Investigation of excess and deficiency of iron in BiFeO3

Iron excess and deficient BFO with a composition BiFexO3 (x = 0.8, 1.0, 1.2) were synthesized by a citrate precursor method. After appropriate thermal treatment, structural, optical, magnetic and electrical properties of the samples were investigated. The X-ray diffraction (XRD) patterns of both BiFe0.8O3 and BiFe1.2O3 show rhombohedral structure, similar to that of BiFeO3 with some impurity phases. The average crystallite size was found to be in the range 48-56 nm. Surface morphology of these isostructural materials were also studied using FESEM. Raman spectral analysis observed shifting and decrement in the intensity of phonon modes with the excess and deficient of Fe in BFO that reveals the doping disorder at octahedral site. With the iron excess in BFO, there was an increase in magnetization but with the iron deficiency, magnetism was found to reduce showing paramagnetic behavior. The values of retentivity, coercivity and saturation magnetization in iron excess BFO was found to be 0.047 emuig, 102 Oe, 0.567 emu/g respectively which is almost double the value of pure BFO. Saturated P-E loop at different frequencies were reported with higher remnant and coercive polarization for BiFe1.2O3 nanoparticles as compared to pure BFO and BiFe0.8O3. (C) 2017 Elsevier B.V. All rights reserved.