Long-range magnetic interaction in Mn $$_{x}$$ x Ge $$_{1-x}$$ 1 - x : 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 $$_{x}$$ Ge $$_{1-x}$$ systems obtained by molecular beam epitaxy deposition of manganese on Ge(001) wafers annealed on temperatures between 50 and 450 $$^{\circ }$$ C. Magnetic ordering can be achieved when the substrate temperature is higher than 250 $$^{\circ }$$ C, when the manganese tends to diffuse into the Ge matrix and segregate in Mn $$_{5}$$ Ge $$_{3}$$ -like compounds, as proved by EXAFS. High spatial resolution photoelectron spectroscopy reveals Mn inhomogeneities in the 5–10 $$\upmu $$ m range, even though Mn is found mostly in the same chemical state all over the surface.