Microstructure and magnetic properties of barium ferrite prepared by sol-gel method

Barium ferrite powders were prepared using a sol-gel process.The influence of the pH value, calcined temperature and the holding time on the crystalline structure,the microstructure and the magnetic properties of barium ferrite were studied by X-ray diffraction,Scanning electronic microscope and vibrating sample magnetometer.The formation of BaFe_(12)O_(19) phase was positive when pH value of sol solution was above 3.The sample with pure BaFe_(12)O_(19) phase was produced with a basically hexagonal laminate structure.The grain sizes of the samples increased when the annealing temperature and the holding time was increased.The magnetic properties of the samples depended on the temperatures of heat treatment. Saturation magnetization and coercivity with optimum values of M_s=75.24 emu/g,M_r=35.18 emu/g,and H_c=3.33×10~5 A/m were achieved at temperature 1200 and 950℃,respectively.