry phase, resulting in an intrinsic AHE in a system that lacks lattice periodicity.