Fast-synthesis of nanoscaled lanthanum-dopped bismuth ferrite

Reference	Presenter	Authors (Institution)	Abstract
08-156	Rodolfo Foster Klein Gunnewiek	Gunnewiek, R.F.(Universidade Federal de Alfenas); Cancellieri, I.C.(Universidade Federal de Alfenas); Garcia, L.A.(Universidade Federal de Alfenas); Perdomo, C.F.(Universidade Federal de São Carlos);	Bismuth ferrite (BiFeO3) is a material that still attracts attention due to the intrinsic magnetoelectric properties and applications as sensors and actuators. When particles are reduced to the nanoscale, some properties are enhanced and this decreasing is behind the crescent interest on research and technological applications for bismuth ferrite. Although this ferrite has shown important applications, the synthesis of pure BiFeO3 is very difficult, because very short stoichiometric fluctuations yield secondary phases. To prevent or reduce the formation of aforementioned secondary phase, many works resorted to adding elements, such as cobalt and barium, to stabilize primary BiFeO3. Taking this into account, the present work aimed to reduce the presence of secondary phases on BiFeO3 nanoparticles synthesis by doping with lanthanum. The bismuth ferrite nanoparticles were synthesized by a water-soluble fast-polymeric based method [1], doped with 5.0 and 10.0% of lanthanum. The resin was dried rapidly by microwave in 30 minutes and calcined at 400, 450, 500 and 550°C, by 120 minutes at heating rates of 5 °C/min. The obtained powders were characterized by X-ray diffraction (XRD1 beamline - LNLS), infrared spectroscopy (FTIR) and microstructural analysis by scanning electron microscopy. Although is possible to find well crystalline primary BiFeO3 phase, secondary phases were also observed in the diffractograms, even in the doped powders. The secondary phase can be attributed to the CO2-rich atmosphere during the polymer decomposition. After Rietveld refinement and using Scherrer´s equation, the crystallite size could be inferred, showing crystallites of around 50 nm. The crystallite sizes are temperature and doping-level dependents.
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