Microstructure and colossal dielectric behavior of Ca2TiMnO6 ceramics

A new colossal-dielectric-constant material Ca2TiMnO6 was successfully prepared. X-ray diffraction analysis indicated that it crystallized into an orthorhombic structure with space group Pnma. The heat-treated sample was dense and compact, with an average grain size between 10 and 20 μm. The permittivity of Ca2TiMnO6 could reach 70,000 at room temperature and could be maintained at 2000 at up to 460 K at 1 MHz. The X-ray photoelectron spectroscopy result suggested that the mixed valence of Mn ions might be responsible for the colossal dielectric behavior of Ca2TiMnO6.