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

Abstract: 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 magnetisation data reveal the in-plane magnetic anisotropy in the samples. Large enhancement of about 24 times in the saturation anomalous Hall resistance (R_Ahs) 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_Ahs and anomalous Hall coefficient, Rs obtained for N= 1 were enhanced by about 5 and 3 orders of magnitude, respectively. The Rs follows the longitudinal electrical resistivity Rho as Rs proportional to Rho^2.1, suggesting side jump as the dominant mechanism of the AHE. The S as high as 22 Ohm/T over a wide operational field range of -8 to +8 kOe has been obtained for N = 1.