Chemical synthesis and characterization of nanocrystalline ABi2Ta2O9 (A = Sr, Ba and Ca) powders

Nanocrystalline ABi2Ta2O9 (A=Sr2+/Ba2+/Ca2+ion) powders have been prepared through decomposition of mixed metal complexes based aqueous precursor solution. Calcination of the resultant carbonaceous residue at 700–750 °C for 2 h yield the single-phase ABi2Ta2O9 powders with average crystallite size ∼12–17 nm. The relative densities of the powders, after compaction and sintering at 950 °C for 4 h, have been found to be 96.1, 96.7 and 97.6% of their theoretical values for the Ca, Ba and Sr compositions, respectively. The dielectric constant values (at 100 kHz) for the sintered pellets of Ba and Sr compositions have been found to be 1165 and 1387 at their respective Curie temperatures (Tc) of 40 and 279 °C. The Tc for the CaBi2Ta2O9 composition has been found to be greater than 500 °C.