Colossal permittivity and excellent temperature stability of BaTiO3 based fine ceramics with controlled grain growth

Dielectric materials with colossal permittivity (CP, ε r > 10 4 ) have attracted the increasing interest of researchers due to their enormous potential in the fields of sensor, capacitor, energy storage, etc. However, for the explored CP materials, their grains are too large to apply. To control grain growth, the sintering aids of MgO–Al 2 O 3 –SiO 2 (MAS) cordierite glass and common suppression grain growth of MgO have been introduced to BaTiO 3 -0.004Y 2 O 3 -0.006MnO 2 ceramics derived from the commercial BaTiO 3 powder with the average grain size of 300 nm. After controlling grain growth, the fine grains with the average grain size of d g ∼300 nm and CP are achieved in BaTiO 3 based ceramics sintered in reducing atmosphere. Notably, excellent temperature stability with Δε r /ε r25°C lower than 17 % is gained for the present BaTiO 3 based ceramics in the temperature range of −60 to 155 °C, meeting the X8S specification (ΔC/C 25°C ≤±22 %, −55 °C–150 °C). Based on the X-ray photoelectron spectroscopy (XPS) and Raman spectra, the outstanding dielectric properties of the present BaTiO 3 based ceramics is ascribed to the electron-pinned defect-dipole (EPDD) effect induced by Y Ti ′ − Y Ba ∙ , Ti Ti ′ − V o ∙ ∙ − Ti Ti ′ and Y Ti ′ − V o ∙ ∙ − Ti Ti ′ defect dipoles. The present BaTiO 3 based fine ceramics with colossal permittivity (∼2.9 × 10 4 ), low loss (∼0.03) at 1 kHz and room temperature, excellent temperature stability and high resistivity of 3.54 × 10 9 Ω cm is a promising candidate for the multilayer ceramics capacitor (MLCC).