Dielectric properties of Al2O3 modified CaCu3Ti4O12 ceramics

• Published in: Journal of materials science. Materials in electronics 2019-08, Vol.30 (15), p.13869-13876
• Main Authors: Zhang, Y., Xue, L. L., Zeng, K., Wang, X. W., Sun, L. Y., Meng, X. H., Shi, Y. C., Li, Y. Y., Cao, M. Z., Hu, Y. C., Shang, J., Shang, S. Y., Yin, S. Q.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Barrier layers; Ceramic powders; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Dependence; Dielectric loss; Dielectric properties; Frequency ranges; Grain boundaries; Grain size; Materials Science; Optical and Electronic Materials; Review; Sol-gel processes
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-019-01810-2

In this work, CaCu 3 Ti 4 O 12 modified by Al 2 O 3 (w = 0, 0.05, 0.1, 1%) powders were prepared via a sol–gel process, and then the ceramics were prepared by conventional process using the obtained powders. The dependence of structure and properties of CaCu 3 Ti 4 O 12 ceramics on the addition fractions of Al 2 O 3 were studied. The results showed that the grain size and density of the samples greatly increase after modifying Al 2 O 3 . Moreover, all the samples exhibit giant dielectric properties (~ 10 4 ) and relatively low dielectric loss over a wide temperature and frequency range (20–200 °C, 10 2 –10 6 Hz). The giant dielectric properties of these samples could be explained by the internal barrier layer capacitance (IBLC) model, which consists of semiconducting grains and insulating grain boundaries. Specifically, the optimal Al 2 O 3 modified CaCu 3 Ti 4 O 12 (w = 0.05%) ceramic shows colossal permittivity (~ 4.29 × 10 4 ) and low dielectric loss (~ 0.06) at room temperature and 1 kHz. The results indicated that the microstructures and dielectric properties of CaCu 3 Ti 4 O 12 were significantly improved after modifying Al 2 O 3 .