⁵⁷Fe₇₅Mo₈Cu₁B₁₆ metallic glass studied by CEMS, CXMS, and HEXRD

⁵⁷Fe₇₅Mo₈Cu₁B_i16 NANOPERM-type alloy was prepared by a planar flow casting method in a form of thin ribbon. As-quenched sample was investigated by conversion electron Moessbauer spectroscopy (CEMS) and conversion X-ray Moessbauer spectrometry (CXMS). CEMS/CXMS spectra exhibit broadened lines what indicates amorphous structure of the alloy. Spectra obtained from both air and wheel side of the ribbon confirmed that no crystalline components are present. These findings are in good agreement with the results obtained by high energy X-ray diffraction (HEXRD) using highly intensive synchrotron source. Regardless the fact that clear doublet-like or sextet-like lines are not observable in the CEMS/CXMS spectra distributions of both electric quadrupole and magnetic dipole hyperfine interactions are expected. The spectra were refined by two spectral components. Furthermore they suggest that the studied metallic glass has close-to-room Curie temperature. Magnetic and HEXRD measurements were performed to confirm this assumption. Curie temperature (T_c) of the analyzed sample determined from temperature evolution of magnetization is T_c = 313 K. Slightly higher T_c was obtained by HEXRD. This analysis shows that T₂ ∼350 K. Due to the fact that magnetic interactions are observable by HEXRD only indirectly with the help of analysis of thermal expansion of the studied material, differences in the determination of T_c can be relatively high. (authors)