The proposed research is a continuation of our long-term project focused on the experimental study of novel materials displaying superconductivity sc and magnetism. From the beginning of the research on sc it was clear that in simple metal superconductors, magnetism had a lethal effect: a small amount of magnetic impurities completely destroy sc. However, in the last three decades this paradigm was increasingly questioned as new materials become available. These new materials are intermetallic alloys containing a lattice of unfilled f-electron shells and show an intriguing interplay of magnetism and superconductivity. Our research focus on the study of particular aspects of this interplay on materials that have come to the spot-light of research during the last five years and is part of the thesis work of two PhD candidates, financed by the SNF.