X-Ray Absorption Studies of ${\rm Fe}_{85}{\rm Si}_{2}{\rm B}_{8}{\rm P}_{4}{\rm Cu}_{1}$ Alloy

The local structure around Cu in ${\rm Fe}_{85}{\rm Si}_{2}{\rm B}_{8}{\rm P}_{4}{\rm Cu}_{1}$ (NANOMET) and ${\rm Fe}_{85}{\rm Si}_{2}{\rm B}_{12}{\rm Cu}_{1}$ alloys was investigated by X-ray absorption fine structure (XAFS) and analytical transmission electron microscopy (TEM). The XAFS measurements indicate that the local structure around Cu atoms for the nanocrystallized ${\rm Fe}_{85}{\rm Si}_{2}{\rm B}_{8}{\rm P}_{4}{\rm Cu}_{1}$ alloy is a bcc-like structure, suggesting that Cu atoms occupy substitutional site of bcc-Fe or Cu atoms form bcc-type clusters in bcc-Fe nanocrystallites. The compositional TEM analysis indicates that Cu atoms distribute in both nanocrystallites and amorphous matrix. These facts suggest that Cu atoms in the ${\rm Fe}_{85}{\rm Si}_{2}{\rm B}_{8}{\rm P}_{4}{\rm Cu}_{1}$ alloy do not form stable fcc-Cu clusters, which act as the nucleation sites in the case of ${\rm Fe}_{73.5}{\rm Si}_{13.5}{\rm B}_{9}{\rm Nb}_{3}{\rm Cu}_{1}$ (FINEMET) alloy.