The chromium and aluminium quantitiesrequired to synthesize nano-sized SrCr x Fe 12-x O 19 and SrAl x Fe 12-x O 19 by the auto combustion route were optimized. XRD analysis showed that the optimum amounts were differed in two cases. A combination of 0.75 wt% of nano-sized SrFe 12 O 19 and 0.75 wt% of the commercial additive, in chromium doped sample from solid state process(Cr 2 O 3 addition), resulted in superior magnetic properties with increased intrinsic coercivity, remanence magnetization and rectangularity ratio.