Hopping anomalous Hall effect in Fe-SiO2 granular films

It was established that the Hall effect in nanocomposite Fe/SiO2 under cond itions of tunnel-activated conductivity is anomalous, that is the Hall resi stivity Q(H) is proportional to the magnetization and results from the spin -orbit interaction. As this takes place, the parametric relation Q(H) propo rtional to Q(xx)(m) between the Hall resistivity and the longitudinal (Q(xx )) one (parameter is temperature) is characterized by a significantly small er exponent m than for a homogeneous ferromagnetic metal. By analogy with t he hopping conductivity, this behaviour was related to features of the Hall effect mechanism in the hopping regime. In our case, it is the amplitude i nterference of tunnel transitions within three granule-sets.