Dependence of coercivity on ferromagnetic layer thickness in FeNiCr/Cr bilayers

In this paper, the bilayer of FeNiCr/Cr film had been fabricated by a direct current magnetron sputtering system onto a polyethylene terephthalate substrate (PET). The thickness of the ferromagnetic layer, FeNiCr layer, was determined to have a great effect on its coercivity in FeNiCr/Cr exchange bias bilayers. When the thickness of FeNiCr layers are arranged from 33 to 189 nm, it can be seen that there is a clear inverse proportion between the thickness and the coercivity. We compared and discussed two previously reported theoretical models, which described the dependence of coercivity on ferromagnetic layer thickness. For FeNiCr/Cr bilayers, the linear dependence of coercivity on inverse FeNiCr thickness is well explained by the 1/tFM (tFM denotes ferromagnetic layer thickness) model. The well agreement between the model predictions and the experimental results provide strong evidence that the 1/tFM model is valid in the FeNiCr/Cr system.