Magnetic interfaces in Fe-based nanocrystalline alloys determined by Mössbauer spectrometry

M\"ossbauer investigations of ${\mathrm{Fe}}_{89}{\mathrm{Zr}}_{7}{\mathrm{B}}_{4}$ nanocrystalline material, performed over the temperature range 4.2--550 K and in applied magnetic fields, are presented and interpreted in terms of the crystalline, amorphous, and interfacial contributions. The results obtained indicate that the interfaces exhibit structural as well as spin disorder with the thermal evolution of the mean hyperfine field similar to that of the crystalline bcc-Fe phase.