Search for coupling in ferromagnetic/superconducting multilayers: Fe{sub 4}N/NbN

Structural, magnetic and superconducting properties of ferromagnetic/superconducting multilayers of Fe{sub 4}N/NbN are examined. The onset of superconductivity occurs at a NbN layer thickness of {approximately}100{Angstrom}. Below this thickness ferromagnetism of the Fe{sub 4}N layers is observed. Above this thickness superconductivity of the NbN is also observed, but there is no evidence for interlayer magnetic or superconductive coupling. The results are used in the formulation of guidelines for future searches of novel interlayer coupling phenomena. The superconducting critical field curves are reasonably well described within the framework of the theory for ferromagnetic/superconducting multilayers