Enhancement of the magnetic properties of Ba1_xBixFe12O19 nanoparticles

Ba1-xBixFe12O19 nanoparticles (0 <= x <= 0.1) were prepared by the chemical co-precipitation method. The structure and morphology of the samples were revealed using powder X-ray diffraction (XRD) and transmission electron microscope (TEM). Both XRD and TEM confirm the synthesis of hexagonal Hexaferrites in the nanoscale, with average crystallite size in the range of 16.5-41.2 nm. Moreover, the octahedral ion-oxygen and tetrahedral ion-oxygen vibration bands were detected by FTIR analysis. Furthermore, the hard magnetic properties of the ferrimagnetic nanoparticles were investigated by analyzing room temperature magnetic hysteresis (M-H). Bi3+ substitution has caused an enhancement in the saturation magnetization by 20% and a reduction in the coercivity field by 50% relative to the pure sample. The maximum energy product (BH)(max) was enhanced by 37%. The effective crystalline isotropy constant and the anisotropy field showed an increase with Bi3+ substitution. The changes in the magnetic parameters are correlated to the changes in the structural parameters induced by Bi3+ substitution.