Structural, Dielectric and Ferroelectric Characterizations of Sol-gel Prepared Ba_1-xSr_xTiO₃ Nanoceramics

Abstract

Ba1-xSrxTiO3 (0.0 ≤ x ≤ 0.5) nanoceramics were synthesized via sol-gel route and the structural and electric properties of the resulting compositions were investigated. revealed A tetragonal crystal structures for x = 0.0 - 0.3 and a cubic structure for x = 0.5 compositions was revealed by X-ray diffraction. The smaller ionic radii of Sr ions resulted in the lowering of c/a ratio with increasing x and a tetragonal to cubic structural transformation was observed at around x = 0.4. The average crystallite size gradually decreased with increasing x from 0 to 0.5. This trend was visible in electron micrographs. The room temperature dielectric constant in these nanoceramics increases with increasing Sr and a maximum value of 1553 was observed for x=0.3. Curie temperature (Tc ) of 125 °C was obtained for x=0.0, which shifted toward lower temperature with increasing x value. The value of Tc was observed as 100 and 75 °C for x = 0.1 and 0.3, respectively. The remnant polarization (Pr ), saturation polarization (Ps ), and coercive field (Ec ) decreased with increasing Sr concentration in BT due to the structural modifications. Value of Pr decreases from 0.637 to 0.229 μC/cm2, Ps decreases from 8.910 to 3.238 μC/cm2 and Ec decreases from 0.631 to 0.255 kV/cm with increasing x from 0 to 0.5.