Moment canting in metallic glass ribbons using spatially resolved Mossbauer spectroscopy

Room temperature ⁵⁷Fe Mossbauer spectra of a field-annealed metallic glass of composition Fe₇₈B₁₃ Si₉ were recorded at ten different 500 μm diameter locations on the ribbon, and compared with spectra obtained using a conventional 1 cm diameter Mossbauer source. Deviations of up to ±1.5% were observed in the difference spectra, indicating significant changes in the directions of the hyperfine fields at the Fe nuclei. Electron microprobe analysis showed that the iron composition of the ribbon varies by less than 0.3 at.%, and that these small variations are not correlated with the Mossbauer results. Mossbauer data show that as well as the possible atomic-scale non-collinear spin structure, changes to the distribution of moment directions occur on a length scale of hundreds of microns