Abstract M-type barium hexaferrite fine particles with composition BaFe 12−2 x Sn x Ru x O 19 (0.0≤ x≤0.3) were obtained by mechanical alloying. The effect of Sn 2+–Ru 4+ substitution on the magnetic properties and microstructure of the powders was investigated by Mössbauer spectroscopy, XRD, vibrating sample magnetometry (VSM) and thermomagnetic analysis. Mössbauer studies revealed that Sn 2+ ions replaced Fe 3+ ions on octahedral sites (4f 2 and 2a), while Ru 4+ preferred the tetrahedral 4f 1 and bipyramidal 2b sites. M s rise up to obtain a value of 64.2 A m 2/kg as x increased. The increase of M s owes to the site preference occupancy of Sn 2+–Ru 4+ mixture. The sharp decrease of the intrinsic coercivity (381.1–109 kA/m) has its origin on 4f 2 and 2b sites replacement.