Investigation of multiferroic and photocatalytic properties of Gd and Mn co-doped BiFeO3

Abstract

The nominal compositions of Bi0.9Gd0.1Fe1-xMnxO3 (x = 0.00, 0.05, 0.10, 0.15, 0.20) ceramics were synthesized by a conventional solid state reaction technique and their structural, morphological, dielectric, and magnetic properties were investigated andstudied. The X-ray diffraction (XRD) patterns revealed that the substitution of Gd and Mn in place of Bi and Fe induces a tendency of phase transition. The field emission scanning electron microscopy images and their respective histograms demonstrated that due to the substitution of Gd and Mn, the average particle size was reduced with a narrow size distribution. The values of dielectric constants are large for all samples at low frequencies and decrease sharply with increasing frequency. The values of dielectric constants show frequency independent behavior at higher frequency region > 103Hz. Frequency independent region is not observed for these samplesgreater than the frequency of 108 Hz. The magnetization vs magnetic field hysteresis loops were carried out using vibrating sample magnetometer. Improved magnetization was observed for 10% Gd and 15% Mn doping in BiFeO3.From the electrical characterization, it was observed that,leakage current density is much smaller for 10% Gd doped and larger for 20% Mn doped BGFO bulk materials. The polarization versus electric filed hysteresis loop is in typical shape for 5% Mn doped BGFO materials system. The gap and area of the hysteresis loop is found smaller for this composition as well. The synthesized samples can absorb light with wavelength from UV to visible region. The band gap energies of the synthesized samples were estimated from their DRS graphs by applying Kubelka-Munk (KM) function. The band gap energy is increased for Gd doped BFO bulk powder materials compared to undoped BFO and thendecreased for the Mn doped Bi0.9Gd0.1Fe1-xMnxO3 materials.