Large Magnetodielectric Effect of BaTiO₃-BaFe₁₂O₁₉ Composites in a Low Magnetic Field

A microwave sintering procedure has been developed to achieve high quality multiferroic composites of (1 - x)BaTiO₃-xBaFe₁₂O₁₉ (x = 0.05, 0.10, 0.15, and 0.20). X-ray diffraction, scanning electron microscopy, and impedance spectra indicate that BaFe₁₂O₁₉ particles are isolated homogeneously by BaTiO₃ particles. In a 1.8 T magnetic field, a large room temperature magnetodielectric effect over 4.3% is observed in the 0.8BaTiO₃-0.2BaFe₁₂O₁₉ composite. The total mechanical energy dissipation (Q ^-1) for the BaTiO₃-BaFe₁₂O₁₉ composites was composed of the mechanical damping of BaFe₁₂O₁₉, the mechanical damping of BaTiO₃, and the loss at the interface. The mechanical damping of BaFe₁₂O₁₉ plays the dominant role in the variation of Q ^-1.