Transition from the collective magnetism towards superparamagnetism in Co–Nb–Cu–Si–B nanostructure

Abstract Amorphous and slightly crystallized CoNbCuSiB alloys were studied by the magnetisation measurements. Precipitation of Co-based crystallites destroys the ferromagnetic ordering of the amorphous alloy and leads to a cluster-glass state. At elevated temperatures, the grains embedded in the paramagnetic matrix exhibit the superparamagnetic behaviour.