Perpendicular L10-FePt/Fe and L10-FePt/Ru/Fe graded media obtained by post-annealing

L10-FePt/Fe and L10-FePt/Ru/Fe films with perpendicular orientations were fabricated by magnetron sputtering and post-annealing. In comparison to films with sharp interfaces, the graded L10-FePt/Fe interface was more favorable for coercivity reduction. Inserting a ruthenium (Ru) interlayer between the hard L10-FePt and the soft iron (Fe) layers yielded a continuous L10-FePt/Fe graded film, which contributed to a large reduction in coercivity. The coercivity of L10-FePt/Ru/Fe films can be manipulated via the Ru thickness when the soft Fe layer is thin and via the Fe thickness when the soft Fe layer is thick.