Perpendicular Magnetization of Ta/Ru/Ta/Co/Fe/MgO Multilayer

Ta/Ru/Ta/Co/Fe/MgO film is studied to investigate the separate roles of Co and Fe in perpendicular magnetic anisotropy. Perpendicular magnetization is successfully obtained in this structure after a field annealing process (275 °C, 3 T, 30 min). Surface magnetic anisotropy at the Fe/MgO interface induces perpendicular magnetization for the Co/Fe bilayer with the critical contribution of the inserted Co. Magnetization properties resulting from the use of various Co and Fe layer thicknesses in the range of 0.36-0.6 nm (Co) and 0.52-0.91 nm (Fe) are analyzed, indicating the formation of a magnetic dead layer between the Co layer and the Ta seed layer. The maximum effective anisotropy energy (K eff ) is estimated as 1.63 × 10 5 J/m 3 for Co (0.36 nm)/Fe (0.65 nm).