Structural, dielectric and electronic properties of Ba1-xSrxZr0.3Ti0.7O3 (x = 0.0, 0.1, 0.2, 0.24, 0.27, 0.3) ceramics: Combined experimental and ab-initio study

•The preparation of Ba1-xSrxZr0.3Ti0.7O3 (x = 0.0, 0.1, 0.2, 0.24, 0.27 and 0.3).•Combined experimental and ab-initio study.•Temperature and frequency dependent Dielectric Function. Ba1-xSrxZr0.3Ti0.7O3 (x = 0.0, 0.1, 0.2, 0.24, 0.27 and 0.3) materials were synthesized using conventional solid state reaction route. Structural properties were investigated using X-ray diffraction analysis. All the samples reveal single phase structure. The dielectric properties of all the samples were investigated at different temperatures of 100 K to 300 K, and at different frequencies of 1 kHz to 500 kHz. The diffusivity rises with increase in Sr divalent cation concentration. It is seemed that with increase in Sr2+ concentration the transition temperature reduces for all compositions. This may because of the introduction of Sr2+ by replacing Ba2+ since Sr+2 has smaller ionic radius than Ba+2. Moreover, the dielectric constant maxima for Ba1-xSrxTi0.7Zr0.3O3 increases up to x = 0.24 and then further increment in Sr content up to x = 0.3, the maxima of dielectric constant shows decrease. Moreover, charge conduction mechanism and optical response of Ba1-xSrxZe0.3Ti0.7O3 (x = 0.0, 0.1, 0.2, 0.3) has been calculated theoretically by using CASTEP. Herein, the calculated density of states (DOS) and three dimensional integrated charge density reveal that concentration of Sr in Ba1-xSrxZe0.3Ti0.7O3 (x = 0.1, 0.2, 0.3) causes variation in energy band gap. As regards optical response of Ba1-xSrxTi0.7Zr0.3O3, with x = 0.3 the high frequency absorption decreases to minimal value in accordance to experimental findings.