Comparative studies of pure BiFeO_3 prepared by sol-gel versus conventional solid-state-reaction method

摘要

In this article, we studied the effect of synthesis route on the multifunctional properties of multiferroic BiFeO_3. BiFeO_3 powders were prepared by conventional solid-state-reaction and sol-gel route. X-ray diffraction (XRD) patterns for these samples were collected at different stages of synthesis to analyze the phase purity of the formation. The XRD patterns reveal that sample prepared by sol-gel route attains the low temperature phase formation as compared to the solid state route. Rietveld refinement has been performed for these samples and lattice parameters, cell volume bond length etc. have been calculated from XRD patterns. Phonon modes were studied by Fourier transform infrared spectroscopy measurements and bond length calculated from XRD shows the good agreement with the bond length calculated from IR spectra. UV-visible spectra showed that BFO nanoparticles exhibit absorption peak at wavelength ～521 nm and band gap is more for the sample prepared by sol-gel route than solid state. The room temperature (RT) magnetic hysteresis (M-H) curve shows the large value magnetization in the sample prepared by sol-gel route in comparison to the sample prepared by solid state route. Similar behaviour is seen in the P-E hysteresis curve. Room temperature dielectric properties of these samples revealed that there is dispersion in the low frequency range that shows normal dielectric characteristics.