GROWTH, MORPHOLOGY, AND CRYSTALLINE-STRUCTURE OF ULTRATHIN FE FILMS ON CU3AU(100)

The growth mode, morphology, and crystalline structure of Fe films on Cu3Au(100) are studied for different growth temperatures (300 and 160 K), using in situ scanning tunneling microscopy and low energy electro n diffraction. Multilayer growth is found to be predominant for both g rowth temperatures. Only in films of 3-4 monolayers (ML) grown at 300 K is a mixed mode of layer-by-layer growth and island growth observed. An fcc-to-bcc structural transformation, accompanied by a distinct ch ange in the surface topography, starts at about 3.5 ML and 5.5 ML for the growth temperatures of 300 and 160 K, respectively. For both growt h temperatures bcc-like Fe in Fe/Cu3Au(100) assumes, most likely throu gh a Bain path, a surface plane with the(100) rather than the (110) or ientation found in the Fe/Cu(100) system. Both the surface morphology and the onset thickness of the fcc-bcc structural transformation are s hown to be strongly affected by the growth temperature. (C) 1998 Elsev ier Science B.V. All rights reserved.