Structural and dielectric characterization of La2/3Cu3Ti4O12 ceramics synthesized via a solid-state reaction combined with a double calcination process

La_2/3Cu₃Ti₄O₁₂ ceramics were synthesized using a solid-state reaction method combined with a double calcination process. X-ray diffraction analysis confirmed the primary phase of CaCu₃Ti₄O₁₂ (JCPDS No. 75–2188) in samples sintered at 1080 °C for 3 and 6 h, along with a minor TiO₂ secondary phase. The La_2/3Cu₃Ti₄O₁₂ ceramics demonstrated high dielectric permittivity values ranging from 3.77 × 10³ to 6.39 × 10³ and low loss tangents between 0.051 and 0.263. Notably, the dielectric permittivity of the 3-h-sintered La_2/3Cu₃Ti₄O₁₂ ceramic at 1 kHz exhibited excellent temperature stability, aligning with the operational requirements for Class III ceramic capacitors, particularly those classified under the X5S, Y5S, and Z5S standards. This indicates the potential of the material for applications requiring stable dielectric performance under varying thermal conditions. The high dielectric permittivity observed in La_2/3Cu₃Ti₄O₁₂ ceramics is attributed to an internal barrier layer capacitor structure. The semiconducting behavior of the grains is likely due to an electronic charge carrier hopping mechanism involving Cu⁺–O–Cu²⁺ and Ti³⁺–O–Ti⁴⁺ networks. These findings highlight the suitability of La_2/3Cu₃Ti₄O₁₂ ceramics for advanced capacitor applications.