A detailed structural analysis of the epitaxial growth of europium using in situ reflection high-energy electron diffraction has been performed for two kinds of buffer layers with different symmetry: (110)niobium (Nb) and (0001)yttrium (Y). Moreover, by varying the preparation conditions of the (110)Nb layer we get either a reconstructed or an unreconstructed Nb surface, which turns out to have a strong influence on the Eu growth: the reconstructed (110)Nb surface favours the stabilisation of an Eu hexagonal surface structure, as well as the (0001)Y buffer, whereas a pure unreconstructed (110)Nb surface enables the growth of single crystalline bcc (110)Eu films. With increasing Eu thickness, the relaxation of the metastable Eu hexagonal surface obtained on (0001)Y or on reconstructed (110)Nb gives rise to a multidomain structure that drastically depends on the nature of the underlying buffer layer. (C) 2004 Elsevier B.V. All rights reserved.