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

TL;DR

This study investigates how changing the number of bilayers in Si/Fe multilayers affects the anomalous Hall effect, revealing significant enhancements and the dominance of side jump mechanism, with potential for high sensitivity applications.

Contribution

It demonstrates the impact of bilayer number on AHE magnitude and mechanism, highlighting a significant enhancement at N=1 compared to bulk Fe.

Findings

R_Ahs and S increase dramatically as N decreases to 1

Rs scales with Rho^2.1, indicating side jump mechanism

High Hall sensitivity of 22 Ohm/T achieved at N=1

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.