In situ Mossbauer and magnetization studies of Fe-Si nanocrystallization in Fe73.5Si13.5B9Cu1Nb1X2, with X = Nb, Zr, Mo, amorphous alloys

The Fe-Si nanosized particles were obtained by controlled partial crystalli zation of Fe73.5Si13.5B9Cu1Nb1X2 (X=Nb, Zr, Mo) amorphous alloys. In situ M ossbauer spectroscopy and magnetization measurements have been used to foll ow the temperature-dependent magnetization of the amorphous as well as of t he nanosized Fe-Si particles. Our results, for the residual amorphous and o f nanoparticles phases, show that the temperature dependence of the hyperfi ne field and magnetization of both residual amorphous and nanocrystalline F e(Si) phases are different from that of the as-quenched bulk amorphous or c rystalline Fe3Si alloys. Likewise, from the temperature dependence studies it was possible to determine that the onset temperature of the nanocrystall ization process increases in the sequence Mo<Nb<Zr, for the same annealing conditions.