Single-phase M-type hexagonal ferrites, SrBixFe12-xO19 (0.0 <= x <= 1.0), were prepared by a co-precipitation assisted ceramic route. The influence of the Bi3+ substitution on the crystallization of ferrite phase has been examined using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Mossbauer spectroscopy. The XRD data show that the nanoparticles crystallize in the single hexagonal magnetoplumbite phase with the crystallite size varying between 65 and 82 nm. A systematic change in the lattice constants, a=b and c, was observed because of the ionic radius of Bi3+ (1.17 angstrom) being larger than that of Fe3+ ion (0.64 angstrom). SEM analysis indicated the hexagonal shape morphology of products. From Fe-57 Mossbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values on Bi substitutions have been determined. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.