Magnetic structure of Sn2+Ru4+-substituted barium hexaferrites prepared by mechanical alloying

M-type barium hexaferrite fine particles with composition BaFe12−2xSnxRuxO19 (0.0≤x≤0.3) were obtained by mechanical alloying. The effect of Sn2+-Ru4+ 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 Sn2+ ions replaced Fe3+ ions on octahedral sites (4f2 and 2a), while Ru4+ preferred the tetrahedral 4f1 and bipyramidal 2b sites. Ms rise up to obtain a value of 64.2 A m2/kg as x increased. The increase of Ms owes to the site preference occupancy of Sn2+-Ru4+ mixture. The sharp decrease of the intrinsic coercivity (381.1-109 kA/m) has its origin on 4f2 and 2b sites replacement.