Controlled Formation and Growth Kinetics of Phase-Pure, Crystalline BiFeO₃ Nanoparticles^†

In situ synchrotron X-ray powder diffraction is used to elucidate the formation mechanism of multiferroic BiFeO3 nanoparticles during moderate heat treatment at ambient pressure of an amorphous precursor. A wet chemical synthesis is used to obtain the precursor, formed after solvent elimination of an aqueous solution containing iron and bismuth nitrates and tartaric acid. The in situ experiments are performed at two reaction temperatures and two heating rates, both giving rise to the growth of BiFeO3 nanoparticles without going through any intermediate crystalline phases. A detailed XRD line profile intensity analysis as a function of time and temperature provides information on the nucleation rate, growth kinetics, and size distribution of the nanoparticles.