Thermal annealing effect on the structural and magnetic properties of barium hexaferrite powders

Samples examined in this experimental work were in the form of hexagonal barium ferrite with various temperatures annealing. Barium hexaferrite (BaFe12O19), is of great importance as permanent magnets, particularly for magnetic recording as well as in microwave devices. The variation of the temperatures annealing was found to affect coercivity, mean effective anisotropy field, magnetic viscosity, and switching field distribution. Moreover the variation of interaction fields with various temperatures was found to be non linear and this can be attributed to the particle interactions in these systems. Single phase of well crystalline BaFe12O19 was first obtained at annealing temperature 1100°C. The SEM results showed that the grains were regular hexagonal platelets. In addition, maximum saturation magnetization was observed at annealing temperature 1200°C. However, it was found that the coercivety of the synthesized BaFe12O19 samples were lower than the theoretical values.