Epitaxial growth of Fe/Pd-multilayers onto sapphire

Epitagial [Fe(0 0 1)/Pd(0 0 1)](n) multilayers are prepared onto sapphire s ubstrates under ultrahigh-vacuum conditions. The topography and structure o f the layers and their interfaces are characterized using in situ STM and R HEED and ex situ XRD. Although the lattice mismatch between the two materia ls amounts to about 4%, we find epitaxial growth up to n = 32 bilayers. Our investigations reveal that with increasing Fe-layer thickness the iron lat tice gradually changes from a face-centered tetragonal (fct) to a body-cent ered tetragonal (bct) structure. (C) 2000 Elsevier Science B.V. AII rights reserved.