Atomic and magnetic structures of Fe70Al5B25 amorphous alloys

Abstract

The short-range order around boron, aluminum, and iron atoms in Fe75B25 and Fe70Al5B25 amorphous alloys has been studied by 11B and 27Al nuclear magnetic resonance at 4.2 K and 57Fe Mossbauer spectroscopy at 87 and 295 K. The average magnetic moment of iron atoms μ(Fe) in these alloys has been measured by a vibrating sample magnetometer. It has been revealed that the substitution of aluminum atoms for iron atoms does not disturb μ(Fe) in the Fe70Al5B25 alloy, gives rise to an additional contribution to the 11B NMR spectrum in the low-frequency range, and shifts maxima of the distribution of hyperfine fields at the 57Fe nuclei. In the Fe70Al5B25 amorphous alloy, the aluminum atoms substitute for iron atoms in the nearest coordination shells of boron and iron atoms. This alloy consists of nanoclusters in which boron and iron atoms have a short-range order of the tetragonal Fe3B phase type.