  A complex oxalate precursor, CaCu3(TiO)4(C2O4)8.9H2O, was synthesized and the
precipitate that obtained was confirmed to be monophasic by the wet chemical
analyses, X-ray diffraction, FTIR absorption and TG, DTA analyses. The thermal
decomposition of this oxalate precursor led to the formation of phase-pure
calcium copper titanate, CaCu3Ti4O12, at 680oC. The bright field TEM
micrographs revealed that the size of the as synthesized crystallites to be in
the 30 to 80 nm range. The powders so obtained had excellent sinterability
resulting in high density ceramics which exhibited giant dielectric constants
upto 40000 (1 kHz) at 25oC accompanied by low dielectric losses, less than
0.07.

Materials Science