Short-range induced ferromagnetism in Mn thin films on Co(0 0 1)

X-ray magnetic circular dichroism (XMCD) as well as magneto-optic Kerr effect display a ferromagnetic coupling at the Mn–Co interface followed by a non-ferromagnetic signal when the thickness of the Mn film on Co(0 0 1) increases. Ab initio density functional with gradient corrections (GGA) can explain this behavior. Within GGA the Mn–Co interfacial alloy with ferromagnetic coupling between Mn and Co is shown to be the ground state. Adding one and two Mn monolayers on it leads to a complex non-ferromagnetic behavior with high magnetic moments on the Mn atoms. As a result of this complex non-ferromagnetic behavior, the Mn mean magnetic moment decreases dramatically for one Mn monolayer and tends to zero for two Mn monolayers in quantitative agreement with the XMCD results.