Effect of Porosity on Electrical Properties of Undoped and Lanthanum Doped BaTi0.6Zr0.4O3

Abstract

In porous media, the porosity introducesinhomogeneity in the bulk, which alters the mechanismsof leakage and breakdown exhibited by the denseanalog. The presence of pores in solid dielectricssignificantly degrades the electrical characteristics andbreakdown strength of the material. Lanthanum dopedBaTi0.6Zr0.4O3 composition in Ba1-xLaxTi0.6[1-5x/12]Zr0.4O3 were prepared by modified chemicalroute. (COOH)2.2H2O, Ba(NO3)2, ZrOCl2.8H2O andLa2O3 are used to precipitate barium oxalate hydrate,lanthanum oxalate hydrate and zirconium oxyhydroxidefrom its water solution onto the surface ofsuspended TiO2 particles. The lanthanum dopedBaTi0.6Zr0.4O3 composition was found to be cubic byXRD analysis. A gradual shift of 2 angles to thehigher angle with increasing lanthanum percentage inthe BTZ reveals the contraction of perovskite lattice.The frequency dependence of dielectric permittivity andloss tan of the ceramics has been investigated. It isfound that dielectric permittivity (r) decreases and losstan decreases with increase in lanthanum percentage.Loss tan increases and dielectric permittivity (r)decreases with increase in porosity. Resistivitydecreases and current density increases with increase inporosity. Neither of the samples showssemiconductivity, which is believed to be because oftitanium vacancy compensation.