Effect of homogeniety on microstructure, dielectric, and ferroelectric properties of strontium barium niobate

Abstract

Strontium barium niobate (SBN) is tetragonal tungsten bronze structured ferroelectric material. It is one of the few lead-free ferroelectrics in the fore-front of environment-friendly electroceramic research and development. The unusual sintering behaviour of SBN exhibits abnormal grain growth, duplex microstructure, and low density that has plagued commercial exploitation of SBN. The formation of duplex microstructure becomes more prominent when synthesised by conventional solid-state approach. Compositional inhomogeneity is believed to be the key player of such ambiguity. Will homogeneous mixing eliminate this problem? To answer this question, first SBN was synthesised by conventional solid-state technique, then coprecipitation technique, a wet chemical route, was employed for synthesis of SBN. In coprecipitate route, the precursors were mixed at the molecular level. It is thought that the improved composition uniformity might help in eliminating micro structure-related problems with improved dielectric properties. The findings in this connection on microstructure, dielectric, and ferroelectric properties of SBN when synthesised by conventional solid-state route as well as coprecipitation route have been discussed.