Transformation of hexagonal to mixed spinel crystal structure and magnetic properties of Co2+ substituted BaFe12O19

M-type barium hexaferrites Ba1−xCoxFe12O19 (x=0.0-1.00 with steps of 0.25) were synthesized by sol-gel autocombination method and were post-annealed at relatively low temperature at 600 °C. The samples were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy and vibrating sample magnetometry. Crystal transformed from pure Ba-hexaferrite to spinel with Co2+ substitution. Results of scanning electron microscope show that the grains are regular and well-defined structured. Infrared spectra support the nature and crystal symmetry that obtained from X-ray diffraction pattern study. Magnetization results show that saturation magnetization and magneton number decreased whereas coercivity increased for x>0.50 Co2+ doping.