Effects of Ce-Co substitution on structural, magnetic and dielectric properties of M-type barium hexaferrite nanoparticles synthetized by sol-gel auto-combustion route

M-type Ce-Co substituted barium hexaferrite nanoparticles were synthesized by sol-gel auto-combustion route. The general formula of ferrites was Ba1-xCexFe12-xCoxO19 in which the x was considered to be: x = 0, 0.1, 0.2, and 0.3. The formed phases in the samples were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, Mossbauer spectroscopy and vibrating sample magnetometer. The results indicated that an increase in substitutional ion amount caused to decrease vibration frequencies of Fe-O band in the tetrahedral site due to the substitution of heavier Co2+ ion for Fe3+ ion in the tetrahedral site. Moreover, some of Ce3+ ions was transformed to Ce4+ and consequently with change in ionic radius from 1.02 to 0.87 . It seems to us that some of this ion substituted for Fe3+ in the octahedral 12k site. The data showed that the saturation magnetization was increased from 41.25 to 46.03 emu/g, and coercivity decreased from 5,500 to 4,700 Oe, with increasing x from 0.0 to 0.2. The network analyzer results showed that the dielectric constant and dielectric loss decreased with increasing Ce-Co substitution.