Inter-layer exchange coupling through charge and/or spin carriers is the key control mechanism for the field of nano-magnetism and is often coupled to other spintronic effects, such as giant-magnetoresistance (GMR) and spin transfer torques. Very recently, Zhu et al. reported a new class of inter-layer exchange coupling, i.e. the RKKY coupling through a superconducting spin-valve structure. They observed a GMR-like response with an infinite MR ratio because of the zero resistance in the superconducting state. One of the conclusions presented in the paper is: 'the behaviour reported here cannot be explained on the basis of any conventional exchange coupling'. We intend to combine PNR studies above and below the superconducting transition with spin-transport studies across the superconducting interfaces in order to investigate the mechanism behind the coupling.