Ferromagnetic MnCoGe thin films produced via magnetron sputtering and non-diffusive reaction

•MnCoGe thin films were produced by magnetron sputtering and non-diffusive reaction.•The usual hexagonal/orthorhombic structural transition was not observed in the films.•Mn clusters form planar distributions parallel to the sample surface.•Mn cluster formation leads to a Mn5Co6Ge6 stoichiometry.•The films display very good magnetic properties similar to bulk stoichiometric MnCoGe.