Giant anomalous Hall effect in ultrathin Si/Fe bilayers

Anomalous Hall effect studies on ultrathin Si(50 angstrom)/Fe(t(Fe)) bilayers were performed at 300 K. Giant enhancements of about 60 times in saturation anomalous Hall resistivity and 265 times in anomalous Hall coefficient (R-s) were observed upon decreasing the Fe layer thickness t(Fe) from 200 to 10 angstrom. The R-s observed for t(Fe)=10 angstrom is about three orders of magnitude larger than that of bulk Fe. Scaling law between R-s and longitudinal electrical resistivity (rho) suggests that the side jump is the dominant mechanism of the anomalous Hall effect. The observed largest Hall sensitivity of 433 Omega/T surpasses that of the semiconducting GaAs and InAs Hall sensors already reported. (C) 2014 Elsevier B.V. All rights reserved.