Multiferroic bismuth ferrates : Synthesis, structure-property relationships and phase transformations

Nowadays, great efforts are made to understand the rich physics of materials that show interesting magnetic, electronic, optic, photocatalytic or even multiferroic properties. Within the scope of this dissertation two of such potentially very promising compounds, perovskite-type (Bi1-xFex)FeO3 and mullite-type Bi2Fe4O9, were synthesized and studied. The primary focus was placed to understand the synthesis conditions that strongly influence the resulting phase composition, structures and corresponding properties. The second main focus was to study the structure-property relationships based on the average crystallite size, chemical composition and phase composition of the materials. It could be shown that the phase system Bi2O3 - Fe2O3 is very complex and sensitive to a lot of synthesis parameters such as the type of complexing agent, pH value as well as calcination time and temperature.