This proposal investigates the interfacial exchange coupling in exchange spring trilayer structures with polarized neutron reflectometry. Hard magnetic materials with high magnetizations show a range of applications in modern power engineering and next generation green energy solutions. However, high-anisotropy materials possess unsatisfactorily low magnetizations, while materials with high magnetizations show only low anisotropies. This dilemma can be overcome by combining hard magnetic materials with high magnetization materials into hybrid structures. The interfacial exchange coupling transmits the hard magnetic properties into the soft layer, while the high magnetic moment is retained. The strength of this exchange coupling depends crucially on the interface structure. In this proposal we aim to investigate SmCo5/Fe/SmCo5 hard/soft/hard-magnetic structures with different interface morphologies. We will investigate the anisotropy transmitted into the soft magnetic layer through the formation of an exchange spring nucleated in the Fe during field reversal. The structural and magnetic morphology of the trilayer will be resolved recording the spin dependent neutron reflectivity.