Enhancement of anomalous Hall effect in Si/Fe multilayers

Anomalous Hall effect (AHE) studies were performed at 300 K on Si/Fe multilayers prepared by dc magnetron sputtering. About 60 times enhancement in the saturation Hall resistance and 80 times enhancement in anomalous Hall coefficient were obtained in [Si(50 A)/Fe(tFe)]20 multilayers when decreasing the Fe layer thickness from 100 to 20 A. The largest anomalous Hall coefficient (Rs) of 1.4 × 10−7 Ω m T−1 was found for tFe = 20 A, which is about three orders of magnitude larger than that of pure Fe and Fe/Cr, Al/Fe, Cu/Fe, SiO2/FePt/SiO2 multilayers. The ordinary Hall coefficient R0 was about two orders of magnitude larger than that of pure Fe. The Rs was found to vary with the longitudinal electronic resistivity, ρ as Rsαρ2.2, indicating the role of interfaces for the enhancement of the AHE in the multilayers. An increase of Hall sensitivity from 9 mΩ T−1 to 1.2 Ω T−1 was observed on decreasing tFe from 100 to 10 A. The high Hall sensitivity obtained was about three orders of magnitude larger than that of Al/Fe and Cu/Fe multilayers, showing it as an emerging candidate for Hall element for potential applications.