Peculiarities of a Solid-State Synthesis of Multiferroic Polycrystalline BiFeO3

Abstract

Studies of a BiFeO 3 synthesis were performed to identify reasons for the appearance of secondary phases, the Bi 25 FeO 39 - and Bi 2 Fe 4 O 9 -type phases, in the reaction product. X-ray diffraction and microstructural analyses, performed on samples with different concentrations of impurities, showed that the impurities in the starting material crucially influence the phase composition of the reaction product. A fraction of the generated secondary phases strongly depends on the nature and concentration of the impurities. The experimental results can be explained by the theoretical consideration of ternary phase relations between Bi 2 O 3, Fe 2 O 3, and an impurity oxide. Single-phase polycrystalline BiFeO 3 was synthesized from ultrapure starting oxides. To avoid using the expensive ultrapure oxides, techniques for reducing the fraction of the secondary phases in the reaction products were developed.