Synthesis and Characterization of Mg and Ti codoped BiFeO3

Abstract

The present thesis focused on synthesis and characterization of Mg, Ti co-doped BiFeO3, [Bi(Fe1- xTix/2Mgx/2)O3, where x=0,0.1, 0.71, 0.75 and 0.79]. BiFeO3 and modified BiFeO3 were synthesized by solid state route using micron and nano size oxide precursors (Bi2O3, Fe2O3, MgO,TiO2). Nanoprecusor powder was used to increase the reactivity of the components. It was observed that nano-precursors are useful to prepare the phase pure BiFeO3. In the case of modified BiFeO3, solid solution can be prepared at 850oC. However small amount (3-4%) of sillenite (Bi25FeO40) and Bi5FeTi3O15 impurities were observed. It was also observed that increase in calcination temperature produces more amounts of impurity phases. Effect of excess Bi2O3 addition was studied on phase formation, densification and electrical properties. The synthesized powders are sintered in conventional and microwave furnace. . In conventional sintering upto 88.6% of theoretical density can be achieved. Dielectric properties of the sintered sample were studied.
BiFe0.25Ti0.375Mg0.375O3 (BFTM 0.375) was also prepared by co-precipitation method and glycine-nitrate solution combustion method. In solution combustion method the effect of fuel to oxidizer ratio was studied on combustion nature and phase formation. Surprisingly both of the solution methods unable to produce phase pure solid solution.