Enhanced Grain Boundary Resistance Resulting in High Permittivity and Low Dielectric Loss in CaCu₃Ti₄O₁₂/LaNiO₃

(1-X) CaCu 3 Ti 4 O 12 + (X) LaNiO 3 composite ceramics were fabricated using pre-reacted calcium copper titanate CaCu 3 Ti 4 O 12 (CCTO) and lanthanum nickelate LaNiO 3 (LNO) and their crystallographic structure and morphology were studied to measure dielectric, impedance, and conductivity values. X-ray diffraction peaks show that CCTO/LNO composites are in a cubic structure. Scanning electron microscopy images show denser and more uniform grains with thin grain boundaries and a smaller average grain size. The permittivity of CCTO is stable in the range 10 2 –10 6 Hz, but the composites show huge progress in permittivity by space charge polarization and relaxation in the range 10 3 –10 4 Hz, demonstrating improved dielectric properties. The 0.98(CaCu 3 Ti 4 O 12 )+0.02(LaNiO 3 ) sample showed a dielectric constant of 2.58 × 10 4 at 1 kHz, which is superior to pure CCTO (2.28 × 10 4 at 1 kHz). The electrical behaviour of the metallic filler on the composites was investigated using impedance spectroscopy analysis. The resistance of grain boundary increases with LNO. Activation energies were found to be 0.92, 0.95, and 0.90 eV for x = 0.1, 0.2, and 0.3, respectively, and these values are better than that of pristine CCTO (0.85 eV) sample. These results indicate that the prepared CCTO/LNO samples could be useul for high energy applications.