Optimization of BFO microwave-hydrothermal synthesis: Influence of process parameters

Multiferroic materials exhibiting ferromagnetic and ferroelectric properties in a certain temperature range are acquiring interest in information storage and sensors applications. Facile microwave hydrothermal synthesis route was optimized for the preparation of BiFeO3 (BFO) pure-phase. Influence of process parameters (i.e. precursor ratio, mineralizer concentration, temperature, time) on phase formation, particle size distribution and morphology was investigated in detail. The BFO powders were characterized by XRD, ESEM and TEM. Single phase BFO was formed using KOH, 8 M at 200 degrees C, 30 min and KOH, 10 M at 180 degrees C, 30 min; the presence of Na2CO3, acting as electron donor, allowed the reaction to be performed at lower KOH concentrations and temperatures, 6 and 8 M at 180 degrees C in 30 min. Particles' morphology evolution with concentration and temperature without Na2CO3 followed the sequence: spherical, lamellar, lamellar semi-cubic, cubic; while with Na2CO3 addition the evolution was: lamellar semi-cubic, cubic and prismatic truncated octahedron shape. (c) 2013 Elsevier B.V. All rights reserved.