We re-examine the onset of ferromagnetism of Fe/Cu(1 0 0) grown at 300 K. We find evidence of superparamagnetism in the thickness interval ∼1.5-1.8 ML since in this regime a description via Ising superparamagnetism works well. The results on Fe/Cu(1 0 0) are being used for a further analysis on our recent data on FCC FexMn1-x films with x∼60%. We observed in this concentration regime non-zero M-H loops yet no hysteresis. We made the additional observation of significant Fe surface segregation. With this in mind, we analyzed these loops in the same fashion and found again a superparamagnetic behavior. © 2004 Elsevier B.V. All rights reserved.