The effect of dielectric constant of the PbTiO3 dispersoid on the conductivity of Na2SO4 was probed. At the Curie temperature, 490C, PbTiO3 undergoes ferroelectric to paraelectric phase transition followed by a sharp change in the dielectric constant. The Na2SO4–PbTiO3 composites were prepared at two different temperatures, namely 600 and 900C. Compositions containing 5, 10, 20, 30, 40, 50m% PbTiO3 were investigated using impedance spectroscopy, differential scanning calorimetry, X-ray diffraction and Rietveld analysis. The series of compositions prepared at 900C exhibited a maxima in the conductivity for 20m%PbTiO3. The composites prepared at 600C exhibited a peak in the conductivity at 20m% PbTiO3 in addition to the percolation threshold at 40m% PbTiO3. An enhancement of conductivity by a factor of 40 at 300C was observed for the system prepared at 600C with an enhancement in conductivity of a factor of 8 at 300C was observed for the system prepared at 900C. Further, the transition temperature of Na2SO4 remains unaltered for both series. A slight nonlinearity was observed in the vicinity of the transition temperature of the dispersoid.

Investigation of the Conductivity of Na2SO4–PbTiO3 Composite Electrolyte System: Non Linear Electrical Behavior At Curie Temperature of the Dispersoid. S.M.Bobade, A.R.Kulkarni, P.Gopalan: Solid State Ionics, 2007, 178[29-30], 1585-9