Synthesis and characterization of single phase Bi1−xSmx/2Dyx/2FeO3 (x = 0 and 0.015) and Bi2−xSmx/2Dyx/2Fe4O9 (x = 0 and 0.03) powders via sol–gel method

Abstract

New Sm3+ and Dy3+ co-doped BiFeO3 and Bi2Fe4O9 nanoparticles have been synthesized by sol–gel method. The co-doping on structural, magnetic and optical properties have been investigated. X-ray diffraction reveals that all samples are single phase without impurities detected. The size and morphology of the nanoparticles have been analyzed using scanning electron microscopy and MAP analysis showed that all ions of synthesized powders (Bi3+, Fe3+, O2+, Sm3+ and Dy3+) are distributed homogeneously in our components. According to the UV–Vis diffuses reflection spectrum, the multiband structure and the band edge position of the nanoparticles are confirmed. The results reveal that the calculated lattice parameters and grain size of the nanoparticles decrease with Sm3+ and Dy3+ doping. The magnetic properties of the nanoparticles were investigated by a SQUID MPMS at 5 K. With the addition of Sm3+ and Dy3+ ions, Bi2Fe4O9 nanoparticles change from paramagnetism to ferromagnetism and BiFeO3 nanoparticles change from weak ferromagnetism to ferromagnetism at room temperature. The remnant magnetization (Mr), coercive field (Hc) and saturation magnetization (Ms) increase gradually.