The chemical environments around Cu in amorphous FeSiBCuNb alloy.

• Strong bonding is present in Cu-Si pair; while in the Cu-Cu and Cu-Nb pairs almost no bonding exists. • We further suggest that the addition of Cu in this quinary amorphous alloy is to promote FeSi cluster units to separate from FeB cluster units. • The Cu-centered cluster connections by one-atom-shared are favored in this quinary amorphous alloy. • The value of B s is 1.28T at 300K, which is close to the experimental value. The chemical environments around Cu in amorphous Fe 73.5 Si 9 B 13.5 Cu 1 Nb 3 alloy were investigated by ab initio molecular dynamics simulation. It is found that there is strong bonding in Cu-Si pair, while almost no bonding exists in Cu-Cu and Cu-Nb pairs. Comparing to the random distribution, Cu tends to attract more Si atoms while to repulse B atoms. Based on the local structure information around Cu atoms, we suggest that no pure Cu cluster exists in this quinary amorphous alloy at 300K. The statistics of vertex/edge/face/intercross shared clusters centered on Cu show that the cluster connections by one-atom-shared are favored in this quinary amorphous alloy, accounting for 23%. The increase in magnetic moment occurs due to the increased average atomic distance caused by the addition of Cu and Nb. The value of B s is 1.28T at 300K, which is close to the experimental value. [ABSTRACT FROM AUTHOR]