Effect of Number of Bilayers on the Anomalous Hall Effect in [Si/Fe]N Multilayers

The influence of varying the number of bilayers (N) on the anomalous Hall effect (AHE) in sputtered Si/Fe multilayers has been investigated. Both the AHE and magnetization data reveal the in-plane magnetic anisotropy in the samples. Large enhancement of ~24 times in the saturation anomalous Hall resistance (R_hs^A) and anomalous Hall sensitivity (S), has been observed upon decreasing N from 20 to 1. When compared with the bulk Fe, the values of R_hs^A and anomalous Hall coefficient, R_s obtained for N = 1 were enhanced by about five and three orders of magnitudes, respectively. The R_s follows the longitudinal electrical resistivity ρ as R_sαρ^2.1, suggesting side jump as the dominant mechanism of the AHE. S as high as 22 Ω/T over a wide operational field range from -8 to 8 kOe has been obtained for N = 1.