A comparative study of BaTiO3-BaFe12O19 multiferroic composites prepared by conventional and microwave sintering techniques

As one of the most important multiferroic composite systems, the 0.9BaTiO₃-0.1BaFe₁₂O₁₉ (0.9BT-0.1BFO) composite was prepared by conventional sintering (CS) and microwave sintering (MS) techniques. High density ceramics were obtained by MS method in 70 min of cycle time, whereas it took 748 min by CS method. The phase composition and diphase microstructure of the composite samples were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was observed that ferroelectric phase BaTiO₃ can well coexisted with the magnetic phase BaFe₁₂O₁₉, and the MS 0.9BT-0.1BFO composite showed more uniform and smaller grain size than those of CS samples. Improvement of the electric properties, including decrease in conductivity and dielectric loss was observed due to high densification, good microstructure and grain refinement in case of microwave sintering. Besides, both samples exhibited a high value of dielectric constant at low frequencies and high temperatures because of the effect of space charges that played an important role in the composites. The value of magnetization and coercive for the MS sample were significantly higher and more saturated than that of CS samples. The area for the future optimization of the sintering schedule in order to produce the dense fine-grained 0.9BT-0.1BFO multiferroic composite is also proposed.