High frequency permeability of Fe-Cu-Nb-Si-B nanocrystalline flakes with the distribution of shape anisotropy fields

•The Fe-Cu-Nb-Si-B nanocrystalline flakes with multi-phase structure are obtained.•There are three magnetic loss peaks in the permeability spectrum.•The multi-resonance is attributed to the magnetic anisotropy field distributions.•The magnetic anisotropy field distributions are caused by the multi-phase structure.