Structural, dielectric and optical studies of Co doped Bi2Fe4O9

The crystal structure, surface morphology, dielectric and optical properties of Bi2Fe4O9 and 20% Co-doped Bi2Fe4O9 is analysed and compared. Bi2Fe4O9 and Bi2Fe3CoO9 were prepared by solid state reaction route at 850 ºC. Using X- ray diffraction technique, lattice parameters of Bi2Fe4O9 are found to be a= 7.96 Å, b= 9.12 Å, and c= 5.26 Å which is in agreement with previous reports. A comparison of SEM pictures depicts more porosity in Bi2Fe3CoO9 as comparison to Bi2Fe4O9. UV visible spectroscopy confirms the increased band gap in Bi2Fe3CoO9 as comparison to Bi2Fe4O9. For a particular frequency and temperature dielectric constant of Bi2Fe3CoO9 is less than Bi2Fe4O9