We have investigated the hetero-interface between molecular beam epitaxy grown MnAs thin films and Mn-Zn ferrite substrates using reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS). The RHEED observations have shown that the mismatch between MnAs and Mn-Zn ferrite is fully relaxed at the film thickness of <16 monolayers (MLs). XPS analyses have revealed that MnAs grows two-dimensionally from the early stage. Although we have observed a slight outdiffusion of Fe from the ferrite substrate, outdiffusions of Zn and O from the substrate are negligible. (C) 2002 Elsevier Science B.V. All rights reserved.