Magnetic interlayer coupling between antiferromagnetic CoO and ferromagnetic Fe across a Ag spacer layer in epitaxially grown CoO/Ag/Fe/Ag(001)

CoO/Ag/Fe/Ag(001) films were grown epitaxially and studied using magneto-optic Kerr effect and x-ray magnetic circular dichroism (XMCD). Instead of exponential decay as reported in previous works, we find that both the exchange bias and the coercivity in the epitaxially grown films exhibit a nonmonotonous behavior with the Ag spacer layer thickness. By purposely increasing the film roughness, the nonmonotonous interlayer coupling evolves into a monotonic decrease by increasing the Ag thickness. Furthermore, we show that the interlayer coupling peak diminishes or shifts its peak position by inserting a Cr layer between CoO and Ag.