The dependence of the formation of the nanocrystalline bcc-Fe phase on the
alloy composition is studied for Fe80M7B12Cu1 (M: Ti, Ta, Nb, Mo) alloys. T
he rf-Mossbauer technique is used to determine the optimal soft magnetic pr
operties. This technique allowed us to compare anisotropy fields in each ph
ase present in the composite alloys. The smallest anisotropy field was foun
d in the bcc-Fe nanograins formed in Nb- and Mo-containing alloys.