Improving the magnetic properties of hydrothermally synthesized barium ferrite

The formation of fine barium ferrite (BaFe 12O 19) powders under hydrothermal conditions at [OH −]/[NO 3 −] ratio of 2 has been examined by employing barium nitrate and ferric nitrate as the starting materials. The effects of Ba/Fe ratio, reaction temperature and time on the formation, particle size, and magnetic properties of barium ferrite were studied. To further enhance the magnetic properties of hydrothermally synthesized barium ferrite, it was subjected to a thermal treatment at various temperatures up to 1200°C. The phase development was monitored using a X-ray diffractometer and the particle size and size distribution of the resulting powders were characterized using light scattering particle size analyzer, together with a scanning electron microscope. The magnetic properties measured using vibrating sample magnetometer show that the saturation magnetization can be improved from 46 to 64 emu/g when the hydrothermally processed powder is calcined at 1100°C and the intrinsic coercivity also increases with calcination temperature and peaks at 1000°C giving an i H c of 2.3 kOe.