Electronic structure of the Fe–Cu–Nb–Si–B alloys by x-ray absorption spectroscopy

Abstract

We measured x-ray absorption near-edge-structure (XANES) spectra of nanocrystalline- (nc-) and amorphous- (a-) Fe73.5Cu1Nb3Si13.5B9 (nc-FCNSB and a-FCNSB) and Fe78Si13B9 (a-FeSiB) alloys at the Fe L3,2 edge using the sample drain current mode and at the Cu L3,2, and Nb L3 edge and Si K edge using the fluorescence mode. The features in the Fe L3-edge XANES spectrum of nc-FCNSB changed shape significantly with the addition of Cu and Nb to the Fe–Si–B alloy under the optimum annealing conditions, indicating that Cu and Nb strongly influence the Fe 3d local electronic structure. Closely examining the Cu L3,2-edge XANES spectrum of nc-FCNSB reveals that the Cu clusters essentially have a body-centered-cubic structure. The white-line features at the Nb L3 edge suggest a slight increase in delocalization of Nb 4d orbits when a-FCNSB is crystallized into nc-FCNSB. The Si K-edge XANES spectrum demonstrates the dominance of Fe–Si bonds around the Si atom in nc-FCNSB.