Electromagnetic Properties of BaTiO₃/BaFe₁₂O₁₉ Core/Shell Particles

Based on the homogeneous coprecipitation synthesis of BaTiO3/BaFe12O19 core/shell particles by using urea as precipitator, transmission electron microscope (TEM), X-ray diffraction(XRD) and Fourier transform infrared (FT-IR) were used to characterize the morphology, structure and composition of BaTiO3/BaFe12O19 core/shell particles precursor and BaTiO3/BaFe12O19 core/shell particles, respectively. Network vector analyzer was used to study the elec- tromagnetic properties of the BaTiO3/BaFe12O19 core/shell particles in 2−7GHz. The results indicate that, BaTiO3/ BaFe12O19 particles exhibited core/shell structure. The BaFe12O19 shell coated on the surface of BaTiO3 is uniform, in- tegrate and smooth. In 2−7 GHz, the real part (e') and the imaginary part (e) of permittivity of BaTiO3/BaFe12O19 core/shell particles are in the range of 10.7−17.0 and 0.3−0.6, which are larger than that of BaTiO3. The increase of permittivity is a result of enhanced interfacial polarization caused by core/shell structure. BaTiO3/BaFe12O19 core/shell particles exhibited magnetic properties which are not existent in BaTiO3. BaTiO3/BaFe12O19 core/shell particles possess much larger real part (μ') and imaginary part (μ) of permeability than that of BaTiO3 and shown obvious magnetic loss in 2−7 GHz, which is owed to the coating of magnetic BaFe12O19 shell.