Enhanced electrical and thermoelectric power properties of BaWO4/CaWO4 nanocomposites

Powdered xBaWO(4)/(1 - x)CaWO4 where (x = 0,0.25,0.5,0.75,1) nanocomposites were synthesized by the co-precipitation method at room temperature (RT). We are reporting DC and AC conductivity and dielectric properties of nanocomposites at room temperature (RT). Structural characterization and HRTEM image confirm interface formation of the nanocomposites. The current density-electric field (i.e., J-E) characteristics of the nanocomposites' studies reveal excellent varistor behavior. Dielectric properties were measured in the frequency 20 Hz-3 MHz at room temperature (RT). The dielectric constant was found to be higher for C2 (0.5BaWO(4)/0.5CaWO(4)) nanocomposites as compared to single phase and was maximum for atomic ratio (Ba/Ca) with optimal value of 'x'. DC conductivity (sigma(dc)), calculated from Jonscher's power law, of C2 (0.5BaWO(4)/0.5CaWO(4)) nanocomposites interfaced is higher than that of single phase, respectively. Enhanced AC conductivity is also observed for C2 (0.5BaWO(4)/0.5CaWO(4)) nanocomposites. These enhanced electrical properties of C2 (0.5BaWO(4)/0.5CaWO(4)) nanocomposites are due to the space charge layer (SCL) formation at the interface. In detail, conduction models for all the nanocomposites are explained. Thermopower investigations on the nanocomposites resulted in Seebeck coefficient (S) showing a transition from negative to positive values with confirmation n-type semiconductors at room temperature (RT). The enhanced power factor of C3 (0.75BaWO(4)/0.25CaWO(4)) nanocomposites is at higher temperature as compared to other nanocomposites. This C2 (0.5BaWO(4)/0.5CaWO(4)) nanocomposite can be considered as an efficient multifunctional nanocomposites due to its enhanced optical and electrical properties, and C3 (0.75BaWO(4)/0.25CaWO(4)) nanocomposite is very good efficient thermoelectric power devices at higher temperature application.