Effect of Nd and Nb co-doping on the structural, magnetic and optical properties of multiferroic BiFeO3 nanoparticles prepared by sol-gel method

BiFeO3, BiFe0.95Nb0.05O3 and Bi1−xNdxFe0.95Nb0.05O3 (x=0.0, 0.05, 0.10, 0.15 and 0.20) nanoparticles are successfully synthesized via a tartaric acid-assisted sol-gel technique for the first time. The effect of Nd and Nb co-doping on the structure, morphology, and magnetic and optical properties is investigated. X-ray diffraction (XRD) and Raman measurements demonstrate that Nd3+ ions and Nb5+ ions co-doping at A and B-sites of BiFeO3 can result in a structural transformation (from single rhombohedral phase (R3c) to two coexisting phases (R3c and Pbam)). The morphology of the nanoparticles seems to be approximately cubic, and by the co-doping, the size of the nanoparticles decreases from ~132 to ~35 nm. Notable improvement in the remanent magnetization of the sample with x=0.15 is observed with a value of 0.285 emu/g, being 20 times higher than that of the undoped sample (BiFeO3). A decrease in the optical band gap is also observed in the Nd and Nb co-doped nanoparticles, indicating their favorable potential in photocatalytic applications.