Influence of stoichiometry on phase constitution, thermal behavior and magnetic properties of Ba-hexaferrite particles prepared via SHS route

Barium hexaferrite magnetic particles were synthesized via self-propagating high temperature synthesis (SHS) route by thermal initiation of compact mixed powders of iron, iron oxide and barium nitrate using various Fe(total)/Ba molar ratios of 9-12. As-SHS treated and post synthesis specimens were characterized by X-ray powder diffraction, VSM, DTA/TGA and SEM. DTA/TGA studies revealed that the formation temperature of barium hexaferrite decreased by increasing of Fe/Ba molar ratio. VSM measurement also indicated that saturation magnetization (Ms) and coercivity (Hc) of the annealed specimens increased by increasing of Fe/Ba molar ratio. XRD results confirmed by those obtained from DTA/TGA and VSM, indicated that the Fe/Ba molar ratio of 12 is favorable for the formation of single-phase barium hexaferrite.