Exchange Couplings in Ni–Fe/Mn–Ir/Fe–Mn Multilayers

Exchange couplings between antiferromagnetic layers and magnetic layers have been investigated in Hf/Ni–20 at.%Fe/Mn–22 at.%Ir/Fe–40 at.%Mn/Ni–20 at.%Fe/Hf/Si multilayers. The Mn–Ir antiferromagnetic layers formed on the Fe–Mn antiferromagnetic layers have γ-Mn crystal structures from the bottom surfaces to the top surfaces. The structures cause relatively high exchange bias fields applied to the Ni–Fe layers neighboring the Mn–Ir layers.