The structural, optical and enhanced magnetic properties of Bi1−xGdxFe1−yMnyO3 nanoparticles synthesized by sol–gel

• Bi1−xGdxFe1−yMnyO3 (BGFMO) nanoparticles were prepared by improved sol–gel technique.
• The band-gap of BGFMO nanoparticles decreases with the increase of Mn concentration.
• The enhanced magnetic properties were obtained in Gd and Mn doped BiFeO3.

Bi1−xGdxFe1−yMnyO3 (BGFMO, x = 0, 0.1; y = 0, 0.05, 0.1, 0.15, 0.2, 0.25) nanoparticles were synthesized by improved sol–gel technique. The structural, morphological, optical and ferromagnetic properties of the as-prepared particles were analyzed by X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electronic diffraction (SAED), Raman spectroscopy, UV–Vis–NIR spectroscopy, and physical properties measurements system. XRD patterns show that the Bi1−xGdxFe1−yMnyO3 nanoparticles with x = 0.1, y = 0–0.20 possess single-phase perovskite structure. TEM and SAED images reveal that the prepared polycrystalline BGFMO particles are structured at the nanoscale. Raman spectra of gadolinium (Gd) and manganese (Mn) co-doped BFO show that there are two additional broadening peaks at around 488 and 630 cm−1, indicating the existence of orthorhombic phase. Optical absorption spectra indicate that the band gap of BGFMO nanoparticles decreases with the increasing concentration of Mn. The enhancement of room-temperature ferromagnetism was obtained in the BGFMO nanoparticles. Obvious hysteresis loops of BGFO, BGFO-5Mn and BGFO-10Mn were observed at room temperature, which indicate ferromagnetic order. The magnetization of the BGFMO nanoparticles increased with increasing of the Mn content.