Temperature stability and low dielectric loss of (1-x)Ba_0.4Sr_0.6TiO₃-xBi(Mg_2/3Nb_1/3)O₃ ceramics for X9R capacitor applications

Based on the popularity of intelligent series products, electric vehicles, and portable PCs, the market demand for multi-layer ceramic capacitors (MLCC) has increased extensively. The development of MLCC tends to be of high capacity and small size. Therefore, it is urgent to develop dielectric materials with a wide temperature range and low loss, which is conducive to the operational stability of devices. In this work, (1-x)Ba_0.4Sr_0.6TiO₃-xBi(Mg_2/3Nb_1/3)O₃ (x = 0.20–0.25) ceramics were prepared using a solid-state reaction method. Introducing Bi(Mg_2/3Nb_1/3)O₃ restrains the oxygen loss, reduces the grain size of the sample, breaks the long-range ordered structure, forms polar nanomicroregions, and improves the temperature stability of dielectric materials. Specifically, the sample with x = 0.25 exhibits good dielectric properties (ε_r = 614, tanδ = 0.0003, at 25 °C and 1 kHz) and high DC resistivity (5.52 × 10⁸ Ω cm) at 300 °C. The dielectric properties of (1-x)BST-xBMN ceramics exhibit good temperature stability in a wide temperature range (− 55 to 200 °C), which meets the requirements of X9R capacitors.