Local atomic and magnetic structures of nanocrystalline Fe75Cr10B15 alloy

The crystal, local atomic and magnetic structures of Fe₇₅Cr₁₀B₁₅ alloys annealed at 440?C473°C for 5 min have been studied using X-ray diffraction and ⁵⁷Fe M?ssbauer spectroscopy. At the annealing temperature T _a = 440°C, nanocrystals of the ??-Fe phase (??1%) precipitate in the amorphous matrix of the alloy. The complete crystallization of the amorphous alloy occurs at T _a = 473°C with the formation of ??-Fe nanocrystals 26 ± 2 nm in size and nanocrystals of tetragonal boride t-Fe₃B 47 ± 2 nm in size. It has been found that chromium atoms are located in nanocrystals of the ??-Fe and y-Fe₃B types. The distribution functions of hyperfine fields in the nanocrystalline Fe₇₅Cr₁₀B₁₅ alloy reconstructed from the M?ssbauer spectra (at T _a = 473°C) show that there are three allowed states of iron atoms in the ??-Fe phase and three equally probable crystallographic nonequivalent states of iron in the t-(Fe,Cr)₃B phase. The chromium concentration x in the ??-Fe(Cr) phase is found to be ??10 at %. The substitution of chromium atoms for iron atoms in t-Fe₃B substantially decreases local magnetic moments of the iron atoms.