Structural and magnetic properties of epitaxial Cu/Fe/Cu/Si(111) ultrathin films

Epitaxial Cu/Fe/Cu heterostructures with Fe film thicknesses between 2.5 and 110 Å were successfully grown on 737-Si~111! substrates, using metal-metal epitaxy on silicon. The evolution of their structural and magnetic properties as a function of the Fe film thickness has been studied by a number of complementary techniques. This revealed that fcc pseudomorphic Fe layers, characterized by a low-spin ferromagnetic phase, grow up to about 6 Å. For larger thicknesses one observes the appearance of three-dimensional bcc Fe ~110! domains in the Kurdjumov-Sachs orientation characterized by a high magnetic moment. A combined study of the magnetic anisotropy constants has been performed by the simultaneous use of both a static technique ~surface magneto-optical Kerr effect! and a dynamic one ~Brillouin light scattering!. An excellent agreement, in both sign and magnitude, between the results of the two techniques has been found.