The magnetic properties of Fe films epitaxially grown on Cu(100) have been correlated to their structure and morphology. Strained fcc iron films with thicknesses between 5 and 11 monolayers (ML) are ferromagnetically ordered at the surface with a perpendicular orientation of the magnetic moment, whereas the bulk of the films remains paramagnetic. The surface magnetism is related to an expanded interlayer distance at the surface. With the onset of dislocation formation at about 11 ML, the films become magnetic in the bulk and the magnetization switches to in-plane orientation.

• Received 8 October 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.3831