Magnetic microstructure of nanocrystalline Fe-Nb-B alloys as seen by small-angle neutron and x-ray scattering

The authors explore here the magnetic microstructure of Fe-Nb-B based nanoperm alloys through small-angle neutron scattering (SANS) and small-angle x-ray scattering (SAXS). Their SANS analysis reveals pronounced magnetic scattering from spin disorder at particle-matrix interfaces, featuring a clover-leaf-like angular anisotropy that is aligned with micromagnetic theory predictions. Exchange constants as well as anisotropy and magnetostatic fields are determined, in this way validating the micromagnetic SANS theory. Additionally, they find that the nuclear and magnetic residual scattering components of SANS share a similar q dependency as the SAXS data.