Transport and Dielectric Properties of Mechanosynthesized La2/3Cu3Ti4O12 Ceramics

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975-1025 degrees C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 +/- 0.5 to 2.3 +/- 0.5 mu m with an increase in sintering temperature from 975 to 1025 degrees C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 x 10(3)-3.4 x 10(3)) and dielectric loss (0.09-0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.