A Scaling Relation of Anomalous Hall Effect in Ferromagnetic Semiconductors and Metals

A scaling relation of the anomalous Hall effect recently found in a ferromagnetic semiconductor (Ti,Co)O2 is compared with those of various ferromagnetic semiconductors and metals. Many of these compounds with relatively low conductivity ?xx?104 ?-1?cm-1 are also found to exhibit similar relation: anomalous Hall conductivity ?AH approximately scales as ?AH??xx1.6, that is coincident with a recent theory. This relation is valid over five decades of ?xx irrespective of metallic or hopping conduction.