Long-range magnetic interaction in Mn[Formula: see text]Ge[Formula: see text]: structural, spectromicroscopic and magnetic investigations

We report the structural, electronic and magnetic investigation using extended X-ray absorption fine structure spectroscopy (EXAFS), photoelectron microscopy, spin-resolved photoemission and magneto-optical Kerr effect on the properties of Mn[Formula: see text]Ge[Formula: see text] systems obtained by molecular beam epitaxy deposition of manganese on Ge(001) wafers annealed on temperatures between 50 and 450 [Formula: see text]C. Magnetic ordering can be achieved when the substrate temperature is higher than 250 [Formula: see text]C, when the manganese tends to diffuse into the Ge matrix and segregate in Mn[Formula: see text]Ge[Formula: see text]-like compounds, as proved by EXAFS. High spatial resolution photoelectron spectroscopy reveals Mn inhomogeneities in the 5–10 [Formula: see text]m range, even though Mn is found mostly in the same chemical state all over the surface.