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Microstructure and colossal permittivity of CaTiO3 ceramics covered with nano-sized CuO and TiO2 by the hydrothermal method.
- Source :
- Journal of Materials Chemistry C; 7/7/2021, Vol. 9 Issue 25, p8011-8019, 9p
- Publication Year :
- 2021
-
Abstract
- In this work, CaTiO<subscript>3</subscript>-based particles covered with nano-sized CuO and TiO<subscript>2</subscript> particles were obtained by the hydrothermal method (CuO/CaTiO<subscript>3</subscript> (molar ratio) = 0.2 and TiO<subscript>2</subscript>/CaTiO<subscript>3</subscript> (molar ratio) = 0, 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30, respectively). The dense ceramics with a colossal dielectric constant at room temperature (ε<subscript>r</subscript> > 1.2 × 10<superscript>5</superscript> at 20 Hz, ε<subscript>r</subscript> > 7 × 10<superscript>3</superscript> at 1 kHz) and good temperature stability was obtained by microwave sintering at 1400 °C. The crystal structure, morphology, dielectric properties, impedance, and oxidation state of the ceramics were systematically analyzed. According to the results, the weak-trapped electrons are derived from defects and in the semiconducting CaCu<subscript>3</subscript>Ti<subscript>4</subscript>O<subscript>12</subscript> regions. A large amount of nano-sized CuO and TiO<subscript>2</subscript> covered on the surface of CaTiO<subscript>3</subscript> blocks the transfer of substances between grains, resulting in small ceramic grains. Simultaneously, the synthesized CaCu<subscript>3</subscript>Ti<subscript>4</subscript>O<subscript>12</subscript> and CaTiO<subscript>3</subscript> form a structure similar to nano-scale barrier layer capacitance (NBLC), and it can be proved by impedance analysis. The results show that a large number of weak-trapped electrons, smaller crystal grains and a structure similar to NBLC are the possible main reasons for the colossal permittivity. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20507526
- Volume :
- 9
- Issue :
- 25
- Database :
- Complementary Index
- Journal :
- Journal of Materials Chemistry C
- Publication Type :
- Academic Journal
- Accession number :
- 151189538
- Full Text :
- https://doi.org/10.1039/d1tc01612a