MAGNETIC PHASES OF ULTRATHIN FE GROWN ON CU(100) AS EPITAXIAL WEDGES

Magnetic wedges of Fe on Cu(100) are explored magneto-optically. In th e region of 6-11 monolayers (ML) of fcc Fe grown at room temperature, in addition to a surface ferromagnetic layer with a Curie temperature approximately 250 K, the Fe bulk is antiferromagnetic with a Neel temp erature of approximately 200 K. This fcc phase is stable only above a growth temperature of order approximately 200 K, below which the ferro magnetic spin-reorientation transition occurs at approximately 6 ML. T he phase boundaries are delineated by cusps in the coercivity along th e wedge.