Temperature Mِssbauer effect study of nanocrystalline FeMCuB alloys

Nanocrystalline Fe80M7B12Cu1 (M=Mo, Nb, Ti) alloys prepared from amorphous precursors are investigated. Controlled annealing treatment in a protective atmosphere favours the emergence of a bcc-Fe nanocrystalline phase, which was identified by X-ray diffraction, transmission electron microscopy and 57Fe Mössbauer spectrometry. Magnetic behaviour of the nanocrystalline, amorphous as well as interfacial phases is studied by Mössbauer effect measurements performed in a wide temperature range (77–675 K). Temperature dependence of bcc-Fe hyperfine fields corresponding to nanosized grains deviate from those of a bulk α-Fe. The results are presented for different volumetric fractions of crystallites and they are demonstrated on samples with different composition. In addition, magnetic structures of the disordered components are also discussed.