SOL-GEL PROCESSING OF SINGLE PHASE BiFeOs CERAMICS: A STRUCTURAL, MICROSTRUCTURAL, DIELECTRIC, AND FERROELECTRIC STUDY

摘要

Multiferroic magnetoelectric are materials that present potential applications where the ferroelectric and magnetic ordered materials have been used. Among these materials, the BiFeO3 is a very promising candidate. Due to the difficult to synthesize this material, nanometric grains are desirables in a powder preparation route. In this sense, the sol-gel synthesis can carry out the requests above mentioned. In this work, a detailed sol-gel process to obtain the BiFeO3 powders and ceramics was studied. A structural and a microstructural study was conducted through X-ray diffraction and scanning electron microscopy. Crystallographic parameters were refined by carrying out a Rietveld analysis. The diffraction peaks were assigned as single BiFeO3 phase. The electron micrographs indicated no compositional fluctuations and that dense ceramics were obtained. The dielectric measurements (impedance spectroscopy) showed a transition near 300 °C. Typical BiFeO3 saturation values and high resistivity shape curves were obtained by ferroelectric hysteresis.