Effects of CrRu–SiO_x underlayer with MgO intermediate layer on the microstructure and magnetic properties of FePt–C thin film

The effect of the CrRu–SiO_x underlayer with different doping concentrations and the thickness of the CrRu underlayer on the microstructure and magnetic properties of FePt–C films were investigated. FePt films exhibited L1₀ (001) texture at various SiO_x doping concentrations. The coercivities were as large as 28 kOe and the slope of M–H loop at coercivity was approximately equal to 1, suggesting that FePt grains were well exchange decoupled. Grain size was only slightly reduced after introducing the CrRu–SiO_x underlayer. But the contact angle between the FePt grains and the MgO intermediate layer around 135° indicated the a MgO intermediate layer was not favored for smaller grains to obtain good L1₀ (001) texture. X-ray photoelectron spectroscopy in-depth profile showed that Si diffused into a whole FePt–C layer and C diffused to the film surface.