Enhancing dielectric stability in anti-reduction BaTiO3-based ceramics through Mn/Y co-doping

BaTiO 3 -based ceramics are widely used as dielectric materials in base metal electrode multilayer ceramic capacitors (BME-MLCCs), and enhancing their stability is of considerable importance. In this study, Mn 2+ and Y 3+ are co-doped into BaTiO 3 via a chemical method. The acceptor Mn 2+ suppresses carrier migration, while Y 3+ promotes the formation of defect associates that further impede carrier movement, leading to a synergistic enhancement in both reduction resistance and dielectric stability. The results demonstrate that the formation of a core-shell structure significantly enhances both the reduction resistance and the temperature stability of the ceramics. Appropriate co-doping of Mn 2+ and Y 3+ effectively reduces the grain size and increases the activation energy of grain boundaries, thereby improving the bias stability. Simultaneously, co-doping helps maintain a low oxygen vacancy concentration and promotes the formation of defect dipoles ( [ M n T i ″ · V O · · ] , [ 2 M n T i ′ · V O · · ] and Y B a · Y T i ′ ), which further synergistically enhances the bias stability. In particular, the BT-M2Y1 ceramic exhibits a high insulation resistivity of 1.63 × 10 11  Ω cm, indicating good reduction resistance. Its temperature stability meets the EIA X8R specification. Under a DC bias field of 2.0 V/μm, the ceramic shows a minimal variation in dielectric constant of only −0.61 %, demonstrating excellent DC bias stability. Moreover, the BT-M2Y1 ceramic maintains a relatively high dielectric constant (∼1550) and a low dielectric loss (∼0.0078) even with a fine grain size of 204 nm. This study provides an important experimental basis for developing highly stable dielectric materials for BME-MLCCs.