Preparation, characterization and magnetic properties of the doped barium hexaferrites BaFe12-2xCox/2Znx/2SnxO19, x=0.0-2.0

A series of powders of M-typed barium hexaferrites doped with Co, Zn and Sn of general formula BaFe12-2xCox/2Znx/2SnxO19 (x=0-2.0) were prepared by the co-precipitation/molten salt method. The structures, particle morphology and magnetic properties of the products were characterized by X-ray powder diffraction, vibrating sample magnetometer and ESEM/EDX. The results show that the crystallinity of the samples decreases with increase in the doping amount x. When x is less than 0.6, it is possible to obtain perfectly crystallized hexagonal BaFe12-2xCox/2Znx/2SnxO19, where the diameters of the particles are around 500 nm. The saturation magnetization of pure barium ferrite BaFe12O19 produced with this method is 71.9 A m2 kg-1 at room temperature and the intrinsic coercivity (Hc) is 367.8 kA m-1. The doped barium hexaferrite powder obtained when x is between 0.3 and 0.4 exhibits high saturation magnetization and a temperature dependence of coercivity close to zero.