Characteristics of Barium Hexaferrite Nanoparticles Prepared by Temperature-Controlled Chemical Coprecipitation

Ba-ferrite (BaFe12O19) nanoparticles were synthesized by chemical coprecipitation method in an aqueous solu- tion. The particle size and the crystallization temperature of the Ba-ferrite nanoparticles were controlled varying the pre- cipitation temperature. The precipitate that was prepared at 0 o C showed the crystal structure of Ba-ferrite in X-ray diffraction when it was calcined at the temperature above 580 o C, whereas what was prepared at 50 o C showed the crystallinity when it was calcined at the temperature higher than about 700 o C. The particle sizes of the synthesized Ba-ferrite were in a range of about 20-30 nm when it was prepared by being precipitated at 0 o C and calcined at 650 o C. When the precipitation tem- perature increased, the particle size also increased even at the same calcination temperature. The magnetic properties of the Ba-ferrite nanoparticles were also controlled by the synthetic condition of precipitation and calcination temperature. The coer- cive force could be appreciably lowered without a loss of saturation magnetization when the Ba-ferrite nanoparticles were prepared by precipitation and calcination both at low temperatures.