Ferromagnetism of monoatomic cobalt films

The magnetic properties of epitaxial Co(111)-films on Cu(111) in the monolayer range were investigated. One group of films, apparently representing the monolayer, is magnetized spontaneously perpendicular to the surface, the magnetizationM_s(T) depending linearly onT up toT_c which results as 0·30T_c() (T_c)() is the Curie-temperature of the bulk).Financial support of this work by the Deutsche Forschungsgemeinschaft is acknowledged.