Dielectric and magnetic properties of multiferroic BiFeO3 ceramics sintered with the powders prepared by hydrothermal method

BiFeO3 ceramics were sintered in the temperature range of 700–900 °C by using the pure BiFeO3 powders hydrothermally synthesized at 250 °C. The low reaction temperature and low sintering temperature prevent the element volatilization and phase decomposition. The ceramics sintered at 800 and 850 °C exhibit much dense microstructure with clear grains and grain boundaries. They also show high dielectric constant, dielectric dispersion and low loss tangent. At room temperature, the dielectric behaviors of BiFeO3 ceramics are mainly attributed to the transition of localized charge carriers and the microstructure of grains and grain boundaries. The temperature dependence of dielectric constant and loss tangent confirms that the localized charge carriers are a main contribution to the dielectric permittivity. Activation energy Eα of relaxation process for the BiFeO3 ceramic sintered at 850 °C is 0.397 eV. The obtained BiFeO3 ceramics show magnetic responses, which are relative to the grain size.

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► Low sintering temperature prevents the element volatilization and phase transition.
► The ceramic exhibits much dense microstructure with clear grain and grain boundary.
► The ceramics enjoy high dielectric constant and dielectric dispersion.
► The magnetic properties of BiFeO3 ceramics are relative to the grain size.