Effect of La substitution on the structural and dielectric properties of BaZr 0.1Ti 0.9O 3 ceramics

Abstract

Lanthanum substituted BaZr 0.1Ti 0.9O 3 (Ba 1−3 x/2 La x Zr 0.1Ti 0.9O 3 and x = 0.01–0.05) ceramic powders were prepared through a solid state mixed oxide technique. Phase formation was confirmed using X-ray diffraction studies. It was also observed that when Ba/Ti < 1, La preferentially occupied the Ba site. The microstructure investigation using SEM showed that La substitution modified the grain size of the BaZr 0.1Ti 0.9O 3 ceramic significantly, from about 100 μm to ∼5 μm. Variation in the La content (from 1 mol% to 5 mol%) has negligible influence on the grain size and morphology of the ceramic. The increase in the La content decreased the Curie temperature of the BaZr 0.1Ti 0.9O 3 ceramic. The dielectric maximum was observed at 2 mol% of La substitution and with further increase in La content the phase transition was found to be broad. The dielectric constant has improved significantly compared to the BaZr 0.1Ti 0.9O 3 ceramic material.