Effects of Fe 3 O 4 on dielectric, ferroelectric, magnetic properties of BaTiO 3 -based multiferroic composites with excellent temperature stability of dielectric properties

BaTiO 3 –BaFe[Formula: see text]O[Formula: see text] multiferroic composites have attracted increasing interest due to promising applications in electric and magnetic devices. However, the lower resistivity and the worse temperature stability of dielectric properties hinder their practical application. Here, BaTiO 3 –BaFe[Formula: see text]O[Formula: see text] multiferroic composites with different BaTiO 3 /Fe 3 O 4 ratios of 2, 4, 6 (referred to as BF2, BF4, and BF6) have been prepared via low temperature sintering and in-situ formation of BaFe[Formula: see text]O[Formula: see text] ferromagnetic phase from the reaction between BaTiO 3 and Fe 3 O 4 . XRD, Raman, and SEM suggest that plate grains of the BaFe[Formula: see text]O[Formula: see text] phase disperse in the core–shell BaTiO 3 matrix with fine sphere grains. With the decrease of Fe 3 O 4 content, the breakdown electric field [Formula: see text] and the resistivity are significantly enhanced from 10[Formula: see text]kV/cm and [Formula: see text].cm for BF2 to 70[Formula: see text]kV/cm and [Formula: see text].cm for BF6, respectively. BF6 exhibits the high permittivity beyond 500 and the low dielectric loss ([Formula: see text]) at 1[Formula: see text]MHz in the temperature range from [Formula: see text]C to [Formula: see text]C. Excellent temperature stability of dielectric properties is achieved for the BaTiO 3 –BaFe[Formula: see text]O[Formula: see text] composites, the temperature coefficient of capacitance (TCC, i.e., (C–C[Formula: see text]C)/C[Formula: see text]C) of BF6 meets the X7D specification, below 3.3% in the temperature range from [Formula: see text]C to [Formula: see text]C. The ferroelectric properties of electric polarization [Formula: see text] [Formula: see text] [Formula: see text]C/cm 2 and coercive electric field Ec [Formula: see text] 18.00[Formula: see text]kV/cm have been achieved for the BF6 multiferroic composites together with ferromagnetic characteristics of magnetic polarization [Formula: see text] [Formula: see text]emu/g and coercivity magnetic field H[Formula: see text] [Formula: see text]kOe. In this work, a simple strategy is provided to prepare BaTiO 3 -based multiferroic composites with excellent thermal stability of dielectric properties and high resistivity for industrial applications.