Ferromagnetic and Para-magnetic Properties of Ultrathin Epitaxial Co/cu Films

Ultrathin epitaxial Co films grown on Cu(001) and Cu(1117) have been studied using the magneto-optic Kerr effect. For both film systems the Kerr ellipticity exhibits a linear dependence on film thickness. Utilizing the same optical set up susceptibilities are measured in situ with monolayer (ML) sensitivity. We report for 2 ML Co/Cu(001) films strong variations of the Curie temperature on the growth temperature of the films.