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 Ba_1?3x/2Y_x Zr_0.025Ti_0.975O₃ 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.