A short-range ordering in soft magnetic Fe-based metallic glasses studied by Mössbauer spectroscopy and Reverse Monte Carlo method

• SRO was investigated by XRD, Mössbauer, RMC and magnetic measurements.
• N=10,9,8 are dominated around Fe atoms for Fe80B20, Fe70Nb10B20 and Fe62Nb8B30.
• N=9, 8 and 7 had the largest population around B atoms.
• Fe-centered clusters with N=12 indicating icosahedral atomic configurations.
• Magnetic after-effects is sensitive to the SRO and concentration of free volume.

Selected soft magnetic amorphous alloys Fe80B20, Fe70Nb10B20 and Fe62Nb8B30 were produced by the melt-spinning and characterized by X-ray diffraction (XRD), transmission Mössbauer spectroscopy (MS), Reverse Monte Carlo modeling (RMC) and relative magnetic permeability measurements. The Mössbauer spectroscopy allowed to study the local environments of the Fe-centered atoms in the amorphous structure of binary and ternary glassy alloys. The MS provided also information about the changes in the amorphous structure due to the modification of chemical composition by various boron and niobium content. The RMC simulation based on the structure factors determined by synchrotron XRD measurements was also used in modeling of the atomic arrangements and short-range order in Fe-based model alloys. Addition of boron and niobium in the ternary model alloys affected the disorder in as-cast state and also influenced on the number of nearest neighbor Fe–Fe atoms, consequently. The distributions of Fe- and B-centered coordination numbers showed that N=10, 9 and 8 are dominated around Fe atoms and N=9, 8 and 7 had the largest population around B atoms in the examined amorphous alloys. Moreover, the relationship between the content of the alloying elements, the local atomic ordering and the magnetic permeability (magnetic after-effects) was mentioned.