Preparation of FeSi/Cu nano-multilayer materials and their magnetic properties

The FeSi/Cu multilayer materials (MLM), as well as the as-deposited FeSi thin film, were prepared by the electron beam physical vapor deposition (EB-PVD) technique. The as-deposited FeSi had a b.c.c (α-Fe) structure with a Si concentration of approximately 6.1 wt.%. The lattice spacing of FeSi in MLM increased with a decrease in FeSi layer thickness. The saturation magnetization (4π Ms) of FeSi/Cu MLM depended on the thickness of the FeSi layer and was found to be 1.75 T when the FeSi layer was thicker than 70 nm, showing a similar value to that of FeSi thin film. Specific saturation magnetization per mg (σ_s) of FeSi increases sharply with decreasing FeSi layer thickness and even exceed that of pure Fe when the FeSi layer thickness is lower than 40 nm. The lowest value of coercivity appeared when the FeSi layer thickness was 116 nm. Resistivity was proportional to FeSi layer thickness, and was twice as great as that of Fe-6.5 wt.%Si alloy when the layer thickness is 174 nm.