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 Sr_1-xY_xBi₂Ta₂O₉ (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 (T_c) 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.