Effect of titanium dioxide on microwave absorption properties of barium ferrite

The composites of barium ferrite and titanium dioxide are prepared with sol–gel method. The crystalline structure, relative complex permittivity and permeability, and sublattice structure were measured with X-ray diffraction, vector network analysis and Mössbauer spectroscopy. The addition of TiO2 is shown to increase the relative complex permittivity and to improve the dielectric loss of BaFe12O19. It also decreases the ferromagnetic resonant frequency of BaFe12O19. The maximum movement of resonant frequency reaches 900 MHz. Some Ti4+ ions have entered the inter space of BaFe12O19 lattice, which results in the quadrupole splitting on 4f2 and 2a sites. The magnetocrystalline anisotropy field of BaFe12O19 is decreased, and some Fe3+ ions are converted into Fe2+ ions.