Effects of yttrium substitution on structural and electrical properties of barium zirconate titanate ferroelectric ceramics

In the present study, structural, dielectric and ferroelectric properties of Ba1-3x/2Yx Zr0.025Ti0.975O3 ferroelectric ceramics have been investigated. The compound was synthesized using solid state reaction technique. The effect of yttrium substitution on structural, dielectric and ferroelectric properties was studied using X-ray diffractometer, scanning electron microscopy (SEM), LCR meter and P-E loops. Phase analysis shows the formation of secondary phase YTi2O6 for Y >= 2.5 mol% substitution. The microstructural investigation shows that Y substitution significantly reduces the grain size. An increase in Y content up to 2.5 mol% increases the Curie temperature (T-c) initially but decreases subsequently. The maximum dielectric constant at T-c has been observed for 2 mol% Y substitution and with further increase in Y content the dielectric constant decreases considerably. The solubility limit is found to be 2.5 mol% of Y and after that some of the yttrium atoms enter B-sites and leading to the formation of the secondary phase. The P-E loop studies show that there is an increase in the coercive field with increasing Y content. (C) 2013 Elsevier B.V. All rights reserved.