Evidence and role of excessive iron in the lattice of M-type barium hexaferrite synthesized by one-step spark plasma sintering method
M-type barium hexaferrite (BaM) compounds with excessive iron, BaFe 12+ x O 19+1.5 x (0 ⩽  x  ⩽ 0.4), have been synthesized by spark plasma sintering method. The grains crystallized in plate-like form. The lattice parameters increased and the grain sizes decreased with increasing values of x . Specific saturation magnetization of 74.53–77.76 emu g −1 is greater than the theoretical value of BaM single crystal. Coercivity of 694.30–1146.58 Oe is far lower than that measured the BaM materials prepared by available methods.