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 (
\({R}_{\rm hs}^{A} \)
) and anomalous Hall sensitivity (
\(S\)
), has been observed upon decreasing
\(N\)
from 20 to 1. When compared with the bulk Fe, the values of
\({R}_{\rm hs}^{A}\)
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
\(\rho \)
as
\(R_{s}\alpha \rho ^{2.1}\)
, suggesting side jump as the dominant mechanism of the AHE.
\(S\)
as high as 22
\(\Omega \)
/T over a wide operational field range from −8 to 8 kOe has been obtained for
\(N=1\)
.