The CaCu₃Ti₄O₁₂ ceramics have been successfully prepared by the sol-gel method. We have set four different temperature gradients (950℃, 1000℃, 1050℃, 1100℃) as the sintering temperatures for CaCu₃Ti₄O₁₂ ceramics to study the influence of different temperatures on the thermistor. The effects of different sintering temperatures on the structure of CaCu₃Ti₄O₁₂ ceramics were analyzed by X-ray diffraction (XRD). Scanning electron microscope (SEM) images demonstrate that the grain size of ceramic samples will increase with the increase of the sintering temperature. X-rayphotoelectron spectroscopy (XPS) has been used to study the chemical states on the surface of ceramic samples. It is confirmed that the coexistence of Cu⁺/Cu²⁺ and Ti³⁺/Ti⁴⁺ is the cause of the conductivity of CaCu₃Ti₄O₁₂ ceramics. All ceramic samples have NTC behavior, room temperature resistivity (ρ₂₅), material constant (B) and the relationship between the nature logarithm of the resistivity and the temperature has been studied in this paper.

Wei Chen. Influence of the preparation conditions on the electrical properties with negative temperature coefficient. Academic Journal of Materials & Chemistry (2023) Vol. 4, Issue 2: 26-30. https://doi.org/10.25236/AJMC.2023.040205.

[1] Gd A, Ebl A, Bl B, et al. The influence of preparation conditions on the electrical transport properties of tetrahedrites [J]. Materials Today: Proceedings, 2019, 8(Part 2):556-561.

[2] R.N. Jadhav, S.N. Mathad, Vijaya Puri, Studies on the properties of Ni_0.6Cu_0.4Mn₂O₄ NTC ceramic due to Fe doping, Ceramics International, Volume38, Issue6, 2012, Pages 5181-5188, ISSN 0272-8842

[3] Adams T., Sinclair D., and West A. (2006), Influence of Processing Conditions on the Electrical Properties of CaCu₃Ti₄O₁₂ Ceramics. Journal of the American Ceramic Society, 89: 3129-3135.

[4] Vangchangyia S., Swatsitang E., Thongbai P. (2012), Very Low Loss Tangent and High Dielectric Permittivity in Pure-CaCu₃Ti₄O₁₂ Ceramics Prepared by a Modified Sol-Gel Process. J. Am. Ceram. Soc., 95: 1497-1500.

[5] P. R. Bueno, R. Tararan, R. Parra, E. Joanni, M. A. Ramírez, W. C. Ribeiro, E. Longo, J. A. Varela, A polaronic stacking fault defect model for CaCu₃Ti₄O₁₂ material: an approach for the origin of the huge dielectric constant and semiconducting coexistent features J. Phys. D Appl. Phys. 42 (2009), 055404.

[6] Hu M, Xu H, Hao Y. Influence of Ti element on the electrical properties of negative temperature coefficient ceramics in Ca–Ce–Ti–W–O system[J]. Journal of Materials Science: Materials in Electronics, 2019, 30(19).

[7] Tao Li, Renzhong Xue, Junhong Hao, Yuncai Xue, Zhenping Chen, The effect of calcining temperatures on the phase purity and electric properties of CaCu₃Ti₄O₁₂ ceramics, Journal of Alloys and Compounds, Volume 509, Issue 3, 2011, Pages 1025-1028, ISSN 0925-8388.

[8] L. Ni, X. M. Chen, Dielectric relaxations and formation mechanism of giant dielectric constant step in CaCu₃Ti₄O₁₂ ceramics Appl. Phys. Lett. 91 (2007) 122905.

[9] Park, K. (2005), Fabrication and Electrical Properties of Mn–Ni–Co–Cu–Si Oxides Negative Temperature Coefficient Thermistors. Journal of the American Ceramic Society, 88: 862-866.

[10] J. C. Slater, Barrier Theory of the Photoconductivity of Lead Sulfide* Phys. Rev. 103 (1956) 1631.