Exchange Coupling between Antiferromagnetic Mn–Ir and Ferromagnetic Ni–Fe Layers

Exchange couplings between antiferromagnetic Mn–Ir and ferromagnetic Ni–Fe layers have been investigated while varying the Mn–Ir composition. These exchange couplings appeared at room temperature at Ir compositions between 20 and 46 at.%. The maximum exchange coupling field of 3.2 kA/m was obtained for Mn–20 at.%Ir(59 nm)/Ni–Fe(20 nm)/Zr(10 nm). Dependence of the exchange coupling fields on each layer thickness was also investigated. The Mn–Ir/Ni–Fe bilayers maintained high exchange coupling fields at Mn–Ir layer thicknesses above 10 nm.