Thickness dependence of surface roughness and magnetic properties of FeNiCr thin films

In order to apply FeNiCr ternary alloy thin films for magnetic machine-readable devices, the thickness effects on the surface roughness and magnetic properties of these films have been studied. The surface roughness of FeNiCr increased from 0.77 nm to a maximum value of 2.16 nm as the film thickness was increased from 33 to 103 nm, and then decreased to 1.75 nm as the film thickness was further increased to 189 nm. The coercivity of FeNiCr films changes with the film thickness in a similar way as surface roughness. The in-plane coercivity of FeNiCr increased from 27.3 Oe to a maximum value of 60.1 Oe as the film thickness was increased from 33 to 103 nm, and then decreased to 10.4 Oe as the film thickness was further increased to 189 nm.