Effect of tantalum substitutions on microstructures and dielectric properties of calcium copper titanate (CaCu3Ti4O12) ceramic

Tantalum (Ta5+) doped CaCu3Ti4−xTaxO12 (x = 0.05 and 0.10) ceramics were prepared by semi-wet route using solid Ta2O5 powder and metal nitrate solutions. Powder X-ray diffraction confirmed the major phase formation of cubic CaCu3Ti4O12 ceramic in the doped samples sintered at 900 °C for 6 h. Microstructure has been studied using field-emission scanning electron microscopy. The grain size is in the range of 150 nm to 1 μm for both compositions. Dielectric constant of the samples increases with increasing tantalum concentrations.

► CaCu3Ti4−xTaxO12 (x = 0.05, 0.10) ceramic was synthesized by novel semi-wet route.
► On increasing Ta5+ content, dielectric constant increases at all temperatures.
► The modulus studies confirm the capacitance of grains and grain boundaries decreases with increasing temperature.