Electrical properties of Ni-doped CaCu3Ti4O12 ceramics

• Published in: Solid state ionics 2021-06, Vol.364, p.115633, Article 115633
• Main Authors: Zhuk, N.A., Sekushin, N.A., Krzhizhanovskaya, M.G., Belyy, V.A., Korolev, R.I.
• Format: Article
• Language: English
• Subjects: Admixtures; Calcium‑copper titanate; Ceramics; Charge transfer; Composition; Copper oxides; Dielectric loss; Dielectric loss tangent; Dielectric permeability; Dielectric permittivity; Dielectric properties; Electric properties; Electrical characteristics; Electrical properties; Equivalent circuits; Impedance; Nickel; Room temperature; Solid phases; Temperature
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2021.115633

Samples of Ni-doped CaCu3Ti4O12 ceramics with the compositions of CaCu3Ti4-4хNi4хO12-δ and CaCu3-3хNi3хTi4O12 (x ≤ 0.06) were synthesized by the solid phase method. X-ray phase analysis revealed the trace amounts of copper oxide (II) admixture in the samples. Electrical properties of the samples of both compositions were studied in the temperature range of 25–400°С. The minimal dielectric loss tangent 0.07 and the maximal dielectric constant 6.0·103 (at 1 MHz) were exhibited by the CaCu3Ti4-4хNi4хO12-δ (х = 0.03) ceramics at room temperature. The equivalent circuit was created based on the modeling of impedance spectra that well describe the electrical properties of the samples. It was proposed that the ionic charge transfer predominated in the studied samples at room temperature. This mechanism allows to explain the giant values of dielectric permeability and the high values of impedance phase at low frequencies. The electrical properties of Ni-doped CaCu3Ti4O12 ceramics were analyzed and discussed. •Ni-doped CaCu3Ti4O12 ceramics were obtained by solid phase synthesis method.•The best electrical parameters are characterized by the CaCu3Ti3.88Ni0.12O12-δ (ε = 6.0·103 at 1 MHz, RT).•The activation energy of the Ni-doped CaCu3Ti4O12 varies in the range 0.81–0.49 eV.•Equivalent circuits have been proposed to describe the electrical properties of the samples.•An assumption was made about bipolar conductivity in the samples.