CORRELATION OF THE MAGNETIC-PROPERTIES WITH STRUCTURE AND MORPHOLOGY IN ULTRATHIN FE FILMS GROWN ON CU(311)

The magnetism, structure, and morphology of ultrathin Fe films deposit ed on a highly asymmetrical Cu(311) substrate has been investigated in situ by spot profile analyzing low-energy electron diffraction and ma gnetooptical Kerr effect measurements. A gradual-structural transforma tion from fee pseudomorphic towards strained bcc Fe via a Pitsch trans formation is observed with increasing coverage; The shear angle and te nsile lateral strain are determined. At a critical thickness d(C) appr oximate to 5 ML the transition is completed and a coalescence of isola ted Fe crystallites is formed. These structural and morphological chan ges caused a spin reorientation transition of the magnetization from a canted perpendicular state at low coverage to an in-plane state above d(C). At d(C) the Curie temperature T-C approximate to 200 K is stron gly reduced with respect to T-C(4 ML)=T-C(6 ML) approximate to 300 K. Below 1.8 ML no ferromagnetic long-range order is found above 140 K.