Granular nanostructures and magnetic properties of FePt–C/FePt–SiO2 films

Abstract FePt–C, FePt–SiO 2 and FePt–C/FePt–SiO 2 films with different segregants concentration on glass substrate with polycrystalline MgO underlayer have been successfully fabricated by magnetron sputtering system. It was found that the FePt–C films had larger coercivity( H c ), chemical order parameter(S) and smaller diameter of the local interaction zone( D n ) but wider magnetic coercive force distribution(Δ H c / H c ) than that of the FePt–SiO 2 films. By using FePt–C/FePt–SiO 2 bilayer structure, the low D n and Δ H c / H c were obtained. FePt–C30 vol %(4 nm)/FePt–SiO 2 45 vol %(4 nm) film with H c higher than 29 kOe and columnar FePt grains of 10 nm in diameter and 13 nm in height were obtained, which would be very suitable for heat assisted magnetic recording media.