Structure and colossal dielectric permittivity of Ca 2 TiCrO 6 ceramics

• Published in: Journal of physics. D, Applied physics Applied physics, 2013-01, Vol.46 (1), p.15303
• Main Authors: Yan-Qing, Tan, Meng, Yan, Yong-Mei, Hao
• Format: Article
• Language: English
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/46/1/015303

A colossal permittivity ceramic material, Ca 2 TiCrO 6 , was successfully synthesized by the conventional solid-state reaction, and was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray photoemission spectroscopy (XPS) and x-ray diffraction (XRD). Rietveld refinement of XRD data indicated that the material crystallized in orthorhombic structure with space group pbnm . SEM displayed Ca 2 TiCrO 6 ceramic grains packed uniformly with the size range 5–20  µ m. XPS analyses indicated that elemental chromium and titanium of the material were in mixed valence. The corresponding dielectric property was tested in the frequency range 1 kHz–1 MHz and the temperature range 213–453 K, and the ceramics exhibited a relaxation-like dielectric behaviour. Importantly, the permittivity of Ca 2 TiCrO 6 could reach 80 000 at 298 K (100 Hz) and was maintained at 40 000 up to 398 K at 1 MHz, which could be attributed to the ion disorder and mixed valence of Cr 3+ /Cr 6+ and Ti 3+ /Ti 4+ .