NiO-thickness dependent magnetic anisotropies in Fe/NiO/Au(001) and Fe/NiO/MgO(001) systems

► We quantitatively study the magnetic anisotropy in Fe/NiO as a function of dNiO by ROTMOKE. ► 4-Fold anisotropy decreases with dNiO in Fe/NiO/Au(001) and increases in Fe/NiO/MgO(001). ► Such opposite relation on dNiO is due to different orientations of AFM NiO spins in two systems.