Impact of neodymium doping on the dielectric and electrical properties of CCTO synthesized by a facile sol–gel technique

Abstract

In this work, Ca_1–xNd_xCu₃Ti₄O₁₂ (x = 0, 0.3 mM) ceramics were prepared by a facile sol–gel technique. The structure and crystalline nature of the samples were analyzed by X-ray diffraction characterization technique. FESEM analysis envisaged the inhomogeneous formation of ceramic material and confirmed the grain size was greatly affected by the dopant. The EDS analysis confirmed the existence of Ca, Cu, Nd, Ti, and O which illustrates the purity and stoichiometric ratios of the products. A colossal dielectric constant (ɛ_r = 5.5 × 10⁵) was achieved for Neodymium-doped CaCu₃Ti₄O₁₂ ceramics in comparison with undoped CaCu₃Ti₄O₁₂ ceramics dielectric constant ɛ_r = 1.1 × 10⁵ at 50 Hz and temperature 500 °C. Complex impedance analysis indicates that the existence of a non-Debye type of relaxation phenomenon of the material, which is further substantiated from the electrical modulus spectrum. Dielectric relaxation time for various temperatures of undoped and neodymium-doped CaCu₃Ti₄O₁₂ ceramics were calculated from both imaginary parts of impedance spectrum and electric modulus spectrum. The activation energy was considerably varied 0.2102–0.1910 eV for undoped and 0.2741–0.2425 eV for Neodymium-doped CaCu₃Ti₄O₁₂ ceramics, which suggests that the electrical conduction behaviour was primarily originated with the mobility of ionized oxygen defects.