Enhanced breakdown properties and dielectric loss of CaCu3Ti4O12 ceramics via SrO minor addition

In this study, CaCu3Ti4O12 (CCTO) ceramics with minor addition of SrO were fabricated by using a sol-gel method, aiming to simultaneously improve the breakdown field strength (Eb) and reduce the dielectric loss (tan delta). The addition of SrO induced precipitation of CuO and (Ca, Sr)TiO3 secondary phases in the grain boundaries, which improved the grain resistance and the grain boundary resistance (R-gb) by increasing the grain boundary density. Moreover, the CCTO ceramics with 6 mol% SrO addition exhibited a high E-b of 37.1 kV/cm and a low tan delta of 0.035 while maintaining a high dielectric constant of 2469. The enhancement in E-b was attributed to the improvement in R-gb, while the reduction in tan delta was associated with the increase in R-gb and the increase in the grain boundary activation energy. This study provides a new approach for the design of high-performance CCTO-based ceramics via the minor addition of SrO.