Antiferromagnetically coupled perpendicular magnetic anisotropic CoFeB/MgO films across a Mo spacer with high thermal stability

The magnetic and magneto-transport properties of the multilayered MgO/CoFeB/Mo/CoFeB/MgO films have been investigated. Perpendicular magnetic anisotropy and alternating ferromagnetic and antiferromagnetic interlayer coupling along the perpendicular direction as well as giant magnetoresistance have been observed in this Mo separated CoFeB/MgO structure. More importantly, the antiferromagnetic interlayer coupling of perpendicular layers is thermally stable against annealing temperature up to 400 °C, showing that the present perpendicular synthetic antiferromagnetic structure is promising for the magnetic engineering of nanodevices based on the perpendicular CoFeB/MgO system. The largest antiferromagnetic exchange coupling is obtained for Mo thickness of 0.8 nm, the corresponding exchange coupling energy density is 0.036 erg/cm2.