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.