M-Zn (M = Sb, V, Nb) substituted M-type strontium hexaferrites were prepared by a ceramic method. The
phase composition, morphology and magnetic properties were studied by x-ray diffractometry, scanning
electron microscopy and vibrating sample magnetometry. Saturation magnetization increases with a substitution up to 75.0 emu/g (2.5 % higher compared to unsubstituted hexaferrite) and then decreases with a further substitution. A coercive field of substituted hexaferrite powders with highest saturation magnetization is more than 3 kOe. Substituted strontium hexaferrite powders prepared in this work are a rare example of high M_S compositions without doping rare-earth elements and would be a promising candidate for a permanent magnet application.