Synthesis and Study of Strontium Bismuth Titanate for Electronic Applications

Abstract

This thesis is devoted in exploring the synthesis and characterization of strontium bismuth titanate (SBTi-SrBi4Ti4O15) ceramics for high-temperature applications. An attempt to enhance the electrical properties of SBTi through three modifications such as doping niobium, tantalum in place of titanium site of SBTi, and addition of CuO as a sintering aid were introduced. The ceramics samples were prepared through solid-state reaction technique. As a first strategy, the structural, microstructural, dielectric, and impedance properties of SrBi4Ti4O15 and niobium doped SrBi4Ti4Nb0.2O15 were investigated. As an extension to the first strategy, structural, microstructural, dielectric, ferroelectric, and piezoelectric properties of tantalum doped SBTi with composition SrBi4Ti4 xTaxO15 (x= 0, 0.03, 0.05, 0.07) were investigated. Further, the electrical properties of SrBi4Ti4O15 ceramics were improved using CuO addition with x varying from 0 wt% to 0.5 wt%. Finally, the thermolectric power factor of SrBi4Ti4O15 was refined by forming SBTi-25wt%CuO composite. At last, a comparative study of the results at room temperature suggested SrBi4Ti3.97Ta0.03O15 as the optimum composition with a dielectric constant = 183, dielectric loss = 0.007, remanent polarization = 1.5µC/cm2, and a piezoelectric coefficient (d33) = 13. The temperature dependent dielectric studies revealed a very high phase transition temperature-510and#9702;C, which makes them potential candidates for non-volatile high-temperature memory devices and piezoelectric sensors. The consistent nature of the dielectric constant (up to 200and#9702;C) can be implemented for designing Class1(X7R) dielectric capacitors.