Synthesis and Characterization of Lead Free Barium Strontium Titanate Dielectric Material

Abstract

The Lead free, Barium Strontium Titanate (BST) with Different stoichiometric compositions (Ba0.5Sr0.5TiO3, Ba0.7Sr0.3TiO3, Ba0.85Sr0.15TiO3) has been synthesised by Sol-Gel method. The synthesised samples have been subjected to the structural, morphological, dielectric characterisation. The X-Ray Diffraction studies have confirmed that Ba0.5Sr0.5TiO3 and Ba0.85Sr0.15TiO3 samples have the cubic phase while Ba0.7Sr0.3TiO3 has tetragonal phase. The SEM studies have shown the good morphological structure and the average grain size of Ba0.5Sr0.5TiO3 samples has been found to be 3.04 micrometre, for Ba0.7Sr0.3TiO3 has been found to be 1.9 micrometre, for Ba0.85Sr0.15TiO3 has been found to be 1.3 micrometre. The temperature dependence of real part of dielectric constant has confirmed the ferroelectric nature of Ba0.85Sr0.15TiO3 samples. Moreover the dielectric constant has been found to be highest for Ba0.85Sr0.15TiO3. But the Tangent loss is also higher for this composition. All the samples have shown the decrease of dielectric constant with increase of frequency, which is attributed the relaxing behaviour of dipoles.