In nanocrystalline Fe90Zr7B3, hyperfine fields belonging to the amorphous residual matrix are distinguished from those of bcc-Fe nanograins by nuclear magnetic resonance spectroscopy on 57Fe nuclei. With this technique, the nanograins located in magnetic domains can be distinguished from those positioned in domain walls.
Structural features of core and surface regions of both types of nanograins are described. Presence of small (~0.2%) inclusions of Zr was identified in the core of nanograins.