Sol–gel synthesized pure CaCu3Ti4O12 with very low dielectric loss and high dielectric constant

Abstract CaCu 3 Ti 4 O 12 ceramics were synthesized by the sol–gel method. The microstructural and dielectric properties were investigated. X-ray powder diffraction analysis indicated that no second phase occurred. The dielectric properties were investigated in the frequency range between 20 Hz and 2 MHz, and the dielectric constants ( e ′) of CaCu 3 Ti 4 O 12 ceramic samples sintered above 1040 °C only changed slightly while f ≤400 kHz. Meanwhile, the loss tangent (tan δ ) was below 0.05 in a relatively wide frequency range in some samples, and a very low tan δ 0.028 was observed in the sample sintered at 1100 °C for 16 h with e ′=18,225 at 1 kHz. These results indicate that the CaCu 3 Ti 4 O 12 ceramics have a promising prospect in future applications with sufficiently low tan δ and high e ′.