High‐Performance BaTiO ₃ ‐Based X7R Ceramics via Core–Shell Structure Design

ABSTRACT

BaTiO ₃ (BT) is one of the widely used materials for multilayer ceramic capacitors (MLCCs). However, the presence of phase‐transition peaks limits its application scope. Here, high‐dielectric constant Y‐doped BaTiO ₃ ‐based ceramics sintered under a reducing atmosphere are reported. The transmission electron microscope (TEM) images prove the successful formation of core–shell structures in these ceramics. The doped Y element mainly occupies the A site and forms at a relatively high doping level. The association between and other defects reduces the grain size and improves the impedance at the grain boundary. Additionally, Y doping plays a crucial role in restricting the migration of oxygen vacancies. Overall, the prepared prototype MLCC meets the Electronic Industries Alliance (EIA) X7R standard (Δ C / C _25°C  ≤ ±15% over the temperature range of −55°C to 125°C, where Δ C / C _25°C is the capacitance variation), exhibits an ε _25°C of 3327, a tan δ of 0.019, and a resistivity of 3.0 × 10 ¹²  Ω cm. These results demonstrate the potential of the designed materials for further practical production.