Dielectric diffuseness and conductivity study of CuNb2O6 incorporated BaTiO3 synthesized by chemical route

The dielectric ceramics of BaTi1-3xCuxNb2xO3 (BTCN) with x=0.0, 0.1, 0.2, and 0.3 were prepared by chemical route with the help of soluble tartarate complexes of Ti4+ and Nb5+ ions. It was found that the substitution of Cu2+ and Nb5+ at the Ti site of BTCN ceramics caused a diffused phase transition. Discontinuous grain growth accompanied with excellent dielectric diffuseness was found with increasing concentration of substitution. The dielectric diffuseness (gamma) was found to be maximum to 1.92 at the substitution of BTCN, x=0.1. The maximum solubility limit was found up to the entire composition range studied. A dielectric study of these compounds as a function of temperature suggested that with increasing substitution concentration the dielectric constant increased to maximum at x=0.3 with minimum tangent loss and the Curie temperature shifted onwards to the higher temperature side. The bulk conductivity indicated an Arrhenius-type thermally activated process. The variation of ac conductivity as a function of frequency obeyed the Jonscher power law. (C) 2007 American Institute of Physics.