Superconductor/insulating-ferromagnet NbN/GdN multilayers reveal that
the superconducting properties of the NbN layers are dominated by the
insulating nature of the GdN layers, which curtail the pair-breaking e
ffect despite the strong ferromagnetism. The effects of ferromagnetic
walls on superconducting slabs have been captured. Very large parallel
critical fields have also been observed.