Enhanced breakdown strength and dielectric loss of Ca_1-3x/2Eu_xCu₃Ti_{4O12 ceramics prepared by polymer pyrolysis}

The CaCu3Ti4O12 (CCTO) ceramic is characterized by high dielectric constant, but its elevated dielectric loss (tan delta) and low breakdown field strength (E-b) limit its practical applications in small electronic devices. Therefore, Ca1-3x/2EuxCu3Ti4O12 (x = 0, 0.2, 0.4, and 0.6) samples were prepared through a combined strategy of substituting with rare earth element and polymer pyrolysis method to improve the tan delta and E-b. XRD analysis revealed that main phase of CCTO was formed in all samples, and Eu3+ ions were incorporated into the lattice. These results suggest that the low concentrations of Eu facilitate grain growth. However, as the concentration increases, it begins to have an inhibitory effect on grain growth, consequently resulting in an elevated grain boundary density. Moreover, the results demonstrated that the addition of Eu enhanced the E-b, reduced the tan delta, and improved the temperature stability of the CCTO ceramics. Interestingly, impedance analysis reveals a notable enhancement in grain boundary resistance. Notably, the Ca0.4Eu0.4Cu3Ti4O12 sample demonstrated an exceptionally high grain boundary resistance of 6.62 x 10(10) Omega cm, surpassing that of pure CCTO by over 100-fold. Ca1-3x/2EuxCu3Ti4O12 ceramics possess low loss and high breakdown performance, making them promising materials in capacitors.