Investigations of dielectric and ferroelectric properties of yttrium substituted SrBi2Ta2O9 ferroelectric ceramics: Investigations of yttrium substituted SBT ferroelectric ceramics

In the present work yttrium substituted samples of compositions Sr1-xYxBi2Ta2O9 (x=0.0-0.1) were synthesized by solid state reaction method. The synthesized specimens were characterized for their structural and electrical properties. X-ray diffractograms of the samples reveal the single phase layered perovskite structure formation for yttrium content x ≤ 0.05. The temperature variation of dielectric constant shows that the Curie temperature (Tc) decreases on increasing the yttrium concentration. The dielectric loss reduces significantly with yttrium substitution. The ferroelectric properties improve with Y substitution and the maximum value of remnant polarization is observed for the composition with x =0.05. The observations have been discussed in terms of contribution from the cation vacancies introduced into the lattice structure due to donor substitution.