Comprehensive characterization of Ba1-x,SrxTiO3: Correlation between structural and multifunctional properties

Considering the superior multifunctional performance and beautiful structural tunability, Ba(1- x)SrxTiO3 (0 <= x <= 1) samples were synthesized in this work by following a conventional solid state reaction technique. The structural, vibrational, optical and dielectric properties of the synthesized materials were characterized extensively throughout the work. Band gap energy of all the materials was evaluated from optical characterizations and correlated with structural properties. Study of leakage characteristics rendered fruitful explanation for electrical properties. At x = 0.4, a structural phase transition from ferroelectric to paraelectric state was observed. All the functional properties were correlated with structural properties. The Ba0.6Sr0.4TiO3 sample showed maximum room temperature dielectric permittivity (similar to 4000 at 1 kHz) with good frequency and thermal stability. The dielectric loss tangent of this composition was reduced to similar to 0.0098 (at 1 kHz) which was even much lower than that of undoped BaTiO3. The detail temperature dependent dielectric and impedance characteristics of this sample were also evaluated. The activation energy, calculated from dielectric characterizations, was found to be similar to 1 eV suggesting the governance of doubly ionized oxygen vacancy for conduction and relaxation mechanism. (C) 2021 Elsevier B.V. All rights reserved.